hygienic engineering design

DOC 44

HYGIENIC DESIGN PRINCIPLES FOR FOOD FACTORIES

First Edition, September 2014

European Hygienic Engineering and Design Group

EHEDG Secretariat

Lyoner Str. 18

60528 Frankfurt, Germany

Tel.: +49 69 66 03-12 17

Fax: +49 69 66 03-22 17

E-Mail: [email protected]

Web: www.ehedg.org

THE ENGLISH VERSION OF THIS EHEDG DOCUMENT IS THE OFFICIAL VERSION. THE RESPONSIBILITY FOR THE PREPARATION, DEVELOPMENT AND ISSUANCE OF SUCH GUIDELINES LIES WITHIN EHEDG. DUE TO THE TECHNICAL AND GENERAL NATURE OF THE GUIDELINES, EHEDG MAY NOT ASSUME ANY LIABILITY RESULTING FROM THE INTERPRETATION, APPLICATION OR USE OF SUCH GUIDELINES.EHEDG GUIDELINES ARE DEVELOPED IN CO-OPERATION WITH 3-A SANITARY STANDARDS.

DOC 44 ©EHEDG 2 of 133

Contents Page

1 Introduction............................................................................................................................................5

2 Objectives and scope............................................................................................................................6

3 Normative References...........................................................................................................................6

4 Definitions / Glossary............................................................................................................................7

5 Site ........................................................................................................................................................215.1 Site location .........................................................................................................................................215.2 Site plan................................................................................................................................................215.3 Site ........................................................................................................................................................22

5.4 Boundary fences and walls ................................................................................................................245.5 Controlled site access ........................................................................................................................24

6 Hygienic Building Design ...................................................................................................................256.1 Buildings ..............................................................................................................................................256.2 Adequate Space for Cleaning, Inspection and Pest Control ..........................................................26

7 Internal Divisions.................................................................................................................................277.1 Segregation..........................................................................................................................................277.1.1 Zoning hazard analysis.......................................................................................................................297.1.2 Hygienic design criteria for zones.....................................................................................................30

7.1.3 Zone barriers........................................................................................................................................347.2 Storage areas.......................................................................................................................................367.3 Personnel areas...................................................................................................................................37

7.4 Cleaning facilities, equipment and chemicals..................................................................................417.5 Food washing facilities .......................................................................................................................41

8 Building Fabric ....................................................................................................................................418.1 Foundations.........................................................................................................................................418.2 Pile Foundations..................................................................................................................................428.3 Superstructures...................................................................................................................................438.4 Secondary Steel...................................................................................................................................458.5 Roofs.....................................................................................................................................................468.6 Floors....................................................................................................................................................518.7 Drains....................................................................................................................................................668.8 Coving, kerbs, posts and barriers .....................................................................................................848.9 Walls .....................................................................................................................................................948.10 Transport docks ..................................................................................................................................99

8.11 Doors ..................................................................................................................................................1018.12 Transportation and/or personnel air-locks.....................................................................................1068.13 Windows.............................................................................................................................................1078.14 Ceilings...............................................................................................................................................1088.15 Insulation and noise reduction ........................................................................................................1098.16 Stairs, walkways and platforms .......................................................................................................1108.17 Elevators ............................................................................................................................................1138.18 Food contact surfaces ......................................................................................................................113

9 Services..............................................................................................................................................113

9.1 General services................................................................................................................................1139.2 Electrical installations.......................................................................................................................1169.3 Ventilation and temperature control................................................................................................1219.4 Process and transport air.................................................................................................................1239.5 Lighting ..............................................................................................................................................1249.6 Water...................................................................................................................................................1259.7 Food and solid waste ........................................................................................................................126

10 References used within the text ......................................................................................................128

11 Hygienic Building Design Checklist ................................................................................................129


HYGIENIC DESIGN PRINCIPLES FOR FOOD FACTORIES*

©EHEDG

The first edition (March 2014) of this document was prepared by

Mr Philip Ansell BASF

Mr Volker Aufderhaar Argelith Bodenkeramik

Mr Karl-Heinz Bahr Cargill Central Process Development

Mr Nick van den Bosschelle PolySto

Mr Rasmus Brandhorst cool it Isoliersysteme GmbH

Dr.-Ing. Thomas Caesar Freudenberg Filtration Technologies KG

Dr. Brigitte Carpentier Anses

Dr. Edwin Delsing Delsing AG

Mr Martin Fairley ACO Technolgies plc

Dr. John Holah** Holchem Laboratories Ltd. (formally Campden BRI)

Mr Holger Hölzemann Kraft Foods R&D Inc.

Mr Jens Johnsson Tetra Pak Processing Systems AG

Prof. Dr. Vladimir Kakurinov Veterinary Faculty, St. Kliment Ohridski

Mr Vaclav Kralicek ACO Industries K. S.

Mr Kristian Kissing cool it Isoliersysteme GmbH

Mr Piet van Lith Marel Stork Poultry Processing

Mr ACO Industries K. S.

Mr Palle Madsbjerg Blücher Metal A/S

Mr Karel Mager Givaudan-Nederland B.V.

Ms Edyta Margas Bühler AG

Mrs Aleksandra Markovska Food Consulting

Mr Frank Moerman Catholic University of Leuven - KU Leuven, Belgium

Ms Tineke Mostert Unilever Vlaardingen

Mr Torben Rogge IKB

Mr Erwin Rüdisühli Bühler Scherler AG

Mr Frans Saurwalt Kropman BV

Mr Martin Frolund Svalgaard Blücher Metal A/S

Mr Jan Oude Velthuis FrieslandCampina Domo Nederland B.V.

Mr Frank Wessel Cargill B.V. Central Engineering

Mr Eric van der Wijst Heinz QACE

Dr. Patrick Wouters Unilever Vlaardingen

Mr Harald Wutz Kraft Foods R&D Inc.

Mr Gunter Zimmermann Nestlé Product Technology Center Konolfingen

* Report prepared by the Subgroup “Building Design” of the European Hygienic Engineering & Design Group (EHEDG)

** Chairman


1 Introduction

To ensure safe food and adequate sanitation programs, BOTH THE EQUIPMENT AND THE FACTORY used for processing and handling food products must be designed, fabricated, constructed, and installed according to sound hygienic design principles.

Hygienic food factory design provides:

— defence against external factory hazards

— defence against internal factory hazards - no harbourage sites and ease of cleaning

— internal flows of people, product, packaging, air and wastes to prevent cross-contamination

— security against deliberate contamination

— the maintenance of hygienic conditions via structure rigidity - appropriate foundations, steelwork, floor slabs

— the maintenance of hygienic conditions via material durability

— compliance with customer/GFSI best practice

This will ensure the equipment and factory can be effectively operated, does not harbour hazards, does not rapidly deteriorate and can be appropriately cleaned and disinfected.

Hygienic design is thus important in all areas of the factory:

— in its buildings and their surrounds.

— for construction of specific elements of the building.

— in factory and industrial services.

— for equipment, its layout and installation.

— for ensuring cleanability of the building and equipment.

— to facilitate all maintenance activities.

With reference to Europe, the requirements for the hygienic design of food premises are contained in Regulation (EC) No. 852/2004 on the hygiene of foodstuffs. Specifically, Annex II, Chapter I General requirements for food premises, Chapter II Specific requirements in rooms where foodstuffs are prepared, treated or processed, Chapter V Equipment requirements, Chapter VI Food waste, Chapter VII Water supplyand Chapter IX Provisions applicable to foodstuffs. The requirements in this standard are generic and

adherence to the advice in this guidance document should meet these requirements. Additional, generic information is given in Regulation (EC) No. 853/2004 laying down specific hygiene rules for food of animal origin on the layout of slaughterhouses and cutting rooms and the requirements for production establishments for minced meat, meat preparations, mechanically separated meat, bivalve molluscs, fishery products, milk production, egg and egg products, frogs’ legs and snails, rendered animal fats and greaves, gelatine and collagen. Essentially, factories must meet all national building standards for food handling establishments,

This document builds upon the minimum hygienic design requirements for the construction of food manufacturing sites as referenced from national food legislation, international and national general food hygiene guidance, international audit bodies approved by GFSI and food industry best practices.

The publication of an earlier EHEDG guidance document, Guideline 26 "Hygienic engineering of plants for the processing of dry particulate materials" (2003) is noted. The essential building design elements from this publication have been incorporated into this guideline, with the intention that, with the publication of this guideline, Guideline 26 will be withdrawn.

All publically available documents from which this guidance was distilled were current at the time of writing, are referenced at the end of the text and if they are freely available, a link is given to the appropriate website. Readers are encouraged to ensure that when referencing these texts, they are using the most up-to-date version of the documents available. There may be other requirements in primarily non-English first language countries, therefore, in which EU, US and CODEX legislation and guidance are not fully implemented or where the country’s own legislation necessitates additional hygiene requirements.


2 Objectives and scope

This document provides those responsible for the design and construction of food factories with best hygienic practice guidelines. Following the advice in this document should, therefore, ensure that the building will be designed to the minimum hygienic building design standards that are applicable worldwide. Whilst primarily aimed at food manufacturing sites, this guidance is also applicable to food service buildings.

This document does not consider any international or national building standards or safety standards (e.g. fire). It also does not cover hygiene within the construction process which is intended to be provided via EHEDG guidance on maintenance procedures.

This document does, however, assume that buildings will be constructed following general civil engineering best practice as failures in the construction process will lead to potential unhygienic features related to hazard harbourage and the reduction of cleaning efficacy.

It is also recognised that during the project development, the scope of some hygienic design features may have changed in an effort to reduce costs. In such cases it may be possible to argue for the hygienic approach based upon the long term costs of any additional measures necessary to ensure the hygienic functioning of the alternative approach, e.g. the extra cost per day of any additional hygienic practices required.

3 Normative References

EN 196 Methods of testing cement

EN 197 Cement

EN 206-1 Concrete - Part 1: Specification, performance, production and conformity

EN 1080 Mixing water for concrete - Specification for sampling, testing and assessing the suitability of water, including water recovered from processes in the concrete industry, as mixing water for concrete

EN 1990 Eurocode 0: Basis of structural design

EN 1991 Eurocode 1: Actions on structures

EN 1992 Eurocode 2: Design of concrete structures

EN 1997 Eurocode 7: Geotechnical design

EN 1998 Eurocode 8: Design of structures for earthquake resistance

EN 1253-1 Standard in development: Gullies for buildings Part 1: Trapped floor gullies with a depth water seal of at least 50 mm

EN 1253-2 Standard in development: Gullies for buildings Part 2: Roof drains and floor gullies without trap

EN 10080 Steel for the reinforcement of concrete - Weldable reinforcing steel

EN 12056 Gravity drainage systems inside buildings

EN 12350 Testing fresh concrete

EN 12390 Testing hardened concrete

EN 12620 Aggregates for concrete

EN 13670 Execution of concrete structures

BS 8500 Concrete - Complementary British Standard to EN 206-1

DIN 1045 Concrete, reinforced and pre-stressed concrete structures

DIN 1054 Ground - Verification of the safety of earthworks and foundations


DIN 4024-1 Machine foundations; flexible structures that support machines with rotating elements

DIN 4024-2 Machine foundations; rigid foundations for machinery with periodic excitation

DIN 18195 Water-proofing of buildings

DIN 18807-3 Guideline for design and execution of double skin metal faced thermal insulated non-ventilated roofs

NEN 6740 Geotechnics - TGB 1990 - Basic requirements and loads

NEN 8005 Dutch supplement to EN 206-1: Concrete - Part 1: Specification, performance, production and conformity

NVN 6724 Regulations for concrete - Cast in situ foundation elements of concrete or mortar

4 Definitions / Glossary

AccessibleSee Easily or Readily Accessible

AggregateA mixture of sand and stone and a major component of concrete

Air changes per hourSupply airflow volume divided by the volume of room per hour

Air gap (drainage system)The unobstructed vertical distance through the free atmosphere between the outlet of the waste pipe and the flood level rim of the receptor into which it is discharging

Air handling Unit (AHU)Type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. Equipment includes a blower or fan, heating and/or cooling coils, and related equipment such as controls, condensate drain pans, and air filters

Air lock

An enclosed space with two or more doors, and which is interposed between two or more rooms, e.g. of differing class of cleanliness, for the purpose of controlling the air-flow between those rooms when they need to be entered. An air lock is designed for and used by either people or goods

AnchorA mechanical device that is either cast or drilled and chemically adhered, grouted or wedged into concrete and/or masonry for the purpose of the subsequent attachment of structural steel

AwningA roof-like canvas or plastic structure, that extends over a doorway, window, deck, etc. and that is supported by a frame and further by the building to which it is attached, to serve as a shelter and to provide protection from the weather (e.g., sun, rain, etc.)

Allergen

Compound that elicits serious adverse reactions in some sensitive individuals

Backflow preventerA device or means to prevent reversal of flow


BarrierStructure or construction providing protection or used to affect movement

Base plateA shop-welded, pre-punched plate on that portion of a structural column that rests on the concrete foundationand is secured by anchor bolts

BeamStructural member for transversely supporting loads between or beyond points of support, usually narrow in

relation to its length and horizontal or nearly so

Block foundation

A foundation laid entirely from concrete blocks with reinforced bedding joints, used primarily for lightweight or temporary buildings

BracketA structural support projecting from a column or rafter for support of something

BroadcastTo hand toss a dry-shake hardener aggregate, or other dry material in a uniform layer over fresh concrete,

overlays, or coatings to add traction

Building ServiceInfrastructures that improve the welfare or safety of the personnel

Cable tray

Cable support consisting of a continuous base with raised edges but no covering, usually of a perforated or mesh type

CanopyAny overhanging or projecting structure with its extreme end unsupportedNote: A roof extension beyond the sidewall of a building

CementitiousMade from finely ground inorganic material that, when mixed with water, forms a paste that sets by means of

hydration reactions and processes, and that, after hardening, retains its strength and stability, even under water

Ceramic tile

A man-made or machine-made clay tile used to finish a floor or wall

Changing room

Room where people entering or leaving a process area put on (don) or take off (doff) their work clothing

ChannelOpen passage for conveying or containing water. Channel of a door - an open-ended “C” shape with no return lips in which a door slides

Checker plateA hot rolled flooring plate with non-slip embossments on one surface

CIP (cleaning-in-place)

System that cleans solely by circulating and/or flowing chemical detergent solutions and water rinses by mechanical means onto and over surfaces to be cleaned, without dismantling (adapted form ISO 22000)Note: CIP efficiency depends on 5T's – time, temperature, titration, turbulence and technology. When CIP is done in a dry area, it should be designed to preclude any water from passing into the environment

CladdingExternal, vertical or near-vertical non-loadbearing covering to a structure, which typically provides protection from the elements


CleaningThe removal of soil, food residues, dirt, grease or other objectionable matter (Codex)

ClinkerPartially fused product that is removed from the cement kiln after burning

Closed surfacePart of a surface that is closed, and that obstructs the view of objects located beyond that surface

Cold bridge

Part of a building envelope where heat is transferred at a much higher rate than the surrounding area.Note: due to the penetration of the insulation layer by a highly conductive or non-insulating material, heat transfer may take place in the separation between the interior (or conditioned space) and exterior

environments of a building envelope

CollarPreformed flange placed over a vent pipe to seal the roofing above the vent pipe opening

ColumnA primary structural member used in a vertical position to transfer loads from roof beams, trusses or rafters to

the foundation

Conditions for intended useAll normal and reasonably anticipated operating conditions, including those of cleaning. These conditions should include limits for variables such as time, temperature and concentrationNote: In the EHEDG context, this expression applies in relation to equipment and parts or other elements e.g. of building, and not in the context of product and consumer

Conduit

A flexible or rigid (e.g. steel or plastic) encasement for electrical wires

ContaminantAny biological or chemical agent, foreign matter or other substance not intentionally added to food, which may compromise food safety or suitability (Codex)

ContaminationThe introduction or occurrence of a contaminant in food or food environment (Codex)

Control boxa container which houses electrical components which regulate the action of something

Control jointTooled, straight grooves made on concrete floors to "control" where the concrete should crack

CorniceOverhang of a pitched roof, usually consisting of a fascia board, a soffit and appropriate trim moldings

CoveConcave moulding at, or fitted to, the internal angle between two surfaces, e.g. between walls and floors

Cross-contamination

Contamination of a material or product with a hazard (food safety) or another material or product (product quality)

Curb/kerb

Border, usually upstanding, at the edge of a carriageway, hard strip, hard shoulder or footway

Damp proof courseA layer of moisture-proof material, such as slate or bitumen, laid in a wall to stop moisture rising


Damp proof membrane

A layer or sheet of material within a floor or similar construction, or vertically within a wall to prevent passage of moisture

DisinfectionThe reduction, by means of chemical agents and/or physical methods, of the number of microorganisms in the environment, to a level that does not compromise food safety or suitability (Codex)Note 1: the destruction of microorganisms, but not usually bacterial spores (BSI 5283). Disinfection reduces the microorganism population to a level acceptable for a defined purpose e.g. a level which is harmful neither to health nor to the quality of foodNote 2: Specifically in USA, the term sanitization is more commonly used in the food industry (see Sanitation)

DockThe sorting or staging platform designed to align the floor of a building with the bed of a truck trailer, where shipments are loaded or unloaded

Down Spout

A vertical pipe for carrying rainwater down from a roof gutter to the ground or to a drain

DrainInfrastructure used for the drainage of one building or any buildings or yards appurtenant to buildings with the same curtilage

Drain tileA perforated, corrugated plastic pipe laid at the bottom of the foundation wall and used to drain excess water

away from the foundation. It prevents ground water from seeping through the foundation wall. Sometimes called perimeter drain

Dry-cleaning

Cleaning which does not involve any (or sometimes minimal) use of waterNote 1: Dry cleaning is used in equipment and in the environment to prevent or reduce the build-up of objectionable matters such as residues of aged or modified productNote 2: Dry cleaning is mostly done manually using brushes and/or vacuum cleaners.

Dry materials

Powdery materials, powdered substances low in moisture, dry particles of matter, a solid consisting of small particles in large numbers

Dry productionAll operations involved in the preparation of dry food product, proceeding in the absence of water, from receipt of dry materials, through processing and packaging, to its completion as a finished dry product

DuctingA large-diameter hollow tube (square or round) that conveys air

EPSExpanded polystyrene, a rigid and tough, closed-cell foam, usually white and made of pre-expanded polystyrene beads. EPS is molded to sheets for building insulation

EPX

Epoxy heavy duty insulation coating with chemical, corrosion, and flame resistance

EaveLower edge of a roof which overhangs the walls

Electrical CabinetPiece of furniture that houses electrical equipment components


Epoxy resin

Materials based on the reactive oxirane group, which are characterized by the attachment of one oxygen atom to two different adjacent carbon atoms. Standard epoxy resins are the reaction product of bisphenol A and epichlorohydrin. Curing of epoxy resins is achieved by the chemical reaction of the epoxy with a second reactant such as amines, polyamines, amine products, or other reactants (at ambient temperatures) or with anhydrides, carboxylic acids, phenol or novolac (phenol-formadehyde) thermoplastic resins (at higher temperatures)

Expansion jointDiscontinuity in the construction works where adjacent products, components or assemblies are put together,

fixed or united, to allow expansion and contraction under thermal or mechanical loads

Expanded metalA metal mesh product manufactured from slitted metal plate or sheet which is stretched to form diamond-shaped perforation.

Extruded plastic

Moulded sections of plastic produced by ejection under pressure through a suitably shaped nozzle or die

FaçadeExterior surface of a wall enclosing a building, usually non-loadbearing, which can include a curtain wall, cladding or other exterior finish

FallDifference in level between a higher and lower point of an inclined surface

False ceilingCeiling that reduces the height of a space or provides space for services

FiberglassA flexible, non-flammable, moisture and rot-proof material made of glass spun into filaments; widely used in blanket form faced with a vapour retardant material for building insulation

Finished productproduct as it is delivered to the next user in the food chainNote: in contrary to an end product that may be shipped as a batch with no packaging, a finished product is

packed in its final container

Floated concreteAn in-situ floor slab finished usually by a machine to produce a uniform hard surface

Floor live load

Loads imposed upon a floor system, the magnitude of which is determined by the use and occupancy of the space

Food hygieneAll conditions and measures necessary to ensure the safety and suitability of food at all stages of the food chain (Codex)

Food safety

Assurance that food will not cause harm to the consumer when it is prepared and/or eaten according to its intended use (Codex)

FootingA pad or mat, usually concrete, located under a column, wall or other structural member, used to distribute loads from the member into the supporting soil


FoundationThe supporting portion of a structure below the first-floor construction, or below grade, including the footings,

which transfers the weight of, and loads of, the structure to the ground

FormworkThe total system of framing in which concrete is to be poured

FreeboardDistance between normal water level and the top of a structure

GHP (Good hygiene practices)

Measures applicable throughout the food chain (including primary production through to the final consumer), to achieve the goal of ensuring that food is safe and suitable for human consumptionNote1: GHP are prerequisite programs as defined in ISO 22000 (see PRP (prerequisite program))

Note 2: Application of GHP is a prerequisite before any HACCP study. (see HACCP (Hazard Analysis Critical Control Point))

GMP (Good manufacturing practices)All procedures, processes, practices and activities aimed at ensuring that the suitability and safety objectives are met consistentlyNote 1: GMP are prerequisite programs as defined in ISO 22000 (see PRP (prerequisite program))Note 2: GMP do apply throughout the food chain

GalvanizedSteel coated with zinc for corrosion resistance

Gangway

A passageway through which to enter or leave, such as one between two buildings

GaugeThe numerical designation for the thickness of sheet metal or wire

GirderA large or principal horizontal or near horizontal structural member that supports concentrated loads at isolated points along its length

Glazed

Materials infill in a door, window or other opening, which will admit light but resist the passage of air or other elements

GradeThe fall (slope) of e.g. a line of pipe or the ground level, in reference to a horizontal plane

Graded

Leveled off to a smooth horizontal or sloping surface

GratingOpen screen within an opening in a wall, floor or pavement

GRP (glass re-inforced plastic)A plastic sheet or application reinforced with glass fibre

Grout

Flowing material that hardens after application, used for filling fissures and cavities

GulleyDischarge fitting intended to receive water from floors either through apertures in a grating or from pipes connected to the body of the gulley


GutterA channel used to carry off water from the valley area which is created behind a sidewall facade, or when two

buildings are joined side by side or when a reverse angle eave canopy is attached to the building

HACCP (Hazard Analysis Critical Control Point)A system which identifies evaluates and controls hazards that are significant for food safety (Codex) Note: A HACCP study must be performed during the development of new products and processes, covering thus new equipment, and when changes are made on existing lines or to products

HazardA biological, chemical or physical agent in, or condition of, food with the potential to cause an adverse health effect (Codex)

Hydraulic capacityThe ability of a current of water or wind to transport detritus, as shown by the amount measured at a point per unit of time

Hazard analysis

The process of collecting and evaluating information on hazards and conditions leading to their presence to decide which are significant for food safety and therefore should be addressed in the HACCP plan (Codex) Note 1: Hazard analysis is a crucial step in the implementation of an HACCP planNote 2: Hazard analysis must not be confused with risk analysis

Hygiene areasSee Zoning

Hygienic design and engineeringDesign and engineering of equipment and premises to assure the control of food safety hazards, to maintain product quality and to enhance cleanability

Impact loadThe assumed load resulting from the motion of machinery and vehicles

IngredientOne of the substances which comprises a mixture

Impervious

Surfaces impenetrable to contamination by either micro-organisms, chemical or other substances

JambThe side and head lining of a doorway, window, or other framed opening. Includes studs as well as the frame and trim

LairageAn area of the factory in which animals (e.g. cattle or sheep may be housed or rested prior to slaughter.

Lavatory(a) a sanitary installation for receiving and disposing of urine and faeces, consisting of a bowl fitted with a water-flushing device and connected to a drain(b) a room containing such an installation together with equipment for washing and drying hands

Leak threshold

A continuous horizontal plate forming the lowest member of a framework or supporting structure, that prevents leaking of water under that framework or supporting structure

MasonryThe combination of stone, brick, concrete, hollow-tile, concrete-block, gypsum block or other similar building units or materials, bonded together with mortar to form a wall, pier, buttress or similar mass


Mechanical ventilationMechanical provision for supplying, moving or removing air

Membrane

Layer or sheet of material placed within a floor or similar construction or vertically within a wall to prevent the passage of moisture

MezzanineIntermediate and partial storey, usually between the ground floor and first floor, and usually fully or partially

open on one or more sides

Microorganism

Living organisms that can be seen only with the aid of a microscopeNote 1: Microorganisms include bacteria, archaea, viruses, and certain protozoa, algae and fungiNote 2: most microorganisms are unicellular

MortarA mixture consisting of sand (fine aggregate), cement, and water which gradually sets hard after mixing

Non-absorbent materials

Materials which, under the intended conditions of use, do not internally retain substances with which they come into contact

Non-product contact surfacesSee also Product contact surfaces

Exposed surfaces from which splashed product, condensate, liquids, or other materials cannot drain, drop, diffuse or be drawn into or onto the product, product contact surfaces, open packages, or the product contact surfaces of package components

Non-toxic construction materials

Materials which do not release toxic substances under intended conditions of use

Open surface

Part of a surface that is open, through which one can see objects that are located after that surface

Panel

A thin flat piece of wood, plywood, or similar material, framed by stiles and rails as in a door (or cabinet door), or fitted into grooves of thicker material with molded edges for decorative wall treatment

PartitionInternal non-loadbearing vertical construction that subdivides a space

Pathogenic microorganismsMicroorganisms that can cause disease/illness in humans and/or animals

PestAn organism that threatens a human valued resource, interferes with human activities, property, or health, or is objectionable

Pile foundations

A category of special foundations, generally applied to transfer the load of a building or a structure to a solid, load bearing layer of subsoil; to support a foundation by friction forces of the piles against the subsoil; to absorb a horizontal or uplift load; or to compact a loose layer of granular soil

Portland cementCement made by heating clay and crushed limestone into a brick and then grinding to a pulverized powder state


Pipe hangerA device which is suspended from a structure and is used to carry the piping load in tension

Pitch

The incline slope of a surface (usually a roof) or the ratio of the total rise to its total width

PlastisolA suspension of PVC particles in a plasticizer; it flows as a liquid and can be poured into a heated mold. When heated to around 177°C, the plastic and plasticizer mutually dissolve each other. On cooling the mold below

60°C, a flexible, permanently plasticized product results

Platform

A horizontal surface or structure with a horizontal surface raised above the level of the surrounding area

PlinthProjection or recess at base of construction, such as a wall, column or construction for raising equipment above the level of the floor

PolymethacrylateAny acrylic plastic derived from methacrylic acid, or an ester of methacrylic acid

PolyurethaneA class of synthetic materials made by copolymerizing an isocyanate and a polyhydric alcohol

PondingThe gathering of water at low or irregular areas

Potable waterWater intended for human consumption according to the specifications of the World Health Organization. Note: Potable water must comply with national legislation

Premises

A parcel of land, a building or part of a building or an easement

PrimerThe first, base coat of paint when a paint job consists of two or more coats. A first coating formulated to seal

raw surfaces and holding succeeding finish coats

Process airAir prepared by filtration or other treatments which is intended to be used in contact with the product for such purposes as heating, cooling, drying, conveying, or similar purposes

Processed foodsA food or food ingredient that has been changed from its original state via a process

ProductThe end-point of a food manufacturing process which may be a finished product or may require further processing in an additional process

Product contact surfacesSurfaces which are exposed intentionally or unintentionally to the product and surfaces from which splashed

product, condensate, liquids or material may drain, drop, diffuse or be drawn into the product or onto product contact surfaces or surfaces that come into contact with product contact surfaces of packaging materialsNote: Product contact surfaces may contribute to cross-contamination, and must therefore be included in the

hazard analysis

ProfileOutline of the surface of usually described by its roughness


PurlinBeam parallel to the eaves that gives intermediate support to rafters or roofing. The members at right angles

to rafters serving to break up the roof board span

Raw materials

A general term used to denote starting materials and ingredients

Readily Accessible

A location that can be safely reached by a personnel from the floor, platform, or other permanent work area, or stable platform (permanent or removable). (3-A SSI)

Readily Removable

Designed, fabricated and installed to be quickly separated from the equipment, with or without the use of simple hand tools.

Ready-to-eatFood that when purchased, does not require a pathogen “elimination step” prior to consumption, (e.g. cooking)

Recirculated water

Water reused in a closed loop for the same processing operation.Examples could include water used in a recirculating product cooling system or recycled product fluming system.

