TECHNICAL SPECIFICATIONS

Part IA: Preliminary Matters

1. Specification

Where no particular specification is given for any material or item of work, the latest edition of relevant British Standard Specification shall apply.

In the event of there being a disagreement between the information shown on the drawings and the specification the drawings shall take precedence.

Any clause that may appear under a given section within this specification shall not be limited to work only of that section but may be applied wherever relevant.

2. Alternative Design

Where the Contractor wishes to propose an alternative method of construction or material to that specified for any part of work, full details shall be submitted with the tender. The acceptance or otherwise of any alternative shall be entirely at the discretion of the Project Supervisor’s Representative.

3. Services

The Contractor shall provide and maintain the following services for the Project Supervisor’s Representative Offices and Accommodation to the satisfaction of the Project Supervisor’s Representative and his relevant authority. – (Not applicable)

4. Communications

The Contractor shall supply and maintain during the period of execution of the works a telephone or other system of communication for the exclusive and private use of the Project Supervisor’s Representative and his staff as described in the Contract.- (Not applicable)

5. Surveying Equipment

The Contractor shall supply surveying instruments, tapes etc, as it will be required in the Contract for the exclusive use of the Project Supervisor’s Representative and his staff during the period of execution of the works or as otherwise directed.

All instruments shall be maintained in accurate working order and replaced if reported inaccurate by the Project Supervisor’s Representative.

6. Testing

Testing equipment shall be supplied by the Contractor for the period of execution of the works as detailed in the Contract. The equipment shall be set up in the laboratories provided under the Contract as directed, and maintained in accurate working order throughout the period of use.

7. Vehicles

The Contractor shall place at the disposal of the Project Supervisor’s Representative and his

staff for their exclusive use at all times vehicles while attending the site works. (Not

applicable)

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In case the vehicle is supplied under this Contract, the Contractor shall supply fuel for the vehicles on all business journeys and shall keep the vehicles fully taxed and insured for any licensed driver and maintained throughout the period of their use. At the end of the Contract period, the vehicle shall be the property of the Client.-(Not applicable)

All vehicles shall be fitted with seat belts on the driver and front passenger seats. At the end

of the Project, the vehicles shall the property of the Client. (Not applicable)

8. Attendance on the Project Supervisor’s Representative

The Contractor shall supply casual labour as required by the Project Supervisor’s Representative for the assistance of his staff.

9. Contractor’s Camp

The Contractor shall be responsible for provision of all offices, workshops etc, which he considers necessary for his own operation and for the satisfactory housing of all his employees.

The Contractor shall be responsible for all negotiations necessary for the establishment of his camps and for compliance with Municipal and Government Regulations.

If it is the Project Supervisor’s Representative’s intention to move the site of his main camp during the course of the Contract notice of such intention shall be given at least six months in advance.

10. Water Supply

The Contractor shall provide an adequate supply of water from an approved source to all parts of the site at all times for the construction of the works.

11. Explosives and Hazardous Materials

The Contractor shall provide suitable storage for explosives and other dangerous materials, which shall be approved in writing by the Project Supervisor’s Representative.

The Contractor shall take all responsibility during blasting operations and shall comply with all conditions set forth in any local authority regulations.

12. Signboards

The Contractor shall provide and erect a signboard of approved design at the entrance of the works, and elsewhere as directed, which shall state the title of the works as in the tender documents, and the names of the Contracting Authority, the Project Supervisor’s Representative, and Contractor and Nominated sub-contractors if any. The proposed presentation for the signboard is as presented in the book of drawings.

13. Mosquito Control

The Contractor shall prevent the breeding of mosquitoes within 300 m of the residential camps by means of spraying and elimination of stagnant water.

14. Access to Site

The Contractor shall maintain vehicular access to the whole site at all times.

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15. Plant and Labour Returns

The Contractor shall supply at the end of each month schedules showing the hours worked by each member of the Contractor’s staff and the hours worked, hours standing and hours broken down of each item of his plant.

16. Setting out Beacons

The Contractor shall be responsible for the maintenance and replacement as necessary during the period of the works of all permanent setting out beacons.

The beacons shall be regularly checked to ensure their accuracy. Any beacon, which has been disturbed, shall not be used until its level and position has been re-established by the Contractor and checked by the Project Supervisor’s Representative.

Boundary pegs established by any other authority must not be covered or damaged in any way. Any pegs or markers, which have been displayed or damaged, shall be replaced by a qualified surveyor at the expense of the Contractor.

17. Levels

No works shall commence upon any portion of the Contract until such time as ground levels have been taken by the Contractor and checked and accepted by the Project Supervisor’s Representative to ensure that a firm basis has been established for measurement purposes.

18. Temporary Works

The Contractor shall submit to the Project Supervisor’s Representative details and calculations where appropriate of all temporary works for checking and written approval at least eight weeks before he intends to start work.

Notwithstanding the foregoing, the Safety of the temporary works remains the responsibility of the Contractor.

19. Site Clearance

The Contractor shall clear each part of the site at the times and to the extent required and approved by the Project Supervisor’s Representative.

Bush cleared shall be carried out over the whole area to be occupied by the works and shall include the removal of bushes, small trees, grass, roots, mud and grass huts and similar structures. Pipe tracks shall be cleared for a minimum distance of 1.5m either side of the excavation unless otherwise directed.

Large trees with girth excess of 500 mm measured 1 m above ground level shall be cut down and the roots grubbed out. No large trees shall be cleared until they have been measured by the Project Supervisor’s Representative and his permission given.

All holes left as a result of site clearance shall be filled with compacted suitable fill material within a period of ten days.

All materials arising from site clearance and not suitable for re-use in the works shall become the property of the Contractor and shall be disposed of by him in a manner approved by the Project Supervisor’s Representative.

Materials deemed by the Project Supervisor’s Representative to be suitable for re-use in the works shall be stockpiled at his direction.

20. Top Soil

Top soil shall be defined as the top layer of soil capable of supporting vegetation.

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Top soil shall be removed from the areas below earthworks and permanent structures, from areas to be used as borrow pits, from the line of pipe runs and elsewhere as directed.

Top soil shall be stockpiled for re-use in locations approved by the Project Supervisor’s Representative unless other-wise directed.

21. Privately Owned and Public Utility Services

The Contractor shall acquaint himself with the positions of all existing overhead and under-ground cables, drains and other services before carrying out the works.

Under no circumstances shall structures and other obstructions in the ownership of public utilities authorities be interfered with without the written permission of the Project Supervisor’s Representative.

If any privately owned or public utilities service passing through the site will be affected by the works, the Contractor shall provide a satisfactory alternative supply in full working order to the satisfaction of the owner of the service and the Project Supervisor’s Representative before cutting the existing service.

22. Fire

Special care should be taken by the Contractor to prevent the starting of bush fires.

The destruction of rubbish by fire will only be allowed with written authority of the Project Supervisor’s Representative.

23. Borrow pits

No borrow pit or access road shall be opened up without the approval of the Project Supervisor’s Representative and the permission in writing of the landowners.

Overburden is to be stripped and stockpiled separately from topsoil.

Pits shall be worked within the limits of area and depth as approved by the Project Supervisor’s Representative.

Where a pit contains material of varying quality it shall be mixed together or screened to obtain a product to the satisfaction of the Project Supervisor’s Representative.

On completion of the operations from a pit the overburden shall be bulldozed back into the pit and the area graded off with no slope greater than one in two to the approval of the Project Supervisor’s Representative and landowner. The topsoil shall then be spread uniformly over the whole area.

