best practice for the construction industry

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Pest minimisationBest practice for the construction industry


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1.0 Introduction

Aim of documentThis document provides guidelinesdesigned to minimise pest problems thatmay be created inadvertently by the workof architects, developers and builders inthe construction industry. It covers thoseaspects of pest management that arerelevant to planning, design, demolitionand construction.

The document has been produced bythe Chartered Institute of Environmental

Health Olympic Working Group. It is notintended to be fully inclusive but aims toprovide the key principles of best practice.The annexes provide more detailedinformation on specific pests.

Although, the 2012 Olympic/ParalympicGames have been the main driver for theformation of this guidance, the principlescan be applied to other constructionprojects at local, regional and nationallevels.

Further documents are planned to form asuite of advice and best practice to helpconsistency in the managementand control of pest infestations.

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Public health risk and pestminimisationThe Chartered Institute of EnvironmentalHealth (CIEH) recognises the importanceof protecting workers and the public fromthe wide range of threats to health andwellbeing from pests, such as rodents, birdsand mosquitoes that may be associatedwith construction work. Such disease risksinclude salmonellosis, toxoplasmosis,ornithosis and leptospirosis. It is alsoimportant to ensure that the planning

and design of new projects do not createavoidable additional problems.

In addition, rats, mice, grey squirrels andother pests can have a serious structuraland financial impact on the buildingsthemselves, damaging thermal insulation,electrical wiring, drainage systems andother structural components.The aesthetic appearance of newbuildings can also be rapidly spoiled bybird fouling.

Apart from problems arising during

demolition and construction of buildings,the Olympic/Paralympic developmentalso involves the creation of new habitatssuch as artificial water bodies. Designand maintenance of such areas shouldbe carried out to avoid increasing risksto workers, local residents and the publicfrom pests such as mosquitoes.

There is a real need for planners, architectsand builders to recognise and minimisethe risks of pest infestation and diseasetransmission within new developmentsand to ensure that they do not create

conditions that encourage and supportpest infestation.

Planners, in particular, need to recognisethat developments in areas of significantpest pressure require potential problemsto be addressed as part of the planningprocess.

This is vitally important for the 2012Olympic sites. The impact of negativepress coverage, with or withoutpublic health incidents, must not beunderestimated.

General expectations on developers andconstruction workersArchitects and building designersare expected to recognise and takeinto account pest minimisation andmanagement issues in the design of theirprojects and to obtain professional adviceon these issues as necessary.

Developers and construction contractorsare expected to employ qualified pestcontrol professionals where necessary,

and to work with them to develop andfollow safe, effective and environmentallyresponsible pest management strategies.Such strategies should be capable ofbeing audited as part of the projectmanagement programme.

Such expectations are part of the generalresponsibility of site management toprovide a safe working environment foremployees, contractors, and others whomay affected by their work, under theHealth and Safety at Work, Etc. Act 1974.

The local environmental health service,within the local council, will be able to givemore information and advice.

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2.0 Design of new build / refurbishment / redesign

To minimise opportunities for pests,it is essential that the design of newbuild property and refurbishmentsdoes not create points of pest ingressand harbourage, and should optimiseaccessibility for cleaning, sanitation andpest inspection.

DrainageSuitable pest proofed drainage systemsshould be used. For example earthenwarebelow ground drainage in preference

to plastic systems which can be morevulnerable to rat damage from gnawing ifnot properly installed.

Rodent proof drainage systems should beadopted on all new build / refurbishmentprojects to prevent rat egress from thesewers to the building structure, forexample incorporating earthenware ratbarrier drainage fitments as appropriate.

Entry pointsTo avoid the risk of pests entering anddispersing through buildings, cracks and

crevices in floors, walls, and ceilings mustbe avoided or, where unavoidable, theymust be effectively sealed.

Supply pipes and cables, such as gas,electricity, water, computer and telephone,must be tightly sealed where they passthrough floors and walls.