RefurbishModification and improvements to an existing plant, building or civil engineering works, in order to bring it up to an acceptable condition

RenderA vertical applied finish exceeding 7 mm and not exceeding 25 mm usually formed with sand and cement

Rest room

A room or suite of rooms providing toilets and lavatoriesNote 1: A term primarily used in North America

RidgeThe horizontal line at the junction of the top edges of two sloping roof surfaces

Riser

Each of the vertical boards closing the spaces between the treads of stairways

RiskA function of the probability of an adverse health effect and the severity of that effect, consequential to a

hazard(s) in food (Codex)Note 1: In Codex terminology 'risk' relates to food safety and not to quality related matters. It is expressed as the probability or frequency of an adverse health effect caused by a specified hazard e.g.” the risk of disease D in Country X is n for 100 000 person per year”Note 2: In non Codex context, risk is synonymous to probability or likelihood

Risk analysisA process consisting of three components: risk assessment, risk management and risk communication (Codex) Note: Whereas hazard analysis is under the responsibility of food manufacturers, risk analysis is a public health matter

Sandwich panelA panel assembly used as a covering consisting of an insulating core material with inner and outer skins

Sanitary convenienceA cesspit, chemical closet, pan closet, septic tank, water closet, urinal or other receptacle for the deposit of human excreta


Sanitation

Cleaning, disinfection if necessary, pest control and waste management (Codex)Note 1: Sometimes used in place of hygiene or as a combined term for cleaing and disinfectionNote 2: Its use as a term is discouraged

ScreedA layer of well compacted material applied in situ to a floor base and finished to a designated level usually to

receive a flooring material

Screen

Barriers non-loadbearing vertical construction that provides a degree of visual privacy or protection or bothfrom noise, wind or gaseous emissions

SealantAny material used to close up cracks or joints to protect against leaks

Secondary steelworkSteelwork framing members that transmit loads to the main structure of the building

SegregationPrimary segregationThe use of physical facility design elements to define the basic organization of the food plant design and establish environmentally controlled work areas around specific steps of the process or zones. It provides distinct environmental protection for the process/product from contamination, and is traditionally accomplished by the designation of dedicated areas, staff, and supporting mechanical systems

Secondary segregation

The use of procedural or chronological controls to minimize potential interactions or contamination e.g. storage of raw materials in different stages of quarantine; clean/dirty equipment areas; and general access paths/process areas. Whereas primary segregation controls the immediate quality of the process, secondary

segregation measures are traditionally implemented to minimize the potential for human error

Setting

Loss of elasticity and formation of a semi-rigid mass of cement paste, mortar, or concrete

Sewer

Pipeline or other construction, usually underground, which conveys wastewater or other unwanted liquids

Sheet flooringFlooring that consists of flexible or rigid sheet material

SillA horizontal framing member forming the lower side of a door or window opening

SkirtingA cover strip placed on the surface of a wall, adjacent to the floor

SkylightA more or less horizontal window located on the roof of a building

SlabA thick, flat molded layer of reinforced or plain concrete, usually of uniform thickness, usually larger than 300

mm and generally used as a floor in most buildings

SleeveA length of pipe built into floor or wall construction to provide an opening through which pipes or cables can later be passed


Slip resistanceFrictional force opposing movement of an object across a surface, usually with reference to the sole or heel of a shoe on a floor

SlitCut lengthwise into strips

SiphonA pipe or tube fashioned or deployed in an inverted U shape and filled until atmospheric pressure is sufficient to force a liquid from a reservoir in one end of the tube over a barrier higher than the reservoir and out the other end

SpanThe clear distance over which a framing member carries a load and that without support between the two outside structural supports. Width of building inside to inside of wall panels (sidewall to sidewall).The horizontal distance from eaves to eaves

Specifications

A statement of particulars of a given job as to size of buildings, quality and performance of men and materials to be used, and terms of the contract, etc.

Stair riserVertical component of a step between one tread and another or a landing above or below it

Stiffener

A member used to strengthen a plate against lateral or local buckling. Usually a bar welded perpendicular to the longitudinal axis of the member

StanchionMetal column that serves as a post in a guardrail system

Structural floorThat part of a floor designed to carry imposed and dead loads

Structural steelwork

System of steel structural members fabricated as a frame

StudA vertical wood framing member, also referred to as a wall stud, attached to the horizontal sole plate below and the top plate above. One of a series of wood or metal vertical structural members placed as supporting elements in walls and partitions, to which external or interior covering or collateral material may be attached.

May be either load bearing or non-load bearing.

SubfloorAn intermediate layer between a structural floor and flooring

Surface profileRoughness of a surface; miniature 'mountain-and-valley' texture of a surface; 'shape' of the surface finish

Suspended ceiling

Ceiling hung at a distance from the floor or roof above

Suspended floorFloor that spans between supports


Structural membersComponents of a building that distribute all vertical, horizontal and dynamic loads and forces (actions) from

and impacting to the building in a safe way into the foundations

Terrazzo

In-situ flooring that consists of Portland cement and marble aggregates with a surface that is ground and polished

Tile

Small, thin, flat or shaped component used to form a covering

Threshold

A strip of metal that spans from jamb to jamb beneath a doorNote: thresholds are frequently adjusted to keep a tight fit with the door and usually act as a kick plate

ToiletRoom in which one or more lavatories and/or a urinal or urinals, and wash basins, are installed

ToleranceA fractional allowance for variations from the specified standards of construction or fabrication

Transport airProcess air in contact with and used to convey product

Transverse jointA joint across the width of a building to allow small relative movements, such as those caused by temperature

change in the building length

Trunking

An openable casing for cables and wiring in an electric installation

TrussBraced triangulated frame designed to act as a beam.Any rafter, ceiling joist and tie assembled in such a way as to span a greater distance than the rafter alone.

TundishA broad, open trough with a tube at the bottom, filled by an outlet pipe above, and used to create a siphonic break in a drainage system and/or to provide visual indication of flow

UrinalA restroom fixture used to catch, collect and flush urine, usually attached to a water source and drain

Utilities

Systems for conveying water, gas, warm air, electricity or that provides water, gas, oil, air to a food manufacturing process or removes waste from it

Vapour barrier

A building product installed on exterior walls and ceilings under the drywall and on the warm side of the insulation, in order to retard the movement of water vapour or moisture into walls and prevent condensation within them. Normally, polyethylene plastic sheeting is used

Vent

A pipe or duct which allows the flow of air and gasses to the outside

VergeA sloping edge of a pitched roof

VitrifiedA substance that is transformed into a glass


Void areaAn empty space, an open space or a break in continuity, unfilled, unoccupied space

Walkway/catwalk

Construction that provides an elevated lateral access for pedestrians

Wash basinConstruction supplied with hot and cold water to allow the washing of the hands or other body parts

WashroomRoom in which one or more wash basins are installed

WasteSubstance or objects for which the holder intends or is required to dispose of

Water trapA water filled barrier placed between the fixture and the system branch to prevent the egress of contaminated air or noxious gas from the sewer into habitable space. As this arrangement is effectively a manometer, it responds to changes in system line pressure and may be depleted by the action of both positive and negative

transients or evaporation.

Wet cleaningCleaning (and disinfection if necessary) of equipment or processing environment with aqueous solutions of detergent (and disinfectant if necessary) followed by rinsingNote 1: Wet cleaning procedure should be carried out only when the product is not exposed using methods that limit the amount of water applied and its spreadNote 2: Use as little water as possible and to be as dry as possible rapidly after cleaning are highly

recommended practices

Weep holes

Openings in flashing, etc., to permit drainage and reduce pressures (usually field drilled)

Wet productionAll operations involved in the preparation of food product, proceeding in wet conditions, from receipt of dry or

wet materials, through processing and packaging, to its completion as a finished product containing water

Wire way

A prefabricated, supporting structure for electrical wiring

Workplace (work space)An indoor area, structure or facility or a portion thereof, at which 1 or more employees perform a service for compensation for the employer, other enclosed spaces rented to or otherwise used by the public; and where the employer has the right or authority to exercise control over the space

Zoning

The physical or visual division of the plant into sub-areas, leading to the segregation of different activities with different hygiene levelsNote 1: Related terms and explanations. Non-food production areas; Food production areas, Basic hygiene area, Medium hygiene area including ingredient preparation and, General processing area, High hygiene areas and Aseptic areas


5 Site

Food factories should be sited with due regard to the provision of services needed, particularly a sufficient supply of potable water, and to avoid contamination from adjacent activities including buildings, operations and land use. Factory buildings and surrounding areas should be designed, constructed and maintained in a manner to prevent conditions which may result in the contamination of food.

5.1 Site location

Whenever possible, factories should be located away from or protected against:

— environmentally polluted or remediation areas and industrial activities which pose a serious threat of contaminating food (e.g. incinerators, landfills, junkyards, etc).

— neighbouring facilities and activities creating possible contamination sources (e.g. waste water treatment plant, farms, heavy chemical industries, etc).

— areas where wastes, either solid or liquid, cannot be removed effectively.

— rivers, canals, ponds, marshes.

— residential areas.

— areas subject to flooding unless sufficient safeguards are provided. Note. Flooding is a major food safety risk and if flood waters penetrate the factory, production must cease and costly remediation is always required. A thorough flood risk assessment is required, particularly for microbiologically sensitive products.

— areas prone to earthquakes or other ground movements.

— areas prone to infestations of pests.

— areas prone to excessive levels of airborne bacteria, yeasts and moulds.

Where a site has been established, the food manufacturer should be aware of risks from neighbouring facilities and activities creating possible contamination sources and the general direction of wind which may transfer any identified hazards, such that factory design can mitigate these risks.

The impact of trafficking of materials in and out of the site should also be considered, both to food safety issues for the product (e.g. microbiological risks from the transport and lairage of animals) and to the surrounding community (e.g. the noise generated from vehicle refrigeration units).

5.2 Site plan

For new plant design, a site plan is a useful tool. A site plan should consider the management of hazards as part of the HACCP study as well as being the basis for any specific discussions on engineering projects(Figure 5.2.1). A site plan could consist of:

— a building layout locating production areas, service areas, storage areas (e.g. chemicals), surrounding areas and main air intake/outlet locations.

— the relevant hazards established from HACCP or equivalent hazards studies including possible cross flow between sensitive and potentially contaminated material.

— access for personnel and traffic (for incoming and outgoing material).

— location of nearby rivers, canals or other water catchments areas (e.g. ponds, lakes, marshes).

— site terrain elevation indicating slopes for natural drainage.

— neighbouring non-industrial sites e.g. commercial buildings, food outlets, housing etc.

— waste collection areas.

— general direction of the wind with reference to odour and airborne contaminants, such that factory design can mitigate these risks.

— main plant areas defined in terms of a hygienic zone classification, their functions and planned cleaning practices in these areas.

— movement of personnel, vehicles and materials including raw materials, packaging materials, intermediate products and waste. The impact of trafficking of materials in and out of the site should be considered, both


to food safety issues for the product (e.g. microbiological risks from the transport and lairage of animals) and to the surrounding community (e.g. the noise generated from vehicle refrigeration units).

— location of utilities including the wastewater treatment plant.

Figure 5.2.1 – Schematic site plan indicating potential risks to and from the food manufacturing plant

5.3 Site

The site should:

— have clearly defined boundaries, e.g. a perimeter fence or wall, with controlled access to the factory grounds to keep out animals, pests or unauthorised persons.

— control the risks of open water ways that attract birds, insects, rodents, etc.

— have adequately draining areas or installed external drainage which should not pass under food processing areas. Grade to storm sewers.

— ensure the building has adequate freeboard over site water levels assumed in flood risk assessment design storm events.

— be sealed or otherwise surfaced, drained and graded. The provision of lawn and landscaping is effective

for sealing large non-traffic areas.

— have roadways of a dense, hard, compacted and dust sealed material (e.g. concrete, asphalt, paving) suitable for wheeled traffic.

— have roadways with suitable slopes to prevent accumulation of water.

— have minimal vegetation and foliage. When present, shrubs and plants should be located at least 3 m / 10feet and trees located at least 9 m / 30 feet from buildings (Figure 5.3.1).

— have a high quality and constant water supply available.


— minimize the presence of grass, plants and flowers, an area of minimum 60 cm to 90 cm around the building should be free of vegetation.

— have weed control to reduce harbourage for insects and rodents but also to prevent air-borne seeds getting into the plant.

— have a ¼ inch / 6 mm pebbled gravel strip around the factory that is at least 90 cm / 36 inches and 10 cm /4 inches to reduce rodent infestation (Figure 5.3.1 & Figure 5.3.2) Plastic sheeting may be used below the gravel for weed control.

— have separate utility buildings, trailers, garages, waste water treatment facilities, storage sheds, guard shacks, and well houses generally designed to meet security and pest control strategies.

— availability of a high quality and constant water supply (for process, potable and cleaning purposes).

External lighting that illuminates the factory entrances should be placed in locations away from the building to avoid attraction of insects to the building. On the outside, car parking lights and building lights should be angled downward, or towards the building, never out and away from the building. Lights showing outward attract insects to the building at night. External lighting should be shielded so they are not visible from above. When external lighting is used, preference should be given to high-pressure sodium lights or equivalent that emit low Ultra Violet (UV) rays. Mercury vapour type lights which emit high UV rays should be avoided but if used, should be located at least 10 m / 35 feet from doors.

Figure 5.3.1 - The site should have a path or pebbled gravel strip around the factory that is at least 90cm wide and 10 cm deep, and trees should be located at least 9 m from buildings.


Figure 5.3.2 - Gravel strip and path around factory building of at least 90 cm, and without any shrubsor plants in close vicinity to the factory building. Air exhaust and air intake positioned in both the

horizontal and vertical plane under an angle of 90°.

5.4 Boundary fences and walls

— Fencing around the site should be 250 - 300 cm (8’-10') high, preferably with a climb and cut-resistant wire mesh and/or an intrusion detection device should be installed.

— A concrete or brick wall base of approx. 50 cm above ground level should prevent the passage of some types of rodents.

— Fencing must be of sufficient height to effectively filter pieces of paper and other debris.

— Fencing must form a barrier to cats, dogs, other domestic animals and some rodents.

— Inside the fence (or wall), an inner drainage channel or a metre border of pebble/concrete should be provided.

— On both sides of the fence (or wall), a minimum area of 50 cm should be clear of trees, bushes, plants, waste and structures. Gravel or concrete should be present on both sides of the fence.

— There should be no buildings against the wall (or fence) - unless with a meter space between the two is provided - exceptions being the case where the buildings make the boundary wall.

— Provide only breaks in the boundary wall (or the fence) for personnel and goods entry with their appropriate security barriers. Ideally, access should be limited to a single entrance at the gate house.

5.5 Controlled site access

The site and the production and storage areas of the factory buildings shall be secured effectively by controlled access in order to prevent unauthorised entry. Site security should be reviewed, and the need for close circuit television (CCTV), and/or security guards should be considered as part of a food defence programme (Figure. 5.5.1).

In particular, material storage tanks, silos, and line hook ups should be provided with adequate enclosure, security, drainage, space and spill control.


Figure 5.5.1 - Protection of products against potential acts of sabotage, vandalism or terrorism by controlled access to the factory site: turnstile, barriers, cameras, access control post, etc.

6 Hygienic Building Design

6.1 Buildings

Buildings must be located, designed, constructed, adapted and maintained to suit the operations carried out in

them, for the placement of equipment and storage of materials, to provide adequate space to allow the hygienic performance of all operations and to facilitate cleaning and maintenance.

Access of personnel and visitors should be controlled. Designated walkways should be provided and marked in internal and external areas such that by simple logical routes, the traffic pattern of personnel (and vehicles) should prevent cross-contamination of the product. Manufacturing areas should not be used as general rights of way for personnel, or materials or storage.

Good hygienic operations are assured by building design that:

— locates buildings on the highest site elevation to avoid water runoff issues and orientated so prevailing winds do not blow into docks and manufacturing areas.

— provides protection against physical, chemical or biological contamination by e.g. poisonous or offensive gases, vapours, odours, smoke, soot deposits, dust, moisture, insects or other vectors.

— prevents entry of contaminants, e.g. no unprotected openings, air intakes are appropriately located and the roof, walls and foundations are maintained to prevent leakage.

— prohibits entrance and harbouring of pests and birds. Holes, drains and other places where pests are likely to gain access should be kept sealed. All apertures in the roof or its eaves or the walls should be closed off or effectively screened and drains and guttering should be fitted with traps to prevent pest access.

— provides building structures that are water tight to prevent egress of water.

— is free of surfaces that can retain water (gutters, ledges or horizontal surfaces) inside the building.

— recognises that building joints are necessary, but expansion joints in critical process areas should be avoided. All expansion joints need special attention - both during installation and maintenance

— contain no structures or equipment which could provide places for microbial contamination or harbourage for infestation. Hollow bodies, having possible potential effect on product, should be eliminated.

— has the least possible number of personnel entries or openings to the exterior - while acknowledging security and fire escape requirements.

— provides main exterior employee entrances located away from waste and refuse areas

— provides all openings to the outside (if not permanently closed) with solid doors or glazed windows, insect-

proof screens and/or self-closing mechanisms.

— provides physical internal separation by walls between departments in which edible (e.g. food products and other food ingredients) and non-edible materials (e.g. boiler rooms, workshops, machinery rooms, living accommodation) are handled.


— provides physical internal separation by walls between departments in which edible materials (e.g. food products and other food ingredients) are processed and with any area in which gas, fumes, dust, soot

deposits, offensive odours or any other impurity is present.

— reduces cross-contamination by segregation that takes into account the flow of product, nature of materials, equipment, personnel, waste, airflow, air quality and utilities provisions.

— provides separate storage areas for raw materials, final products, chilled or frozen products, packing materials and cleaning and other equipment

— minimises criss-crossing of products, raw materials, services, personnel, and wastes.

— provides suitable temperature-controlled building and storage conditions of sufficient capacity for maintaining foodstuffs at appropriate temperatures and designed to allow those temperatures to be monitored and, where necessary, recorded.

— permits segregation of non-conforming facilities and materials.

provides separate routes of entry and movement for vehicles and personnel.

Businesses must ensure that the premises are provided with the necessary services of water, waste disposal,

light, ventilation, cleaning and personnel hygiene facilities, storage space and access to toilets. Services shall be designed, maintained, controlled and monitored so as to avoid the risk of contamination of food.

The design and layout of rooms should permit good food hygiene practices, including protection against contamination between and during operations. Hygienic room design should:

— protect against the accumulation of dirt and the shedding of particles into food.

— protect against contact with toxic materials, dirt, dust, fumes, smoke and other contaminants.

— protect against the formation of condensation (humidity control) or undesirable mould growth on surfaces.

— permit adequate cleaning and/or disinfection and maintenance.

— permit immediate drying after cleaning and disinfection.

— provide adequate lighting and ventilation.

Specific rooms should be considered for e.g. label and package printing, quality control stations, maintenance and equipment repairs, staff facilities, first aid facilities, laboratories.

Fixtures and fittings must be designed, constructed, located and installed so that:

— there is no likelihood that they will cause food contamination.

— they are able to be easily and effectively cleaned.

— adjacent floors, walls, ceilings and other surfaces are able to be easily and effectively cleaned.

— to the extent that is practicable, they do not provide harbourage for pests.

For processes involving dry materials, it is important to contain dust as far as possible in an enclosed system and, with the aid of dust removal and extraction systems, to maintain a high standard of cleanliness.

6.2 Adequate Space for Cleaning, Inspection and Pest Control

To allow planning of room sizes, especially when the size of equipment to be installed in the room is known, all parts of the equipment should be installed at sufficient distance from walls, ceiling and adjacent equipment to allow easy access for inspection, pest control, cleaning and maintenance and should not be placed directly over floor drains. This is especially important if ladders or personnel lifting equipment is required. Individual items of food processing equipment, service equipment, electrical control boxes etc. should be installed directly onto floors and walls with a suitable seal to prevent liquids and dust penetrating between the equipment and the support surface or installed sufficiently away from the floor/wall to allow adequate cleaning. The distance away from the floor/wall/ceiling, or indeed any structure, to allow such cleaning is dependent on the size of the equipment, particularly its width. A minimum clearance under the equipment, for different equipment widths, is suggested as (Figure 6.2.1):

— up to 36” / 90cm wide: 8” / 20cm clearance,


— 36-60” / 90-150cm: 12” / 30cm clearance,

— 60-84” / 150-210cm wide: 18” / 45cm clearance,

— greater than 84” / 210cm wide: 24” / >60cm clearance.

Figure 6.2.1 - Required clearance between equipment of different widths and a surface (wall, ceiling, floor) to facilitate cleaning

Essentially, for equipment over 1 meter wide, there should be sufficient clearance between the equipment and the floor to enable a brush, held at a 30° to the horizontal to reach the machine’s centre line allowing the complete floor under the machine to be cleaned form both sides without excessive stooping.

For equipment access, a minimum clearance of 90 cm / 36 inches from walls and between equipment of 120-150 cm / 48-60 inches is suggested.

For warehousing, 45 cm / 18 inches perimeter strips should be provided around permanent racking or pallet curbing to allow for cleaning, inspection and rodent control device placement.

Equipment that has components requiring maintenance and cleaning should be designed and positioned for easy access.

7 Internal Divisions

7.1 Segregation

All food processing operations should be carried out in a way in which the risk of contamination of the food product or packaging materials by any hazard (including other food ingredients/products) is avoided. Such hazards may include:

— pathogenic microorganisms

— allergens

— foreign bodies (e.g. metal, glass, plastic, insects)

— chemicals (e.g. cleaning chemicals, lubricants)

In addition, segregation of ingredients may be required with respect to handling requirements, labelling or brand protection issues, including:

— wet and dry storage and production areas

— vegetarian product claims (in a factory handling meat ingredients)

— organic product claims (in a factory handling non-organic ingredients)

— GMO free claims (in a factory handling GMO ingredients)

— Halal or Kosher claims (in a factory handling non-Halal or Kosher ingredients)

— meat species claims (in a factory handling mixed meat species - pork, beef, chicken, lamb etc.)


Microbial pathogens have always been considered as the major food hazard and traditionally, factories have been segregated into separate areas or zones (the terms have identical meaning) to control such

microbiological hazards. These are described below and the descriptions of the zones are, in many ways, a compromise between terminology that has been used historically in the different sectors of the food industry, e.g. dairy, low moisture (e.g. aw <0.85) foods, frozen and chilled ready-to-eat foods.

— Non-food production areas

— Food production areas

o Basic hygiene areas

o Medium hygiene areaso High hygiene areas

Non-food production areas contain those activities that are outside the food production area e.g. offices and canteens.

Basic hygiene areas are the first zone of the food production area, in which raw materials are initially processed (e.g. sorted and cleaned of soiling) and where ingredients and finished products are stored whilst

contained within their primary and/or secondary packaging.

Medium hygiene areas are where raw materials are prepared as food ingredients and/or food products are processed and packed.

High hygiene areas are for products, particularly those that are described as ready-to-eat, for which a microbiological reduction process is undertaken (heating, frying, roasting, washing etc.) and then further manipulation of the product is required prior to primary packaging.

The zones are shown schematically in Figure 7.1.1. Products can be manufactured entirely within Basic hygiene, may pass from Basic to Medium and then back to Basic hygiene or pass from Basic to Medium to High and then, via Medium, back to Basic hygiene.

Figure 7.1.1 - Schematic representation of food manufacturing zones showing potential routes of product flow dependent on the product’s need for microbiological protection from the manufacturing

environment.


7.1.1 Zoning hazard analysis

Food manufacturers should undertake a hazard analysis to determine how many processing areas or zones are appropriate for the safe manufacture of their product range. The hazard analysis should consider, for example:

— hazards present in raw materials.

— hazards present in the processing environment.

— the degree of product handling necessary.

— the degree of product exposure to the environment (i.e. when not enclosed in vessels and pipelines).

— intended people, product, waste, water, air and other utility flows within the factory.

— any hazard reduction steps within the process.

— the microbiological susceptibility (microbial growth) of the product, particularly with respect to pathogens and shelf-life.

— the potential for pathogen survival within the product.

— the potential for product microbial spoilage.

— the type of consumer (elderly, infants, immunocompromised, pregnant women).

— the degree of brand protection required.

There is no perfect factory zoning solution and a number of solutions may satisfy a food manufacturer’s hazard analysis. For example, some food processing operations such as the sorting/grading of vegetables for size/weight could be undertaken in the field. Alternatively, such operations can be undertaken in Basic hygiene areas in the factory. Basic hygiene areas also include warehousing in which ingredients and finished products are protected by (as a minimum) their primary packaging. Food processing that prepares products for cooking by the consumer (e.g. raw meats, fish and vegetables) or produces ready-to-eat (RTE) products that are effectively preserved (e.g. canned or baked products) will require processing in Medium hygiene areas. RTE products that have undergone a decontamination process and in which spoilage and pathogenic micro-organisms could survive or grow during the product’s shelf-life, will require processing in a high hygiene area. The degree of hygienic design applied to the high hygiene area will depend on the degree of microbial decontamination undertaken, the likelihood of spoilage and pathogenic microorganism growth or survival in the product, and the risk of cross-contamination from the external environment.

Non-microbial contamination, particularly allergens, may be reduced by manufacturing in separate locations/factories, by separation of operations and equipment within the same factory, by enclosed systems, by partition, by air flow, by time with effective intermediate cleaning and, where appropriate disinfection, or other effective means. Manufacturing within the same site is the most likely scenario and this is illustrated in Figure 7.1.2


Figure 7.1.2 - Schematic separation of non-microbiological hazards via horizontal segregation throughout as many factory zones as necessary to prevent product cross-contamination. Segregation

is extended until the product is in its primary packaging.

7.1.2 Hygienic design criteria for zones

Food production areas must be segregated from non-food production areas e.g. locker rooms, canteens/restaurants, smoking areas, boiler rooms, workshops, machinery rooms, laboratories, offices, meeting rooms, living accommodation. Separation must be by physical means e.g. walls, sufficient to prevent contamination of food production areas by pests, particulates, gases and fumes.

Microbiology laboratories, particularly those undertaking pathogen testing, shall be physically separated from production areas (and from other laboratory areas). Microbiology laboratories must have separate air and effluent discharges and safe solid waste discharge.

Food production areas

For food safety and potential bioterrorism considerations, there should be a clear, defined, single entrance for all staff (production, engineering, quality, management, visitors, contractors, auditors etc.) into food production areas. Single entrances can be used to develop a ‘you are now entering a food factory’ mindset in staff, which can help to reinforce hygienic behaviours. Truck drivers should not be allowed to enter the factory via goods-in or despatch, but will need to talk to warehouse staff via windows or hatches. Rest and toilet provisions may be needed for drivers if they remain on site for significant time periods.

Basic hygiene areas

The Basic hygiene area is the first described zone within the food production area. The Basic hygiene area is a zone in which raw agricultural products are sorted and cleaned (e.g. vegetables are washed to remove field soil) and/or where the storage of food ingredients, products and packaging, which are fully enclosed, is undertaken.

Basic hygiene areas are designed to facilitate all minimal good manufacturing practices (GMP) and good hygienic practices (GHP) and to control external and internal hazards specific to the building location and food

product type. These could include product flows, ease of cleaning, personal hygiene and handwashing, ease of maintenance, potable water supply, pest control and waste control etc. Providing these basic hygiene requirements are met, building design can be simplistic and could include for example, sealed concrete floors, exposed steel work and natural, screened, ventilation and lighting.

Ingredient preparation areas may also be used for the storage and handling of waste materials prior to disposal.


It should be noted, however, that if factories are extended or refurbished, warehouse areas often become Medium hygiene areas. Building warehouses to Medium hygiene food production standards at the beginning

of the construction process may, therefore, be more cost efficient in the long term.

Medium hygiene areas

The Medium hygiene area is where cleaned raw materials and prepared ingredients are handled, processed and packed. The Medium hygiene area can be subdivided into areas of different cleanliness, termed ingredient preparation areas and general processing areas and is built to provide at least the minimum recommended processing standards designed for all legislated, food handling activities.

Products produced in a Medium hygiene area typically include raw fish and meat, raw prepared products, fresh fruit, vegetables and nuts, beverages, alcoholic drinks, bakery, dried food ingredients, and oils and fats.

Ingredient preparation area

Ingredient preparation areas are usually the first stage in the processing of meat and fish products (the slaughter house or gutting area) in which the food product is known or likely to be contaminated with hazards.

The hygienic implications of these areas are as much about the prevention of the spread of the hazards

associated with the raw materials to other (cleaner) parts of the factory as to the prevention of contamination to the product from the processing environment. As such, ingredient preparation areas are physically segregated from general processing areas, but usually share the same operatives with no operative barriers (other than possibly boot washing) between the zones.

General processing area

General processing areas handle both ingredients suitable for further processing, exposed packaging and processed products.

Within the processing area, further segregation may be required.

— Ingredients may need to be stored separately. Storage may be temperature orientated (ambient, chilled or frozen) or ingredient related, and separate stores may be required for e.g. fruit and vegetable, meat, fish dairy and dry ingredients.

— Segregation (and colour coding) of allergen-containing ingredients and products during storage and production and packing is essential.