24. Safety, Health and Environmental Reports

The Contractor shall be responsible of preparing safety, health and environmental manuals for Project Supervisor’s Representatives approval. The Contractor shall also issue monthly reports on safety, health and environmental.

25. Forms for Monthly Statements

Monthly statements shall be submitted in the manner set out hereunder on forms to be provided by the Contractor. Each statement shall be submitted to the Project Supervisor’s Representative through his representative, interim statements being in quadruplicate and the final statement being in quintriplicate.

Such forms shall be printed or duplicated to the approval of the Project Supervisor’s Representative’s Representative as soon as practicable after the order to commence the Work has been given.

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Part IB: General Matters

1. Work Programmes

Within 14 days of signing the Contract the Contractor shall prepare a time and progress chart showing the time and order in which the proposed work is to be carried out within the total construction period stated in the Contract. The chart shall show in detail the construction time and order in which each section of the work is to be carried out and be subdivided into trades or tasks. The chart shall also show critical path, alternative path and ordering and delivery times for materials and components. If the Contract contains individual installations and buildings a separate chart shall be provided for each.

Upon the letting of Subcontracts the Contractor is to incorporate each separate Subcontractor's work and the chart shall be designed to accommodate this information.

At the end of each week the Contractor is to mark on the chart, in a different colour, the actual time taken to complete the respective stages and section of the work. Actual progress to be superimposed on the chart

Before the 25th day of each month the Contractor shall submit a monthly progress report in triplicate to the Project Supervisor’s Representative indicating progress and giving details of any delays caused by inclement weather or other reasons beyond his control. The report must include information on labour employed, and the progress of all trades, including nominated subcontractors. The report shall be based on the Contractors own daily reports.

2. Progress Photographs

The Contractor shall arrange with a photographer the taking of progress photographs during the construction. The photographs shall be taken at intervals of one month and delivered in triplicate in an appropriate folder A4 size. The pictures shall be accompanied by a descriptive text.

3. Checking Schedules, Drawings, etc.

The Contractor shall be responsible for checking all schedules and drawings supplied by the Project Supervisor’s Representative. In the event of any discrepancy being found between such schedules and drawings the Contractor shall report such discrepancy to the Project Supervisor’s Representative for instruction at least 28 days before the works concerned are to be executed.

4. Working Drawings

The Contractor shall prepare all working drawings to such detail that works can be carried out on site.

One copy of all working drawings shall be submitted to the Project Supervisor’s Representative for acceptance. The working drawings shall be in SI units, i.e metres and millimetres only. Following acceptance by the Project Supervisor’s Representative two copies shall be submitted.

5. As built drawings

For the As-built documentation see the requirements in the Technical Specifications.

After completion on site, the Contractor shall prepare As-built Drawings of the implemented and completed Contract Works. Site record drawings and other documents shall be available to the Project Supervisor’s Representative for inspection and checking, and copies submitted on request.

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Recording of the actual work, which has been implemented, shall be kept up to date and completed by the date of sectional or overall completion.

The Project Supervisor’s Representative will review the site recording drawings to see whether they are up to date before approving the Contractor's requests for interim payments.

Completed As-built Drawings shall be prepared on approved transparencies.

Catalogues, Final documentation, and Operating and Maintenance instructions for equipment and plant supplied and installed shall be submitted together with the As-built drawings.

For preparation of Working Record Drawings the Contractor will be supplied with prints of Contract Drawings where required.

6. Access to Contractor's Records

The Project Supervisor’s Representative may request copies of all files, drawings, documents, records etc. in connection with the execution of the works.

7. Details to be Private and Confidential

The Drawings, Bills of Quantities and Contract Documents applicable to this Contract are protected by copyright.

The Contractor shall treat the details of this Contract as private and confidential for own information only and shall not publish or disclose the details of the Contract in any trade or technical paper or elsewhere without the previous written consent of the Contracting Authority.

8. Faulty Work

Any work, which fails to comply with the Contract, may be rejected and the Contractor shall, at his own expense, make good any defects, as directed by and to the satisfaction of the Project Supervisor’s Representative.

9. Existing Services

The Contractor shall investigate the location of all existing services, such as drains, underground and overhead telephone and electricity lines, ducts poles, water mains, fittings, etc. before any excavation or other work likely to affect the existing services is commenced.

The Contractor shall be responsible for arranging the removal or alteration of such services in conjunction with and to specifications of the owner.

10. Setting Out the Works

The Contractor shall set out the Works in accordance with the dimensions and levels shown on the drawings and shall be responsible for the correctness of all dimensions and levels so set out. The Contractor will be required to amend all errors arising from inaccurate setting out at own cost and expense. In the event of any error or discrepancy in the dimensions or levels marked on the drawings being discovered such errors or discrepancies must be brought to the Project Supervisor’s Representative’s immediate attention.

11. Samples

Samples of proposed materials and workmanship shall, if required by the Project Supervisor’s Representative, be submitted for approval, and those samples will be left on site by the Project Supervisor’s Representative who shall have power to reject all such materials and condemn such workmanship that does not correspond with the approved samples.

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Any material, which has failed to obtain approval by the Project Supervisor’s Representative, shall be removed from the site within 7 days.

12. Tests

The Project Supervisor’s Representative may, whenever it is considered desirable, test any materials before they leave the maker's premises as well as after delivery on the site, and the Project Supervisor’s Representative shall be entitled to reject any materials after delivery should he consider them unsatisfactory, notwithstanding the preliminary test and approval of the materials at the maker's premises. The costs of these tests are to be borne by the Contractor.

When directed by the Project Supervisor’s Representative, samples of materials are to be supplied by the Contractor for laboratory tests and shall be delivered by the Contractor at own cost to the test laboratory in Dar es Salaam or as otherwise directed.

The Contractor shall, whenever so instructed by the Project Supervisor’s Representative, cut out sections of work executed or samples of materials incorporated therein and shall deliver them where directed for the purpose of testing.

All work disturbed shall be made good forthwith by the Contractor. All costs incurred in cutting out, making good and delivering as aforesaid, shall be borne by the Contractor unless the result of the test shows that the materials etc. are in accordance with the specifications.

If work carried out by the Contractor does not fully comply with the Specifications and the Project Supervisor’s Representative has given adequate notice to the Contractor who subsequently fail to rectify, the Contracting Authority shall deduct from any payments the Contractor all reasonable expenses related to the failure of the Contractor to properly comply with the provisions of these Specifications.

13. Land Compensation and Royalties

The Contracting Authority will also generally provide additional land that may be required by the Contractor for the construction of the works including the temporary works.

14. Clean up and Disposal of Waste Materials

All household, office, workshop and other solid waste shall be collected on a daily basis and disposed as advised by the Project Supervisor’s Representative.

Upon completion of the works and in connection with the clean up all waste pits shall be emptied and the waste removed.

Prior to completion of the work, the Contractor shall remove buildings, rubbish, unused materials, concrete forms, and other like material used during construction.

Left over and unused steel such as plate cuttings, piping ends and pieces of structural steel shall be stockpiled as directed by the Project Supervisor’s Representative.

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Part II: Materials

1. Submission of Samples

The Contractor shall submit to the Project Supervisor’s Representative a list of suppliers from whom he proposes to purchase the materials necessary for the execution of works. Each supplier must be willing to admit the Project Supervisor’s Representative or his representative to his premises during normal working hours for the purpose of obtaining samples of the material in question. Alternatively, if required by the Project Supervisor’s Representative the Contractor shall deliver the samples of the materials to the Project Supervisor’s Representative office. Samples shall be taken in accordance with the relevant British Standard where applicable.