ExternalExternal structures should be designedto avoid creating unnecessary pestharbourage. For example windows, ledges,flat roofs, roof edges, air vents and otherfeatures should be designed to preventroosting of birds such as feral pigeons Etc.

Suitable areas should be designed intoall property and environmental layoutsto facilitate effective waste managementpractices including recycling.

External ground surfaces should be gradedto drain into suitable drainage systems toprevent ponding.

When landscaping sites, the use ofground-hugging or thorny plants andshrubs should be avoided, in order to denyharbourage for rodents and to allow accessfor inspection and treatment.

Annex 1 has more detailed informationon rodent proofing; Annex 2 coversmosquitoes, midges and flies; and Annex 3

bird proofing.

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3.0 Demolition / refurbishmentand construction of properties

DemolitionDemolition of buildings containing a pestinfestation can result in a dispersion ofthese pests into the surrounding area andmay also result in the same pests infestingthe new buildings.

Six weeks prior to the commencementof any demolition, individual blocks,properties and the surrounding areashould be surveyed by professional pestcontrol staff in order to identify the

presence and extent of any infestations.Where infestations are identified,appropriate treatments must beimplemented to eliminate infestationbefore demolition.

Unprotected exposure to the debris arisingfrom bird infestation in disused buildingscan result in disease such as ornithosis.Such debris should always be dealt with byfully trained persons wearing appropriatepersonal protective equipment.

Sewers and rodents

Rats live in sewers and move throughdrainage systems. They come to thesurface and enter buildings through breaksand faults in the drainage system.

Capping of drainage systems should becarried out where appropriate to isolateold redundant sewers /drains, includingthose servicing properties that have beenvacated and are awaiting clearance anddemolition.

Redundant drains and sewers should begrubbed out and the connection with the

sewer effectively sealed.

Live sewer connections should beappropriately sealed and capped whileconstruction works are in progress toprevent rat egress from the sewers.

To prevent rat egress from live drainsand sewers to new systems, the livesystems should be temporarily sealed offwith expanding drainage stoppers untilconnection to new drainage is completed.

Pest monitoring and baiting programmesshould be instigated on construction andrefurbishment sites, including a proactivesurface monitoring baiting programmeduring the demolition / constructionprocess. Exposure of construction staff torisks associated with a rodent infestationmay contravene the Health and Safety atWork, Etc. Act 1974.

An all-encompassing sewer rat monitoringprogramme should be implemented in the

sewer systems within the project area forthe duration of the project.

Sewers and drains should be cleared ofany remaining building debris.

Site hygieneContractors should ensure thatconstruction sites are kept as clear andtidy as possible. Accumulations of surplusor damaged building materials can actas harbourage for pests, and should beremoved and disposed of promptly andsafely.

Construction staff should not leave fooddebris within buildings under construction,as this will encourage pests to becomeestablished.

Staff site facilities including canteens,accommodation and sanitary provisionshould be constructed and maintainedin a clean and hygienic manner and inaccordance with relevant regulationsand codes of practice. Waste must bestored safely in suitably located, pest-resistant, closable containers and removed

frequently.

Further information on the Workplace(Health, Safety and Welfare) Regulations1992, which apply to construction sites, isavailable from the London Hazards Centre(see www.lhc.org.uk/members/pubs/factsht/48fact.htm).


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4.0 Working with pest control contractors

Working practicesMost pest control work on site will becarried out by a professional pest controlorganisation, typically either from thelocal authority environmental healthdepartment, or from a pest controlcompany which is a member of arecognised trade body.