— Segregation (and colour coding) may facilitate separate storage and processing of different meat or fish species, organic foods, GMO components, vegetarian components and Kosher or Halal components to facilitate their separate storage and processing.

— Packaging should be stored separately.

— To prevent microbial growth, water sources should not be present in areas dedicated to the processing of dry products. Areas should be designed so that as far as possible, no water systems (potable, non-potable, external and internal drains, cooling water, fire water etc.) should pass through these areas and thus form a threat due to leakage. Wet and dry areas and different hygienic zones may be separated by drainage channels to minimize cross contamination, though floors should not be sloped to High hygiene area entrances.

— Ideally, production areas where processed foods are exposed should be physically separated, where possible, from areas where unprocessed or partially processed food is stored, prepared or handled.

— There may also be the requirement for separation within a food processing areas based on general building regulations related to e.g. fire or noise protection.

Building design requirements for Medium care area should facilitate all national and international GHP and GMP requirements and control all external and internal hazards specific to the building location and food product type. The primary design requirement for this area is to prevent the ingredients and processedproducts from being contaminated from all potential external and internal chemical and physical hazards.

Medium area building requirements should include:

— weather and pest proofed external walls and roofs.


— impervious, easily cleanable internal floor, wall and ceiling surfaces.

— coving to wall/floor and wall /ceiling junctions.

— adequate drainage.

— trapped drains which can effectively be cleaned and disinfected.

— barrier protection to structures.

— no dead areas or horizontal surfaces where soils or fluids can accumulate.

— clean filtered or treated air.

— protected lighting.

— services free of contaminants and contained in false ceilings or corridors.

— facilities to allow personnel to use toilets, change from street to factory clothing and enter food production areas via handwash stations.

— equipment cleaning facilities.

— a layout designed to allow flows of product, packaging, personnel, services and wastes to minimise cross-contamination.

— appropriate storage facilities for ingredients, intermediate and finished products and packaging etc.

Some food manufacturers denote ‘intermediate’ zones as buffers between Medium and High hygiene areas. In some cases and for smaller zones, this can be defined as a transportation lock (Section 8.11). The purpose of the intermediate zone is to provide a clean area immediately adjacent to the entrances of High hygiene areas (for ingredients, packaging and people) and thus reduce the challenge of any hazards on these barriers. However, it must be realised that for microbiological hazards in particular, both ingredient preparation and general processing areas are in effect the same hygiene zone as they contain the same equipment, utensils, transport systems, maintenance equipment etc. and are accessed by the same people in the same clothing. Only High hygiene areas provide adequate protection from microorganism challenges.

In some food product sectors, the Medium hygiene area has been termed Low Care or Low Risk. This terminology is not liked because it could imply that good hygienic practices are not required which, of course, is not the case.

High hygiene areas

The manufacture of RTE foodstuffs that may allow the survival or growth of pathogens prior to consumption, following the final microbiological reduction step (heating, steaming, frying, washing etc.) is undertaken in High hygiene areas. The decontamination process forms the barrier between the Medium and High hygiene areas and the High hygiene area continues until the product is in its primary packaging, from which further activities can be carried out in a Medium hygiene area.

High hygiene areas typically process products which conform to, for example, the following scenarios:

1. have received less than a pasteurisation* process (e.g. produce washing typically resulting in an approximately 1-2 log reduction) and are susceptible to the growth of pathogens during their shelf-life.

Such products could include prepared fruit and vegetables, raw cured fermented meat and cold smoked salmon.

2. have received a pasteurisation process and are not susceptible to the growth of pathogens during their shelf-life. Pathogens may, however, survive in the product during its shelf-life. Such products could include pasteurised hard cheeses, ice cream, cooked meat with preservatives, processed nuts, confectionary, breakfast cereals, snacks and dried milk powders.

3. have received a pasteurisation process and are susceptible to the growth of spoilage microorganisms. Such products could include extended shelf-life baked products.

4. have received a pasteurisation process via a heating process and are susceptible to the growth of pathogens during their shelf-life. Such products could include cooked meat and fish and ready meals.

5. have received a pasteurisation process via a heating process and are not susceptible to the growth of pathogens during their shelf-life, but in which there is a high degree of potential contamination from microorganisms external to the high hygiene zone and/or the product may be consumed by infants or immunocompromised individuals. Such products could include scenario 2 products but manufactured for infants (e.g. infant formula) or immunocompromised consumers.


*For the purposes of these scenarios, the term ‘pasteurisation’ is taken as a general term to denote any defined thermal or non-thermal process for a specific product (e.g. milk pasteurisation at 71.7°C for at least 15

seconds) or for multiple products (e.g. 70°C for 2 min or equivalent) and to cover national or international requirements (e.g. a 5 or a 6 log reduction process).

Within the chilled and frozen RTE industry, the high hygiene area necessary for the processing of scenario 1 products is often referred to as a High Care area and for scenario 4 products, as a High Risk area. High Care areas are designed to minimise cross-contamination whilst High Risk areas are designed to prevent cross-contamination to food products.

Within the dry food industry, traditionally, a high hygiene area has not always been adopted. However, due to Salmonella outbreaks in RTE dry foods (chocolate, cereals, milk powders, peanuts etc.) and the concept that Salmonella can survive in these products during their shelf-life, a controlled zone known as the Primary Salmonella Control Area (PSCA) has been proposed (GMA, 2009). Within the definitions noted in this document, the PSCA would be described as a High hygiene area following scenario 2.

The design of high hygiene areas is undertaken on a hazard analysis basis to ensure that all requirements for

the safe manufacturing of the product are undertaken. For example, higher hygienic design standards might be appropriate for the manufacture of scenario 4 and 5 products as compared to scenario 1, 2 and 3 products.

The design of the High hygiene area must allow for the accommodation of five basic, primary requirements, i.e.:

— the processed materials and possibly some ingredients to formulate the product.

— the processing equipment to produce the product and the necessary tools to maintain it.

— the staff concerned with the operation and maintenance of such equipment.

— the primary packaging materials to enclose the product.

— and cleaning equipment.

All other secondary requirements should be considered as unnecessary and, to reduce the number of potential environmental niches for microorganisms wherever possible, should be kept out of the High hygiene area. These secondary requirements include:

— secondary packaging, cardboard, wooden pallets etc.

— structural steel framework of the factory.

— service pipework for water, steam and compressed air; electrical conduits and trunking; artificial lighting units; and ventilation ducts.

— compressors, refrigeration units and pumps.

— maintenance personnel associated with any of these services.

— ‘furniture’ and computers etc. associated with office facilities.

In addition to the requirements of Medium hygiene areas, High hygiene areas must be fabricated and designed to a high standard of hygiene and:

— be physically separated from Medium hygiene food processing areas.

— be as small as is practicable with as few entrances/exits as possible.

— be serviced by staff dedicated to that function only and who enter the High hygiene area via separate changing room facilities or a buffer area in which separate head gear, clothing and footwear are donned.

— have footwear that is captive to and cleaned within High hygiene.

— have transfer points where packaging materials can enter High hygiene, usually after the removal of the

packaging materials outer wrapping.

— have transfer points that are dedicated to the decontamination of ingredient containers, equipment, spares and tools and cleaning equipment etc. entering the High hygiene area.

— have transfer points from which High hygiene waste can safely exit.

— be serviced with segregated (colour coded) equipment, utensils and cleaning equipment.


— have a filtered air supply of a minimum of F7.

— have a balanced air supply such that air does not move from Medium to High hygiene areas.

— should be as small as possible as their maintenance and control can be very expensive (to reduce costs, particularly for any heating, ventilating and air conditioning (HVAC) system).

— have drainage systems that run from High care to Medium or Basic hygiene areas.

Some building elements may be only part of one area but clearly others may be passing from one zone to another (e.g. services (pipes), drainage systems, conveyers, waste). Their impact on the success of the zoning and barriers must be considered and adequate preventive measures chosen.

More stringent hygienic design requirements could include:

— a HEPA filtered air supply of at least E10.

— a positive pressure of a minimum target value of 2 Pascals under all operational conditions (processing, production downtimes, cleaning etc.).

— separate drainage systems which flow directly from High hygiene to external collection drains.

— arrangements for any condensate from freezing or chilling equipment to be safely led to drain, preferably

in Medium or Basic hygiene areas.

For some food products e.g. the drinks industry, High hygiene areas may incorporate the requirements for ‘clean’ and ‘ultra-clean’ filling, which may require additional control measures such as:

— a supply of HEPA filtered air directly over the food product, particularly at the point of filling.

— further physical segregation of the process line with access to the line only via glove ports.

— packaging decontamination.

Aseptic areas

Aseptic areas or machines process products which have received a sterilisation process (>6 log reductions of microorganisms including spores) and are susceptible to the growth of pathogens during their potentially extended shelf-life. Aseptic areas are designed to eliminate microorganisms in the product, the product packaging and all open areas immediately surrounding the product during filling and sealing. In addition, all other services to the filling zone (air, gasses, cleaning fluid etc.) are sterile.

Aseptic machines may be installed in either Medium or High hygiene areas dependent on a hazard analysisassessment to determine the risk of microbiological hazards exterior to the aseptic machine.

7.1.3 Zone barriers

Factories should be constructed as a series of barriers that aim to limit the challenge of hazards on the factory and on subsequent processing zones. The site reduces the challenge of hazards on the factory envelope. The factory envelope reduces the challenge on the Basic hygiene area. Segregation between Basic and

Medium hygiene areas reduces the challenge into the Medium hygiene area. The Medium hygiene area reduces the challenge onto the High hygiene barrier. The High hygiene barrier reduces the challenge into the High hygiene area.

The concept of area or zones within a food processing facility, and the barriers which separate them, are summarised in Table 7.1.1.


Table 7.1.1 - The range of potential areas or zones within a food manufacturing facility and the barriers between them. The number of manufacturing zones required will be dependent on the

food product produced.

Site barrier Security fencing, gatehouse

Site Grounds, driveways / boundary roads, effluent treatment facilities, rubbish

tips/trash management areas.

Maintenance workshops, storage tank areas etc. located outside the factory buildings.

Building envelope

Foundations, floors, walls, roofs, air filtration

Non-food production area

Areas not associated with manufacturing processes e.g. offices, utility rooms, locker rooms, toilets, rest rooms, canteens, laboratories.

Food production area barrier

Physical barrier from non-food production area. Ideally one entrance to plant. Develop concept of “You are now entering a food production area”. Food area protective clothing to be worn and handwashing to be undertaken.

Basic hygiene areas

Any manufacturing area in which raw materials and/or finished products (within their primary packaging) and packaging/labelling materials are received, sampled or stored prior to despatch.

Areas in which raw agricultural products are sorted and cleaned.

Areas in which waste is handled.

Designed to minimize spillage, minimize product harbourage and avoid cross contamination.

Basic GMPs and GHPs apply.

Medium hygiene barrier

Basic physical segregation by means of walls and doors. Hand washing is required on entry to Medium hygiene area. Requirement for operative footwear or clothing change on a hazard analysis basis.

Ingredient preparation area

Area in which all legislated food handling activities are undertaken.

Areas in which animals are slaughtered and dressed.

Areas where products are subjected to further processing and are known to have the potential to be contaminated.

All GMPs and GHPs apply.

Food safety risk is low.

General processing area barrier

Basic physical segregation by means of walls and doors. Hand washing is required on entry to general processing area. Requirement for operative footwear or clothing change on a hazard analysis basis.

General processing area

Area in which raw materials are received, sorted, and sampled.

Area within the plant where products susceptible to contamination and/or microbial growth are processed, treated or handled.

Areas in which animal carcasses are cut into fresh meat products. Areas in which vegetables and produce are packed.

Further separation of ingredients and packaging stores, wet and dry processing


areas and areas for specific ingredients e.g. allergens may also be required.

All GMPs and GHPs apply.

These zones can also be the intermediate area to a High hygiene area.

Food safety risk is medium

High hygiene barrier

Physical segregation via walls, floors, air and drainage. Entrance of products via a decontamination step. Entrance of packaged, decontaminated ingredients via an outer packaging decontamination step. Controlled packaging entry procedures. Entrance of utensils, tools, equipment etc. via a decontamination procedure. Personnel entry via a changing room, SAS, sluice, etc. where captive footwear and clothing is donned.

High hygiene area

Any manufacturing area where microbiologically decontaminated ingredients or formulations are sampled, handled or further processed and where such activities expose the product to microbiological contamination and where such products may allow the survival or growth of spoilage and pathogenic microorganisms and where these food products are intended to be consumed as supplied without a heat cooking step, e.g. ready to eat.

The degree of hygienic design required for the High hygiene area is dependent on a risk analysis of the products to be manufactured in this zone.

Food safety risk is high.

Aseptic barrier Aseptic barriers prevent the ingress of all contamination into the aseptic area or machine.

Aseptic area or machine

A sterile filling zone in which sterile product can be filled into sterile containers.

7.2 Storage areas

Food

Storage rooms must be available for the hygienic handling and separation of food, ingredients, packaging and hazardous chemicals.

Food storage facilities should be designed and constructed to:

— permit adequate maintenance and cleaning.

— avoid pest access and harbourage.

— enable food to be effectively protected from contamination during storage.

— provide an environment which minimises the deterioration of food.

— enable unimpeded movement to all parts of the warehouse such that effective stock rotation can be easily carried out.

— segregate allergen-containing products during storage, where required.

— locate dry stores away from wet areas.

Cold storage facilities must meet the following requirements.

— Sufficient refrigeration capacity must be available to chill, freeze or store chilled or store frozen the maximum anticipated product throughput with allowance for periodic cleaning of refrigerated areas and to maintain product temperatures within specification under worst case ambient temperature.

— Each freezer and cold storage compartment used to store and hold food (and any heating facilities) capable of supporting growth of microorganisms shall be fitted with an indicating thermometer,


temperature measuring device or temperature recording device and should be fitted with an automatic control for regulating temperature or with an automatic alarm system to indicate a significant temperature

change in a manual operation. Doors must be able to be opened from the inside.

— Cold store walls shall be effectively insulated to prevent condensation on the other side of the walls. Freezers, cold rooms and chillers are normally constructed of prefabricated wall and ceiling sections with internal lining finishes constructed of anticorrosive materials with a smooth, light coloured finish.

— Temperature control units and fans shall be equipped with condensate catch pans with trapped drains connected directly with the waste system for use use during defrosting of refrigeration coils.

Consideration should be given to the requirement for anti-slip floors and any drainage requirements. Refrigeration and freezing equipment must be installed in a room separate from food handling, processing and storage areas.

— Thawing of product must be undertaken in equipment and rooms designed with adequate drainage and environmental moisture control to prevent condensation.

— Adequate product loading and unloading facilities must be provided and must also be sealed and protected from the weather by covered bays, an awning or other suitable means. For refrigerated products,

the loading and unloading bays shall be designed to allow transfer of products between the cold store and the refrigerated vehicle with the least exposure to ambient temperature and with the least possible handling.

The need for deboxing-debagging areas for the removal of external packaging should be considered.

Liquid or dry raw materials and other ingredients received and stored in bulk form shall be held in a manner that protects against contamination. Storage tanks, bins and silos shall be constructed of suitable materials and be fitted with suitable, close fitting covers and, if vented, the venting shall be designed and maintained so as to not contaminate the contents.

Packaging

Packaging materials should be stored in a designated, dry area separate from raw materials and finished product, and in such a manner that the packaging is not exposed to a risk of contamination.

Ancillary items

Food premises must have adequate storage facilities for the storage of items that are likely to be a source of contamination to food including chemicals, clothing and personal belongings. Storage facilities must be

located where there is no likelihood of stored items contaminating food or food contact surfaces.

Waste

Waste material (refuse/trash) stores are to be designed and managed in such a way as to enable them to be kept clean and where necessary, free from animals and pests.

7.3 Personnel areas

Within the factory building, there must be suitable and adequate staff facilities and amenities for changing, washing eating and resting. Staff facilities (e.g. restaurant, canteen, recreational area, smoking area) must not lead into food processing areas directly. Where catering facilities are provided, they should be designed and suitably controlled to prevent contamination of the food product. Where provided, designated smoking areas shall be isolated from production areas to an extent that smoke cannot reach the product.

As a means of entry to a food processing environment, a simple changing room layout is shown in Figure 7.3.1 which illustrates a number of good practice points. These include:

— Toilets are placed before the changing area. This is undertaken to ensure that food operatives only go to the toilet whilst wearing their street or civilian clothes.

— On arriving at work, food operatives are likely to have contaminated clothing, footwear and hands, with such contamination having arisen from the home and the journey to work. On entering the changing area, outer clothing is removed and street footwear is placed in racks in a boundary wall or bench. Hairnets can be donned at this point so that loose hairs are not dislodged on the food manufacturing side of the barrier(Figure 7.3.2).


— Operatives than step over the bench/low wall into the washroom areas and immediately wash their hands (a bench/wall may be omitted in Medium hygiene areas). The three primary routes of staff external

contamination (clothes, footwear and hands) have now been controlled.

— Operatives then put on factory protective clothing and footwear. The dress and appearance can be checked in non-glass mirrors.

— Operatives then enter the food manufacturing area via a hand disinfection station, usually an alcoholic hand rub.

— At the end of the work period, operatives enter the washroom area and discard their factory clothing and footwear. Clothing can enter a laundry room whilst footwear remains captive to the food production area and is cleaned and disinfected in a separate area.

— Operatives then step over the barrier, change into their street clothing and then use the toilet facilities (rest room), go to the canteen or recreational areas or leave the building, etc.

— The wall or barrier thus defines the start of the food manufacturing area and, via only wearing factory clothing past this point, reinforces personnel hygiene requirements and prevents cross-contamination from non-food production areas.

Figure 7.3.1 - Basic layout of a changing room area which aids hazard removal from food operatives as they enter a separate, distinct, food processing area.


Figure 7.3.2 - Lockers with sloped roof top, and a step-over bench in front. All junctions with the floor are coved.

In more specific detail, the changing room arrangements should provide an adequate number of flush lavatories connected to an effective drainage system. An example of the number of lavatories (toilets, sanitary conveniences) that should be available is given in Table 7.3.1. Lavatories are not to open directly into rooms in which food or packaging is handled, nor into rest rooms or changing rooms. Essentially, after using the toilets, there should always be two hand washes prior to re-entering production areas; one within the toilet washroom and one at the entrance to the production area. No toilet facilities, other than hand wash basins, shall be located in HIGH HYGIENE areas. Sanitary conveniences must have adequate natural or mechanical ventilation and ideally be under negative pressure.

Adequate changing facilities for personnel should be provided of a size to allow the storage of personnel effects and street clothing. Lockers for storing outdoor clothing must be separate from those for storing work clothes. In addition to toilet and handwashing facilities, personnel should have access to showers where appropriate. Changing facilities should be sited to allow personnel direct access to the production, packing or storage areas without the need to walk through any external areas wherever possible.

Table 7.3.1 – Suggested number of lavatories, urinal stalls and hand wash basins per number of staff employed

Staff number Number of sanitary conveniences

Men Women

Lavatories Urinals Wash basins Lavatories Wash basins

10 1 1 1 1 1

20 1 2 2 2 2

40 2 3 2 3 3

60 3 3 2 4 4

80 4 4 3 6 5

100 4 4 3 8 6

120 5 5 4 9 7

140 5 5 4 10 8

180 5 6 5 11 8

Add 1 lavatory, 1 urinal and 1 wash basin for

every 70 persons in excess of 280 persons

Add 1 lavatory, and 1 wash

basin for every 35 persons in excess of 280 persons

Hand hygiene is essential in food manufacturing and the provision of hand hygiene facilities is usually a legal requirement. An adequate number of permanently installed wash basins must be available in toilet and washroom areas and be designated for washing hands only. Wash basins must be:


— Suitably located, e.g. at each entry point to the processing area and within the washroom. Essentially, if operatives go to the toilet they should wash their hands twice (in the washroom and on entering the

factory) before commencing food handling duties.

— Of a size that allows easy and effective hand washing but discourages washing of other items, and constructed out of stainless steel or similar non-corrodible material.

— Fitted flush to the wall (with no crevices) or set at least 5cm away from the wall to facilitate cleaning.

— Fitted with trapped waste pipes leading directly to drain.

— Provided with hot and cold running water, with mix valves as appropriate, materials for cleaning hands and

for hygienic drying.

— Knee, foot, elbow or automatically (hand contact-free) operated.

Whilst disposable paper towels, hot air and high velocity air dryers are acceptable for drying hands, reusable or multiple use towels should not be used.

Where necessary, the facilities for washing food, equipment, utensils and containers shall be separate from the hand-washing facilities.

The overall design philosophy of the changing facilities or washroom area should facilitate cleaning. The washroom should have at least one floor drain, to which the floor is sloped to (Graham, 2005) and toilet bowls, urinals and handwash basin should be ceiling or wall hung (Figure 7.3.3).

Changing facilities for personnel are to be provided when moving from one risk area to another. With regard to operatives in High hygiene areas, personnel facilities and requirements must be provided in a way that minimises any potential contamination of High hygiene operations. The primary sources of potential contamination arise from the operatives themselves and from Medium hygiene operations. This necessitates

further attention to protective clothing and, in particular, special arrangements and facilities for changing into High hygiene clothing and entering High hygiene areas.

High hygiene footwear should be captive to High hygiene; i.e. it should remain within the High hygiene area, operatives changing into and out of footwear at the Medium/High hygiene boundary.

Figure 7.3.3 – Toilet and cubicle divides mounted from the walls to facilitate cleaning

Boot baths and boot washers should not be used (unless mandated for safety reasons to prevent operative slips and trips) as they are unable to remove all organic material from the footwear treads, such that any pathogens within the organic material remaining are protected from any subsequent disinfectant action. In


addition, boot baths and boot washers can both spread contamination via aerosols and water droplets that, in turn, can provide moisture for microbial growth on High hygiene area floors.

The washroom and changing room layout for the Medium/High hygiene area changeover is very similar to that of the outside/Basic or Medium area changeover with the following considerations:

— The barrier to divide Medium and High hygiene area floors is a physical barrier such as a small wall (approximately 60 cm high), that allows floors to be cleaned on either side of the barrier without contamination by splashing etc. between the two.

— The washroom should be constructed within a double door arrangement to help maintain positive air pressures within High hygiene areas.

— Where the entrance to a High hygiene area is via another food processing area, the entrance should not have toilet facilities. Toilet facilities should always be outside food production areas.

— Within dry processing operations, there is an option to have hand washing sinks on the Medium hygiene side of the Medium/High hygiene barrier. This eliminates the need for water on the High hygiene side, but requires High hygiene area operatives to remove High hygiene area clothing before crossing the barrier to wash their hands. High hygiene area clothing is then donned on re-entry. This may be difficulty to

effectively manage.

7.4 Cleaning facilities, equipment and chemicals

Adequate facilities must to be provided, where necessary, for the cleaning, disinfection and storage of working utensils and equipment. Such facilities should be adequately separated from food storage, processing and packaging areas to prevent contamination and be constructed of corrosion resistant materials, be easy to clean and have an adequate supply of hot and cold water.

Cleaning agents and disinfectants must be stored separately, in clearly identified containers, from areas where food is handled. A separate lockable area inside a food handling, ingredient or packaging store is not acceptable.

Cleaning chemical stores should:

— be sound, dry, well ventilated, frost proof, have ease of access and have sufficient light to enable the operator to read the label.

— be designed so that drainage from this area must be contained in the event of a hazardous spill.

— be secure (lockable), with controlled access.

7.5 Food washing facilities

Adequate provision is to be made, where necessary, for washing food that is separate from hand washing and equipment washing. Every sink or other facility provided for the washing of food is to have an adequate supply of hot and/or cold potable water and be kept clean and, where necessary, disinfected. There should be no possibility of any back-flow of drained liquids.

8 Building Fabric

8.1 Foundations

The provision of hygienic wall and floor finishes is not possible if there is any movement in the building structure which would cause such finishes to move or crack to form microbial and other hazard harbourage sites. The formation of surface cracks in building elements should be avoided by the right choice of techniques, materials and certified workmanship.

Foundations are one of the most important structural members. They are responsible to lead loads and forces (actions) from and impacting to the building in a safe way into the building ground. Foundations shall be designed to guarantee stability and structural safety of the entire building structure and should be concrete based (avoid wood, brick, and block foundations).


The loads and forces impacting on a structure are divided into permanent and variable actions (loads). Stability of a building or structure means:

— No settlement of the entire structure which leads to a “disconnection” of (utility) lines such as cables, water, waste water, No different settlements are allowed which lead to cracks in a building structure or to vertical misalignment.

— The structure shall not tilt (over) and due to horizontal actions (earth/water pressure) nor slide horizontal or on inclined soil layers.

— The foundations should take into consideration the vibrations and harmonics that may be produced by the equipment needed for the installation.

Due to the permanent and variable actions the sub soil (building ground) underneath the foundation will be compressed and result in a vertical offset, called settlement. The compaction consists of elastic and plastic components. Special attention is required for buildings where the variable actions are much higher than the permanent actions (i.e. silo - empty/filled). Depending on the planned building structure and usage, the existing ground, and based on the foundation proposal of the geotechnical expert (Sub Soil Investigation Report), the foundation design should be developed and calculated by a civil engineering professional.

A geotechnical investigation of a construction site in accordance EN 1997 (Eurocode 7) is a requirement for a reliable civil design and construction and obtains detailed information about the soil on which a building/ structure shall be erected (e.g. kind of soil, load bearing capacity, level of groundwater, contamination).

The key code for geotechnical design is with the following content:

Foundations should be at least 60 cm / 24 inches below grade and should be coated with asphalt waterproofing. Adequate planning for storm water control should be undertaken, including the installation of

drain tiles around the foundation perimeter.

Foundations should also be designed to prevent the access of pests to the building. For example, to prevent rodents burrowing under the floor slab, entry of rodents can be prevented by pouring a concrete L-shaped foundation 610-915 mm below grade or ground level, with a horizontal slip extending 300 mm out from the base (new building, Figure 8.1.1), or with a curtain wall of concrete or 0.457 mm thick galvanized sheet metal of the same dimensions (existing building).

8.2 Pile Foundations

Pile foundations are a category of special foundations and are generally applied:

— to transfer the load of a building or a structure to a solid, load bearing layer of subsoil;

— to support a foundation by friction forces of the piles against the subsoil;

— to absorb a horizontal or uplift load;

— to compact a loose layer of granular soil

The decision of applying pile foundations instead of foundation plates or block foundations is based on the subsoil examination and the expert’s report. Pile foundations are commonly used if no or insufficient load bearing capacity of the subsoil is available, or these factors are combined with a high level of groundwater. E.g. commonly pile foundations are used on subsoil consisting of loose sand or soft clays and silts. Further applications are constructions in port and water areas, were the above-mentioned circumstances are mostly combined.


Figure 8.1.1 - Pest proofing measure to prevent entry through foundations

8.3 Superstructures

After constructing the foundations, the structural members are the backbone of a building, since they are the main load bearing elements. Their task is to distribute all vertical, horizontal and dynamic loads and forces (actions) from, and impacting to, the building in a safe way into the foundations. The design shall guarantee the functionality, stability and structural and operational safety of the entire building structure and these elements together with the foundations forms the largest part of the construction works.

The following features guarantee maximum stability of a building or structure.

— The structural members shall bear the loads and actions as designed.

— Floor slabs bear loads which are impacting to surface areas (small equipment, live loads, maintenance). Loads will be distributed to (horizontal) beams, walls or other load bearing constructions.

— Beams take loads from floor slabs, equipment and piping. The loads will normally be distributed to columns or other compression-loaded vertical members.

— Columns have, especially in structures without walls, a load-bearing function. Vertical loads will be lead directly to the foundations.

— Walls can have a load bearing and/or an enclosing function. Additional they can be used to brace the building against horizontal loads (wind, horizontal impacts).

— Catastrophic load cases such as fires and earthquakes must be taken into account in the structural calculations and construction practice.

Vertical elements should be:

— Of steel or reinforced concrete - but without accessible routes for passage of contaminants or pests and oriented to minimise accumulation of dirt and debris.

— In sufficient numbers - suitable span distances are required to prevent weak points, which could crack and become residue collection sites and/or harbourage for pests.

— Flush with the interior side of adjacent walls - to reduce residue collection.

— If not built into the walls, a gap of 15 cm / 6 inches should be provided between framing and walls.

— Not of open steel structures with H or I type profiles in Medium and Hgh hygiene areas - which have large areas where dust and residues can accumulate and are difficult to clean (Figure 8.3.1).


— Protected by galvanizing or plating e.g. with zinc, particularly in wet manufacturing areas. Exposed steel structures are only suitable for processes with lower hygiene requirements.