For the Tender Prices the Contractor shall include the costs for the execution of testing herein and for supply of the requisite equipment. After initial testing and approval of materials, it is the Contractor's responsibility to ensure and to demonstrate by the submission of further similar samples when so required that subsequent deliveries conform to the quality, grading and (where applicable), colour of the approved samples.

Samples of all materials are to be submitted for approval of the Project Supervisor’s Representative at least two weeks before it is desired to commence deliveries.

No sources of supply shall be changed without prior approval.

All sub-standard material or material which becomes damaged or contaminated or deteriorates so as not to comply wit this specification shall be rejected by the Project Supervisor’s Representative and shall be removed from the site immediately and replaced at the Contractor’s expense.

All sub-standard material or material which becomes damaged or contaminated or deteriorates so as not to comply with this specification shall be rejected by the Project Supervisor’s Representative and shall be removed from the site immediately and replaced at the Contractor’s expense.

Should any of the samples tested be found, in the opinion of the Project Supervisor’s Representative, in any respect unsatisfactory or likely to produce unsound work, the whole parcel, consignment or load from which samples were taken will be rejected, and the Contractor shall forthwith remove it from the site. Notwithstanding that any sample of the material may have passed the test, the Project Supervisor’s Representative may later reject such parcels, consignment or loads if it is found that the quality has deteriorated.

No materials shall be stored or stacked on suspended floors without the Project Supervisor’s Representative's prior approval.

2. Aggregate for Concrete

Aggregates for concrete shall consist of naturally occurring material complying with the requirements of BS 882 and 1201.

Flakiness index when determined by the sieve method described in BS 812 shall not exceed 35 for any size of coarse aggregate.

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For structural concrete of specified compressive strength 40 N/mm2 or more at 28 days, the ‘ten per cent fines’ value of the coarse aggregate determined in accordance with BS 812 shall not be less than 100 kN and for other structural concrete not less than 50 kN.

Aggregates shall be stored on approved hard self draining areas. The stockpiles shall be so arranged to prevent mixing of the different types of aggregate.

Aggregate shall comply with British Standards as follows: Fine - BS 882 Table 2 Zones 1 to 3 only Coarse - BS 882 Table 1 "All in" - BS 882 Table 3

Each type of aggregate shall be obtained from one approved source, capable of maintaining adequate supplies of consistently graded material throughout the Contract. Aggregates shall be free from all impurities likely to cause discoloration and shall be of consistent colour throughout the work.

Fine aggregates and sand shall be clean, sharp, coarse, of hard materials and equal at all times to the samples which shall be deposited with and approved by the Project Supervisor’s Representative. The caustic soda test for organic impurities shall show a colour not deeper than that of the standard solution. The settling test for natural sand shall be made and after being allowed to settle for three hours the layer of silt deposit on the coarse material shall not exceed 10%.

The Contractor shall supply all necessary equipment for the testing of fine aggregates and sand for the use by the Project Supervisor’s Representative.

Coarse aggregates shall be hard, clean gravel or broken stone from approved qualities and shall be free from earth, decomposed stone, and extraneous matter. Aggregates shall be granite and not coral stones. They shall conform to B.S. 882 Table 1 and shall be "Graded Aggregate" 19mm to 5mm.

Thin, elongated, friable, flaky or laminated pieces, mica or shale shall only be present in such small quantity. The amount of fine particles occurring in a free state or as loose adherent shall not exceed 1% when determined by the laboratory sedimentation test. After twenty-four hours in water, a previously dried sample shall not gain more than 10% in weight.

Each grade of aggregate shall be stored in the works in separate heaps so that there shall be no possibility of any inter-mixing. Any materials, which have become inter-mixed, shall be removed from the site forthwith by the Contractor.

If, in the opinion of the Project Supervisor’s Representative, the aggregate is dirty or adulterated in any manner, it shall be washed and/or screened by the Contractor to the satisfaction of the Project Supervisor’s Representative.

Graded sample of all types of aggregate each weighing 10 kg, shall, after approval, be kept on site behind glass for visual checking or subsequent deliveries for grading, shape, and where applicable colour.

Aggregates shall be stored at mixer positions on drained concrete paved areas, with stout dividing walls between different sizes and types of aggregates. It shall be allowed to stand for at least 24 hours before being used.

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Before work commences and when subsequently instructed, the Contractor shall take sites samples, by methods given in BS 812 and deliver these to the nominated Testing Authority for testing.

3. Cement

Ordinary Portland cement shall normally be used (and shall comply with the requirements of BS12)

Where specified or approval is given other cements may be used and shall comply with the relevant British Standards. These include:

Rapid hardening Portland Cement – BS 12

Portland blast-furnace cement – BS 146

Sulphate resisting Portland Cement – BS 4027

High Alumina Cement – BS 915

Low Heat Cements – BS 1370 or BS 4246

Supersulphated Cement – BS 4248

Where White or coloured Portland cement is specified it shall comply with BS 12. Pigments used shall comply with BS 1014 and shall be incorporated in the concrete mix in the proportions approved.

Delivery of cement shall be made in sealed bags or in an approved bulk container and shall be used directly from the bag or from an approved storage silo in the same sequence as it was delivered.

Cement shall be stored in a weather proof shed with poised floor of approved design.

Rapid hardening cement may be used in lieu of ordinary Portland cement only with the prior approval of the Project Supervisor’s Representative provided that all conditions applying to its use are strictly observed. Any additional expenses in connection with the use of such cement shall be borne by the Contractor.

The use of high alumina cement will not be permitted. All cement shall be delivered to the site in sealed bags bearing the mark of the manufacturer. Debagged cement, cement in plain bags and cement in torn bags will not be allowed on the site.

Each consignment of cement shall be accompanied by the manufacturer's certificate showing that a representative sample of the consignment has been tested and complies with the appropriate specification. From time to time as requested by the Project Supervisor’s Representative, copies of the cement manufacturer's test certificates shall be delivered to Project Supervisor’s Representative on the site promptly, but such documents shall not preclude the Project Supervisor’s Representative from rejecting any cement which does not in every way comply with the specification.

Any cement, which has failed to pass the tests or has been damaged by water or contaminated in any way on site, shall immediately be put into bags and removed from the site.

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Cement shall be kept dry and used in rotation of deliveries. If delivered in bags these shall be stored off the ground in a well ventilated and weather proof shed used exclusively for this purpose.

The shed is to be sufficiently large to contain a working stock and provided with partitions or such other means as may be necessary, to endure the effectual separation of the various consignments and type of cement. Stacking of cement in bags over a height of ten bags will not be permitted. Cement may be delivered in bulk containers provided additional suitable arrangements are made for bulk storage on site to the approval of the Project Supervisor’s Representative.

Any bag of cement that is opened shall be used on the same day or be discarded from work. Before work commences and when subsequently directed, the Contractor shall take 6 kg samples, in accordance with BS 12 procedure, of cement and deliver these in tins approved by the Project Supervisor’s Representative to an approved Testing Laboratory for testing.

Each consignment of cement to the site, which shall be accompanied by the manufacture's advice note and forwarded without delay to the Project Supervisor’s Representative, shall be delivered to the site at least 7 days before it is intended to be used in works so that the required tests may be carried out without retarding the progress of the works.

4. Water for Concrete

Water used for concrete shall be clean and free from all harmful matter in suspension or solutions. Where directed the Contractor shall provide a chemical analysis of the water in accordance with BS 3148.

Water for use in concrete, mortar mixing and curing shall be obtained from an approved source and shall be of a quality as not to affect the setting time, strength, durability of the concrete or mortar, or the appearance of hardened concrete or mortar by discoloration or efflorescence nor the reinforcement at any age of the concrete or mortar.