Maintaining and recording Pest monitoring should be planned

and documented. This will include

the use of site plans/drawings. Theplacing of monitoring devices needsexperience and knowledge of pestbehaviour. If this expertise is notavailable in your organisation it will benecessary to consult with a professionalpest controller. Local authorityenvironmental health departments,pest control firms, or specialistconsultants can provide this assistance

All pest monitoring devices shouldbe labelled with a date and placed ina recorded location. This should be

mapped or recorded in document form

Insect and rodent survey points shouldbe placed in potential harbourage oractivity areas and checked monthly forinfestation. Results from inspectionsshould be recorded

A building perimeter inspection shouldbe conducted to verify that thereare no access routes for rodents. Thisincludes doorway thresholds, pipepenetrations and any other location forpest entry

An interior inspection should beundertaken to check that the plumbingfixtures, especially WC traps, foodpreparation areas, and waste storageare free from pest problems

Full records of inspections, notificationsof pest problems, visits by pest controlprofessionals, use of pest controlmethods/pesticides including safetydata sheets should be maintained.These records should be kept safelysince they may be required in the event

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It is particularly important that anyrecommendations made by the contractorshould be discussed and implemented asappropriate. The developer and buildermust share in the responsibility to addresspest problems.

The pest controller should be givenadvance notice of any changes to the site,such as demolition or completion, so thatany pesticide bait points can be removedif necessary. This also relates to any

damage caused by construction workers toany bait points, etc.

Use of pesticidesGood pest control is based on creatingconditions which prevent pests frominfesting premises. However, often thiswill not be possible and many controlmeasures will involve the use of pesticides.

Under the Control of PesticidesRegulations 1986 and 1987 (as amended)it is illegal to advertise, sell, supply, storeor use a pesticide in the UK unless it has

been approved by ministers for that use.

All approved pesticides carry an HSEreference number on the label confirmingthat they have been approved under theControl of Pesticides Regulations 1986 or1987 (as amended). Checks should beundertaken to ensure that only approvedpesticides are being used, since the useof illegal pesticides may have insuranceconsequences.

Many of the pesticides used in theconstruction industry will be approved for

professional use only. In this context,professional use is defined as use bysomeone who has received appropriateinformation, instruction and training; iscompetent to carry out the duties they arecalled upon to perform; and is required touse the pesticide as part of their work.

This means that only a properly qualifiedpest control operator should be employedto carry out any work required.

The usual minimum general qualificationin the pest management industry is the

RSPH/BPCA level 2 in pest management.

Details are available from the RoyalSociety for the Promotion of Health.

Additional specialist courses are alsoavailable, such as for the control of birds,mosquitoes and drainage. Builders shouldensure that pest control contractorsstaff have attended these courses, whereappropriate.

Storage of pesticides and personalprotection equipment

There are health and safety guidelinesfor the storage of chemicals and otherequipment (particularly PPE) used in pestmanagement and these should always befollowed.

Pesticides should not usually be left onsite. However, where this is unavoidable,they should always be stored in well-ventilated, secure areas where there isno risk of spillage contaminating watercourses. Guidance is available from thelocal Health and Safety Executive office orfrom www.HSE.gov.uk/pubns/ais16.pdf.

Post treatmentResearch has shown that where rodentsare controlled with second generationanticoagulant rodenticides, there is adanger that non-target species, such asRed Kites, may take the carcass as a foodsource and so risk secondary poisoning.Pest control contracts must allow forseeking and collecting rodent carcasses aspart of the treatment. It is also importantthat unused bait is also collected at theend of the treatment and disposed ofsafely.


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Pests can only infest a building if they cangain entry and then survive and breed init. Good proofing is based on denying thepest either entry or the right conditionsin which to survive, ie food, water or safeharbourages.

BUDGS

Holes and openingsRats can squeeze through any openinggreater than 6mm wide. Smaller openings

are often enlarged by gnawing. Mice canenter a building through openings greaterthan 5mm wide.

To prevent rodent entry, such holes shouldbe plugged with durable materials. Coarsesteel wool is a good temporary plug whenpacked tightly into openings. Copper andstainless steel wool are also effective andlast longer. Close openings around augers,pipes, and electrical conduits or cableswith concrete, mortar, or metal collars. Fillholes with crushed wire mesh before usingcement. Any unprotected opening is an

invitation to rodents.

Foundations and floorsNormal foundations will normally preventrodents from burrowing beneath them.

They will normally exclude rodents if theyextend vertically to a depth of about900mm or have an L shaped curtainwall which is about 600mm deep and a300mm projection away from the building.

There should be no breach in thefoundations larger than 9mm.