— Connected to masonry walls - with minimal risks of crack development, thereby minimizing dust accumulation points and possible harbourage sites. To improve connections with masonry walls, steel columns can be embedded with concrete - but then the wall to column connections must be easy to clean:

o for Basic hygiene areas - H or I type profiles should be filled at floor level with concrete (pitched at 60°)

o for Medium and High hygiene areas - columns or walls should be embedded in reinforced concrete to about 60cm high - slanted at the top (Fig. 8.3.2).

o to prevent broken edges from becoming a source of hygiene problems, especially in food processing areas, walls and columns should be protected with steel angles to a minimum height of 1.5 m, if exposed to heavy traffic.

Figure 8.3.1 - Unhygienic and hygienic steel structures: in medium and high hygiene areas, horizontal ledges where dust can settle should be avoided. Horizontal ledges may be appropriate in basic

hygiene areas following a hazard analysis including the need for cleaning.

Figure 8.3.2 - Medium and High hygiene areas – columns should be embedded in reinforced concrete to about 60cm high,slanted at the top.

Horizontal elements:

The concrete floor slab must be properly designed by a structural engineer in accordance with building standards to meet the stresses of the in-service environment.


— Suspended and re-enforced concrete floor slabs on the ground floor - should meet the following requirements.

o Sloped dependent on drainage requirements.

o Joint cracks must be avoided between the slab and building, especially where there is the potential for rising humidity and where residues could collect in the cracks.

o Rising moisture can lead to failure of floor material. If local instructions are not available, the German DIN 18195 can be taken into account to protect the building from humidity and water. To protect the ground floor slabs from rising moisture, a damp proof membrane should be installed below the concrete floor.

o Ideally slabs should not contain pits or trenches.

o Hygienic voids can exist for suspended sewage piping and can become places where contamination can be harboured, insects such as cockroaches can accumulate.

o Access for maintenance and inspection must be provided if the void cannot be eliminated.

o The insulation of floor slabs in freezers is essential to prevent freeze/thaw degradation of the slab. Specialist advice should be sought for the design of such slabs.

— Floor slabs on upper floors should have good joints, without cracks that can harbour residues.

Joints in floor slabs should meet the following requirements:

— All joints in the substrate concrete (e.g. joints in floor slabs or walls) will need to be continued up through the floor finish. To avoid cracks on tiled floors between the joints, an anti-crack membrane should be used between the concrete floor and tiles. Since joints are maintenance items and are weak points in floors, every effort should be made to minimise the number of joints, and those that are required should be positioned in less critical areas.

— Expansion joints must have special attention. Although flexible, they should not be made of material that accumulates residues. Expansion joints ideally should be placed at the high points of the floor.

— Metallic joints across floors can be difficult to clean. Epoxy type floor covering (or brick tiles, etc.) should be employed to prevent corrosion and surface damage to concrete.

— Shrinkage control joints are often sawn into general floor slabs, producing a 6 metre grid of joints. A well designed slab with adequate steel reinforcement can minimise the need for such joints.

The following are requirements with respect to the application of damp proof membranes.

— If required membranes can be installed beneath concrete/screeds on suspended floors to protect production areas below from possible moisture ingress and on ground floors to ensure containment and protect the environment.

— Care should be taken in detailing the membrane at the wall/edges to facilitate the installation of coving and ensuring a leak path under the floor is not created. Membranes on suspended (upper) floors should be laid to falls to drain.

— To minimise the risk of cracking, concrete/screeds on top of membranes or insulation must be properly designed by the engineer to accommodate the stresses of the in service environment.

8.4 Secondary Steel

Secondary steel structures are not part of the main load bearing structures. They are intended to allow maintenance and operations in a safe manner. Secondary steel structures are used by employees (platforms, stairs, and ladders) or as fixation of smaller equipment (piping, cabling, and ventilation/HVAC) at/on other (main) structural members.

Their task is to distribute all vertical, horizontal and dynamic loads and forces (actions) from and impacting to the supports in a safe way to the main structure of the building. The design shall guarantee the functionality,

stability and structural and operational safety of the entire equipment (fit for purpose). The loads and forces impacting on a secondary steel structure are split in permanent and variable actions (loads).

The hygienic design requirements for secondary steel structures are the same as those for the load bearing structures.


8.5 Roofs

Roofs may become a major source of microbial pathogens, primarily derived from birds that roost on the roof or feed on food debris discharged through air extracts. All routes of contamination from the roof into the building, either via personnel access, air intakes and inadvertent leakage, should therefore be controlled. Specifically, roofs should:

— be designed in accordance with drainage Standards (EN12056 part 3), have emergency drains and heating elements in cold areas where freezing may occur

— provide a barrier against infiltration, be waterproof and be easily cleanable

— have good construction and protection at expansion joints or building connections to prevent infiltrations. Roofs should be hermetically sealed under all weather conditions, formation of condensate on the inside of the roof should be prevented by adequate ventilation.

— all roof openings (e.g. vents, air intakes, exhausts) should be kept to a minimum and must be properly protected against ingress of water (rain), debris and pests. No protruding ledges or architectural elements which may attract birds (Figure 8.5.1) . Bird spikes can be used to prevent perching as appropriate.

— allow for uncluttered installation of utilities externally to the building envelope (Figure 8.5.2)

— access to outside roofs and structures should be from outside the plant.

Figure 8.5.1 - Non weather- and waterproof asphalted roof. Liquids may leak to the inside through the many crevices in the asphalt barrier. The roof does not allow adequate drainage and cleaning. Roof openings are unscreened, permitting ingress of rain, debris and pests. Many horizontal ledges may

provide an optimal platform for nesting of birds, and the cluttered installation of utilities makes it easy for rodents to hide.

Figure 8.5.2 - Uncluttered installation of utilities externally to the building envelope, with sufficient clearances between all utility piping and the roof, hence allowing proper access of cleaning and

maintenance.


Roof drainage

— Roofs should be sloped to a minimum of 1-2% to ensure positive drainage. Specific minimum slopes apply to roofs with and without transfer joints (figure 8.5.3)

Figure 8.5.3 - Roof pitches for roofs with and without transverse joints

— For flat roofs, water can be transported in channels on the roof over the hygienic areas (Figure 8.5.6), and

then lead into a gravity or vacuum/siphonic system outside the hygienic areas (Figures 8.5.4 and 8.5.5).

— In case of flat roofs, down spouts should be present. Down spouts should be equipped with bullet-nosed

grates that project upwards to prevent blocking.

— All down spouts should run externally of the building envelope (Figure 8.5.7). If this is not possible, they should run outside hygienic areas.

— Downpipes must always be secured through traps that help prevent rodents entering the building through the downpipes (Figure 8.5.8).

— Horizontal roof drainage piping should be kept away from food processing areas.

— Methods to prevent condensation should be used on internal pipework.

Figure 8.5.4 - Siphonic vacuum roof drainage transports rain water in horizontal water filled piping under the roof which reduces pipe size and amount of downpipes in hygienic areas.


Figure 8.5.5 - Gravity roof drainage is the traditional system which if combined with roof channels (Figure 8.5.6) transports water in downpipes outside hygiene areas.

Figure 8.5.6 - Roof channels can help in avoiding rain water downpipes in hygiene areas. Channels can be made of roof material or stainless steel

Figure 8.5.7 - Hygienic drainage of a ridge and valley roof with external downpipes


Figure 8.5.8 – Access of rodents to the roof can be avoided by inserting a ‘rat stop’ into the roof drainage downpipe

Roof Cladding

The roof has to meet substantial protective functions against the following exposures: changing weather conditions, increased environmental pollution, structural-physical exposures and mechanical stresses. A number of roofing formats are possible.

Insulated single sheet roof

The single corrugated sheeting if externally insulated, is usually called a warm roof and is the most commonly used type for roof construction for industrial application. The span of the corrugated steel sheets can be vertical, leading over purlins from roof ridge (highest point) down to the eaves (lowest point) or horizontal, usually laid as a continuous beam from roof truss to roof truss and usually installed (one sheet is spanning over more than 2 trusses). The supporting structure of the roof consisting of purlins and trusses is usually made of steel, preferably hot galvanized steel. Technically concrete beams are also possible.

Non-insulated single sheet roof

Due to the operational and environmental situation the single sheet roof can also be designed without insulation, although this is recommended for buildings where no condensation will occur, e.g. rooms with high room temperatures during operations and basically no shut-down periods (e.g. Spray Dryers).

Insulated double sheet roof

Insulated double sheets and non-ventilated roofs are very reliable over several years, they are easy to maintain and durable. Its installation is almost independent from the weather conditions.

From bottom to top, the roof structure consists of load-bearing lower sheeting from corrugated steel, a vapour barrier, a spacer for thermal separation, the thermal insulation and the upper sheeting. A separate roofing membrane is not installed. The lower load-bearing sheeting can be installed in any direction horizontally or vertically though to ensure that the roof is water and wind proof, the upper sheeting must be installed in vertical direction from the roof ridge down to the eaves.


Raintight architectural design details for the required interfaces at the roof ridge and the boundaries, as well as for cut-outs for piping penetrations and roof light domes/smoke evacuation vents, are available from the

suppliers.

With an insulated double sheeting roof, all requirements from the building physics (thermal and noise insulation, energy savings) can be solved, providing that the vapour barrier is installed with accurate and tight connections to interfaces and obstacles. Reliable solutions for the vapour barrier are warm or cold processed bituminous membranes.

Roofs with sandwich elements

The main advantage of the sandwich sheets compared to a double sheet roof is increased load bearing capacity with simultaneous high thermal insulation properties. Moreover, roof sandwich elements bear low maintenance costs, and are long lasting.

Material combustibility and any associated issues relating to insurance of the building for fire risks should be considered and all local building regulations should be met. Sandwich elements form an innovative roof system and contain in one element all of the layers required for a fully functional roof such as:

— load bearing layer (bottom)

— vapour barrier

— thermal insulation

— tightness against water (rain, snow)

— airtight building shell

Sandwich elements usually consist of corrugated steel sheets (outer shell) of different thicknesses (depending on loads and span) and a core of PIR (polyisocyanurate) foam or mineral wool (Rock wool), with visible or invisible connections/fixings.

On applying sandwich roof elements filled with mineral wool, it shall be considered that all seams on the inner shell are airtight closed (vapour barrier). During installation the walkways shall be covered with load spreading covers.

At the exposed parts such as verges, eaves and ridges or roof openings, the connections between the inner shell of the roof and the wall elements respectively the inner shall of the roof and the fitting parts of roof openings shall be installed airtight.

A smooth single ply of thermoplastic membrane (PVC, flexible polyester or polyolefines), resistant to animal fats and other chemicals, is recommended over processing areas so they can be swept, hosed off and kept cleaned with minimal effort (Figure 8.5.9).

Figure 8.5.9 - Fully sealed and protected roof that is easily cleanable.


Ballasted Roofs

Roofs containing stone ballast (Figure 8.5.10) should be avoided in the food industry as they are not cleanable.

Figure 8.5.10 - Uncleanable ballast roof

Similarly, ‘green’ or ‘environmentally friendly’ roofs, which sustain the growth of grasses and other plants, have hygiene implications. These roofs must be fully sealed from the building, have external drainpipes and all access to the roof should be from outside the building.

8.6 Floors

Floors provide the foundation for safe, hygienic food production in factories. The hygienic design and installation of floors to ensure a correct level of ongoing hygiene is thus critical and must be undertaken as part of an integrated plan. Such an integrated plan must take consideration of:

— the requirement for protection of the floor from any traffic and spillages within the building

— falls to drain to ensure that all fluids generated by the process and cleaning are effectively removed from the process area

— the prior installation of drainage elements

— the requirements for the installation and supporting of process equipment

— the requirements for effective kerbing and supports for walls

— the requirements for installation of doorways and thresholds

— the requirements for the installation of effective barrier protection systems

— the requirements for the health and safety or food operatives, particularly with respect to slips and trips

— the relationship between the choice of floor surface and the characteristics of the food products and process.

Floors are critical areas, for example they are places where Listeria monocytogenes are likely to be found and where the bacteria could persist despite cleaning and disinfection [1-3]. Slipping accidents correspond to around 20% of work place injuries. For these reasons, slip-resistance and hygiene are mandatory. According to the EC regulation 852/2004 “floor surfaces are to be maintained in a sound condition and be easy to clean and, where necessary, to disinfect. This will require the use of impervious, non-absorbent, washable and non-toxic materials unless food business operators can satisfy the competent authority that other materials used are appropriate. Where appropriate, floors are to allow adequate surface drainage”. According to the European Directive 89/391/EEC employers are responsible for implementing a process of prevention of accidents. As collective protective measures must be taken before individual protective measures, floors in greasy and/or wet food processing areas should be rough enough to avoid slipping accident.


The food and beverage industry contains a wide range of environments which can be very challenging to floor coverings. In particular the floor may have to meet requirements for chemical resistance - against acids, alkalis,

oils, fats, cleaning products and disinfectants - and process - for abrasion resistance, especially against the small hard wheels widely encountered in the food industry - and for temperature and thermal shock resistance.

If the floor is not resistant to the in service conditions, it will be damaged, degrade or fail and will not be able to meet the other requirements of the floor, such that it is easy to clean and provides a safe and attractive working environment.

Repairing a failing floor often involves high costs, not least in the management times and lost production

involved. Good floor design and selection of materials to meet the technical performance and durability requirements can minimise maintenance and remove the need for future repair works.

All joints and edges on floors, and connecting equipment / fixtures to floors must be sealed. In wet areas floors should drain easily. Floor drains must be connected to a drainage system. The design of drainage systems is covered in section 8.7.

Poor hygiene of floors can be expressed at three levels:

1. Failure of floor installation. For example drainage across the floor may be inadequate leading to ponding of water with associated microbiological and health and safety issues.

2. Failure of floor interfaces. For example, if drains are not installed correctly, gaps may appear between the channels and the floor finish leading to the ingress of moisture and microbiological issues.

3. Failure of the flooring material. This may be related to potential excessive absorption of moisture by the flooring materials per se or the development of surface features which can retain soil and microorganisms, e.g. the formation of gas bubbles which burst during the laying of the material or the exposure of voids within the materials due to wear or the opening of joints in a tiled floor.

The control of hygiene of floors is thus complex and is reflective of the initial installation of the floor, interfaces of the floor (with e.g. drains, equipment, barriers, kerbs), the correct selection of flooring materials and the effect of wear.

It is clear from the above that the quality of workmanship during the installation of the chosen floor finish is critical to the performance of a floor. Care should be taken in selecting flooring contractors and guidance from the flooring manufacturer should be sought in this regard.

This chapter shall give guidance on good floor design and finding the right floor material to meet all the requirements for different hygienic areas in food or beverage production facilities.

Falls and tolerance

In wet areas undrainable, standing water (ponding) upon the floor should be prevented as floors then become

unsightly, unhygienic and potentially slippery. Liquids evaporating to dryness on the floor become chemically more aggressive and so reduce the life of the floor. In addition, scale deposits can build up on the floor which are difficult to remove and which might harbour bacteria.

The required fall depends upon the activity in the area under consideration, whether a floor is permanently wet, whether it is dry, the frequency and nature of any spillages, the frequency and methods of cleaning. Generally more textured floors will require steeper falls to be free draining.

Good surface tolerance is required to avoid standing water. Floors should be specified such that over a 3 mlength, a tolerance of 3 mm under a 3 metre strait edge, or better, is acceptable. A simplified method to check the efficient runoff of water from sloped areas is using a sufficient amount of water. The area shall be

completely free of standing water after about one hour. No ponds shall remain.

Floors in dry production areas should normally be flat <1%, (< 10 mm/m) for ease of construction; slopes in wet areas should be up to 2% (< 20 mm/m); extreme falls should be avoided (Figure 8.6.1). Generally a fall of 1.5% (15 mm/m) provides a largely free draining floor. It should be noted that especially in greasy environments steeper falls will require a more slip resistant surface to ensure worker safety.


In tiled floors there should be close tolerance between adjacent tiles, tile lipping should be avoided.

Figure 8.6.1 - Floor sloped towards the drain

Joints

All joints are weak points in a floor and will become maintenance items. Joints should be positioned away from areas subject to regular discharge of liquids from vessels and in locations where they are accessible for inspection and maintenance. Some floor materials require joints at certain intervals, while many resins and

vibrated tile floor materials can be laid in very large areas without joints provided that the substrate concrete is jointless.

Joints will be required to accommodate thermal and vibrational movements in the floor to prevent random cracking of the substrate.

Typical situations where joints are required include:

— boundaries between different substrates

— boundaries between different floor materials

— to isolate load supporting columns set in the floor

— around ovens and other process equipment

— adjacent to channels

— around areas subject to thermal shock

Care should be taken to avoid perimeter joints adjacent to walls where a coved skirting is required.

Joints must be designed to accommodate the anticipated movements. The width (and depth) of the joint will depend upon the amount of movement expected and the flexibility of the joint sealant. Joints must be properly detailed with a closed cell packing rod (backing material) to achieve the required sealant depth and to allow the sealant to move freely (Figures 8.6.2 and 8.6.3).


Figure 8.6.2 - Good movement joint detail without steel edge protection (for non-traffic areas)

Figure 8.6.3 - Good movement joint detail with steel edge protection (for traffic areas)

All joints must be regularly inspected, and in the event of the joint sealant splitting, delaminating or degrading, the sealant should be removed and the joint refilled with fresh sealant.

Floor materials selection criteria

A wide range of chemicals are encountered, both strong acids and alkalis are used for cleaning. Products and ingredients, flavourings and essences can also be very aggressive as are bleaches and other disinfectingagents used to maintain hygiene. Chemicals can be divided into a few basic groups.

— Oils and fats: vegetable oils for example can degrade some resin systems. When vegetable oils and

animal fats oxidize they can form organic acids, see below.

— Organic acids: many animal and vegetable products are naturally acid. Spirit vinegar is widely used in cleaning and is very aggressive.

— Mineral acids: nitric acid, sulphamic and phosphoric acid in particular are widely used for cleaning purposes.

— Alkalis: sodium hydroxide (caustic soda) in particular is widely used for cleaning. In CIP areas it can be

particularly aggressive due to the strength and temperature of the solutions employed.

— Solvents: alcohol is also used for disinfecting. Some essences, for example peppermint oil, can behave like solvents and be very aggressive.

— Disinfectants: sodium hypochlorite, peracetic acid, hydrogen peroxide as well as organic disinfectants can be very aggressive, particularly undiluted solutions.


— Salts: salt solutions do not normally damage floors unless at high temperatures.

— Sugars: strong solutions at high temperatures can be very aggressive due to their high specific heat

capacity resulting in extreme thermal shock.

It is important that the nature of the cleaning and disinfection chemicals, ingredient and product spillages are known when choosing a floor covering. Frequency and size of any spillage together with the concentrations and temperatures help determine the suitability of floor finishes.

Thermal shock resistance

Sudden temperature changes, resulting from accidental spillage or deliberate discharges of hot water and oils

from plant and equipment or from steam and high temperature cleaning, can be very damaging to floors. If not designed to accommodate the thermal stresses and movements created, the subfloor can crack leading to failure of the floor material.

Thermal shock can cause complete delamination of floor materials or micro-cracking in the surface of resin floors, and can erode cementitious floors and cause the failure of joints in tiled floors.

The temperature, frequency and magnitude of any spillages should be taken into account when choosing a

floor material taking special attention to its thickness which has to be high to reach high thermal resistance.

There are no flooring materials that can withstand any significant spillage of cryogenic materials - e.g. liquid nitrogen. Normally cryogenic liquids are safely contained within the process plant and should a significant leakage occur, this is likely to damage the floor underneath and necessitate a localised repair. If there is a regular dripage onto the floor in one location the floor should be protected with a stainless steel drip tray or plate.

Mechanical resistance traffic and load

Traffic ranges from light foot traffic to heavy fork lift and pallet truck movements. Tray racks and bins on small hard wheels are very aggressive, especially when concentrated at doorways, for example. Loads from heavy machinery and tanks (steel feet, vibrating machines) must also be taken into account when designing the subfloor.

The abrasion resistance and mechanical durability is influenced by a number of factors, in general terms thicker floors last longer, especially where there is heavy, or frequent hard wheeled traffic. The weight of traffic

in terms of both frequency and load, especially hard wheeled traffic, should be taken into account when choosing a flooring material.

Hygiene

Floors should be capable of being easily cleaned with industry standard cleaning equipment chemicals andtechniques. This will require dense and impervious systems such that soil remains at the surface where it can be readily removed by cleaning. Cracks (whether caused by structural or thermal movements, impact damage or poor adhesion) are likely to provide harbourage for bacteria. When delamination also occurs water can penetrate underneath both tile and resin floors leading to fouling and rapid floor failure.

Cementitious and very lean resin floors are often porous or rely on a thin seal coat for their hygienic properties, which can be relatively short lived in service. Porosity can also be caused by chemical attack or extreme thermal shock in some flooring systems.

Other floor damage caused by impact, scratching or gouging actions on the floor surface may also have a negative impact on floor hygiene. Surface defects are also caused by the crushing of weak aggregates and aggregate pluck out. Bubbles sometimes appear at the surface of resin floors as a result of the mixing and curing process which may also affect the hygienic properties and cleanability.

Micro-defects can be detected under a stereomicroscope at × 40 magnification with double lighting. Counting undesirable features over a 100 cm² area is advised to select floors. The number of defects should be kept to a minimum (Carpentier, 2011). Furthermore aggregates should not be easily detached by simply scratching them with a metallic object. Some micro defects are illustrated in Figures 8.6.4and 8.6.5.


Figure 8.6.4 - Bubble holes in a heavy duty polyurethane floor covering, cross section.

Figure 8.6.5 - Top view of undesirable features in new flooring materials by scanning electronic microscopy. Top row from left to right (large scale): bubble hole in a resin based floor, a crumbled aggregate in an epoxy resin, cracks around an aggregate in a ceramic tile; Bottom row from left to

right (small scale): hole due to a removed aggregate in an epoxy resin, hole in a ceramic tile, an acrylic cementitious flooring that was wrongly applied (Carpentier, 2011).

Slip resistance and tread safety

Tread safety has to be provided to the staff to help prevent accidents. It should be noted that to prevent slips, trips and falls an adequate level of cleaning, good working practices and appropriate footwear are also required.

Because of the amount of oil/fat and other food products that get onto the floor of food factories, slip resistant floors are required to help provide a safe working environment. The degree of texture / slip resistance necessary will vary widely throughout a food processing facility and will depend upon the level and frequency

100 µm

____

20 µm

__


of spillage, the frequency of cleaning, the type of traffic and the work activities that take place in that location. Floors with high difference in slip-resistance should not be positioned adjacent to each other. When walking

from a smooth floor to a rough one, people may be destabilized which increase the chance to fall.

In resin floors anti-slip properties are usually obtained by inclusion of large aggregates (with size in the millimetre range) which increase floor roughness. These can be sprinkled on the mortar before curing (multi-coat systems) or be incorporated in the mortar prior to application (one coat systems). Thin antislip coatings that are applied after the base mortar has cured should be avoided as they are short lived in trafficked environments.

With multi-coat systems the size, nature and amount of aggregate incorporated into the surface have a significant impact on the durability of the slip resistant profile. Fine aggregates <0.75 mm provide relatively short lived profiles where there is hard wheeled traffic. Quartz/silica aggregates are relatively weak and are eroded by hard plastic and steel wheeled traffic. The use of granite, basalt, silicon carbide, bauxite and other hard aggregates will help retain the slip resistant profile over a long service life.

Multi-coat systems normally require a finishing/encapsulation coat to round out the valleys of the texture in

order to provide a cleanable surface.

On tiled floors antislip properties are obtained either by the inclusion of aggregates in the surface or by forming (moulding) a structure in the surface during manufacture.

There are several procedures to measure slip-resistance: the German standard DIN51130 (ramp test which is applicable in laboratory only), the EN13036 Pt 4 (pendulum test which can be applied both in laboratory or in situ) or measurement of the coefficient of dynamic friction which is applied in France either in laboratory (NF S 73.010 designed to test slip resistance of shoes) or in situ with a portable friction tester (CNAM, 2011). There is no European agreement on the best method to assess slip-resistance. Different methods lead to different and sometimes contradictory floor classification, and requirements are different from one state to another.

The type of surface profile on the floor will determine the most appropriate cleaning regimes. Squeegees are not appropriate to clean heavily textured floors. In greasy and wet areas profiled floors are best cleaned with industrial means such as an industry standard scrubber drying machine.

Aesthetics

The aesthetics of the floor is also a consideration. A good looking floor creates the right environment that encourages operatives to maintain that environment to the required standard.

The use of colours can also be used to assist in the demarcation of different hygiene zones and to control the movement of personnel and traffic helping to improve safety and reducing the risks of contamination.

Durability/longevity

A failing floor is neither hygienic, safe nor attractive and could lead to contamination of foodstuffs or accidents. If a floor lacks the required durability the surface will be eroded and become unhygienic.

If a floor is to be long lived it must have the necessary chemical, temperature and mechanical resistance. A short lived floor will require a high level of maintenance.

Repairs of floors needs to be managed carefully to prevent contamination of product. The area may be at chill (or freezer) temperatures, it may be wet or contaminated. There may be product or raw materials as well as plant and equipment in the close vicinity and the needs of production may severely limit the amount of time for flooring works. In many cases it will be necessary to close production and remove plant and equipment in order to carry out floor repairs. Generally the long lived floor is the safest and most cost effective option.

Floor fixings

Plant and equipment often needs to be mechanically fixed to the floor.

For very big pieces of equipment, large anchors are often required that go deep into the substrate concrete (Figure 8.6.6). These are usually installed prior to the application of the floor finish, and the bolts protected


during the installation of the floor. In most circumstances the floor is installed first, the plant positioned on the floor and then secured with holding down bolts. This involves drilling through the floor finish into the substrate

concrete and installing holding down bolts. Such bolts should be made of the same quality of stainless steel as the plant and should be secured into the floor with resin anchors ("injection mortars") which reinstate the integrity of the floor. Mechanical anchors should not be used as they may create pathways for chemicals and other contamination to penetrate into the subfloor. The void underneath the foot plate of plant fixed (anchored) to the floor should be filled, at the time of installation, with a resin mortar or sealant.

For light pieces of equipment, a small footplate fixed directly to floor can be used as shown in Figure 8.6.7.

Figure 8.6.6 - Large footplate onto anchors cast into substrate concrete and subsequently grouted

Figure 8.6.7 - Small footplate fixed directly to floor with resin anchors


Figure 8.6.8 – Footplate attached to 30cm high sole or plinth

Flooring materials

There is a wide range of resin, cementitious and tiled floors available on the market.

It follows that the actual performance of the floor finish will depend upon the manufacturer, the actual specification, and the quality of the installation. The purpose of this section is to give some guidance to the relative advantages and disadvantages of the various types of finishes. This information which is summarized in Table 1 can only be of the most general nature.

Cementitious

Power floated concrete floors

— A well finished and polished concrete floor can look very attractive and is a good floor in Basic hygiene areas and other warehouse environments.

— Being cementitious it is porous and cannot be used in food and beverage processing areas.

— Chemical resistance is poor especially against acids and sugars which will erode cementitious floors.

— Abrasion resistance will depend upon the concrete mix design but is normally inferior to resin or tiled floors.

— When used in warehousing care should be taken to avoid trafficking of fats, sugars or other food products into the warehouse which can lead to chemical attack of the concrete.

Polymer modified cementitious floors

— Styrene butadiene rubber (SBR) or acrylic polymers are used to modify a cementitious screed to reduce shrinkage, reduce porosity and improve the chemical resistance.

— These are typically installed at 10 - 20 mm thick. Curing time to put into service is typically 3 - 5 days.

— Its big advantage is its ability to apply to substrates with high moisture content and with rising moisture, (e.g., where a damp proof membrane is missing or has failed). This property facilitates repair.

— These floors are not acid resistant. In service the cement matrix is often etched away exposing the aggregate which results in a highly slip resistant floor. It is widely used in abattoirs where large amounts of material fall to the floor. Resistance to hot running water and thermal shock is limited.


Resin floors

Not all resin floors, even if based upon the same chemistry, have the same performance. There may be big variations in chemical and temperature resistance, the choice of different aggregates will affect slip resistance, and the durability will be influenced by resin content, by resilience and by thickness. In general floors with larger aggregate have better scratch resistance and are more durable, especially where there is hard plastic or steel wheeled traffic. The tougher the largest aggregate in a system the more durable the floor. The more resilient the resin floor, the better the impact resistance. Brittle materials are more likely to crack under impact.

Epoxy resin floors

There are three main types of resin floors:

i. thin coatings of < 1 mm which should only be used in plant rooms or service areas as they are easily damaged and are not appropriate to process area floors.

ii. flow applied systems (self-smoothing floors) ~ 2 -3 mm thickness which can be broadcast to produce slip resistant floors.

iii. trowel applied screeds ~ 6 mm thick. Two types of products are encountered. (1) Semi-dry mortars

have a low resin content such that the spaces between the aggregate particles in the mortar are empty. Such mortars rely upon a thin surface seal coat for their hygienic properties. Should this surface layer be damaged moisture can quickly ingress into the floor. As these semi-dry mortars are

easily rendered they are often used for coved skirtings but are not recommended for floors. (2) Resin rich systems are also available where there is sufficient resin to fill all of the spaces between the aggregate particles and produces a mortar that is dense and can provide a robust floor finish.