The water shall preferably be obtained from the Ministry of Water and Minerals. The water shall be clean, demineralised, blended or unblended with a Ph between 5.0 and 9.0. On the Project Supervisor’s Representative's request the water shall be tested in accordance with BS 3148 and the following limits are not to be exceeded:

Total dissolved solids (TDS) Not greater than 2000 ppmSuspended solids Not greater than 2000 ppmChlorides (C1) Not greater than 500 ppmSulphates (SO3) Not greater than 1000 ppmAlkali (HCO3/CO3) Not greater than 1000 ppm

Water shall be stored in approved, clean containers, which are protected from sun, sand, dust, organic contamination or from contamination by any other source.

5. Mortar and Grout

Mortar and grout shall be mixed in the proportions given in Table B1 according to the mortar class described in the Contract.

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For work in which a Class 3 and 4 mortar is required, the Contractor shall select the appropriate mortar from one of the mixes for this class given in Table B1. If this work is to be carried out in the frosty weather and the bricks are wet when laid, then a 1:5-6 cement, sand mortar with an approved air entraining plasticiser shall be used. The plasticiser shall be free from calcium chloride or similar salts.

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Table B1- Mixing proportions

Location Class of Mortar

External Walls above D.P.C 3External Walls below D.P.C 2 or 3Engineering Construction 2Internal Walls 4

Class

Proportions By Volume

Portland Cement: Sand

Portland Cement: Lime: Sand

Portland Cement: Sand with Plasticiser

1 1:22 1:33 1:3 1:5-6 1:5-64 2:8-9 1:8

The proportions of lime given in Table B1 are for lime putty. If the lime is measured as the dry hydrate, the amount may be increased up to 1½ volume for each volume of lime putty. Where a range of sand contents is given in Table B1, the higher shall be used for sand that is well graded and the lower for coarse or uniformly fine sand.

Sand shall be natural sand or crushed natural stone or a combination of both as specified in BS 1200 and complying with the requirements of this specification for fine aggregate for concrete work where applicable.

Mortar shall be mixed thoroughly either by hand or mechanically until its colour and consistency are uniform. The constituent material shall be accurately gauged, allowance being made for bulking of sand. Mortar shall be made in small quantities only as and when required. Mortar which has begun to set or which has been mixed for a period of more than 30 minutes in the case of Classes 1 and 2 mortars, or more than 2 hours in the case of other classes shall be discarded.

6. Steel Reinforcement

Mild Steel bar reinforcement shall comply with the requirements or BS 4449.

Cold worked steel bar reinforcement shall comply with the requirements of BS 4461.

Steel fabric reinforcement shall comply with the requirements of BS 4483. The wires shall be welded at all intersections.

The Contractor shall procure and furnish to the Project Supervisor’s Representative certificates from the manufacturers that all steel supplied is in accordance with these conditions.

Reinforcement shall be stored on racks clear of the ground.

Tying shall be either 16 S.W.G soft annealed wire of 18 S.W.G stainless steel wire.

Reinforcement shall comply with the following standards:

Mild steel rod reinforcement shall be hot rolled grade 250 complying with B.S. 4449.

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Hot rolled deformed high tensile bars having a guaranteed minimum yield stress of 410 Newton’s/sq mm and other physical properties complying with BS 4449, or

Cold worked steel bars complying with BS 4461.

Welded steel fabric reinforcement shall comply with BS 4483.

The Contractor will be required to submit at own expense certified test date of the following characteristics, ultimate tensile stress, yield point stress, elongation, cold bend test. Should such certificates not be submitted by the manufacturer, the Contractor shall have the requisite tests made at his own expense at an independent testing laboratory.

Should the Project Supervisor’s Representative require reinforcement to be tested, it shall be tested at the Contractor's expense and representative test pieces of such reinforcement to be used in the works are to be sent to an approved laboratory for testing.

Manufacturer's test reports of reinforcement shall be supplied to the Project Supervisor’s Representative for all reinforcement to be used in the works.

If such tests reveal the steel not meeting the specified standards, the Contractor will carry out the rectifications in the reinforcement to the direction of the Project Supervisor’s Representative at own expense.

7. Pipe Bedding and Granular Backfill Material

Granular material for pervious backfill, filter drains and pipe bedding shall consist of free draining readily compactable material conforming to the following grading or as otherwise approved by the Project Supervisor’s Representative.

Table: Pipe Bedding and Granular Backfill materials

Sieve Size Percentage Passing By WeightType A Type B Type C

63 mm - - 10037.5 mm 100 - 85 – 10020 mm 90 – 100 100 0 – 2010 mm 55 – 80 45 – 100 0 – 5

3.35 mm 40 – 60 25 – 80 -600 micron 15 – 35 8 – 45 -75 micron 0 – 3 0 – 10 -

In addition the material passing 420-micron sieve should be non-plastic.

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Part III: Concrete Work

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Part III: Concrete Work

1. Formwork General

Formwork shall include all temporary or permanent forms required for forming the concrete, together with all temporary construction required for their support.

2. Adequacy of Formwork

The Contractor shall be responsible for the design of all formwork.

Forms shall be constructed so that the concrete can be properly placed and compacted and so that the hardened concrete will conform accurately to the required shape, position and level, and to the finishes specified. Care should be taken to maintain the stability of the formwork during vibrating operations.

Props and struts to forms should be arranged to spread the load safely. The use of rough timber poles will not be permitted. In the case of large concrete spans the Contractor should bear in mind that there may be significant deflection due to dead load after removal of the props and should allow for this.

Joints in forms shall be sufficient tight to prevent the leakage of mortar. Unless specified otherwise all joints shall be either horizontal or vertical.

Wedges and clamps shall be used in preference to nails for securing the form components. The practice of nailing cleats to concrete will not be permitted. If, contrary to this requirement, cleats are so nailed to concrete, the Project Supervisor’s Representative may order the demolition and reconstruction of the affected concrete member at the Contractor’s expense.

3. Ties in Concrete

Where necessary and permitted, tie bolts and tie rods through the concrete shall be used to connect the forms. Wire ties will not be permitted except with the express permission of the Project Supervisor’s Representative. The material and position, where not shown on the drawings, of any ties passing through the concrete shall be approved by the Project Supervisor’s Representative. The whole or part remaining embedded shall be nearer the surface of the concrete than the specified cover of the reinforcement. The Contractor’s attention is particularly drawn to the necessity for all ties in exposed concrete faces, where permitted, to be accurately positioned in line and pattern. Any holes left after the removal of these shall be filled with grout of approved colour and composition and finished to the Project Supervisor’s Representative’s approval.

Ties passing through liquid-retaining slabs shall not be used unless approved in writing.

4. Top Formwork

Top formwork shall be used on any concrete face steeper than 150 to the horizontal.

5. Arises

All exposed arises shall be chamfered 25 mm by 25 mm unless otherwise indicated on the drawings.

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6. Removal of Debris

Rubbish, debris and water shall be removed from the interior of forms and top of blinding before concrete is placed and temporary openings shall be provided in the form to facilitate this removal.

7. Permanent Forms and Formwork

Permanent forms and formwork shall be of approved material as directed on the drawings and shall be fixed to the structure by approved means. Joints between them shall be made tight with mortar or other means of preventing loss of material from the concrete.

8. Formwork Preparation

The inside surfaces of forms shall, except for permanent formwork or unless otherwise agreed, be coated with an approved material to the manufacturer’s instructions and shall not come into contact with the reinforcement or pre-stressing tendons and anchorages. Only one manufacturer’s type of such material shall be used in formwork to concrete, which will be exposed in the finished works.