Cracks in foundations should be repairedwith concrete or masonry grout. If ratshave access to a building crawl space,

modify the floor to prevent them fromgetting into the walls.

Oversite concrete floorsThese should be laid so as to covercompletely the area within the containingwalls. To prevent rodent entry the oversiteconcrete should also completely fillbetween the walls. Gaps left to allowfor movement should be filled with nonhardening sealant.

External and cavity wallsThese should be built so that there are

no holes externally or internally greaterthan 5mm.

Ventilator bricks should have no holeslarger than 5mm unless they are protected

with a wire mesh of 4mm nominal size ofopening and should be cased through thecavities.

Use of cavity closers at the tops of wallshave the added advantage that theycan deny rodents and birds access to thecavity wall at roof level.

DoorsDoors should be designed to close onto alevel threshold which will deny rodents a

gnawing edge, with the gap beneath thedoors of no more than 5mm. To excluderodents, letter plates must not be lowerthan 460mm or they must open outwards.

In cases where external doors provideaccess to high risk areas such as kitchensand food stores they should be either ofmetal construction or fitted with metalkicking plates on the outside. These kickingplates should be no less than 300mm high.Hinged or sliding doors should be fittedwith self closing devices.

RoofsSpaces between joists and rafters shouldbe filled at the eaves so that if rats or mice(or birds and squirrels) can gain accessunder the eaves, they cannot enter the

Annex 1- Rodent proofing

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roof space. Ridge and hip tiles in pitchedroofs, and those at gable ends, should alsobe bedded in mortar.

nternal walls and ceilingsInternal portioning and ceiling cavitiesshould be sealed efficiently to denyaccess. Floor joists should be built in orhung on joist hangers so that any cavitybetween floor and ceiling is effectivelysealed from that in the adjacent wall orpartition.

Hollow spaces behind skirting boards,architraves and other moulding should beavoided as far as possible. All holes cut forpipes, jacketing or other fittings should besealed.

FittingsPipes, ducts and trunking should be tightlybuilt in wherever they pass through walls,floors, ceilings or foundations. Spaces ofmore than 5mm must be avoided.

It is particularly important that pipes,

cables, drains, ducts and ventilators thatpass between buildings through outerwalls and foundations are also carefullybuilt in.

SERES

Refuse disposalRefuse disposal areas present a highrisk of infestation. Design should enableeffective cleaning, inspection and avoidopportunities for the accumulation ofresidues.

Access between the storage and collectionareas for refuse should avoid entry todwellings. Doors to bin storage areasshould ideally be metal, tightly closing andself closing unless they open directly to theoutside in which case they should be keptlocked.

Hoppers, chutes and containers for rubbishneed careful design to ensure that theirwalls do not provide traps for the rubbishor footholds for rodents.

ift shaftsRodents must be prevented from accessinglift shafts, not only to prevent access tothe building but also to avoid damage toelectrical systems.

The base areas of lift shafts must beaccessible for cleaning and the removal ofaccumulations of rubbish.

nterior rodent controlWhen rats or mice are present in a

building, attention must be given tointerior as well as exterior rodent-proofingto remove all sources of shelter.

Eliminate hiding places for rodents. Payattention to storage rooms, feed rooms,closets and other areas where constructionmay be poorly finished, allowing rodentsaccess to walls, floor spaces, or attics.

Miscellaneous debris provide shelter torodents and make rodent control moredifficult. Such debris needs to be removedand disposed of regularly. Store refuse

pending removal in properly coveredcontainers.

Protect perimeter insulationPerimeter insulation is a necessarypart of energy-efficient construction.Insulation that is installed on the exteriorof foundation walls, however, is subject toboth mechanical damage and destructionby rodents.

To prevent damage to perimeter insulation,use sandwich wall construction that hasinsulation placed within the concrete.

GroundsMaintain a clean, weed and accumulationfree area around buildings. Maintain bymowing vegetation regularly.