Generally these floors are attractive and are available in a wide range of colours; some yellowing occurs in UV light, especially in paler colours.

Curing time to put into service is typically 1 - 3 days, but can be much longer at temperatures below ~ 12°C.Generally, they require a dry substrate, but moisture tolerant primers (so called surface damp proof membranes) are available to enable application to damp substrates. The chemical resistance is limited especially to organic acids which severely limits the life expectancy in many food environments. Temperature resistance is limited to < 60

oC. Mechanical resistance can be limited

especially in thinner systems.

Thin epoxy systems are not recommended in wet areas as long term / frequent water exposure tends to result

in delamination from the substrate. Generally epoxy resin floors are appropriate for dry floors in light to medium duty environments including warehousing.

Polyurethane floors

These are flow applied systems typically 2 - 3 mm thickness which can be broadcast to produce slip resistant floors. The main benefit of these floors is their flexibility which means that they can be installed on more dynamic substrates and are less likely to crack in the event of movements in the substrate. Generally these floors are attractive and are available in a wide range of colours. Non-yellowing versions are available but this

normally relies upon a topcoat. Otherwise yellowing occurs in UV light.

Curing time to put into service is typically 1 - 2 days depending upon temperature and humidity. Generally, they require a dry substrate, but moisture tolerant primers (so called surface damp proof membranes) are available to enable application to damp substrates.

The chemical resistance is overall similar to epoxies but they have better resistance to organic acids. Temperature resistance is limited to < 60

oC.

They are not recommended in wet areas as long term/frequent water exposure tends to result in delamination

from the substrate. Generally polyurethane floors are appropriate to dry floors in light to medium duty environments including warehousing.

Heavy duty polyurethane floors

Heavy duty polyurethane systems (also called Water dispersed polyurethanes, PU-concrete or PU-cement systems) are installed at thicknesses from 4 - 12 mm thick and may be flow applied, trowel applied or multi-


coat broadcast systems. The resins yellow quite strongly in UV light and a limited range of strong colours are used to help hide the yellowing affect.

Curing time to put into service ranges from ~5 hours to 2 days depending upon the system.

Substrate moisture tolerance varies from product to product, some require a dry substrate (or a moisture tolerant primer) others can be installed directly onto early age concrete or other damp substrates.

Thermal shock resistance depends on floor thickness, 9 mm floors with temperature resistance up to 120°C are available. The chemical resistance is generally good against all the chemicals typically used in the food industry. Generally polyurethane floors are appropriate for process floors in medium to heavy duty

environments including warehousing.

Heavy duty polyurethanes work well in permanently wet environments.

Polymethylmethacrylate floors

Polymethylmethacrylate floors (also called PMMA, MMA, Methylmethacrylate, Methacrylate or Methacrylic Floors) are normally installed as coloured quartz systems from 2 - 6 mm thickness. They provide attractive floors which are non-yellowing in UV light. These are often hard, brittle floors with limited impact resistance. They are rapid curing and can be installed at minus temperatures down to –30

oC depending upon product.

Generally they require dry substrates but moisture tolerant primers are available. The liquid resin monomer is highly volatile with a low flash point ~ 10°C and a strong odour that can affect the taste of foods in adjacent areas during the installation.

Temperature resistance is limited to 70°C for thicker systems. The chemical resistance is comparable with epoxy resin bases systems, but resistance to organic acids is especially limited, which severely limits the life expectancy in many food environments. Hot vegetable oils can melt through PMMA floors. Generally

polymethylmethacrylate floors are appropriate to floors in light to medium duty environments.

Ceramic Tile floors

Tiles vary in shape, size, thickness, density and chemical resistance and are available in a wide range of colours; tiles are colourfast against UV light and chemicals, they are inert and do not off-gas.

The resistance against thermal shocks and to mechanical loads depend on the thickness and on the size of the tile that is used. Tiles >320 cm² should not be used as it is essential to fully embed tiles to the substrate, otherwise they would crack under load. Smaller tile sizes also allow easier creation of slopes.

Tiles which are suitable for industrial applications can be classified into extruded tiles (also called “split tiles”), dry pressed clinker tiles and fully vitrified porcelain tiles. For all heavy duty areas, e.g. with forklift or pallet traffic or heavy machinery placed on the floor, a tile thickness from 18 mm is suitable; for light duty areas a tile thickness of 12-15 mm can be adequate.

The performance of a tiled floor also depends upon the method and quality of installation. A common, fast and economical way for industrial tile floor installation is the so-called vibration installation. This installation method creates perfectly even floors with very small joints. As tiles need to be very size accurate for butt-jointing in vibration installation, only pressed tiles are suitable for this method of installation. For all tiled floors in food and beverage industries it is essential to minimize lipping of tiles.

Tread safety is either rolled onto the tiles (extruded tiles) or pressed into the tile body (pressed tiles). The harder or less porous a tile is, the less effect abrasion has. With pressed tiles there should be no loss of tread safety from usage.

Chemical resistance of tiled floors can be fully provided for all chemicals and liquids that appear in food and beverage industries, this depends on the type of grout used for the joints (epoxy resins, vinyl-esters). It is necessary to fill the joint between tiles completely to the bottom, also the top of the joint is best at the same level as the tile (Figure 8.6.8). Cement grouts are only suitable for Basic hygiene areas as they are porous and not resistant to many chemicals Resin grouts are the essential hygienic choice for all food processing areas.


Generally tile floors can be used in all dry and wet processing and traffic areas. The smaller the joints in tiled floors are, the better these tiles perform in wet areas. The thicker the tiles are, the better the performance is for

heavier loads.

Figure 8.6.8 - Incorrect (top) and correct (bottom) jointing of tiles

Hexagonal tile floors (ry-pressed fully vitrified porcelain)

Unglazed, dry-pressed fully vitrified porcelain tiles exhibit the lowest micro-porosity of all types of tiles.

— For industrial use they are available in thicknesses from 15 to 18 mm.

— Due to the hexagonal shape, they offer some key advantages for industrial use: traffic rolls over tiles at acute angels to the tile edges so that impact loads are further reduced compared to rectangular or square tiles.

— Drainage also becomes very efficient as hexagonal tiles can be laid in envelope designed floors without edge lipping.

— The small size of a tile of about 100 cm² provides best adhesion to the subsurface and therefore highest point load capability.

Tile Norm: EN 14411, Group BIa

Norms:

AGI S10 – Protection of Structures Against Chemical Attack - tile floors

AGI S20 – Protection of Structures Against Chemical Attack - Coating Systems

AGI S40 – Chemically resistant vibrated floor surfaces

Dry-pressed fully vitrified porcelain tile floors

These tiles are from the same tile classification group as the hexagonal tiles and provide the same characteristics. They are found around the world in many different sizes and are used also as residential and sanitary ceramics.

— Basically the same product is used for industrial projects, but thicknesses should be 18 mm for heavy duty and wet production areas, and between 12 and 15 mm for light duty areas - never below.

— These tiles are fine-ceramic, very size accurate and produced with a prefabricated spacer so that they can mm or butt-jointed by the so-called vibration installation.

— Noise and impact loads on tile flanks are minimized and the life performance of the floor is increased.

— Due to the narrow joints, which do not wash out, the floor becomes virtually seamless.

Floors made of 18 mm thick tiles provide temperature resistance >150°C.


Tile Norm: EN 14411, Group BIa

Dry-pressed clinker tile floors

Pressed clinker tiles have been used in the food industry for a number of years but are now not seen as the state of the art. Pressed clinker tiles are analogous to extruded tiles in that they are coarse-ceramic with high porosity.

— They are available in thicknesses from 15 mm and provide good chemical resistance for all chemicals seen in food and beverage industries. They are also suitable for traffic and heavy duty areas.

— As these tiles are pressed, the size accuracy is good so that the joint width can be reduced to 3-5 mm,

meaning that noise and impact loads on tile edges are reduced and the life performance of the floor increased.

— Due to the high porosity of this tile, the cleaning capability is reduced over the lifetime - black staining of the tiles show this and they are thus not seen as the best option for hygienic areas.

Tile Norm: EN 14411, Group BIb

Extruded tile / Split tile floors

— Similarly, extruded tiles have been used in the food industry for a number of years but due to the high porosity of this tile they are not seen as the best option for hygienic areas and the cleaning capability is reduced over the lifetime - black staining of the tiles show this.

— Extruded tiles are available from about 6-8 mm thicknesses, while sufficient thicknesses for commercial and industrial use are from 18 mm.

— These tiles provide good chemical resistance for all chemicals seen in food and beverage industries. They are also suitable for traffic and heavy duty areas.

— Extruded tiles are not very size accurate so that these floors are laid with 6-10 mm wide joints. When moving over these floors with e.g. hard plastic wheels, a chattering sound occurs and can cause cracking due to the constant impact on the tile edges. This can cause floor failure leading to hygiene failure.

— It is very difficult to keep grouting at the same level as the tiles, as the joints are often washed out in wet production and can cause hygienic failing of the floor.

Tile Norms: EN 14411, Groups AIb, AIIa, AIIb, AIII (depending on water absorption percentage).

Other floor materials

Sheet flooring systems, vinyl, linoleum, rubber, may be appropriate to very small scale operations for example sandwich bars and other retail food handling. Critical to the hygienic performance of these materials is the effective sealing of joints and that they are easily cracked after the fall of a sharp object. Panels systems should not be used. These materials are not generally appropriate for modern industrial food processing, but may be appropriate to laboratory and amenity areas.

There are a number of other flooring materials that have historically been used in food handling areas but which are unhygienic and not generally considered appropriate for modern food processing facilities, these are briefly covered below.

i. Asphalt and other bituminous materials can be suitable for dry warehouse areas but note that they will soften in contact with animal fats and vegetable oils.

ii. Concrete terrazzo floors are suitable for dry warehouse areas. See notes for “power floated concrete floors” above.

iii. Natural stone floors would need to have the joints properly filled and grouted to provide a hygienic surface. Inert and impervious stone such as granite may be appropriate in some areas. Marble is

porous and has very limited resistance to acids and is not recommended.

iv. Wooden floors were historically used in flour mills for example, but are no longer considered appropriate and should not be used.

A summary of all flooring material properties is given in Table 8.6.1.


Application

The workmanship is a very important fact at all floor materials. Dryness of the substrate and of the atmosphere must be respected according to the manufacturer‘s recommendations (for example, recommendation for the climate above an uncured epoxy resin is classically 3°C above the dew point). Time for full curing must be respected.

It is very important that the specified floor thickness is maintained at all times. This can be verified by checking the coverage rate. After installation it can only be measured by taking core samples.

Floor repairs frequently involve a disruption to production which can be costly so it is important to choose the best floor for the application and ensure that it is installed to a high standard by an experience specialist contractor.

The best option is to ask the manufacturer of the flooring materials for specialist installation companies who are familiar and experienced with the specified product.


8.7 Drains

Drainage of effluents generated in the food production process is a critical requirement for any building, especially so in relation to food production facilities. Drainage should be considered holistically from a site perspective as the site and each subsequent level of analysis has potential impact on hygienic operation.

The drainage system can either be a point - or a linear drainage system, or a combination, depending on the actual circumstances and designed in accordance with EN 12056.

Applications

Internal drainage splits broadly into 3 general applications:

Interception of fluids

The type of drainage selected - gully or channel, will depend on the nature of the operation and its requirements. Channels simplify floor gradients and offer better interception than gullies. Ideally drains should be positioned near the wastewater/fluid source with space allowing access. Where drainage is required from machinery, splashing can be minimised by use of funnels above the drain body which provide an air gap between the drain and the machine water outlet.

The air gap is essential to avoid cross contamination and backflow from the drainage to the machine (Figure 8.7.1). To be fully accessible for cleaning and inspection, drains should not been positioned under machinery.


Figure 8.7.1 - Tundish or funnel directly connected to drain gully grating

Transport of fluids

Transport of contaminated water should preferably be achieved in a sealed pipe system. Use of open linear channel drainage systems lined in tiles or resin have been used in the past but are now no longer seen as a hygienic solution.

Barrier between zones, processes or rooms

Linear channel systems can be used to provide a physical barrier to fluids, and can be used to separate dry

and wet areas (Figure 8.7.2).

Figure 8.7.2 - Linear channels as a barrier


Drainage in specific areas: Dry production areas

Drainage in dry production areas may be required to facilitate occasional wet cleaning.

The dry production can be split into 3 areas:

Dry production with only dry cleaning

In such areas gullies and channels should be avoided. If drainage is unavoidable, it should be a sealed, gas tight system with a smooth surface which can be opened by a vacuum handle for access or disinfection

(Figure 8.7.3). For additional protection against possible aerosol release from drains, a special trap preventing overpressure in the connected drainage piping can be installed. Drains that are used only occasionally should be placed as far away from hygienic production as possible.

Dry production with controlled wet cleaning

In such areas channels should be avoided. Gullies should be sealed and gas tight with a smooth surface which can be opened by a vacuum handle for access and disinfection. For additional protection against possible aerosols release from the drain a special trap preventing overpressure in the connected drainage piping can be installed.

Dry production with wet cleaning

In such areas, channels and gullies should have gratings of a high hygienic standard. The floor should have an adequate slope towards drain. Drains should be placed away from hygienic production areas but close enough to allow efficient drainage of liquids. Linear channels should preferably be kept shallow and ideally placed along a wall.

Figure 8.7.3 - A sealed, hygienic drain for dry production areas avoids aerosols and odour

Drainage in different area

Areas with solid waste on floors such as meat residues

In such cases the drainage system should have a built-in sediment basket to capture solid material. This basket shall be sized with respect to the desired hydraulic flow given the expected amount of waste and expected emptying frequency of the basket. Size and slope should be increased to support transport of solid

waste. The waste should have unrestricted access to the drainage system (Figure 8.7.4).


Figure 8.7.4 - Example of channel with gratings having open sides allowing solid waste into the drain

Areas with CIP systems

Water should be directed into the drainage system by a pipeline. Nevertheless to avoid waste water backflow and to protect line hygiene, air gaps are necessary. The volume and temperature of water must be considered when selecting products and manufacturing materials for the complete drainage system as some materials may soften due to heat.

Multi-storey buildings where drainage is required above ground level

This application needs special attention to prevent contaminated water entering the hygienic areas below such as a membrane or similar construction technique.

Drainage piping should not be visible in hygienic room below. If unavoidable then the piping should be double walled or have a leakage indication system, as well as being isolated it should be insulated to prevent condensation. Machinery and open product should not be placed under the piping.

Pipe penetration through ceilings should be secured against water penetrating to hygienic areas below and made from non-flammable material class A1 according to EN 13 501-1.

Floor drainage, general specification

Floor Drain components should be designed in accordance with the EHEDG guidelines (DOC 13) for steel constructions or EN 1672-2 Figure A3, A4, A11, A13 and A14.

Of relevance to drainage products the following hygienic features can be economically integrated into drainage product design:

— continuous welding of joints

— radiused and rounded corners

— drainability

— no crevices or dead spaces

Features of hygienically poor design and preferred design are shown in Figures 8.7.5 and 8.7.6 respectively.


Figure 8.7.5 - Gully of poor design

Figure 8.7.6 - Gully of preferred design

Drainage materials

Generally, hygienic production areas should have a drainage system that is manufactured from austenitic stainless steel of a minimum grade EN10088: 1.4301 (AISI 304) for both wet and dry production areas as well as storage rooms, however the chemical and physical composition of the fluid may require alternative materials in specific circumstances.

Where hygiene is of concern stainless steel to EN10088: 1.4301 (AISI 304) or above should be used. This

austenitic family of alloys has good corrosion resistance. Higher grades of stainless steel 1.4401/ 1.4571 (AISI 316L / AISI316Ti) should be used in specific circumstances (chlorine disinfection, salt, etc.).

It is important to ensure dip pickle passivation of the drainage components post-fabrication has been carried out as it is described in the EHEDG guidelines (DOC 18).


Hydraulic Capacity

Flow rates in gullies or channels should comply with EN 1253, however both gullies and channels have the useful capability of providing a buffer for short term hydraulic load.

The capacity of the system should be based on maximum flow rate expected plus any allowance for change of use in the future. Capacity also depends on inlet characteristics, such as grating slot size and orientation, and outlet characteristics, such as trap and debris basket influence. The required flow capacity for the specific application is required to calculate the dimensions of the drainage system.

Detailed analysis should be requested from the equipment manufacturer including peak capacity in l/s and period of flow.

Direction of flow

Flow direction should be from High to Medium hygiene areas. Where possible, High hygiene area drainage should run in a separate system until the point of external connection to the sewer. An ideal system allows rodding or jetting access from a point external to the High hygiene area as shown in Figure 8.7.7.

Figure 8.7.7 - Idealised drainage flow incorporating backflow prevention and jetting access

Drainage infrastructure

Generally the drainage system should be positioned as near to the fluid source as possible while ensuring accessibility for inspection, cleaning and maintenance.

Drain position and traffic

Where possible eliminate traffic over gullies and channels (Figure 8.7.8). All production areas with access for trolleys and vehicles must be able to resist applied loads and turning stresses. In cases where heavy traffic is

unavoidable, care must be taken to ensure correct selection and fastening of gully, channel frame and gratings to ensure stability for the specified load.

Rodding / jetting access

High Risk area drainage

Sewer

Automated Backflow valve – highly recommended

High Risk area

Low Risk area

Low Risk area drainage


Figure 8.7.8 - Drain positions for optimum interception and zoning

Load Classes

Load classes for vertical stress should be in accordance with EN 1253, horizontal stress should be achieved through appropriate installation detail such as solid construction and good fastening in the floor.

Gullies

Design of gullies

The gully should have a round body, slopes towards the water trap and must be able to completely drain. The gully must have a removable water trap that allows full accessibility to the pipe system for jetting (cleaning with water jets) and rodding (cleaning via physical scrappers and brushes, both attached to flexible structures pushed or propelled down the pipes).

The size in production areas should have a frame of min. 200x200 mm or OD 200 mm to be able to enable solid waste collection. Gullies can be designed to fit into specific flooring materials such as tiled floors (Figure 8.7.9), resin floors (Figure 8.7.10) and vinyl floors (Figure 8.7.11).

Figure 8.7.9 - Square gully for tiled and resin floors. The square section facilitates tile installation


Figure 8.7.10 - Round gully preferred for resin floors wherever possible as their round profile does not lead to the physical stresses that may occur at the corners of square profiles

Figure 8.7.11 - Drain for vinyl flooring. The drain has a clamping flange for fastening the vinyl in a waterproof hygienic joint

Water traps

Gullies should have a removable water trap. Water traps should have no seals under the waterline and allow easy access for cleaning. When the water trap is removed the drain body can be completely dried out.

Water traps must have their water level maintained to prevent foul odours and possible pest entry.

The capacity of the water trap should be tested in accordance with EN 1253. The water seal height of the water trap shall be of a minimum of 50 mm in accordance with EN 1253.

Use of a ‘P-trap’ (Figure 8.7.12) should be avoided or minimized because:

— There is always retention of polluted water in a P-trap and it is therefore difficult to clean and disinfect

— There are areas which are invisible and cannot be checked

— P-traps do not create an effective rodent or pest barrier

— Access for rodding and jetting is difficult via the P-trap


Figure 8.7.12 - P-trap

Sediment basket

Sediment baskets are necessary to prevent sediment build-up which may block the drain. They should be removed regularly and should be robust in design as they are often subject to rough handling. As with water traps, spare sediment baskets should be kept on-site. Sediment baskets should be chosen with appropriate aperture sizes for the food products manufactured (meat, glass, salads, etc.).

Figure 8.7.13 - Sediment baskets

As the sediment basket is designed to trap particles it also affects flow rate. The design should allow fluids to flow through the sides (Figure 8.7.13), and be hydraulically oversized to ensure the required design capacity of the system is maintained when sediments are present.

Installation of gullies in the floor

The correct installation of gullies in the flooring material is critical, as leakage between the floor and drainage

element is a common problem, causing permanent contaminated moisture around the drain which itself is a source of bacteria.

The drainage frame has to be installed below the final floor level.

Installation of gullies in resin floors

For resin floors a round gully should be used with frame of solid steel, 5-10 mm thick depending on application, to avoid cracks. Gullies have to be secured very well in the floor through anchors. Thickness of flooring material should be increased around the gully, and the sealant specification should be determined by the flooring supplier.

Installation of gullies in tiled floors

For tiled floors a square gully should be used with U-shaped visible edge profile of not less than 1.5 mm thickness of steel. Any edge profile should be filled by the drainage supplier with a waterproof material to resist vertical and horizontal stress and eliminate areas for bacterial growth. The frame height should be deeper than the thickness of the tiles, normally10-20 mm (see Figure 8.7.14). Proper sealant application is important to effectively separate the floor surface from the sub-surface construction.


Anchoring and outside flanges must be adapted to each layout, and anticipated traffic load in the area, and types of membranes used in the floor.

Figure 8.7.14 - Gully frame illustrating ‘U’ shaped edge

Design of channels

Channels should have removable gratings of a maximum length of 500 mm in order to facilitate removal and

enable cleaning. Close attention should be paid to the hygienic attributes of gratings, which should be similar to those for gullies.

Channels should have a lateral slope towards the outlet of the channel (Figure 8.7.15), forming a profile such as a V (Figure 8.7.16) or U (Figure 8.7.17) shape in the base of the channel. Channels should have the same constant slope in the longitudinal direction toward the outlet of the channel of minimum 1 % but preferably more. In areas of high solid waste, effective drainage requires a larger slope.

Figure 8.7.15 - Side view of channel with slope towards outlet

Figure 8.7.16 - Example of V shape channel


Figure 8.7.17 - Example of U shape channel

In general a channel should be produced as a single, purpose made unit and should be straight. If a channel system needs to be assembled on site the channels can be TIG welded by a certified welder and manually pickled, or alternatively assembled by a hygienic joint sealing system. Channel length should be considered if there is the possibility of thermal expansion.

Visible edge profiles must be installed so that they are rigid, which can be accomplished by the thickness of the steel (not less than 1.5 - 2 mm thickness) and the method of installation. The channel frame edge should

be filled by the drainage supplier with a waterproof material to resist vertical and horizontal stress and eliminate areas for bacterial growth.

Channels profiles are designed according to floor type. Examples of channel profile types are as shown below (Fig. 8.7.18 - 8.7.21).

Figure 8.7.18 - Channel profile with infill and anchor and a minimum 10 - 12 mm outside frame for thin layer resin floors and tiles up to 8 mm

Figure 8.7.19 - Channel profile for tiled floors with membrane

Figure 8.7.20 - Channel profile with infill and anchor and with 20 mm highL-profile for tiles of thickness up to 18 mm


Figure 8.7.21 - Channel profile with infill for vibrated tiled floors. This also can be combined with tile L-profiles

Proper sealant quality is important to separate effectively surface of the channel and floor from the space below tiles/resin and channel.

The shape of channel must be supported through crossbars during building process to resist deformation caused by hardening concrete or other installation procedures.

Channels should have access for manual cleaning and allow for complete visual inspection. Narrow slot channels (Figure 8.7.22) should be avoided in areas with a high hygiene requirement, significant solid waste, or large flow.

Figure 8.7.22 - Typical slot channel profile

Adequate outlets must be provided to suit the channel capacity and hydraulic loading of the installation.

Installation of channels

Secure fastening of channels in the floor material is even more important for channels than for gullies.

Installation of channels in tile floors

For tiled floors, it is important that the frame is very resistant to horizontal stress which influences the durability and the lifetime of the flexible sealant. This sealant ensures that no contaminated water is harboured

permanently around the channel. The outside frame should be fixed in the surrounding concrete, not leaving any void space under the system and constructed in a way that no contaminated water can be accumulated under or within the edge profile (Figure 8.7.22, 8.7.23). Depending on the tiling type, the frame should also be able to resist influence from the vibration tools used during installation of such tiles.


Figure 8.7.23 - A high edge profile installation in concrete ensures better hygiene with no void space for contaminated water and better stability as the outside frame is fixed in the concrete layer

Figure 8.7.24 - Example of a poor solution with a low outside edge allowing void space under the profile. The profile is only fastened in flexible sealant giving less stability. When the sealant leaks, void

space under channel profile harbours contaminated water

Fastening channels in resin floors

To fasten channels in resin floors it is important that they are anchored securely in the floor. Therefore the outside of the concrete filled profile should be embedded in the resin or concrete and not just in the sealant (Figure 8.7.25). Frame edge anchors or anchoring rails are recommended in areas with heavy duty or frequent traffic.

Figure 8.7.25 - Frame of channel edge fastened in anchor groove of flooring material. A thicker layer of flooring material around the drain is recommended for resin floors.


Channels constructed from flooring material

In the past it was quite common to form channels using the flooring material, such as resin or tile. Flooring materials are not suitable for carrying gratings. Therefore channels were supplemented by a stainless steel frame to carry the gratings (Figure 8.7.26). None of the solutions are considered as long lasting hygienic solutions because neither flooring joints nor materials are designed for the hydraulic loads imposed in food processing plants which are often hot and chemically aggressive.

Figure 8.7.26 - A channel constructed from the flooring material is not recommended. In this example the tile has loosened due to the influence of hot, aggressive drainage water although the installation

was relatively new (note: grid has been lifted at discharge point to show loose tile)

Gratings

Design of gratings

Gratings should be stainless steel and have a hygienic pickle passivated or electropolished surface. Gratings should be removable and easy to clean. Crevices should be avoided and welds minimised. The grate should allow solid waste to enter unrestricted to the drainage. Examples of hygienic gratings are shown in Figures 8.7.27 and 8.7.28 and unhygienic gratings in Figures 8.7.29, 8.7.30, 8.7.31 and 8.7.32..

Figure 8.7.27 - Cast grating with no welds and rounded corners is hygienic. Open sides allow solid waste to easily enter the drain

Lose tile at discharge point


Figure 8.7.28 - Ladder grate with fully welded bars is hygienic. This grate exhibits good flow properties

Figure 8.7.29 - Typical mesh gratings have many crevices and are unhygienic

Figure 8.7.30 - Perforated gratings are unhygienic and may also keep solid waste on the floor

Figure 8.7.31 - Damaged grating and damaged drain surrounding


Figure 8.7.32 - The grate prevents solid waste to enter unrestricted to the drain. Crevices and dead spaces provide build-up of contaminants

Figure 8.7.33 Circular gratings in resin floors can reduce the effect of impact damage, particularly on corners as shown in Figure 8.7.31

Slip resistance

Generally the surface of gratings can be rougher than other drainage surfaces in order to provide slip resistance. Slip resistance should be similar to the surrounding floor. In the absence of agreed standards on slip resistance it is necessary to request data from flooring and drainage supplier, and choose products with an equal slip resistance.

Access covers:

Access covers for drainage and cleaning wells should be avoided in hygienic areas. The access covers create a hygienic risk and prevent the use of modern pipe cleaning nozzles for pipe cleaning.

If access covers are unavoidable they must be as small as possible and equipped with a reliable and tight seal.

Drainage piping

Drainage piping systems should be designed with swept bends allowing cleaning throughout the complete system through the drains (Figure 8.7.33). To facilitate easy cleaning through drains, a removable water trap

in the gully or channel is essential.


Figure 8.7.33 - A drainage systems consisting of swept bends, 45 degree branches and no p-water traps can be cleaned through the drains

Figure 8.7.34 - Piping layout with swept tees and soft bends which allows mechanical cleaning of piping system or jet cleaning by high pressure hoses through each drain equipped with

removable water trap. This layout allows the cleaning wells to be placed outside hygienic areas reducing risk of spread of pests from the sewage system


Figure 8.7.35 - Piping layout with cleaning wells within hygienic area increases risk of spread of pests from the sewage system when opening the access covers for cleaning

Clogging of drainage piping causes a hygienic risk by possible ponding of contaminated water on the floor. To avoid clogging it is important to:

— have filter baskets to trap the expected amount of solid waste and to describe emptying frequency

— have an efficient piping cleaning system

— the cleaning procedure must accommodate materials that could entry the drainage system, for example fats with melting point above 30°C

— have pipe cleaning integrated in the permanent cleaning procedures

— secure piping material with a smooth surface

— secure a piping material which can resist environmental factors such as heat and cleaning chemicals (Figure 8.7.36)

— secure a piping which is 100% resistant to rodent attack.

Figure 8.7.36 - It is difficult to see a collapsed drainage pipe under the building, but increased blockage is often caused by collapsed piping due to softening through high temperature water from

CIP water, and in a few cases, rodent attack


8.8 Coving, kerbs, posts and barriers

In order to keep walls and doors in a hygienic condition, wall and door protection should be used to protect them against impacts from tray racks, pallet trucks, forklifts, containers, bins, electrical trolleys etc. If the surface of the door or wall becomes damaged, pests and microorganisms may be harboured and, if the surface opens onto a void or absorbent materials, fluids may penetrate which could give rise to microbial growth.