Before re-use forms shall be re-conditioned and all surfaces, which shall be in contact with concrete, shall thoroughly cleaned in such a manner as to avoid damage to the surface.

9. Notice of Intention to Place Concrete

The preparation of the formwork shall be approved before concrete is placed.

10. Removal of Formwork

The Contractor shall give the Project Supervisor’s Representative not less than 24 hours notice of his intention to strike any formwork. The time at which the formwork is struck shall be the Contractor’s responsibility, but the minimum periods between concreting and the removal of forms, unless otherwise approved, shall be as stated in Table D1.

Forms shall be removed without shock, vibration or other damage to the concrete. The Project Supervisor’s Representative may direct the manner in which the forms are struck.

The times in Table D1 are given in days where each day is to be of 24 hours duration, which the concrete temperature is above 5oC (40oF).

The Contractor’s attention is drawn to the necessity for the props to remain in position when striking the forms. Should the design of the formwork necessitate the removal of the props at the same time as the forms, both the forms and props shall remain in position for the longer period.

Table D1 – Minimum Formwork Striking Times

Location Ordinary Portland Cement Concrete

Rapid Hardening Portland Cement Concrete

Hours HoursSide of Beams, Walls, Columns and Piles 24 12

Days Days

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Slab Soffit Forms (props left under) 4 2

Beam Soffit Forms (propos left under) 8 4

Props to slabs 11 7

Props to beams 15 8

11. Quality of Finish

The quality of finish shall be as indicated on the drawings and shall not be inferior to that described herein.

If any portion of the face work should prove unsatisfactory on removal of the formwork it shall, without delay, be cut out and made good as directed. No plastering of concrete surfaces shall be allowed. At the discretion of the Project Supervisor’s Representative, board marks or minor discontinuities on exposed faces may be removed by rubbing down with carborundum, and pinholes, small voids or minor porosity of the surface, may be filled, by rubbing down with cement and sand mortar of the same richness as in the concrete.

Any concrete surface, which has been treated without consent, shall be liable to rejection.

All concrete faces to be exposed in the finished works shall be adequately protected against damage and surface staining during the execution of subsequent works.

12. Class of Finish, Formed Surfaces

On formed surfaces the under listed classes of finish shall be used:

Class F1 Finish is for surface against which backfill or further concrete will be placed. Formwork shall consist of sawn boards, sheet metal or any other material, which will prevent the loss of material from the concrete when it is vibrated.

Class F2 Finish is for surfaces, which are permanently exposed to view but where highest standard of finish is not required. Forms shall be faced with wrought and thicknesses boards with square edges arranged in a uniform pattern. Alternatively, plywood or metal panels may be used if they are free from defects likely to detract from the general appearance of the surface. This finish shall be such as to require no general filling of surface pitting, but fins, surface discolouration, and other minor defects shall be remedied by approved methods.

Class F3 Finish is for surface prominently exposed to view where good appearance, uniform colour, and alignment are of special importance. To achieve this finish, which shall be free of board marks, the formwork shall be faced with plywood or equivalent material in large sheets. The sheets shall be arranged in an approved uniform pattern. Wherever possible, joints between sheets shall be arranged to coincide with architectural features, sills, window heads, or changes in direction of the surface. All joints between panels shall be vertical and horizontal unless otherwise directed.

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Suitable joints shall be provided between sheets to maintain accurate alignment in the plane of the sheets. Unfaced wrought boarding or standard steel panels will not be permitted for Class F3 finish.

13. Class of Finish, Uniformed Surfaces

On uniformed surfaces the under listed types of finish shall be used:

Class U1 Finish is a screeded finish for surfaces of roads or of foundations, beds, slabs and structural members, which are to be covered, and on exposed surfaces of paving where a superior finish is not required. It is also the first stage for finishes U2 and U3. The finishing operations shall consist of levelling and screeding the concrete to produce a uniform plain or ridged surface, surplus concrete being struck off by a straight edge immediately after compaction.

Class U2 Finish is a floated finish for surfaces of beds and slabs to receive mastic paving or block tile paving where a hard smooth steel towelled surface is not required. Floating shall be done only after the concrete has hardened sufficiently, and may be by hand or machine. Care shall be taken that the concrete is worked on more than is necessary to produce a uniform surface free from screed marks.

Class U3 Finish is a hard, smooth steel-trowelled finish for surfaces of concrete paving, tops of walls, copings and other members exposed to weathering. Surfaces of beds and slabs to receive thin flexible sheet, and tile pavings bedded in adhesive, and snearing for bearing plates and the like where the metal is in direct contact with the concrete. Trowelling shall not commence until the moisture film has disappeared and the concrete has hardened sufficiently to prevent excess laitance from being worked to the surface. The surfaces shall be trowelled under firm pressure and left free from trowel marks.

14. Tolerance

The permissible tolerances in formed and unformed surfaces for the various classes of finish specified above shall not exceed the limits shown in Table D2.

Table D2 – Tolerances on finished concrete work

Type of irregularity

Tolerances (millimeters)

Formed surfaces Unformed surfaces

F1 F2 F3 U1 U2 U3Departure from alignment and grade as shown on the drawings

+25 ±5 ±5 ±10 ±5 ±3

Variations in cross sectional dimension

+10-5 ±3 ±3 NOT APPLICABLE

Abrupt 10 3 2 10 5 3

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Deviation from template in long dimensions ±10 ±5 ±3 10 5 3

The template to be used in determining the deviation in long dimension shall be 3 metres long.

15. Applied Finishes

Where an applied finish is to be used the concrete shall normally be finished to Class U2. Approved faces shall be treated in one application and dry joints shall be made where directed. After application no remedial treatment will be permitted to any face apart from complete reapplication.

16. Cleaning of Reinforcement

Steel reinforcement shall be kept clean and free from mortar grease loose rust and mill scale at the time of fixing in position and subsequent concreting.

17. Bending of Reinforcement

Reinforcement shall be bent to the dimensions given in the bar schedules and in a manner that will not injure the material.

Cold worked and hot rolled bars shall not be straightened or bent again once having been bent.

All reinforcement shall be bent at temperatures in the range of 5oC and 100oC.

Where it is necessary to bend mild steel reinforcement already cast in the concrete, the internal radius of bend shall not be less than twice the diameter of the bar.

18. Placing of Reinforcement

Reinforcement shall be accurately placed and maintained in the position shown on the drawings. Unless otherwise approved all intersecting bars shall be tied together and the ends of the tying wire shall be turned into the main body of the concrete.

No splices shall be made in the reinforcement except where described on the drawings or where approved.

Reinforcement in structures shall not be welded except where permitted on the drawings. All welding procedure shall be subject to prior approval in writing.

The Contractor shall use approved methods for supporting the steel in the correction position.

19. Cover to Reinforcement

Unless otherwise described in the Contract the following concrete cover to all steel reinforcement shall be used:-

Internal 20 mmBelow ground 75 mmExternal above ground 40 mmColumns 40 mm to main steel

20. Manufacture of Precast Units off the Site

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The details of the method of manufacture shall be approved before work is started. When the method has been approved, no changed shall be made without fresh approval.

Copies of all cube test results relating to the work shall be given to the Project Supervisor’s Representative.

In the case of pre-stressed concrete units additional information may be required by the Project Supervisor’s Representative relating to stressing of the steel. The Contractor shall give the Project Supervisor’s Representative not less than 24 hours notice of stressing, casting and transfer of stress.