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Annex 2- Mosquito and fly breeding prevention

Mosquito preventionSome types of mosquito bite peopleand therefore have the potential tocause nuisance, and to transmit disease.Currently in the UK mosquitoes areprimarily a nuisance pest. The immaturestages of mosquitoes are found in water,and the adults then emerge to seek bloodmeals.

For construction sites, the most commonmosquito breeding sites are temporary

accumulations of water such as:

Canvas and plastic sheets Puddles on the ground/concrete floors Discarded receptacles and

building waste Water storage drums, tanks and

containers Discarded used tyres Bulk waste containers Trenches Uncompleted lift wells Drains or channels temporarily

constructed to drain off water

Water in ruts, uneven orwaterlogged ground

The above will pose a greater risk ofbreeding mosquitoes than properlydesigned and maintained water-features,ponds and lakes.

Water conveyance and storage systemsshould not allow leakage and seepagethat may create water-logged areas.

Unsewered water from construction andindustrial uses should be adequately

contained and disposed off to preventponding.

Ponds and lagoons should be kept free ofdebris and algal blooms.

If mosquitoes or other biting, flying insectsare causing a nuisance, a professionalpest control organisation should surveythe area and make recommendations asnecessary to remedy the problem.

Qualified pest control operators will holdthe RSPH level 3 certificate in mosquito

control.

Midge preventionSome dockland and canal-sideregeneration schemes have experiencedproblems with chironomid midgesbreeding in large numbers in disuseddocks. The midges have caused significantnuisance and allergy problems for nearbyresidents and food contaminationproblems for catering premises.

Midge breeding can be reduced byretaining a flow of water through such

docks. Where this is not possible, thenartificial aeration may be required toreduce breeding, and in some casespesticide use may be required althoughthis will require the use of pesticides withspecial approvals.

Housefly preventionSignificant problems with houseflies areprimarily associated with inappropriatestorage or disposal of putrescible oranimal waste.

Putrescible waste from construction

staff accommodation and from cateringpremises should be sited, stored anddisposed of in accordance with bestpractice. The risk of fly problems is greatlyincreased in warm weather.

In the event of problems, the wastestorage area may be need re-locating,the waste removed more frequentlyand waste containers cleaned afteremptying. Inspection and treatment by aprofessional pest control organisation maybe required.

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Damage potentialFeral pigeons and certain species of gull,for example the Herring Gull and LesserBlack-Back Gull are potentially a sourceof risk to health and safety in the urbanenvironment. A range of diseases havebeen shown to be carried by birds living inurban environments.

Buildings are defaced by the droppingsdeposited by pigeons and in some casesbuilding structure can be undermined by

the large accumulation of droppings.

The feral pigeon uses urban buildings asconvenient roosting sites while waiting tofeed on debris from fast food outlets andby well meaning members of the public.

Both Herring Gulls and Lesser Black-BackGulls are becoming an increasing problemin towns and cities, nesting on rooftops.They will aggressively protect theirterritory, especially when they have young.

These species of bird are attracted mainly

by the abundant food source availableand the available roosting sites providedin towns and cities.

egal statusUnlike most other pest species, birds have

legislative protection unless it can beproved that their presence is detrimentalto man in some way.

Under the European Wild Birds Directive1979, applied through the Wildlife andCountryside Act 1981, all wild birds, theireggs, nests and habitat are protected.However, member states may derogatefrom the provisions in the directive, wherethere is no other satisfactory solution, forthe following reasons:

In the interests of public health andsafety

In the interests of air safety To prevent serious damage to crops,

livestock, forests, fisheries and water For the protection of flora and fauna

In the UK, General Licences, issued andrevised annually by Natural England, listthe birds that can be taken. The licencesalso state the reasons for such action,methods of control and that the workmust be carried out by an authorised

person (authorised person means theowner, occupier or someone authorised bythe owner or occupier in writing).

These licences do not have to be appliedfor. They are a legislative means of

removing the protection of certain birds,regarded as pests, from the generalprotection afforded them through theWildlife and Countryside Act 1981.