The junction between the wall and the floor is a critical zone from a hygiene perspective and has to fulfil anumber of functions including:-

— prevention of the accumulation of soils and promote the ease of cleaning

— prevention of water ingress into the wall, particularly for sandwich panels

— protection of the walls from damage, particularly from transport systems

— effective separation of one processing area to another at floor level. There should be no possibility for water movement underneath the kerb.

An analysis of traffic movement and service conditions needs to be made to establish the correct level of

protection that will provide a durable and hygienic solution. As a minimum, wall-to-floor junctions must be coved, followed by kerbing to protect against potential light and moderate damage and crash barrier protection for walls and doors.

Coving skirtings

The purpose of coved skirtings is to improve cleanability and hygiene and to prevent the ingress of water into the floor-to-wall junction. Surfaces should be non-porous and easy to clean. All ledges and lips should be avoided and particular attention must be taken in sealing between coving and wall.

Covings can be made of:

— resin floor finish

— coving tiles

— prefabricated coved skirtings

o stainless steel

o polymer composite

o PVC and others

Resin floor finish

The resin render must be non-porous and of sufficient thickness to be impervious to water (Figure 8.8.1). It’s widely used for solid wall and kerbs.

Figure 8.8.1 - Resin floor finish


Coving tiles

Care should be taken to eliminate any voids behind the coving tiles and that all joints are completely sealed (Figure 8.8.2 & Figure 8.8.3). It’s widely used for solid wall and kerbs.

Figure 8.8.2 - Tiled cove detail, complete with tiled floor and wall

Figure 8.8.3 - Coving tiles complete with tiled floor


Prefabricated coved skirtings

Stainless steel

Care should be taken to eliminate any voids behind the stainless steel coved skirting and that all joints are completely sealed (Figure 8.8.4). It’s widely used for panel walls.

Figure 8.8.4 - Stainless steel coved skirting

Resin composite

Care should be taken to eliminate any voids behind the resin composite skirting and that all joints are completely sealed (Figure 8.8.5). It’s widely used for panel walls

Figure 8.8.5 - Resin composite skirting – technical drawing

Kerbs

Kerbs should be designed with a bevelled top edge to aid the run off of water and cleaning products and with a curved or sloped coving to the floor to avoid build-up of dirt. Kerbs should be finished with a smooth, non-porous and easy to clean surface. Kerbs should be filled to avoid hollow spaces and to provide mechanical strength. To prevent water infiltration behind the kerb it is recommended to apply a line of polymer adhesive or silicone as a second water barrier. Joints between the kerbs and wall should always be sealed with a curved food grade silicone seal or two component PU sealant in such a way that water runs off.


Insulated panel walls in particular must be protected from impact damage and when kerbs are not present stainless steel crash bars/protective barriers should be used.

Impact wall protection in food preparation areas can be made from:

— prefabricated polymer composite kerbs with a smooth gelcoat finish

— cast on site or prefabricated concrete kerbs finished with the floor finish

— prefabricated polymer composite kerbs finished with a bonded stainless steel surface

— prefabricated stainless steel kerb filled with concrete on site

The thickness and size of the kerbs vary depending on the size of traffic used inside the rooms:

— hand driven pallets and trolleys up to 1000 kg

o concrete: minimum thickness of 10 cm and a minimum height of 20 cm

o polymer composite: minimum thickness of 6 cm and a minimum height of 20 cm

— electrical trolleys and forklifts up to 1 - 5 ton

o concrete: minimum thickness of 15 cm and height of 30 cm

o polymer composite: minimum thickness of 10 cm and height of 30 cm

In heavy duty areas kerbs should be anchored into the structural floor slab.

The floor to wall internal angle should be rounded or sloped to prevent accumulation of dirt and micro-organisms.


Prefabricated polymer composite kerbs with a smooth gelcoat finish

Prefabricated polymer composite kerbs with a smooth gel coat finish are quickly installed, stronger than concrete and chemical resistant (Figure 8.8.6 & Figure 8.8.7). If damaged by heavy impact, water infiltration is not possible as the polymer composite filling is water resistant. Prefabricated systems are more easily removed if required subsequently.

Figure 8.8.6 - Prefabricated polymer composite kerb

Figure 8.8.7 - Pre-fabricated polymer composite kerbs with a smooth gel coat finish

Cast on site or prefabricated concrete kerbs coated with the floor finish

Prefabricated or cast on site concrete kerbs coated with the floor finish can be made in such a way that a minimum of joints are required (Figure 8.8.8 & Figure 8.8.9). If damaged by heavy impact, water can infiltrate through hair cracks as concrete is porous. Cast on site kerbs are difficult to remove if required subsequently. The resin coating should be of sufficient thickness to resist the abrasion of traffic in use. If damaged it should be repaired promptly to maintain a hygienic finish.


Figure 8.8.8 - Cast on site concrete kerb with resin finish - technical drawing

Figure 8.8.9 - Cast on site concrete kerb with resin finish

Prefabricated polymer composite kerbs finished with a bonded stainless steel surface

Prefabricated polymer composite kerbs finished with a bonded stainless steel surface (Figure 8.8.10 & Figure 8.8.11) have the advantage that water infiltration behind the stainless steel surface is prevented by bonding the stainless steel to the polymer composite core. Corrosion is a risk in areas with a lot of impacts, heavy cleaning products containing chloride and salty conditions. Prefabricated systems are more easily removed if they are required to be subsequently.


Figure 8.8.10 - Prefabricated stainless steel kerb

Figure 8.8.11 - Prefabricated stainless steel kerb and stainless steel wall cladding

Prefabricated stainless steel kerb filled with concrete on site

Prefabricated stainless steel kerbs are often used with insulated panel walls (Figure 8.8.12 a, b). Care should be taken to insure the complete filling of the kerb to exclude voids. Corrosion is a risk in areas with a lot of

impacts, heavy cleaning products containing chloride and salty conditions. On site kerbs are difficult to remove if conditions require.


(a) (b)

Figure 8.8.12 - (a) Prefabricated stainless steel kerb with concrete filled on site (b) technical drawing

Posts and barriers

Walls, doors and other structures such as columns, external wall corners and machinery, need protection to an appropriate height to prevent impact damage from e.g. vehicular traffic and storage containers (Figure 8.8.13).

Figure 8.8.13 - Examples of posts and crash bars to protect wall and door structures

Stainless steel crash bars can be used to protect structures and should have the following dimensions.

— Loads up to 1 ton

o Diameter of a minimum of 100 mm - height of 1000 mm: hand pallet trucks and tray racks, trolleys.

— Loads more than 1 ton

o Diameter of a minimum of 200 mm - height 1000 mm: electrical pallet trolleys and forklifts.


It is recommended to fill hollow tubes with concrete or polymer composite for extra strength (Figure 8.8.14).

Figure 8.8.14 - Stainless steel posts filled with concrete or polymer composite

The stainless steel legs should be fixed into the structural floor slab as a foot plate is difficult to seal and clean. The joints between the crash bar and the floor must be rounded out and sealed with a food safe sealant

(Figure 8.8.15a, b & c). Galvanised steel crash bars (with or without coating) should not be used in food preparation areas as corrosion will appear very quickly.

Figure - 8.8.15a - Insertion of crash bars into floor structure


Figure 8.8.15b - Insertion details. Post is fixated with 2 component epoxy

Fig. 8.8.15c - The joints between the crash bar and the floor must be rounded out and sealed with a food safe sealant

Alternatively, protection bars can be built into preformed stainless steel kerbs if protection at a low height (distance from the wall surfaces) will prevent collision damage at higher heights (Figure 8.8.16). Such structures prevent the need for penetrating the floor structure.


Figure 8.8.16 - Crash barriers built into preformed stainless steel kerbs.

8.9 Walls

Exterior walls

External walls should be weather, water, insect and rodent proof (rodents can gain entrance through a 12.7 mm hole (rats) and 6.4 mm hole (mice). Walls should also be well isolated, contain no cold bridges and be easy to repair. Wall exteriors should not have horizontal surfaces (gradients 45°) (Fig. 8.9.1). External walls are commonly constructed out of concrete, brickwork, steel plating or sandwich panels.

Fig. 8.9.1 - To be insect and rodent proof, wall exteriors should not have horizontal surfaces (gradients 45°)

Facades of concrete

In-situ concrete walls

Walls can be constructed on site (in-situ cast) using a formwork and reinforced with steel bars inside. This

method allows very individual shapes and plan views. In plant construction the walls will be used mostly without any further surface treatment (with exception of painting). The surface has to be smooth and uniform. Therefore a formwork of coated plywood, aluminium or plastics is used.


Prefabricated walls

Prefabricated wall elements are large scale structural members, are produced in plants and workshops and are designed for use as either internal or external walls. The surface of the elements is very smooth and as they are constructed indoors, a higher accurateness and quality is achievable.

Double wallsDouble walls are prefabricated elements which are consisting of two concrete “skins” (thin slabs) connected together with lattice girders and are provided with an in-situ concrete filling after installation. A special type contains an integrated thermal insulation.

Lightweight concrete wall panels

Lightweight concrete wall panels are a part of the solid external wall construction and made of gas concrete. The key advantage of these wall panels are their low weight and the thermal insulation properties. They combine rapid installation with cost-effective building (energy-saving). For their hygienic application in the food industry the installation of special surface coating systems is required to avoid dust and the penetration of moisture in the elements.

Facades of brickwork

Masonry can be executed in sand-lime stone, brick, porosity brick, concrete brick or aerated concrete bricks. Steel cladding may also be applied on the outside as a weather protection shell.

— When laying brickwork for facades moisture-repellent applications such as damp proof course (dpc) foil should be inserted for, e.g. compartments, window and door openings, connections to the foundations and floors.

— Masonry composed of cavity walls for insulation purposes should be filled with rock-wool insulation and be capped at the base and top.

— All other cavities should be avoided and if bricks or blockwork themselves have internal cavities, these should be filled with mortar, at least for the first few courses.

— In brick and grout work, Portland cement should be used.

— Facade masonry should include weep holes. Brickwork should be layed with the necessary expansion joints

— All openings in the brickwork, e.g. for pipe work, should be effectlvely sealed.

Facades for sandwich-panels

Sandwich panels are composite panels of a lightweight core material that bridges between dense, structurally acting, facing materials (Figure 8.9.2) so as to combine high rigidity with a minimal weight. Panel face materials include: steel, aluminium, PVC and glass fibre reinforced polyester and vary in thicknesses between 40 and 200 mm. Core materials include: polystyrene foam, polyurethane foam, polyisocyanurate foam, phenolic foam and mineral wool (foamglass).

Figure 8.9.2 – Sandwich panel construction

Sandwich-panels should be durable, fire resistant and strong and stable and comply with the requirements of the ECCS/CIB European recommendation for sandwich panels. Their selection is dependent on the thickness

and materials of construction of the panels (Table 8.9.1) and the fire resistance of their cores (Table 8.9.2), which affects their thermal insulation properties and their load bearing capacity.


Table 8.9.1 – Sheet thickness and materials of construction

Pre-finished (coil-coated) galvanized steel sheet (0.45 - 0.7 mm thick)

Standard for most food processing areas.

Most economical choice.

Pre-finished aluminium sheet (0.8 - 1.25 mm thick)

Exterior face for roofs and facades, because it is resistant to atmospheric corrosion.

Not suitable in food processing areas

Stainless steel (0.45 - 0.8 mm thick) For highly corrosive and heat exposed environments, such as brine rooms, smoke rooms, etc.

Glassfibre-reinforced polyester (GRP)

ca. 1 mm thick

Resistant against chemical attack.

Especially used in the wet milk and cheese industry.

PVC, > 1 mm thickness Getting less popular for reasons of cost price, fire safety and environmental issues

Table 8.9.2 – Core insulation characteristics

EPS XPS PUR PIR Phenolic Foamglass Rockwool

Fire ratingFlame spreadFire behaviourEnvironment friendlyWater penetrationStructural behaviourThermal insulationRelative cost

0(1)

melts at 80°Cnot an issue

2%poor

excellentvery low

0(1)

melts at 75°Cnot an issue

excellentmediumexcellent

low

0(1)

toxic fumes(2)

excellentmediumexcellent

low

(30 min)acceptablecarbonizes

(2)excellentmediumexcellentmedium

60 min(1)

ask supplierask supplier

excellentrigid

excellenthigh

> 180 minexcellent

stable < 600°Cfair

excellentbrittle, rigid

poorvery high

> 180 minexcellent

stableexcellent

(3)(4)

mediumlow-medium

Notes:

(1) requires flame retardant additives, otherwise inacceptable

(2) foam must be CFC-free (20 year ago, PU-foams contained ozone-depleting foaming agents)

(3) with hydrophobic additive equal to (2%), not suitable for sub-zero (freezer) stores

Sandwich panels can be installed horizontally and vertically (most common) and are typically installed horizontally on facades where lower positioned roofs and facades join together. When sandwich elements are horizontally assembled the vertical joints in the area of structural steel columns are covered by pilaster stripes

with different shapes and colours.

Joints between panels should be sealed with (food grade) joint sealant, e.g. silicon with added fungicide (durable for approximately 5 years) or food grade polyurethane (durable for approximately 15 years). All fittings used to join and assemble the panels should be made of stainless steel. All compartments and openings in the sandwich panels should be properly sealed and if necessary, finished with sheeting of the same coating and colours of the panels.

Facades of customized steel plating

Steel cladding systems can either be of single or double skin. Single sheet cladding is unusual within food factories because of possible condensation problems, though can be used in warehouses and rooms maintained at high temperatures (e.g. spray dyers).

The double layer wall cladding is comparable with the double layer roof system. The load bearing inner layer consists usually of smooth liner trays (C-shape, the outer shell of corrugated profiles for additional stabilization. By using sealing tapes between the inner shell elements the wall can be used as a vapour barrier and for thermal insulation, semi-flexible mineral wool boards are assembled inside the inner shell (C-shape). The outside plate can be coated with a Plastisol- -

a setting, such as a corner fitting, leak thresholds, cornices to provide additional protection.

The outer shell (weather protection) is regularly connected with the upper flange (stiffeners) by fasteners and is acting simultaneously as a stabilization element for the inner shell.


Internal walls

Inner walls can be executed in brickwork, concrete, sandwich-panels, metal sheeted and studded and as movable prefabricated separation walls. All internal wall partitions separating the work areas shall be erected up to the height of the ceiling to eliminate cross-contamination of food products.

Specifically:

— walls must be light coloured

— walls must be dense, tough, impact resisting, durable, rust proof and dust proof and be able to withstand cleaning chemicals and methods used

— walls must be impervious, non-absorbent, washable, water repellent and constructed of non-toxic materials

— smooth and free from cracks and have any joints sealed with an impermeable sealant, unable to absorb grease or food particles or provide harbourage for pests.

— resistant to microorganisms (particularly mould growth), rodents and insects

— walls must be protected from damage by moving equipment by for example, guard rails or barriers,

particularly at corners

— joints at the wall to wall and wall to ceiling junctions and corners are generally rounded or coved and all joints and edges must be sealed, tight fitting and water proof with no cracks or crevices that may provide access for pests and vermin

— when curbs are used to protect walls, they must be high enough to prevent damage by the envisaged transport system e.g. from palette or fork lift traffic. For larger transport systems, curbs >30cm in height of 50-75 mm wide may be required

— the use of mould resistant paint is not recommended due to its reduction in effectiveness over time

— because of absorbance of humidity, the use of gypsum material is not acceptable for process areas.

— openings to over-pressured high hygiene areas should be closed

— insulation, if required, should be placed on the side of the wall located in the area of lower hygienic classification

— horizontal surfaces and sills should be avoided

— walls with a cement render and smooth finish, glazed tiles, prefabricated insulating panels or similar materials are acceptable.

Walls and columns of reinforced concrete in production areas should be executed as profiled concrete. Walls and columns of profiled concrete in production areas should always have a finishing, which should consist of a mould resistant coating that is approved for use in the food production industry. Similarly, masonry walls, particularly in wet production areas, should be suitably finished with a hygienic coating.

Sandwich panel wall joints for internal walls usually run vertically and are designed to withstand pressure hosing.

Wall coverings

Walls can be coated with appropriate waterproof coating technologies

EU regulation 852/2004 on food hygiene states that "wall surfaces are to be maintained in a sound condition

and be easy to clean and, where necessary, to disinfect. " and that "This will require the use of impervious,

non-absorbent, washable and non-toxic materials and require a smooth surface up to a height appropriate for

the operations unless food business operators can satisfy the competent authority that other materials used

are appropriate;”

There are three ways in which this is commonly achieved,

1) To attach a preformed plastic panel /sheet to the wall,

2) To tile the wall,

3) To apply a resin coating system.


Which of these three methods of providing a hygienic finish is most appropriate depends upon a number of

factors including

— whether there is likely to be differential movement between different elements of the wall

— the aggressiveness of the food production environment, for example the likelihood of thermal shock, and

impact the chemical nature of any spillages or splashes

— whether there is likely to be moisture movements passing through the wall, particularly in older buildings

— the flatness and tolerance of the wall to be coated

With all wall systems it is important to avoid creating horizontal lips or edges that can harbour dirt and bacteria

and be difficult to clean, especially at height. The relative strengths and weaknesses of the three options

identified are summarised below.

1) Panels can be made out of a wide range of plastics, common are uPVC and glass fibre reinforced

polyester or epoxy resin. All these panels can provide an easy to clean and attractive finish however the

detailing of edges and joints in the sheets are very critical to the hygienic performance of the wall finish

and there is a risk of creating a void behind any panel attached to a wall which could harbour bacteria and

mould as well as allowing insects and vermin free passage. To minimise the risk of such a void forming

behind a panel sheet, it should be bonded to the wall with a full bed adhesive. All joints should be sealed

properly with a good quality mould resistant silicone sealant. Once sealed these systems are moisture

tight and particular care should be taken in older buildings and where rising moisture is present. Such

moisture can condense on the reverse side of a panel, especially in chill environments, causing softening

of adhesives and provide an environment for biological growth. Because of the number of joints within a

panel wall finish these systems are not suited for use in aggressive environments and are not

recommended for industrial scale food preparation facilities.

Stainless steel pannels can be used in situations of high water use (e.g. wash rooms), high heat levels

and where there is the potentail for high potential wall damage, The same hygiene requirements are

applicable to stainless steel panels as for plastic panels, but extra caution on the sealing of the stainless

steel to the substrate is required, particularly in wet areas. For ease of cleaning, the miicrotexture on the

surface of panels should be less than 8 microns.

2) Walls can be covered with extruded or vitrified tiles, which have the same properties as those used for

flooring (see section 8.6). Glazed wall tiles typically have dimensions of 150 mm x 150 mm and are

approximately 5 mm thick with the tile joints approximately 4 mm. Glazed tiles are more vulnerable to

impact damage than fully vitrified tiles. Extruded tiles generally have dimensions of 110 x 240 mm and are

approximately 10 mm thick with joints of approximately 6 to 8 mm wide. It is important that all tiles are

fixed with full bed adhesive for maximum security of the fixing and to ensure there is no void behind the

tiles. Cementitious adhesives may be used for fixing and are preferred to water based adhesives which

may soften if moisture is present. In all cases an epoxy grouting material should be used to provide a non-

porous and hygienic seal around the tiles.

On outward corners, stainless steel corner protectors should be fitted in the tile work and properly sealed.

Inward corners should be filled with mould resistant silicone sealant. If there are moving cracks, or if

movement is anticipated between different elements of a wall then tiled systems should be avoided as

generally they cannot accommodate such movement and failure will result.

3) There is a wide range of resin polymers used to make hygienic wall coatings including water and solvent

based acrylic resins, polyester, water based and solvent free epoxy and polyurethane resin systems. The

systems available range from thin coatings a few hundred microns thick to fibre mesh or fleece reinforced

systems several millimetre in thickness. These systems are applied directly to the wall, so there is no

possibility of a void being present between the wall coating and the substrate wall. It is important to ensure

that the surface of a rough brick or blockwork wall has been smoothed over prior to application of thin

coatings as any texture will be present in the final surface and make cleaning, especially at height, difficult.

This can be done with a formulated cement based skim coat or with a resin primer designed for the

purpose. There should always be at least two coats applied to help ensure that there are no holes in the

finished coating which would give access to the porous substrate underneath. Many of the systems

available are water vapour permeable which enables them to be applied to substrates with high moisture


contents or rising moisture. It also ensures that any moisture does not get trapped behind the coating,

where it might lead to delamination and damage, but can escape into the atmosphere. A number of the

coating systems available are highly flexible coatings which enable them to bridge moving cracks in the

substrate, which is of particular benefit in older buildings, The best movement accommodating systems

are those that combine the flexible coating with a fibre reinforcement. The fibre reinforced systems are

also able to withstand a considerable amount of stress from thermal shock and impact and so are suitable

for heavy duty applications in industrial scale food processing facilities.

With all three types of wall finishes, panels, tiles or coatings, expert installation is essential. It is important that

the substrate preparation and installation are done correctly and to the manufacturer's instructions, by skilled,

professional applicators if a good result is to be realised. To choose the most appropriate wall finish a clear

description of the key parameters is required:-

1) What is the substrate? How old is it? How strong is it? What preparation is required?

2) Are there any moisture issues? Is a vapour permeable system required?

3) Are there any cracks or movement in the substrate? is a crack bridging system required?

4) Is there likely to be thermal shock?

5) What sort of food/chemicals/cleaning agents might impact the wall?

6) Is the wall likely to be subject to mechanical impact, how tough does the wall system have to be?

Attention should be given to how the wall finish will meet the floor and the proposed detail provided to both

wall finish and flooring contractor. With resin wall coating systems it is possible to bring the wall coating over

the top of the coved skirting to provide an efficient run off from wall to floor without an intervening joint of any

kind.

The manufacturer of the wall coating system should be able to verify that the system under consideration will

meet all these challenges, be able to show some references for inspection and suggest appropriate installation

companies.

8.10 Transport docks

Preventing direct access into the factory at ground floor level reduces the challenge of environmental contamination (mud, soil, foreign bodies etc.), particularly from vehicular traffic (forklift trucks, raw material delivery etc.) and food operatives to food processing operations. This can also act as a barrier to pathogenic microorganisms typically found in the environment, particularly Listeria spp., Bacillus spp., Campylobacter and Clostridia spp. and to a lesser extent Salmonella spp. and E. coli. To facilitate this, the internal factory floors should be higher than the outside ground levels such that there is a physical barrier to traffic (personnel and vehicular). The internal floor level may only be a few cm above outside ground level or, typically in modern

factories, at the height of the loading dock. External vehicles have thus to place their load onto the internal floor as they cannot access the factory. In older factories which have a common ground/floor level, plinths of approximately 15 cm in height and just over a pallet width in depth, can be built at factory entrances which prevent the entry of e.g. forklift trucks, only allowing them to deposit their load on the plinth. Differential factory and external floor levels also control the potential for flooding.

The siting and construction of factory openings should be designed with due consideration for prevailing environmental conditions, particularly wind direction and drainage falls. A canopy over vehicle loading/unloading areas should be constructed so that loading and unloading is not subject to adverse weather conditions. Canopies should be completely enclosed on the underside so birds cannot gain access for roosting or nesting (Figure 8.10.1). The use of dock seals around vehicles may preclude the use of canopies.

Loading docks should be solid structures, built to match the height of the loading bed of transport vehicles. Some dock doors, however, have leveller plates, which can be raised or lowered to match the height of vehicle loading beds so as to allow fork lift trucks to load or unload pallets (Figure 8.10.2). Ideally dock levellers should have no pits under the plates as this pit is open to the outside environment and rodents are able to access the pit and enter the factory by squeezing through the space between the leveller plate and the factory floor. Such pits should be fitted with brush seals. Dock doors should ideally be fitted with dock seals to fully seal the rear of the delivery vehicle, particularly when dealing with chilled or frozen deliveries.


Dock doors may be vertical lift doors, garage type ‘up-and-over’ overhead doors or roller shutter type doors. Wherever possible, door opening and closing should be a safe and rapid process to minimise air and pest

movement into the factory. With doors that are regularly opened, air curtains can be installed to help repel flying insects, or plastic strips/curtains may be used. Air curtains should extend all the way across the door and should be on the outside to direct the air down and out. Strip curtains are suited to packaged food, but not open food products.

Fig. 8.10.1 - Dock doors should ideally be fitted with dock seals and a canopy over the vehicle loading/unloading areas, the latter being completely enclosed on the underside so birds cannot gain

access for roosting or nesting.

Fig. 8.10.2 - Dock doors with leveller plates, which can be raised or lowered to match the height of vehicle loading beds. Factory floor level is a few cm above dock floor level. Access should be

available for cleaning and pest control activities.


8.11 Doors

Doors play an integral role in building design by helping to segregate production areas whilst presenting a barrier to contamination such as dirt, insects and other pests and vermin. However, as food products have to move through doors, there is a possibility that contamination can drain, drip, diffuse or be drawn into the product from door surfaces. Doors must, therefore, be hygienically designed.

General/ factory layout

— A minimum number of entrances and exits to processing areas should be adopted to reduce the potential for contamination.

— Doors should be high and wide enough to allow movement of vehicles and product without coming into contact with the door or jamb.

— Door closing systems are important in relation to hygiene in entries for traffic. Personnel entries do not need such systems.

— The closing plates of the door lock should be fitted flush into the frame, to avoid gaps and sharp edges.

— Doors should be easy to clean and, where necessary, to disinfect.

— Doors should have a good inspection access.

— Doors should be self-closing and equipped with kick plates and push plates.

— Sliding doors should have all gaps closed between the door and the frame closed with gaskets of rubber or bush stripes. (No brush strips in High hygiene areas).

— Escape doors: use security sealed panic bars and/or alarms (21CFR Part 110.37(2C), 21 CFR Parts 110.10, IS 324-1997).

Construction standards

Doors should:

— not have hollow spaces; the hollow should be foam filled with PU (polyurethane)

— be easy to clean (open equipment)

— be able to withstand cleaning

— not be constructed from wood, other absorbent materials or hollow profiles. Wood is not suitable as it is vulnerable to rodent attack

— have tight fitting frames and lack of gaps at floor-to-door contact will be necessary. The maximum of clearance of less than 6 mm is needed

— interfacing of doorframes with walls and floors must be smooth and contain no cracks and holes were dirt and insects can be harboured

— avoid the use of windows. If present they should be polycarbonate or reinforced glass. Window ledges should be avoided

— not have an inverted U channel at the top that acts as a dust and dirt trap

Material/door surfaces should be:

— light coloured

— of nontoxic material

— washable

— dense/ impervious

— non-absorbent/water repellent

— unable to absorb oils and grease

— able to withstand cleaning chemicals

— tough and impact resisting

— durable

— rust proof

— dust proof (stofdicht)

— resistant to damage by the thermal conditions


Door/floor interfaces

Doors should have a close fitting to the floor, with a maximum clearance of 6 mm. The closing device must not collect residues. The bottom seal is not able to compensate large gaps without being damaged by continually rubbing on the floor (Figure 8.11.1). Therefore the floor area below the doors should be well constructed and levelling devices which have hollow bodies should be avoided.

Figure 8.11.1 - Unsealable gap between door and floor if floor levels are not maintained

Best practice is to install a door with a threshold (Figure 8.11.2). This ensures that there never will be a gap between the seal and the floor. A proper adjusted door will protect the sealing from rubbing, creating a lasting gap free door. Doors with thresholds have to be mounted before the floor is built.

Figure 8.11.2 - Door threshold installation

Exterior doors/essential openings in the envelope

Exterior doors must be primary barriers to infestation and ingress of dust etc. Doors and other apertures should be self-closing. If they were opened for ventilation, they must be protected by fine screens. Stand alone plastic strip doors should not be used because they are not efficient barriers. They can be used, however, as a backup for external doors as they are effective in keeping out birds and flying insects.

External doors:

— should not open directly into food production areas

— shall be rodent proof, with gaps not exceeding 6mm

— should open outward so that any insects on the door panel are not swept into the building by an individual’s passagemust be defended against damage/knock-open by wind. Best available technology is to use a door closer.


— should be reinforced with a 0.6 mm metal plate up to 1 m from the ground

— which are used at night, should have lightning 9 to 12 m away from the door to prevent attraction of insects (avoid high-UV amenity lighting such as mercury vapour lamps) of low-UV sodium discharge lamps)

There are two ways to reduce gaps to < 6 mm

1. Doors with a rubber strip at the base. A disadvantage is wear of the rubber strip with time or subsidence of the floor, for which the barrier for rodents decreases. Regular inspections (and replacement if necessary) can eliminate this problem.