When the Project Supervisor’s Representative required tests to be carried out, members to which the tests relate shall not be dispatched to the site until the tests have been satisfactorily completed.

21. Storage of Pre-cast Units

When members are stored, they shall be firmly supported at such bearing positions as will ensure that the actual stress induced in them are always less than the permissible stress.

22. Handling and Placing of Pre-cast Units

Members shall be lifted or supported only at the points described in the Contract, and shall be handled and placed without impact.

23. Marking of Units

All members shall be indelibly marked to show on which production line they were manufactured, the date on which the concrete was cast, the load applied and, if they are of symmetrical section.

24. Concrete Mixes

Unless otherwise directed in the Contract or approved ordinary Portland Cement shall be used. The quality of water used shall not exceed that required to produce concrete with sufficient workability to be placed and compacted where required. In the case of water retaining structures the Project Supervisor’s Representative may require the Contractor to work between both minimum and maximum limits of water content. In all circumstances the cement must be so regulated to meet the requirements of strength and water: cement ratio.

Grades of concrete shall be in accordance with BS 5328.

The quantity of cement shall be measured by weight and each batch of concrete is to use one or more whole bags. The quantity of fine aggregate and coarse aggregate shall be measured separately by weight batching plant. Volume mixing will not be permitted.

Table D3- Properties and Crushing Strengths

Grade Min. Cement Content

Max. size of Coarse Ag-gregate

Max. Water Cement Ration by Weight

Min. Crushing Strength of Works Test Cubes

7 days 28 daysMPa Kg Mm - N/mm2 N/mm215 220 20 - 10 15

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20 260 14 0.55 13.3 2030 300 14 0.55 20 30

The above properties and crushing strengths are to be considered as the minimum standard that will be accepted in the finish at works. The average crushing strengths should be at least 15% higher than the minimum permissible values given in the above table.

If the strengths required in the table are not attained and maintained during the duration out of the contract, the Contractor will be required to increase the proportion of cement or substitute better aggregates at own cost. The Contractor may be required to remove and replace at his own cost any concrete, which fails to attain the required strength as, ascertained by the Works Cube Tests.

The total acid soluble chloride content of the concrete mix shall be determined in accordance with BS 1881: Part 6: 1971 modified by using excess acid (Volhard Titration method). Chlorides from all sources shall be included.

For concrete made with cement complying with BS 12 having a C3A content of more than 7% and for plain concrete the maximum total acid soluble chloride content expressed as % of chloride ion by weight of cement shall be 0.250.

The maximum total acid soluble sulphate content of the concrete mix from whatever source expressed as % SO3 by weight of cement shall be 4.0.

25. Mixing Concrete

The weighing and water-dispensing mechanisms shall be maintained in good order. Their accuracy shall be maintained within the tolerances described in BS 1305 and checked against accurate weights and volumes when directed.

The weights of cement and each size of aggregate is indicated by the mechanisms employed shall be within a tolerance of ± 2 percent of the respective weights per batch agreed by the Project Supervisor’s Representative. The weight of fine and coarse aggregates shall be adjusted to allow for the free water contained in them. The water to be added to the mix shall be reduced by the quantity of free water contained in the fine coarse aggregates, which shall be determined by the Contractor immediately before mixing begins, and further as may be directed.

Unless otherwise approved, concrete shall be mixed in a batch type mixer manufactured in accordance with BS 1305 or in a batch type mixer a specimen of which has been tested in accordance with BS 3963 and having a mixing performance within the limits of BS 1305.

Where appropriate the batch capacity, method of loading, mixing time and drum speed shall conform to the details furnished in accordance with the requirements of B.S. 3963 for the mix which corresponds most closely to the mix proportions being used.

The mixing blades of pan mixers shall be maintained within the tolerances specified by the manufacturer of the mixer and the blades shall be replaced when it is no longer possible to maintain the tolerances by adjustment.

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Mixers, which have been out of use for more than 30 minutes, shall be thoroughly cleaned before any fresh concrete is mixed. The first batch of concrete through the mixer shall contain only two-thirds of the normal quantity of coarse aggregate. Mixing plant shall be thoroughly cleaned before changing one type of cement to another.

Concrete shall not be mixed when the air temperature in the shade is below 3oC unless special precautions are taken which have been approved. No frozen material or materials containing ice shall be used.

During hot weather the Contractor shall ensure that the constituent materials of the concrete are sufficiently cool to prevent the concrete from stiffening in the interval between its discharge from the mixer and compaction in its final position.

If approval to the mixing of small quantities of concrete by hand is given, mixing shall be down on a close-jointed wooden floor, the material being carefully turned over twice in a dry state and three times after the addition of water. Cement shall be increased by 10 per cent in hand mixing and not more than 0.5 cubic metres shall be mixed at one time.

Before the commencement of any work, the Contractor shall submit the following for the Project Supervisor’s Representative written approval:

The concreting method, including the size and type of machines for weighing and mixing concrete and the methods of transporting, placing and compacting.

Details of formwork proposals, clearly indicating the general method of construction and assembly, the methods of achieving surface finishes required herein, include linings, fixing of linings together with positions of joints and the make and type of mould oil proposed.

The proposed position and type of every construction joint not already shown on the Project Supervisor’s Representative drawings.

Such approval by the Project Supervisor’s Representative shall not be deemed to relieve the Con-tractor of obligations to comply with any of the provisions herein.

Concrete mixing and discharge from mixers shall be under permanent cover to the Project Supervisor’s Representative approval.

All cement is to be measured by weight, the 50 kg bag of cement being used as a unit.

The amount of water shall be the minimum required to produce a dense cohesive concrete of adequate workability, to be determined by trial mixes. This amount shall be accurately gauged and adjusted from time to time to compensate for variations in moisture content of the aggregate by an approved method.

All concrete shall be mixed in a batch type mechanical mixer of approved type having a drum rotating about a horizontal or inclined axis. The speed of the drum is to be not more than twenty and not less than fourteen revolutions per minute.

Each mixer is to be fitted with a water-measuring device capable of accurate measurement to five litres for one cubic metre mixers and prorata for smaller sizes and so arranged that the

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accuracy is not affected by variations in the pressure of the water supply line. The fine and coarse aggregate and the cement shall be mixed for at least four turns, after which the required amount of water shall be added gradually while the mixer is in motion and the concrete mixed for not less than one and a half minutes to uniform colour and consistency.

The volume of concrete mixed in any one batch is not to exceed the rated capacity of the mixer.

The whole of the mixed batch is to be removed before materials for a fresh batch enter the drum.

Concrete as mixed in accordance with the foregoing shall not be modified by the addition of further water or in any other manner. On the cessation of work, including all stoppages exceeding twenty minutes, or any change of type of cement used in the mix, the mixers and all handling plant shall be washed out with clean water.

At least one slump test shall be made each day concreting is in progress, under the supervision of the Project Supervisor’s Representative.

26. Ready-mixed Concrete

The Project Supervisor’s Representative may allow the use of ready mixed concrete provided he is satisfied that the mix will fulfill the specification requirements and the recommendations of BS 1926.

Each load shall be accompanied by a delivery note stating date and time of mixing, slump at mixing, delivery time, the grade of concrete and mix proportions thereof.

Works slump tests, compaction and cubes may be required of each load.

The concrete shall be carried in purpose-made agitators, operating continuously, or truck mixers. The concrete shall be compacted and in its final position within two hours of the introduction of cement to the aggregates. The time of such introduction shall be recorded on the delivery note, together with the weight of the constituents of each mix.

When truck mixed concrete is used, water shall be added under supervision either at the site or at the central batching plant as directed but in no circumstances shall water be added in transit.