Population controlReduction in numbers by one of theapproved methods, shooting, trappingetc will provide only short term relief. Thismethod should only be used to providetemporary relief until proofing work iscomplete, or to clear derelict buildings of

pest birds prior to demolition.

Management of pest birds can be dividedinto three distinct categories:

i Reduction/removal of food sourcesThe number of birds in an area willbe directly influenced by the foodsource available. Therefore, goodwaste management and discouragingmembers of the public from feedingthe birds (mainly feral pigeons) willnaturally reduce the bird numbers overa period of time.

ii Removal of roosting sitesDesign of new buildings should takeinto consideration ledges, windowsills and any other feature that mightprovide roosting sites for birds. An

Annex 3- Problems with pest birds

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angle of 45 or more will prevent birdsfrom roosting. Maintenance of existingbuildings should be carried out toremove potential ingress points for feralpigeons. These would include missingroof tiles, broken windows and areaswhere maintenance work has beencarried out and holes left in the fabricof the building.

Roofs should be designed and detailedspecifically to exclude birds by keeping

all gaps and openings below 20mm

iii Proofing against bird nestingand roostingProofing measures such as netting andstainless steel spikes can be used todeter birds from roosting on buildings.

Netting mesh sizes for bird proofing willvary according to the species of bird.As a guide, the following mesh sizes arerecommended:

Sparrows and similar size birds - 19mm

mesh size Starlings - 28-30mm mesh size Pigeons - 50mm mesh size Gulls - 75mm mesh size

Spike systems will deter birds fromroosting on ledges that cannot be

made inaccessible by netting. Theyshould be fixed in a manner that willensure that the ledge is adequatelycovered by the spikes.

Bird proofing is specialist work. Anexperienced installer should beconsulted for advice and proofingstrategies.

It should be noted that birds other thanthose listed on the general licences

cannot be prevented from accessingtheir nest site during the breedingseason. To do so would be a breach ofthe Wildlife and Countryside Act 1981and prosecution could follow. NaturalEngland should be consulted in allcases where non-listed birds need to bedisplaced.

Urban pest bird control is a complexsubject and requires an integratedapproach which will include wastemanagement regimes to minimiseattractive food sources; maintenance

and design of buildings that will reducepotential roosting and nesting sites andproofing strategies that will excludepest birds from prioritised areas.

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Building Research Establishment Digest 238, August 1992:Reducing the risk of pest infestations: design recommendationsand literature review. ISBN 0 85125 173 0

Building Research Establishment Digest 415, May 1996: Reducingthe risk of pest infestations in buildings. ISBN 1 86081 0862

Iatrou, G., Maskalidos, G., Garlis, N., Politis, M. 2006. Wide areapest control : the examples of the Olympic Games (2004).Abstract Book of the SOVE 15th European meeting, Serres, Greece,10-14 April, 2006. p.28

Lea, R.G. 1996. Cockroaches in the UK: designing buildings toreduce the risk of infestation. Proceedings of the 2nd InternationalConference on Insect Pests in the Urban Environment. K.B. Wildeyeditor. p 573-578

Murphy, R.G., Todd, S. 1993. Towards pest free dwellings inthe urban environment. Proceedings of the 1st InternationalConference on Insect Pests in the Urban Environment. K.B. Wildeyand W.H. Robinson, editors. p 423-432

Russell, R.C. 1999. Mosquito-borne disease and mosquitomanagement in Australia for the Olympic Games in the year2000. Proceedings of the 3rd International Conference on UrbanPests. W.H. Robinson, F. Rettich, G.W. Rambo: editors. p 59-66

Willems, K. and Russell, R.C. (1997). Freshwater mosquito controlfor the 2000 Olympics. Arbovirus Research in Australia, 7: 357-358

Further electronic copies are available from www.cieh-npap.org

References and further reading


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The National Pest Advisory PanelChartered Institute of Environmental Health

Chadwick Court, 15 Hatfields, London SE1 8DJTelephone 020 7928 6006 Fax 020 7827 5831This report is printed on totally chlorine-free and recyclable paper, produced from sustainable forests.

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