2. Doors in a small channel. A disadvantage is that the channel can fill with dirt and/or water (rain). This can be eliminated by mounting a rubber strip on the outside of the base of the door (that will close on the floor). This will prevent rain and dirt from entering the channel (and even gives a double barrier). Regular cleaning of the channel still is needed.

Best practice for traffic entries

Rapid closing doors such as roller shutter doors or sliding doors are best practice. They should be self-closing and fit closely at the base and have a rubber strip.

Best practice for personnel entries

Busy entry points should be constructed as double doors with an internal lobby and a self-closing door, in which electrical insect traps can be placed.

If this is impracticable, then a backup alternative could be:

— overlapping plastic strip curtains

— rubber swing doors

— fans or air curtains which provide sufficient air velocity

Electric access control should be built into the inner door, to protect the electric parts from environmental influences. The lobby must have a pressure compensation valve to ensure that both doors will always shut correctly.

The doors should be protected by a well dimensioned rain-roof, so that no water will drip from the sealing inside the building when the door is opened.

Interior doors

Interior doors often play an important role in maintaining positive air pressure in areas requiring higher hygiene levels, requiring a door with good sealing that fits tightly fitting in the frame.

Medium hygiene areas

In Medium hygiene areas, doors can either be solid or from a single sheet made from 15 mm PE material (Figure 8.11.3) or transparent PVC (Figure 8.11.4).


Figure 8.11.3 - 15 mm- PE double swing door

Figure 8.11.4 - 5 mm transparent PVC swing door

Doors in forklift or pallet areas must be of heavy duty construction, reinforced with frames and plates. They should be made from a metal plate with a minimum of 0.6 mm thickness up to 1 m from the ground or PE crash protection layer with 15 mm thickness (Figure 8.11.5).

Figure 8.11.5 - 15 mm PE- reinforcement on a sliding door


— Doors should be self-closing and equipped with kick plates and push plates.

— The closing device must not collect residues and therefore floor level devices which have hollow bodies should be avoided.

— Sliding doors should have all gaps between the door and the frame closed with brush strips.

Microbiologically controlled areas

— All doors should be made of metal, stainless steel or aluminum.

— For easy cleaning the construction should be open and accessible, or easy to open.

— All surfaces should be fully drainable and sloped with a minimum of 3°.

— From a hygiene point of view, vertical opening roller shutter doors are not acceptable. This is because debris from the bottom of the door seal (potentially containing pathogens) can drip into product/packaging etc. passing underneath. If used, the seal should be frequently cleaned and well-maintained.

— Ideally, high speed double leaf sliding doors, which open sideways, should be used (Figure 8.11.6).

— Brush stripes are not acceptable.

— All door operating systems, especially those containing lubricants, should be effectively sealed (Figure 8.11.7).

— Door hatches for smoke ventilation, mounted in the inner roof of the building, should open out of the High hygiene area.

Figure 8.11.6 - Double leaf high speed sliding door. Suspension rails and bottom tracks should be accessible for cleaning and pest control activities.

Figure 8.11.7 - Effective sealing of door operating systems

Cold/refrigerated rooms


In refrigerated or cooled areas, insulated doors should not have any open areas and should be covered with fully welded metal cladding, and fully filled with PU-foam. They must be effectively sealed to prevent hazards

caused by condensation.

The construction of the door should not have any thermal bridges, to prevent condensation on the “warm side” at bolts, door locks and hinges.

8.12 Transportation and/or personnel air-locks

Transportation locks are primarily used as mechanisms for material entry into High hygiene areas or as small passages to allow staff entry into High hygiene areas, where the use of barrier changing facilities is not appropriate (See section 7.3). Transportation locks consist of two doors one within the processing area and one within the High hygiene area. The doors are usually interlocked so that only one door can be opened at any one time. Transport locks are hygienic compromises in that the area between the doors is neither a Medium nor a High hygiene area and may effectively be accessed by both production zones. Some companies refer to the area within the transportation locks as a separate zone, often terming it ‘medium’ care.Whilst a necessary mechanism for staff entry into High hygiene areas, because of their hygienic compromises, they should only be used for the transport of materials where the nature of such materials makes them

unsuitable to be passed into the microbiologically High hygiene area in any other controlled way, e.g. passed through hatches (Figure 8.12.1).

Figure 8.12.1 - Material transport through hatches that consist of two doors one within the processing area and one within the High hygiene area. The doors are usually interlocked so that only one door

can be opened at any one time.

Design requirements will vary according to the type of transport-lock but in general:

— entry and exit doors should be tightly fitting with self-closing devices (not floor level, as these constitute hollow bodies).

— tightly fitting doors allow the transport lock to be under positive pressure (if the High hygiene area is positively pressurised) when the High hygiene door is open. To establish an overpressure, pressure differentials of >3 Pa or air velocities > 3m/sec are required.

— the entrances of transportation locks should have a minimum width size determined by the transport of goods and the means of transport.


— if the High hygiene area is not positively pressurised, the transport lock can be fitted with an air extractor so that it is under negative pressure.

— electronic fly traps should be installed just outside the outer door rather than in the transport lock.

— the floor should slope towards the wet side - if the air lock connects a critical dry area to a wet area.

— the use of drainage channels running across entrances can prevent the movement of water from wet areas into the air lock.

— if vehicles are required in High hygiene areas, they should be restricted to these areas and carriage of goods such as pallets should be exchanged from a Medium hygiene vehicle in a designated area

(Figure 8.12.2).

— consideration should be given to the safe design of areas where the movement of both people and vehicular traffic is necessary.

— wooden pallets are not permitted in High hygiene areas.

— if something has to be supplied in an High hygiene area it must be repacked or restacked e.g. packaging material on a wooden pallet must be restacked on a plastic pallet in a intermediate zone or air lock and must be stripped (removal of outer foil) just before entering an air lock.

— transport locks as changing areas must be as small as possible whilst giving enough space for people to carry out their change procedure without compromise (as an indication: air lock for personnel entry to an

High hygiene area is typically 2x3 m) (Figure 8.12.3).

— transport locks for personnel entry to an High hygiene area require:

o lockers or storage for overalls which need to reflect the total number of workers (shift teams and day workers)

o provision for visitors who will not have their own locker e.g. locker with disposable coats and overshoes/ shoe covers

o hand washing and drying facilities

Figure 8.12.2 - Air lock with floor plinth acting as a traffic barrier

8.13 Windows

Traditional best practice has been to design food processing areas as far as possible without windows. Currently, however, some companies believe that psychologically, allowing staff to see outside (via windows) improves productivity and are thus encouraging their fitting.

Where present and where they would result in contamination if opened, windows are to remain closed and fixed during production. Windows which can be opened to the outside environment are to be fitted with insect-proof screens which can be easily removed for cleaning.


Windows, including windows in external and internal walls, vision panels, windows in doors etc., should:

— be constructed to prevent the accumulation of dirt, light coloured and be easy to clean.

— be ideally double glazed or double windowed to prevent condensation.

— be of toughened glass (laminated) or shatterproof plastic, protected against breakage, e.g. with a protective film.

— be installed at least 1.2 m above floor level.

— be fitted with frames which are dense, tough, impact resisting, durable, rust proof, impervious, non-absorbent, washable, water repellent, smooth, crevice free, constructed of non-toxic materials and able to

withstand cleaning chemicals and methods used. Window frames should not be made of wood.

— be installed in close fitting frames which are fitted flush and continually sealed to the walls.

— when windows are also used for ventilation, tight fitting, properly sized screens must be in place to prevent the ingress of insects. Screens must be removable for cleaning.

— window screens located within 1 m from the floor should be reinforced with a 6 mesh, 1.0 mm gauge(diameter) stainless steel wire to keep out rodents.

— window screens higher than 1 m from the floor should be reinforced with a 18 mesh, 0.23 mm gauge stainless steel, nylon or PVC coated fibre glass wire to keep out insects.

— openable windows should open outwards - to allow easy cleaning from the outside.

— have no sills or horizontal ledges. However, if unavoidable, exterior and interior window sills should be sloped to avoid accumulation of debris.

o outside window ledges should have a minimum 60° slope to prevent bird nesting

o inside window ledges should be avoided but if fitted, should be sloped to prevent them being used as a shelf, typically having a slope of 20-45°.

Skylights should be clean, free from condensation and shall not open.

8.14 Ceilings

A ceiling must be provided in all processing areas. Ceilings (or where there are no ceilings the interior surface of the roof) and overhead fixtures (e.g. ducts, pipes, stairs and elevators) must be constructed and finished so as to prevent the accumulation of dirt and to reduce condensation and the shedding of particles.

Ceilings must be:

— light coloured finish that has desirable light reflectance characteristics and cleanable.

— dense, tough, impact resisting, durable, rust proof and dust proof.

— impervious, non-absorbent, washable, water repellent and constructed of non-toxic materials.

— smooth and free from cracks and have any joints sealed with an impermeable sealant.

— unable to absorb grease or food particles or provide harbourage for pests.

— resistant to microbial (particularly mould) growth.

— resistant to rodents and insects.

— able to withstand cleaning chemicals and methods used.

— to a height of at least 3m to help prevent condensation.

Specifically:

— ceilings should not support any item or structure which contains inaccessible horizontal surfaces.

— the ceiling should seal off all structural roof elements from the production area; all utilities should be run on the roof side of the ceiling to avoid horizontal piping in the production area.

— junctures between wall and ceiling should be rounded, sealed and easily cleaned.

— above the ceiling, there should be sufficient space so as to give appropriate access for cleaning and maintenance, without influencing processes proceeding below the ceiling.

— the ceiling will be normally constructed from 'sandwich' panels with smooth, impervious, easy cleanable surfaces.

— double ceiling constructions should not be applied, since they accumulate dust and form hollow inaccessible cavities.


— ceilings should be constructed as a walk-on type for maintenance and inspection. The minimum clearance on the roof side should be 1.5 m.

— perforated or porous materials should not be used for sound absorbing (noise reduction) ceilings as these materials will accumulate dust.

— all ceiling throughputs for conveyors, vents, piping etc should be well sealed with a sealant or a collar. All throughputs should be vertical.

— suspended ceilings using small panels should not generally be used in production areas as they are difficult to seal and effectively clean (these are suitable for offices etc.).

— dry wall or gypsum ceilings must not be used in wet environments because of their intrinsic porosity.

— corrugated metal should not be used as ceiling material, due to the high heat transfer of these materials this may cause condensation problems and the joints at the centre are difficult to clean.

False ceilings should be adequately supported and be sealed at their joints using a continuous flush seal. They should be provided with catwalks where necessary to facilitate cleaning and maintenance (Figure 8.14.2). Adequate access to the void shall be provided, which should be external to the processing area. Where thereis no access to the space above the ceiling, the ceiling shall be totally sealed. Pressure differentials between

the area above and below the false ceiling should be considered.

Figure 8.14.1 - Suspended ceiling suitable for foot traffic and supporting arrangement

8.15 Insulation and noise reduction

The major justification for insulating walls and ceilings is to prevent heat losses, condensation or to reduce noise. Hygienic processing areas should, in principle, be fitted with insulation material only when this is required as a safety measure. Such insulation should be water tight, but not necessarily vapour tight. It should be checked regularly to ensure that it remains dry.

Thermal insulation of a building that contains a processing area should never be mounted on the inside wall of that building. This is to prevent possible mould growth on the inside surface.

Absorbent material can be a source of contamination, especially where ingress of water is possible. Therefore such materials should not be used as insulation material against noise reduction. If noise reduction is essential, hygienically approved acoustic panels that are cleanable and easily removable should be selected to meet the needs of regular inspection as part of hygienic control procedures. Instead of soft absorbent material

structures, vertical baffles on walls or from ceilings should be used as noise attenuators.


8.16 Stairs, walkways and platforms

Stairs, walkways and platforms comprise secondary steelwork. In general, the following hygienic practices should be followed:

— Avoid crevices, ledges and voids, which could harbour insects, food residues and dirt. Supporting and framing members should be designed to eliminate as many free ledges as possible and to minimize accumulations of dirt and dust (Figure 8.16.1). This can be best accomplished through the selection of structural shapes such as square, rectangular or round tube, and these should be used as far as is practically possible. If other structural shapes have to be used, then consideration should be given regarding their orientation. Open profiles should be used for vertical parts of a framework. Hollow square section closed profiles, in fact all hollow structures, should be avoided. If closed profiles have to be adopted, frequent inspection for cracking should be carried out to prevent risk of contamination from such a source.

— If handrails are made from circular tube, they should be welded to the stanchions and any tube joints should also be welded and ground flush. All open ends of tubes, and e.g. any holes to facilitate the galvanisation process, are to be sealed with a welded plate. All welds should be continuous.

—

Figure 8.16.1 - Correct and incorrect inclination of supporting structures. Keep horizontal surfaces to a minimum

— All fixed access equipment located in areas where foods are prepared, manufactured or consumed should be manufactured from stainless steel grade 304.

— For wet areas, stainless steel grade 304, aluminium or galvanised mild steel should be used, but consideration should be given to the type of cleaning agents used to clean the equipment in the area concerned. For example some cleaning agents will corrode aluminium and galvanised surfaces.

— For dry areas, painted mild steel or galvanised mild steel may be used


Stairs

Stairs must meet the following requirements:

— must be easy to clean

— must be self-draining (if wet-cleaned)

— closed-tread stairs with single support post either attached to a base plate or preferably embedded in concrete, are acceptable for production areas.

— if a concrete stairway is not part of the High hygiene area - it is not necessary to coat the steps (e.g. with

epoxy) nor install solid handrails.

— if single step stairs are chosen - cleanability is obviously of greatest concern in the High hygiene areas.

— latticed metal plate should be used - instead of difficult-to-clean open metal grid - unless there is a specific need for air circulation.

— stairs should be encased (Figure 8.16.2) to restrict the movement of any debris of operative’s footwear.

Figure 8.16.2 - Encased risers of a staircase

Walkways and platforms

Walkways and platforms (Figure 8.16.3) should meet the following hygienic requirements:

— All parts of a walkway framework and platform installed should be easily accessible for inspection, maintenance and cleaning.

— Horizontal ledges, projections and pockets should be avoided because they can retain dust.

— The framework of walkways should be constructed from open profiles. Hollow square section closed profiles, in fact all hollow structures, should be avoided. If closed profiles have to be adopted, frequent inspection for cracking should be carried out to prevent risk of contamination from such a source. Open profiles should be used for vertical parts of a framework. The same applies to horizontally mounted profiles and framework directly attached to the ceiling.

— The framework of walkways is best supported from the ceiling instead of standing on floors although this is seldom possible. Therefore when connecting framework to a floor, a fixing bolt should be first

securely fastened and sealed into the floor, and the framework then mounted on the bolt, but with a rubber seal between the floor and the framework to ensure a tight fit. This minimises the possibility for microbial presence and growth. Frameworks should not be mounted directly on to floors, as they are inevitably uneven.


— Raised walkways and platforms over open processes that expose product to the environment should be avoided to restrict soil and foreign material cross-contamination.

— If personnel movement is required in these areas, the equipment should be fully enclosed. Kick plates should be installed and where possible the kick-plates and decking should be designed as a one-piece construction (Figure 8.16.4). Stair risers should be encased and the use of expanded metal or mesh must be avoided as this accumulates.

a b c

Figure 8.16.3 - Correct (a) and incorrect (b) design of stairs passing over production lines and platform upstands (c) of 150 mm to protect food processing activities below

Mezzanine floors, stairs, catwalks, bridges, gangways and platforms etc. over production lines shall be

completely sealed and shall include side walls and walls around openings, at least 150 mm high, to preclude contamination of the area below (Figure 8.16.3). They should be constructed of impervious, non-corrodible, easy to clean and impact resistant materials.

Drainage of walkways and platforms etc. is always difficult as the floors are rarely sloped to drains. The drains themselves have then to be piped and led to factory drains in the floor below in a way which does not endanger product safety. Untrapped drain lines shall be provided with an air gap at the discharge to the sewer

and shall be removable for cleaning. If possible, the use of water on such structures should be avoided. If unavoidable, safe mechanisms of disposing surface water should be planned at the time of construction.

Figure 8.16.4 - Encased risers of a staircase and a platform with the kick-plates and decking should be designed as a one-piece construction.


8.17 Elevators

An elevator is a convenient means for moving personnel and materials from one building level to another in a tall building housing a hygienic process. However, consideration should be given to the following:

— Elevators should not be located in High hygiene areas due to the non-accessible spaces in the shaft above and below the elevator. Furthermore, air drafts created in the shaft cause airborne dust movement and can be a major source of contamination.

— Elevators should never connect zones of different hygienic classification.

— The area beneath the elevator should be kept free of debris and checked regularly.

— The drain at the bottom of the shaft, and the ventilation effect in the shaft should be considered in the zoning concept.

— The floor of the elevator should not be of the ‘double floor’ type, as the lower floor element cannot be cleaned.

The elevator itself is not tight, which means that dust, insects and pests can infiltrate. Checks for possible infestation within the elevator and/or shaft should be regularly carried out. Good accessibility is necessary for these regular checks.

Separate elevators should be used for incoming and outgoing transport of goods, raw materials and end products to avoid possible cross contamination risks. However, when an elevator is installed in the same zone classification area and used to transport materials that are tightly packed, it can be used to bring in both dry raw materials and to take out end products.

8.18 Food contact surfaces

If any of the building surfaces will be used as food contact surfaces, they must be constructed of materials that will not contribute a food safety risk. Specifically, such surfaces should:

— be of food grade materials.

— be maintained in a sound condition and be smooth, free of open joints or seams, washable and easy to clean and, where necessary, to disinfect.

— be able to withstand repeated cleaning and disinfection.

— be durable, impact resistant, corrosion resistant, non-absorbent, unable to absorb grease and food

particles, not yield substances which might migrate or be absorbed into the food and be inert to the food.

— meet the requirements of EHEDG Guidance document No. 32 Materials of construction for equipment in contact with food

Stainless steel, hot dipped galvanised steel, aluminium, fibreglass, polyvinyl chloride and nylon are examples of approved materials. The use of different materials in such a way that contact corrosion can occur should be avoided.

It should be recognised that materials which are difficult to clean and disinfect, for example wood, may pose a

contamination risk and should be avoided whenever possible. Where this is technically unavoidable (e.g. in the manufacture of some cheese and bakery products), special attention should be given to cleaning and inspection (e.g. for splinters) of such materials. Note: Whilst EU regulations allows for the use of wood according to national derogations, some audit bodies now consider that wood is no longer acceptable as a product contact surface in any food handling area.

9 Services

9.1 General services

Pipes should run in separate accessible gangways (pipe trains) and enter the process area through the ceiling. If this is impossible, open trays that are fixed to walls or columns close to the ceiling should be used. These trays should be designed hygienically to minimise presence of horizontal ledges, crevices or gaps where inaccessible dirt can accumulate.

Pipework, suitably protected light fittings, ventilation points and other services in manufacturing areas should be installed (e.g. flush mounted or mounted an appropriate distance away from the wall or ceiling) to minimise dirt accumulation, to avoid creating recesses which are difficult to clean (See Section 2.1, Adequate Space for DOC 44 ©EHEDG 113 of 133

Cleaning and Pest Control). The anchor points of support racks should be sealed to the building (floors, walls, columns, ceilings).

As pipework may expand and contract in use, when passing through walls, ceilings and floors, pipework should be mounted in sleeves to prevent damage to the substrate it penetrates (Figure 9.1.1 & 9.1.2).

When several pipes penetrate the floor, these can be circumvented by a larger curbed floor to improve the cleanability of the surrounding process area. However, the open curbed floor creats an area where pests may harbour and where dirt, water, etc. may accumulate. It must be completely closed, therefore, with a cover that leaves no gaps around the penetrating piping (Figure 9.1.3).

Figure 9.1.1 - Pipe mounting through a wall

The manufacturing environment should be controlled or insulation materials should be used to ensure that drips and condensation do not form on e.g. pipework which could contaminate foods, raw materials or food

contact surfaces.

Fig. 9.1.2 - Openings in floors for pipes also should be guarded with a sleeve. That sleeve should extend far enough above the floor to avoid spill of cleaning solutions to a lower floor.


Fig. 9.1.3 – When several pipes penetrate the floor can be circumvented by a larger curbed floor to improve the cleanbility of the surrounding process area. However, the open curbed floor created an area where pests may harbour and where dirt, water, etc. may accumulate. It must be a completely

closed curb with a cover that leaves no gaps around the penetrating piping.

To avoid residue collecting points, piping networks should have clearances of:

o 100 mm between each pipe

o 50 mm (minimum) from the walls and floor

o 250 mm (minimum) free space left between parallel rows.

— Covering piping only creates an area where dust accumulates.

— Wall openings can be sleeved with a 100 mm ridge slab opening.

— All pipe work must be drainable. In general a 3° slope towards the drainage point achieves this. Pipe size reductions, fitting of pumps etc should be designed so as to ensure this.

— Pipe lengths between supporting trays and process equipment should be as short as possible.

— Pipework should be designed without dead-legs, but If un-avoidable then it must be as small as possible. For pipe work > 25 mm the dead leg should be <28 mm, for pipe work smaller than 25mm the dead leg should be less than the diameter of the pipe.

— The exterior surfaces of pipes that traverse walls should have water and airtight contact with the wall when the wall separates different hygiene zones (Figure 9.1.4). If both sides of the wall are the same hygiene zone, water and air tightness is not essential but any openings should be large enough (at least 50mm) for access and cleaning.

— To create a total barrier - seals of flexible material are necessary - or a material which expands and contracts in a similar way to the pipe.

— Pipe hangers and brackets should be strong but of simple design - to facilitate cleaning. Angles and supports (if used) must be oriented so that dust and debris do not accumulate. Painted mild steel supports in wet processing areas present a continual problem with flaking paint - even in dry areas painted surfaces should be avoided. Stainless steel is the preferred material.

— Pipe hangers of the strut channeltype or with exposed thread should not be used.

— Correct choice of insulation material (with well-executed installation) will prevent problems common with insulated pipelines.

— Piping for 'hot' service lines (e.g. steam or cold water) should never be painted - paint will peel.


— Condensation on piping should be prevented. If present, and if the condensation is a risk to the process, appropriate sloped and drained drip trays can be used as a temporary solution.

— The correct choice of insulation material (with well-executed installation) will prevent problems common with insulated pipelines. It is recommended that the insulating material does not absorb and retain water. Extruded polystyrene , foam glass (calcium silicate) or rigid non-chlorine foam are better choices over fibrous materials. The problem with fiberglass batting is that it is an excellent harbourage of dust, insects and rodents. Fibreglass is acceptable in non-processing areas. Insulation should be watertight (not necessarily vapour tight).

— It is highly recommended to install fully welded, water tight, metal cladding (e.g., aluminium) or plastic covering (e.g., PVC) suitable for use in a food area. The exterior of the insulation protection should be smooth, properly sealed to avoid ingress of dust and liquor, and should be installed in a correct way to

avoid dust traps, e.g. joints facing downwards. It should be impossible to walk on the insulation during maintenance.

Conveyors, services, vents etc. should be sealed into any walls, ceilings and partitions through which they pass to prevent pest ingress.

For dry food products, dust extraction equipment may need to be installed where considerable amounts of dust are generated and where dust is a hazard to product cross-contamination and to operative health and

safety. The capture velocities of extractor fans and canopies must be sufficient to evacuate all dust, heat, fumes and other aerosols to the exterior as appropriate.

Compressed air or other gasses mechanically introduced into food or used to clean food-contact surfaces or equipment shall be dry and treated to be free of microorganisms, chemicals and particulates. Compressed air, carbon dioxide, nitrogen and oxygen shall be filtered through a micron filter (to remove particles of 5 microns or greater) located close to the point of use and should have non-return valves to preclude the entry of food.

Steam should be generated from potable water and should be adequate to meet operational requirements and should have traps to ensure adequate condensate removal and elimination of foreign materials.

Fig. 9.1.4 - All ceiling throughputs for piping should be well sealed with a sealant or a collar.

9.2 Electrical installations

Electrical installations should be avoided in food production areas as much as possible. Electrical installationsshould have a minimum Ingress Protection category (IP rating) in wet areas of a minimum of IP 65 but preferably IP 67 (to EN 60 529).


Cable runways

— The amount of wire ways and conduits, as well as cable routing, must be kept to a minimum in production areas with exposed product (raw materials, semi- finished goods or finished goods).

— Wall or piping rack installations are preferred over. cable routing along conveyors, tanks, and other production equipment.

— Cable ladders should be as open as possible whilst offering adequate support. Perforations and 90 degree angles are difficult to clean (Figure 9.2.1).

— If cable routing cannot be avoided where product is exposed, to avoid soil accumulation, horizontal surfaces must be kept to a minimum and the design shall be sloped at 45 degrees.

— Minimize use of horizontal trays for electrical cabling, especially those close to the ceiling, as inaccessible dust layers form hygienic risks (Figure 9.2.2).

— Open supports are preferred vs. hollow profiles. If hollow supports are used they must be hermetically sealed.

— Rods/hangers must not be threaded (threads should be minimized and only present at the end to allow fixing at the correct tension). The amount of hangers shall be minimized. Above exposed product zones, e.g. conveyors/ bins etc., they must not be installed at all.

— Vertical cable trays should be used wherever possible, as they are more accessible and easily cleaned (Figure 9.2.2 & figure 9.2.3).

— Strut channel type support systems must not be used for any application in High hygiene areas.

— If cable trays are used in areas were accumulation of soil is possible (e.g. under equipment), they must have a removable cover

— Where possible, cables under lines should be avoided - especially in areas where they might become covered with product residues.

— Dead areas must be avoided, e.g. cables shall only be installed in a single layer. Bundling of cables must

be avoided and cables shall have sufficient distance to each other to allow for cleaning (e.g. use of spacers).

— The use of cables clips should be avoided. Cables should preferably be routed loosely or routed through ring system (see example below). If cable clips are used they must be of metal detectable design.

— Clips to attach cable labelling over exposed product and in dusty/wet areas must be avoided. The labelling of cables shall be done using shrink foil.

— Conduit may be used for routing cabling, but is a major food safety risk if not appropriately sealed at both ends. Unsealed ends can allow the ingress and can harbour moisture, soil, microorganisms or pests (Figure 9.2.2 & figure 9.2.4).

— Design and material selection must be compatible with periodic cleaning regimes (e.g. dry steam, saturated steam, wash down, dry ice etc.)

— Cable trays shall never be installed in a way that personnel can use them as a step

— When cables can pass from one hygiene zone to another, care should be taken to avoid the formation of pest ingress channels. For example, cables can be passed through the wall via a frame in the wall or a

cable transit box. Both elements should be accessible for inspection and cleaning.

— The drop connection to the final device (such as motor cables, power supply cable to cabinets) shall be kept as short as possible; no spare cabling shall be looped close to the device.


A

B

C

Figure 9.2.1 - Cable ladders must not have any perforations, holes, angles, flat surfaces etc. A = Correct, B and C = Hygiene risk


Figure 9.2.2 - Example of hygienically designed cable wall mounting

Figure 9.2.3 - Vertical cable routing is preferred to horizontal installations


A

B

C

Figure 9.2.4 - Conduits should be completely sealed and cleanable and sealed connectors shouldcomply with hygienic design requirements. A and C = Correct (sealed conduit and or wiring), B =

Hygiene risk (unsealed conduits)


Control boxes

— Electrical cabinets shall be designed and installed in a way that they are cleanable and compatible to the environment where they are used, e.g. wet rooms require IP 66 / NEMA 6 and stainless steel. Aluminium can be used in dry processing areas

— Hinges should be inside the cabinet and the use of piano type hinges should be avoided.

— Door seals must not have any gaps and the sealing shall be easy to remove and easy to distinguish in the product (following any contamination incident).

— Cable entry shall be from the bottom: entirely with glands, same material as for the cabinet (stainless steel for wet areas, brass for dry areas).

— No optional entries for future use shall be made to avoid caps. To avoid accumulation of soil and for drainability the roof should be sloped

— Open control centres should not be installed in production areas.

— Control panels should be elevated from the floor, using a solid concrete plinth, steel framework or affixed to the wall, leaving a minimum space between the wall and the panel (See Section 2.1, Adequate Space for Cleaning and Pest Control) (Figure 9.2.5).

— Electrical boxes, HMI’s, and PLC panels should not be located directly over exposed product zones (Figure 9.2.5).

— Control panels with touch screens are preferred over devices with buttons (push buttons, position switches, mushroom buttons) or keyboards with computer mice. Keyboards/mice should be integrated in the panel or a wall and of retractable type.

— Buttons at switch boxes and control panels shall be hygienically designed preventing the ingress of moisture and dirt.

— Power panels are best enclosed in dedicated rooms close to the control panels.

A B

Figure 9.2.5 - Control panels should be appropriately affixed (See Section 2.1, Adequate Space for Cleaning and Pest Control) and should not be sited over product streams A = Correct, B = Hygiene risk

9.3 Ventilation and temperature control

See EHEDG Guideline document No. 30 "Guidelines on Air Handling in the Food Industry".