Truck mixer units and their mixing and discharge performance shall comply with the requirements of BS 4251. Mixing shall continue for the number and rate of revolutions recommended in accordance with item 9 in Appendix B of BS 4251 or, in the absence of the manufacturer’s instructions mixing shall continue for not less than 100 revolutions at a rate of not less than 7 revolutions per minute.

Plant shall be checked regularly. If any fault is detected it must be rectified before any further use is made of the equipment.

Slump or compaction factor tests shall be carried out in accordance with the relevant British Standards and Codes of Practice. Slump test results must be within ± 25 mm and compacting factor ± 0.03 of design figures.

27. Transport and Placing of Concrete

The method of transporting and placing concrete is subject to approval. Concrete shall be so transported and placed that contamination, segregation or loss of the constituent materials does not occur.

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Concrete shall not be placed in any part of the structure without consent.

If concreting is not started within 24 hours of consent being given, consent shall again be obtained. Concreting shall then proceed continuously over the area between construction joints. Fresh concrete shall not be placed against insitu concrete, which has been in position for more than 30 minutes unless a construction joint is formed.

When in situ concrete has been placed for 4 hours no further concrete shall be placed against it for a further 20 hours.

Concrete when deposited shall have a temperature of not less than 5oC and nor more than 32oC. It shall be compacted in its final position within 30 minutes of discharge from the mixer unless carried in purpose-made agitators, operating continuously, when the time shall be within 2 hours of the introduction of cement to the mix and within 30 minutes of discharge from the agitator.

The Contractor shall notify the Project Supervisor’s Representative of the methods he proposes to use to maintain the specified concrete temperatures.

No frozen materials or materials containing ice shall be used for making concrete.

Any concrete damaged by frost shall be classed as defective work.

Concrete shall be deposited in horizontal layers to a compacted depth not exceeding 450 mm where internal vibrators are used, or 300 mm in all other cases.

Concrete shall not be dropped into place from a height exceeding 2m. When trunking or chutes are used they shall be kept clean and used in such a way as to avoid segregation.

Concrete shall not be placed in flowing water. Under water concrete shall be placed in position by tremies, or by pipelines from the mixer. Details of the method proposed shall be approved before placing beings. Where the concrete is placed by a tremie, its size and method of operation shall be in accordance with Civil Engineering Code of Practice, ‘Foundations’. During and after concreting under water, pumping or dewatering operations in the immediate vicinity shall be suspended until the Project Supervisor’s Representative permits them to be continued.

Water shall not be allowed to flow over or extend any pressure against concrete until at least 48 hours after deposition.

Where concrete is to be pumped, details of the methods and plant to be used are subject to approval.

At all times when reinforced concrete is being placed a competent steel fixer shall be in continuous attendance on the concretors to adjust and correct the position of any reinforcement which may be displaced.

The Contractor shall keep on site a complete record of the works showing the time and date when concrete is placed in each part of the works. This record shall be available at all times for inspection by the Project Supervisor’s Representative.

In no circumstances shall concrete, which has partially hardened, be deposited in the work, nor shall any concrete be re-tempered by the addition of water or other materials.

Drying out of fresh concrete before deposition shall be prevented by the provision, where necessary in the opinion of the Project Supervisor’s Representative, of tarpaulins or other covers.

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Premature drying out of the concrete to be placed shall be prevented, thoroughly damping down ground or older concrete, masonry or other absorbent surfaces upon or against which the fresh concrete is to be placed. At the time of concreting, however, there shall be no free water upon such surfaces.

Where plums are permitted these shall be placed by hand.

Concrete to ground floor slabs shall be placed in panels not exceeding 22.5 m2 in area and having a maximum length of side of six m2 or as approved. The concreting shall be carried out in alternate panels. Concreting of the adjacent panels shall not be carried out within twenty-four hours of the neighbouring panels being cast.

Once concreting has been commenced it shall be carried on as a continuous operation between prearranged construction or expansion joints.

In hot dry weather suitable means shall be provided to avoid premature stiffening of concrete placed in contact with hot dry surfaces. Where necessary, the surfaces, including reinforcement, shall be shielded from the direct rays of the sun.

No traffic whatsoever, wheeled or foot shall take place over placed concrete and the Contractor shall provide all necessary stools, walkways, platforms and barrow runs. Concrete shall be placed in its final position as rapidly as practicable by methods which preclude segregation or loss of ingredients and in any case, within 30 minutes from the time that water is added to the mix; compaction shall be completed before initial set commences. Partially set concrete shall not be re-worked or used. Placing and compacting in shallow layers in quick succession shall avoid “Flowing” in form work.

Fresh concrete shall not be placed against previously placed concrete which has been in position for more than 30 minutes or where the initial set has taken place.

Concrete shall be placed into the forms at the least a height as possible and shall in no case be dropped from a height of more than 1500 mm.

Concrete shall be thoroughly compacted and carefully worked, with suitable tools, into formwork and round reinforcement and fixtures so as to avoid displacement. A competent steel fixer shall attend throughout concreting to correct any unavoidable displacement.

Compaction shall be by means of vibrators, these shall be of an approved pattern, of the immersion type, clamp-on external vibrators in adequate number shall be used only where the density of reinforcement precludes immersion.

Attachment to reinforcement is expressly forbidden and accidental contact with reinforcement shall be avoided. Vibration shall be executed by a competent operative and shall not be carried out to the detriment of adjacent partly hardened concrete.

An accurate record is to be kept by the Contractor showing dates and times when various portions of the work were concreted. The concrete foreman must not vary the approved mix or water content without the permission of the representative of the Project Supervisor’s Representative. The workability of the concrete must never be altered by the use of additional water or sand alone.

All concreting shall be continuous to completion.

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Methods of placing and vibration generally are to comply with the specifications for vibrated concrete as laid down by the Cement and Concrete Association or the manufacturer of the vibrators used on the works.

During placing of all concrete a workman shall be in constant attendance with a hose pipe to wash off any cement slurry which appears on the face of any previously poured concrete immediately it occurs.

Concrete shall not be poured in forms to depth exceeding 1500 mm without the prior approval of the Project Supervisor’s Representative.

28. Compaction of Concrete

All concrete shall be compacted to produce a dense homogenous mass. It shall be compacted with the assistance of vibrators. Class E concrete may be compacted by hand or by mechanical vibration. Sufficient vibrators in serviceable condition shall be on site so that spare equipment is always available in the event of breakdowns.

Internal vibrators shall be capable of producing not less than 10,000 cycles per minute, and external vibrators not less than 3,000 cycles per minute.

Vibration shall not be applied by way of the reinforcement, where vibrators of the immersion type are used, contact with reinforcement and all inserts shall be avoided, so far as is practicable.

Care shall be taken to ensure that exposed concrete faces are of a similar appearance and that the forms for such faces are not damaged during compaction.

Concrete shall not be subjected to vibration between 4 and 24 hours after compaction.

29. Curing of Concrete

Immediately after compaction and for 7 days there after the concrete shall be protected against harmful effects of weather, including rain, rapid temperature changes, frost and from drying out. The methods of protection used are subject to approval.

Protection against loss of moisture shall be accomplished by one or more of the following methods:

Retaining forms in place.

Ponding of water on exposed surfaces.

Covering with sand, earth, straw, sawdust, cotton or jute mats or similar moisture

retaining materials kept continuously wet.

Sprinkling or spraying with water at sufficiently frequent intervals to maintain the

exposed surfaces in continuously wet condition.

Covering with a water proof material of suitable type firmly held in place.