Where natural ventilation is appropriate, ventilation should be through openings (or openable sections) which are directly connected to the outside air and so positioned in the external walls and/or roof that effective cross-ventilation is possible: provided that such openings shall have a surface area equal to at least 5% of the floor area of the room concerned.


Mechanical ventilation should be provided to:

— provide fresh air for personnel.

— effectively distribute the air throughout the room space so that no dead zones are created.

— control odours which might affect the suitability of food.

— control humidity (or condensation). It is recommended that conditioned air has a relative humidity below 55% to restrict the growth of microorganisms, in particular moulds.

— control ambient temperatures to ensure the safety and suitability of foods.

— effectively remove fumes, smoke, steam and vapours.

— effectively remove excessive heat.

— reduce the number of airborne contaminants, including microorganisms.

The mechanical ventilation system should:

— consist of Air Handling Units (AHUs) of food grade quality.

— be comprised of AHUs designed so as to allow easy access for inspection, maintenance and cleaning and which are positioned as far as possible, out of the processing area.

— include air control facilities including temperature, humidity and filtration, appropriate to both the operations undertaken within the processing area and to the external environment.

— have appropriately sited air intakes and extracts that allow appropriate air movement through the room space without short circuiting between inlet and outlet.

— have minimal ducting to allow for the natural flow of the ambient air.

— supply air from a filter/fan utilities service room, which is separated from food material processing areas. This room is part of the zoning concept.

— filter all incoming air before it comes into contact with the internal cooling coils. This is to prevent condensation of moisture on entrained dust particles.

— install air cooler siphons correctly (see picture) and care that it is always filled

— install air filters correctly (work from coarse to fine). And do not use fibre-glass wool filters. Always ensure that there is no leakage between the filters and support frames

— be located so that dirty filter elements/mats are removed within an area of the lowest hygienic zone classification and away from product streams. This to prevent dust being generated in an area of higher hygienic zone classification.

— provide sufficient air changes per hour in Medium hygiene processing areas (typically between 5-25changes per hour) and High hygiene areas (>10 changes per hour).

— provide airflows that are from clean areas (e.g. process areas) to dirty areas (e.g. raw material storage).

— be comprised of air supply and extraction trunking that does not introduce contaminants into products.

— have air intakes which are suitably screened against pest access, at least 1m above internal and external ground levels (taking into account typical snow accumulation levels) and away from any other possible source of contamination e.g. noxious solids, vapours or gases or exhaust of materials which could contaminate other products (Figure 9.3.1).

— have intakes and extraction units positioned with due regard for the local environment and the avoidance of nuisance (odour, noise or dust emissions).

Air filtering of supplied air is recommended for Medium hygiene areas within the range EU-class M5 to F7 (seeEN 779). For High hygiene areas, filtering should be F7 or greater dependent on the external factory airborne risk, the length of time the product is exposed to ambient air and the microbiological sensitivity of the product such that in some circumstances, High-efficiency particulate absorption (HEPA) filters (H13-H14) may be appropriate.

Air should flow from a higher to lower hygienic zone classification and from lower to higher dust loaded areas. Usually an air pressure differential between the zones meets this requirement. The process plant should be operated under a slightly positive pressure (2-5 Pa) in order to prevent ingress of unfiltered air. To meet different hygienic requirements (zone classification), random airflow between floors via stairways, lifts etc. must be prevented by installation of air lock systems.

Where there is a risk of microbiological contamination of the product by the surrounding air, the working area should be enclosed as far as possible and be maintained at a positive pressure using filtered air drawn from a clean source.


Figure 9.3.1 - Pay attention to the prevalent wind direction when positioning air intakes. Air intakes should be positioned away from any possible source of contamination, such as the air exhaust. During

most of the year, a minimum of exhausted air, noxious solids, vapours or gases should be drawn within the factory.

9.4 Process and transport air

— Process and transport air must be supplied from areas least likely to contain concentrations of airborne dust and micro-organisms. Process air should be drawn from the atmosphere outside the process plant building through an inlet at least 3 metres above ground level (see also the German VDI-regulation No. 6022). Any air intake should be sited as far away as possible (minimum 10 metres) from any outlet air streams or other likely contamination sources (e.g. droplets from cooling water equipment, wet scrubbers

and exhaust ducts etc.).

— Process and transport air must be effectively filtered for dust particles. Air coming in direct contact with the product is more important than room air. Coarse filters may be used for raw materials, however, the air coming in contact with dry ingredients and products must be filtered with a fine filter (e.g. EU-class F7). The possible need for coarse dry filtering followed by fine filtering has to be evaluated as such a need depends on the type of plant or process and the product risks involved, e.g. in a bakery process, only coarse filtering may be sufficient, whereas in a milk powder/infant formula process, additional fine filtering is required.

— As a general guideline, air used to transport product should be filtered to two grades of air filter or better than for room air. For example, if F7 filters are used for the room air in which the product is being transported to/from, the transport air should be filtered to F9 or more.

— Air filters should be considered as part of the boundary between hygienic zones, e.g. Medium hygiene on the unfiltered air side and High hygiene on the clean, filtered air side.

— Process or transport air must not be drawn from dry material handling and packing areas, as these are

usually potential areas of high dust loading.

— Systems using process and transport air operating below atmospheric pressure should not cross process areas of lower hygienic zone classification. The air should be conditioned to prevent condensation, as this may cause dry product agglomeration and microbial growth. The degree of air conditioning has to be decided on a case-to-case basis.

— Airflow in process equipment handling dry materials should preferably be under conditions of a slight vacuum to prevent possibility of egress of particles into the surrounding air. This also protects personnel within the process areas.


9.5 Lighting

All areas where food is examined processed or stored, and where equipment or utensils are cleaned, and in personnel changing areas, must have adequate natural and/or artificial lighting for the activities conducted. Where necessary, lighting should provide sufficient colour rendering, such that the lighting gives product and surface colours the same appearance as they have under daylight and incandescent light. Lighting of poor colour rendering gives marked distortion of the original product colour.

Table 9.5.1 – Suggested illumination levels for different food production areas

Location lux (lm/m2)

Exterior, plant perimeter

Receiving docks

Shipping docks

Warehouses

Process areas

Inspection points

Packaging area

Offices

Corridors

110

110

110-220

220

440-660

550- 1500

440-825

440-550

220

Note: Luminance is a measure of the intensity of illumination on a surface, and reveals how much

luminous flux, as a measure of the total "amount" of visible light, is spread over a given area. The

amount of lux is the ratio of the totally received amount of light, expressed in lumen, and the size of

the illuminated area expressed in square metres (1 lux = 1 lm/m²).

Natural lighting must be by means of unobstructed transparent surfaces in the external walls and/or roof which admit daylight, with an area equal to at least 10% of the floor area in the room concerned. Work surfaces

(horizontal, vertical, inclined) should be evenly and sufficiently illuminated. The lighting intensity should be adequate to the nature of the operation and should meet the requirements in Table 9.5.1.

The following hygiene requirements should be followed:

— Lighting (and fire detection systems) should be suitably sealed to the ceiling or walls in a way that avoid any projections where dust can accumulate or spaced off them to give easy access for inspection and cleaning with the top of the light fitting sloped to 45° to enable cleaning (Figure 9.5.1).

— Lighting fixtures and their supports are designed to avoid accumulation of dust, especially where cross-contamination risks could arise. Horizontal surfaces need to be minimised.

— Where possible, light sources should be integrated into ceilings (Figure 9.5.2) and walls in a way that avoids any projections where dust can accumulate. Where direct lighting in specific positions within the equipment is necessary, lighting fixtures should also be integrated into the equipment design according to hygienic design requirements.

— Light sources should not be placed above open processes, to prevent broken fragments falling into open process equipment if damaged. When such a light source cannot be avoided e.g. above a monitoring point, non-glass tubes or shatter-proof glass should be used.

— Light (bulbs or tubes) sources must be covered with a protective film or by polycarbonate plastic to prevent glass shattering on breakage. These lights should be changed regularly as protective films become brittle over time.

— Light sources should have watertight, dust-tight and insect-tight enclosures.

— For ease of cleaning or maintenance in areas where product is exposed, it is preferable that fittings can be

removed from their support (e.g. attached to wall or ceiling only by a cable and plug-in socket). An alternative is to have light fittings accessible from a walk-on ceiling.


Figure 9.5.1 - Examples of un-hygienic and hygienic lighting design

Figure 9.5.2 - Lighting should have a sloped body; (right) Lighting integrated in the ceiling flush with that ceiling

9.6 Water

Food factories must have an adequate supply of potable (hot and cold) water, which is to be used whenever necessary to ensure that foodstuffs are not contaminated.

Where appropriate, facilities for water storage, distribution and temperature control shall be adequately designed, constructed of approved materials of a size that prevents stagnation, shall be covered and shall have air vents which are insect and rodent proof.

Plumbing shall be of adequate size and design and adequately installed:

— to carry sufficient quantities of water to required locations throughout the plant.

— to ensure potable water is not contaminated with non-potable water.


— to prevent a source of contamination to food, water, equipment, utensils or create an unsanitary condition.

— so that all hoses, taps, and other similar sources of possible contamination prevent backflow or back-siphonage.

— to properly convey sewage and liquid disposal waste.

In dry processing factories, the infrastructure and equipment must be specifically designed to accommodate water. Water (and associated drainage if required) should only be piped to areas requiring such water. If possible these areas, or the operations requiring water, should be grouped together and placed at one edge of a factory to minimise water and drainage runs. For areas where water may constitute a microbiological risk, no

water or drainage pipes of any description should run through these areas. Close attention should be paid,however, to fire regulations and if sprinkler systems are required, dry systems should be considered.

Recirculated water should be treated, monitored and maintained as appropriate to the intended purpose. Recirculated water must have a separate distribution system which is clearly identified (e.g. by colour, markingor printed notices).

Where non-potable water is used, for example for fire control, steam production, refrigeration and other similar

purposes, it is to circulate in a separate, duly identified system. Non-potable water is not to connect with or allow reflux into, potable systems.

Local legislation must be followed with regard to protection of the potable water supply. A connection between the water supply piping and a make-up tank, such as for storage, cooling or condensing, should be protected by an air gap or effective backflow preventer.

The guidance in EHEDG Guidance Document numbers No. 24 "The prevention and control of Legionella spp. (including legionnaires disease) in food factories", No. 27 "Safe storage and distribution of water in food factories" and No. 28 "Safe and hygienic water treatment in food factories" should be followed.

9.7 Food and solid waste

Adequate provision must be made for the storage and disposal of food waste, non-edible by-products and other refuse, taking into account local legislation requirements for waste categorisation.

Food waste, non-edible by-products and other refuse should be deposited in appropriately constructed, labelled, closable containers which are made of impervious material, are leak-proof and are easy to clean and

disinfect.

The routing of how waste products should move to internal or external waste storage facilities and, if internal, form storage areas to the outside of the factory, should be considered. Waste should be moved out of High hygiene areas via openings in the segregated barrier. For the disposal of small quantities of bagged waste in High hygiene areas, existing hatches should be used e.g. the wrapped product exit hatches or the packaging materials entrance hatch (Fig. 9.7.1), as additional hatches increase the risk of external contamination and put extra demands on the air handling system. For waste collected in bins, it may be necessary to decant the waste through purpose built, easily cleanable from the High hygiene area, waste chutes that deposit directly into waste skips.

Waste storage areas must be designed and constructed so that the risk of contaminating food or the potable water supply is avoided and to minimise the potential for odour. Storage should be in a separate room or in an external area that is constructed of impervious material and suitably sloped and drained. Refuse stores are to be designed and managed in such a way as to enable them to be kept clean and be fly-proofed and free from animals and pests.

Microbiological and chemical wastes from laboratories require special attention, may require special disposal methods, including sterilisation, and may need to meet local legal requirements.


Fig. 9.7.1 - Waste should be moved out of High hygiene areas via openings in the segregated barrier.


10 References used within the text

Carpentier, B. (2011)A suggested method for assessing the cleanability of flooring materials. EHEDG Year book 2011/2012:16-20.

CNAM. (2011)Bien choisir les revêtements de sol lors de la conception/rénovation/extension des locaux de fabrication de produits alimentaires-Recommandation adoptée par le Comité Technique National des Services, Commerces et Industries de l’Alimentation (CTN D) le 13 septembre. http://www.ameli.fr/employeurs/prevention/recherche-de-recommandations/pdf/R462.pdf accessed 12 April 2012.

Grocery Manufacturers Association (GMA) (2009) Control of salmonella in low-moisture foods.

February 4, 2009http://www.gmaonline.org/downloads/technical-guidance-and-tools/SalmonellaControlGuidance.pdf

Timperley, A. W. 2002Guidelines for the design and construction of floors for food production areas (second edition). Campden and Chorleywood Food Research Association, Chipping Campden, UK.

Useful information

National Legislation

— European Regulation EC 852/2004 on the hygiene of foodstuffs www.fsai.ie/legislation/food/eu_docs/Food_hygiene/Reg852_2004.pdf

— European Regulation EC 853/2004 laying down specific rules for food of animal origin www.fsai.ie/legislation/food/eu_docs/Food_hygiene/Reg853_2004.pdf

— South African Government Notice No. R.918 of 30th

July 1999 as corrected by Government Notice No. R.723 of 12

thJuly 2002. Regulations Governing general Hygiene Requirements of Food Premises and the

Transport of Food www.doh.gov.za/docs/regulations/2002/0723.pdf

— New Zealand Food Hygiene Regulations 1974, (SR 1974/169), Reprinted as at 3 September 2007 http://www.legislation.govt.nz/regulation/public/1974/0169/latest/DLM42658.html?search=ts_regulation_food+hygiene&sr=1

— Singapore Government Code of Practice on Environmental Health http://www.nea.gov.sg/cms/ehd/cop.pdf

International and National Guidance

— CODEX CAC/RCP 1-1969, Rev. 4-2003. Recommended international code of practice: General principles

of food hygiene http://www.codexalimentarius.net/web/more_info.jsp?id_sta=23

— Australia New Zealand Food Authority. Food Safety Standards. Standard 3.2.3 Food premises and

equipment. 2001 http://www.foodstandards.gov.au/_srcfiles/3_2_3.pdf

— USA Code of Federal Regulations, Part 110, Current Good Manufacturing Practice in Manufacturing, Packing or Holding Human Food. Title 21 Food and Drugs, Volume 2, Revised April 1, 2003 http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=110

— Canadian Food Inspection System Implementation Group, General Principles of Food Hygiene, Code of Practice, First Edition, June 18, 2004 http://www.cfis.agr.ca/english/regcode/gpfh/gpfhc_e.shtml

— South African Standard 049, Edition 3, 2001. Code of practice: Food hygiene management.

— Institute of Food Science and Technology. Food & drink good manufacturing practice. A guide to its responsible management. 5

thEdition, 2006

http://www.ifst.org/site/cms/contentChapterView.asp?chapter=1

International audit standards

— SQF Institute. Guidance for developing, documenting and implementing an SQF 2000 system. General Food Processing – Level 1, Annex 1: Guidance; premises and equipment construction and design http://www.sqfi.com/documentation/SQF_2000_Guidance_Gen_Operations_Level_1.pdf

— British Retail Consortium (BRC) Global standard for food safety, Issue 5, 2008 http://www.brc.org.uk/standards/default.asp?mainsection_id=2&subsection_id=66

— International Food Standard (IFS) Standard for Auditing Retailer and Wholesaler Branded Food Products. http://www.food-care.info/index.php?page=home&content=ueber_uns

— AIB International. Consolidated Standards for Inspection; Prerequisite and Food Safety Programs, 2008 https://www.aibonline.org/2009Standards/DownloadStandards.html


11 Hygienic Building Design Checklist

Site

— Have appropriate surveys been undertaken to ensure that the site (soil, water, subsurface structures etc.) is free of hazardous chemicals and/or pollution?

— Has a survey been undertaken to list the potential hazards to the food product from the surrounding site environment (industrial activities, farm activities, water sources, waste areas, pests etc.) with particular reference to prevailing wind conditions?

— Is the site subject to flooding and is there adequate freeboard over water levels?— Is the site free of structures and vegetation that could encourage or harbour pests?— Are raw materials, finished product or packaging stored on the site which could be subject to deliberate or

accidental contamination?— Are entrances to the production facilities and walkways appropriately lit at night?

Boundary fences and walls— Is the site secure from unwanted pest and human activities?

Buildings

— Are buildings appropriate to the food processing operations that they contain?— Are buildings sited with respect to prevailing winds and ground levels?— Is the level of the factory floor higher than the surrounding ground levels?— Is adequate space available to allowhygienic operations, maintenance, cleaning and pest control

activities?— Is sufficient space available above, below and around equipment and service structures to ensure that

they are effectively cleaned, maintained and free of pests?— Is personnel access to food production areas adequately controlled with a minimum of entrances?— Does the structure adequately prevent the ingress of external hazards, particularly with respect to doors,

windows, service entries, exhausts and drainage?— Are the flows of product, packaging, personnel, services and wastes designed to minimise cross-

contamination?

Internal divisions

— Are all non-food activities (offices, boiler rooms, electrical switch gear, engineering facilities, canteens/restaurants, accommodation areas etc.) effectively separated from food production areas, both physically and via appropriate management of air flows and drainage?

— Have specific rooms been provided for e.g. labelling/printing, quality control, maintenance, laboratory functions and first aid?

Segregation— Are food products effectively segregated from microbiological, chemical and physical hazards?— Are e.g. vegetarian, organic, GMO, Halal, Kosher, allergenic ingredients effectively segregated?— Has a hazard analysis been undertaken to ensure that food production activities are undertaken in the

appropriate hygiene zones for the safety of the food product; Basic, Medium or High hygiene areas?— Is each manufacturing zone designed to an appropriate hygiene level?— Are effective barriers in place to prevent the challenge of hazards entering manufacturing areas,

particularly the High hygiene area?

— Does air, waste and drainage flow effectively out of higher hygiene zones in lower hygiene zones?— Has attention been paid to the isolation of microbiology laboratories, particularly those handling

pathogens?

Storage areas – food, packaging, equipment, waste— Are appropriate facilities available for the storage of all ingredients, intermediate products, finished

products and packaging?— Are appropriate facilities available for hazardous chemicals and lubricants that are used within production

areas; chemicals, lubricants?— Do chillers and freezers have sufficient monitoring and control devices to maintain correct temperatures?— Are loading bays covered to prevent contamination to ingredients and finished products?— Are external silos and bulk storage facilities suitably protected and vented to prevent the entrance of

hazards. Are only factory owned pumps and hoses used to unload/load materials?— Is waste stored in a manner that limits access to pests?


Personnel areas— Is there adequate provision for staff amenities and facilities for changing, washing, eating and resting,

exterior to food processing areas?— Are sufficient toilets provided for the workforce? Are they separated from food processing areas by at

least two doors and two handwash facilities? Are toilets appropriately ventilated by natural or mechanical means (ideally under negative pressure)?

— Are facilities available for personnel to store their possessions prior to work?— Are changing facilities organised so that personnel can remove street clothing and footwear, store them

separately from factory clothing, cross into the food production side of the changing area, wash hands, don factory footwear and clothing and decontaminate hands on entry to food production areas?

— Are handwash facilities (and ideally soap dispensers) non-hand operated and designed to be cleanable?

— Are hand drying facilities non-contact and if high velocity air, positioned in such a way that droplet dispersion is controlled. If paper towels, is adequate provision made for foot or knee operated towel disposal bins?

— Is High hygiene area clothing visually different to open area clothing and is High hygiene area footwear captive to that area?

— Is there adequate provision for the washing or laundering of dirty footwear and protective clothing following personnel work periods?

— Is provision for smoking only installed outside the factory building?

Cleaning facilities— Are adequate facilities provided for the cleaning and disinfection of equipment and utensils, with

appropriate provision for drainage and ventilation?— For High hygiene areas, are cleaning facilities sufficiently separated to prevent the movement of cleaning

aerosols into food production areas?

— Are facilities for the washing of food materials separate from those of equipment and utensils?

Foundations

— Have the building foundations been built with respect to soil type and structural loads?— In areas where burrowing rodents may be a problem, have the foundations been designed to limit pest

access through the foundations?— Is there any evidence of settlement that could have led to stresses in the building resulting in cracks and

crevices that could harbour hazards?

Superstructures

— Are structural elements sufficient to support the structure and prevent movement of the building due to external influences?

— Is structural steelwork suitably protected (particularly H profile elements) and enclosed to prevent dust and soil traps?

— Are load bearing floor slabs sufficient for the weight of installed equipment and traffic patterns?— Do floor slabs have appropriate membranes and are expansion joints in place and suitably sealed?

Roofs

— Is the roof well draining and waterproof?— Does the roof structure prevent condensation in all seasonal conditions?— Are openings to the roof minimised and effectively sealed?— Are down spouts external to the building? If not, are they protected within the building?— Are downspouts protected from pest access?— Is there access to the roof from the exterior of the building? If not, is access controlled?

Floors— Are all falls to drain effective in ensuring that all process and cleaning water is removed from the process

area?— Are all joints and edges on floors, and connecting equipment/fixtures to floors properly sealed?— Are floor toppings impervious, non-absorbent, non-toxic and cleanable?— Are floor toppings rigid, durable, slip resistant, food product and ingredient resistant (acids and alkalis, oils

and fats, sugars), chemical restaurants and corrosion resistant?— Are equipment floor fixings effectively sealed?


Drains

— Is the design of the drainage capable of removing all waste water from the floor?

— Is the drainage system effectively sealed into the floor structure to prevent movements that could give rise to crevices allowing the flow of fluids to the subfloor?

— Is all pipework stainless steel and welded or sealed? Are gullies of stainless steel, hygienically designed

and containing sediment baskets and water traps?— Are drains dedicated to hygiene zones? If not, do they flow from High hygiene to Medium or Basic

hygiene areas and have backflow devices if backflow is possible?— Is the water trap of a removable type which enables the drain bowl to be complete emptied of

contaminated water?— Are cleaning wells for drainage piping placed outside hygienic areas?

Coving, kerbs, posts and barriers— Are walls, doors and other structures adequately protected against traffic damage?— Is the wall/floor interface suitably protected from water ingress?— Are kerbs non-porous, free of ledges that can accumulate dirt, free draining and easy to clean?— Are barriers suitably fixed into the floor or kerbs and effectively sealed?

Walls— Are external walls weather, water and pest proof and free of cavities?— Are sandwich panels durable, fire resistant and appropriately jointed and sealed?— Are internal walls light coloured, dense, tough, impact resisting, durable, rust proof and dust proof, able to

withstand cleaning chemicals, impervious, non-absorbent, washable, water repellent and constructed of non-toxic materials?

— If wall panels have been fitted, are they adhered to the wall substrate over their complete surface area?

Transport docks— Where the factory floor level is at the same height as the ground level, are there slabs or plinths at factory

entrances on which goods have to be placed and thus act to prevent the entry of transport systems directly into the factory?

— Are loading docks and leveller plates designed to prevent pest access?

— Are dock doors of a rapid opening design?

Doors— Are all external doors weather and water proof, effectively sealed against pest ingress and not opening

directly into food production areas?— Are all doors fitted with kick plates, push plates and self-closing?— Are internal doors light coloured, not hollow, tough, impact resisting, durable, rust proof, able to withstand

cleaning chemicals, impervious, non-absorbent, washable, water repellent and constructed of non-toxic

materials?— Are internal doors close fitting to the floor and frames so as to prevent excessive air movements and pest

access?— In High hygiene areas, roller shutter doors should not be fitted. If fitted, are bottom seals without hollows

and easy to clean?

Transport and/or personal locks— Are entry and exit doors tightly fitting, self-closing and interlocked?— If the transport lock is used for transport movement, is there a plinth in the lock to prevent transport

moving from the entry to the exit?

Windows— If windows are openable, are they fitted with pest screens?— Is window glass toughened or protected against breakage or, if plastic, shatterproof?— Are window frames light coloured, tough, impact resisting, durable, rust proof, able to withstand cleaning

chemicals, impervious, non-absorbent, washable, water repellent and constructed of non-toxic materials?— Windows should have no ledges. If fitted, are they appropriately sloped?

Ceilings— Are ceilings provided, particularly in High hygiene areas?

— Are ceilings light coloured, tough, impact resisting, durable, rust proof, dust proof, able to withstand cleaning chemicals, impervious, non-absorbent, washable, water repellent and constructed of non-toxic materials?

— Are ceiling joints effectively sealed?


— If suspended ceilings are fitted, is there sufficient space above the ceiling to allow access for maintenance and cleaning and, for High hygiene area ceilings, is this space accessible only from outside the High

hygiene area?

Insulation and noise reduction

— If fitted, are acoustic panels hygienic and adhered to the wall substrate over their complete surface area?

Stairs, walkways and platforms

— Are stairs, walkways and platforms free from ledges, voids and drainable? — Are stairs, walkways and platforms made from tough, impact resisting, durable, rust proof, impervious,

non-absorbent, and easy to clean materials? Is checker plate used instead of open metal grid?

— Are handrails of a circular profile, welded and with sealed ends? — Is all supporting framework open, or if not, are all hollow sections fully enclosed?— Do all stairs, walkways and platforms over exposed product have effective kick plates?

Elevators— Do elevators connect zones of different hygienic classification?— Is the base (and headspace if applicable) of the elevator protected from pest access and easily accessible

for cleaning?

Food contact surfaces— Are building surfaces in which ingredients, intermediate and final products come into contact with

constructed of food grade materials, which are durable, corrosion resistant, impervious, non-absorbent, cleanable, able to withstand cleaning chemicals and do not yield substances which might migrate into food products?

General services— As far as possible, are services contained within suspended ceilings, service corridors or service

basements?— If services pass through food processing areas, do they pass over exposed food products and are they

sufficiently spaced from each other and supporting walls or ceilings to allow easy cleaning?— Is pipework drainable and free of dead legs? Is it suitably insulated to prevent condensation?— When services pass through walls or ceilings, are they enclosed in sleeves and effectively sealed?— Does compressed air meet the requirement of the British Compressed Air Society Food Grade

Compressed Air Best Practice Guide, http://www.bcas.org.uk/index.php— Is steam made from potable water and contains only food safe treatment chemicals. Is it filtered through a

5 µm filter?

— In dry processing areas, is dust extraction sufficient to prevent excessive settlement of dust onto environmental surfaces?

Electrical installations— Are all electrical installations protected from pest, dust and water ingress?— Are cables routed on vertical or sloped, open profile ladders/trays and are cables sufficiently spaced apart

to allow cleaning?

— If used (not preferred), are conduits fully sealed?— Are control boxes/electrical cabinets mounted either directly to a supporting structure and entirely sealed

to it or mounted sufficiently away from the support to allow cleaning? Are they mounted above exposed food products?

— Are all control buttons, switches etc. cleanable?

Ventilation and temperature control— Are all food production areas adequately ventilated to provide fresh air to operatives, to control odours and

to remove fumes, smoke, steam and vapours?— Where applicable, does room air effectively control temperature, humidity, particles, microorganisms and

any other hazards?— Are air handling units and ductwork designed for access and cleanability?— Does air flow in controlled pathways from ‘clean’ to ‘dirty’ areas?

Process and transport air— Is all air used for processes and product transfer supplied from an uncontaminated source and as a

minimum, dust filtered?

— For static process air, is the supplied air filtered to the same standard as the room air in which the process is situated?


— For air that is used for cooling or transport of product, is the supplied air filtered to a higher standard than the room air in which the process or transport system is situated?

— Is air supplied to High hygiene areas filtered to a degree that reflects the level of external microbial challenge and the time of product exposure? Is a positive pressure in the High hygiene area maintained as appropriate?

Lighting— Is lighting in all food production areas appropriate to ensure that hygienic operations can be undertaken?— Are all lighting fixtures and their supports designed to prevent the access of water, soils and pests and, on

their external surfaces, prevent the accumulation of dust?— Are all light sources suitably protected so as not to form a glass or hard plastics risk?

Water

— Does the factory have an adequate supply of potable water?— Is potable water stored securely and is access by unauthorised personnel and pests sufficiently

controlled?— Are all water potable and non-potable water streams completely separated in identified pipework such that

cross-contamination is not possible?— If non-potable water sources are used for product ingredients, as processing aids or for cleaning, has the

use of such water been risk assessed?— In dry food production areas, is the routing of water pipework eliminated?— Is sewage and domestic waste entirely separated from other water waste streams?

Food and solid waste— Is waste removal counter to food production flows and unable to contaminate open food products?— Is waste disposed to appropriately constructed, closable containers made of easily cleanable, impervious

materials?— Are waste disposal areas designed and constructed to have impervious floors, sloped to drain and

segregated from food manufacturing areas so that food products and potable water cannot be contaminated?


hygienic engineering design

Documents

ehedg guidelines

hygienic design principles

hygienic design criteria

hygienic building design

ehedg document

site location

site plan

controlled site access