Application of suitable approved liquids, which will form a moisture retaining membrane.

Attention is drawn to the necessity to eliminate any curing materials or methods of application, which will stain, mark, contaminate or otherwise damage the concrete.

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30. Early loading

Concrete shall at no time be subject to loading, including its own weight, which will induce a compressive stress in it exceeding 0.33 of its compressive strength, at the time of loading or of the specified 28 days strength.

For the purpose of this clause, the assessment of the strength of the concrete and the stresses produced by the loads shall be subject to the agreement of the Project Supervisor’s Representative.

31. Construction Joints

Where construction joints are not shown in the Contract the Contractor shall submit for approval proposals for the layout of construction joints before concreting is started.

Where vertical construction joins are required, the joint face of the first cast concrete shall be finished against a stopping-off board or vertical end shutter and suitably notched to pass the reinforcement. Where horizontal or slightly inclined construction joints are required, the concrete shall be screeded off. Suitable keys shall be formed at all construction joints.

The surface film of the first place concrete shall be removed whilst the concrete is still green to expose the aggregate and leave a sound irregular surface.

Just before concreting is resumed, the roughened joint surface shall be thoroughly cleaned and freed from loose mortar, preferably without rewetting and then treated with a thin layer, worked well into the surface, of cement grout, or of cement: sand mortar in which the ratios of sand to cement and water to cement do not exceed those in the new concrete. The Contractor shall take precautions to avoid segregation of the concrete along the joint plane and to obtain thorough compaction.

For horizontal joints the layer of grout or mortar may be omitted at the discretion of the Project Supervisor’s Representative, provided the workability of the batches of concrete placed in contact with the joint is slightly increased.

All construction joints shall be straight, truly vertical or level, as the cast may be, of the profile shown and formed in the exact position shown on drawings or if not shown on the drawings, with prior approval of the Project Supervisor’s Representative.

The rate and method of placing concrete and the arrangement of construction joint bulkheads shall be such that the concrete between construction joints shall be placed in a continuous operation.

An adequate and acceptable key for succeeding work shall be formed by using stop boards, which shall be constructed tightly to prevent any grout leak. As early as possible boards shall be removed and the surface thoroughly hacked and brushed to remove all laitance. Any leakage past stop boards shall be hacked off as soon as the concrete has set. The surface shall be left clean and dry. Immediately prior to further concreting he joint face shall be soaked with water and covered with sand cement mortar of proportions identical to that in the concrete to be placed, punned into the body of the set concrete.

For exposed finishes, care shall be exercised to preserve an unbroken line at the exposed edge of the joint.

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In the case of horizontal joints, any excess water and laitance shall be removed from the surface after the concrete is deposited and before it has set.

32. Movement Joints

The Contractor shall pay particular attention to ensure that all movement joints are protected from the entry of debris.

Stopping-off boards, or vertical end shutters, shall be used in vertical joints as specified in Clause E/36.2.

The surface of the first cast concrete of Contraction joints shall be treated with bituminous solutions, as specified in Clause 309 to prevent adhesion between new and old concrete. All surfaces shall be thoroughly dry before the treatment is applied.

The two concrete faces of a sliding joint shall be plane and smooth. A rigid screeding board or other suitable means shall be used to ensure that the top of the lower layer concrete is as flat as possible. The surface shall be finished with a steel float and after initial set, rubbed down with carburundum.

The Contractor shall furnish details of the types and makes of joint fillers, water-bars, joint cover plates, joint sealing compounds and other proprietary materials for approval. These materials must be used in compliance with the manufacturer’s recommendations.

33. Waterproof Concrete

All work so indicated on the drawings shall be watertight.

The Contractor shall include in his rate for such water-bars and waterproof additives as he deems to be necessary but the use of such additives shall be subject to the prior approval of the Project Supervisor’s Representative.

When in the opinion of the Project Supervisor’s Representative damp patches or leakage of water in the finished works are due to failure of the Contractor to comply with this specification the affected work shall be made good at the Contractor’s expense.

All construction in contact with water or soil and all exposed concrete-faces shall be impermeable to the passage of water. Special care must be taken by the Contractor to ensure impermeability at construction joints.

Any water-stops or concrete admixtures intended for use must have the prior approval of the Project Supervisor’s Representative but the Contractor will be held entirely responsible for the impermeability of the construction. In the event of such impermeability not being achieved, the Contractor shall, at his own expense, take such measures, as the Project Supervisor’s Representative shall direct.

34. Blinding Concrete

Where called for in the Contract and elsewhere when directed the bottom of excavations are to be covered with a 75 mm layer of E mix concrete immediately below the foundation level.

No casting of any concrete on the ground shall take place until the Project Supervisor’s Representative has passed the ground as satisfactory. All ground to carry reinforced concrete shall be covered with a blinding layer of concrete the thickness shown on the drawings, or if not so shown, a minimum of 50 mm.

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35. Forms to Retarded Concrete Faces

The retarding of the setting time of the concrete face shall be by the use of an approved retarded fluid applied to the forms in accordance with the manufacturer’s instructions. Extreme care must be taken that the fluid does not come into contact with any reinforcement. Forms which have had retarder applied to them shall not be used for other types of exposed concrete faces.

Forms for retarded concrete faces shall be removed 24 hours after placing concrete and the concrete face wire brushed and washed with running water to expose the aggregates. Care must be taken in brushing the concrete to achieve a uniformly textured face similar in all respected to the approved samples made.

36. Fixing Blocks, Chases and Holes, Brick Ties

The cutting or forming of any hole or chase in the concrete other than those required in the Contract or otherwise approved by the Project Supervisor’s Representative, will not be permitted.

The Contractor shall be responsible for the coordination with sub-contractors for incorporating any electrical conduit or boxes, pipes, bolts, stop irons, frames, fixing blocks etc. in the concrete.

The Contractor shall submit full details of these items to the Project Supervisor’s Representative whose approval shall be obtained before the work is put in hand. Such approved items shall be of the correct sizes required and shall be accurately set out and maintained in position during concreting.

Where walls or partitions abut on concrete columns or walls, 14-gauge hoop iron ties 40 mm wide and 450 mm long shall be cast in the concrete. Ties shall project 225 mm from the concrete face and occur at 450 mm vertical centers.

Where required, a key for plaster shall be obtained by approved means without any damage caused to the structure.

No holes or chases shall be cut in reinforced concrete works. The Contractor shall ensure that all necessary holes and chases, including fixing holes for railings and balustrades etc., are carefully formed in the correct position by requisite measures prior to the placing of concrete.

All conduits, pipes, tubes and the like shall unless otherwise derailed, be run on top of the bottom reinforcement of the concrete work. It shall be the Contractor's responsibility to ensure full co-ordination with

Sub-Contractors in the setting out for this purpose.

Generally conduits, pipes, hooks for wall beams and special fixtures shall be concreted in where required and in the exact positions demanded.

Concrete fixing blocks shall not affect the strength or cover of the structure nor affect finished work due to movement or other cause.

Details of the positions of all holes, chases and fixing blocks shall be submitted to the Project Supervisor’s Representative for approval prior to putting the work in hand.

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37. Supervision

At all times when concrete is being mixed and placed, the operation shall be under the direct supervision of a suitably qualified foreman who is acceptable to the Project Supervisor’s Representative.

39. Records

A complete record shall be kept covering the quality and quantity of concrete placed, its position in the work, the curing its receives, and the position of all construction joints not shown on the drawing.

A maximum and minimum thermometer shall be kept on site, close to the works and in the shade. A daily record of maximum, minimum morning and evening shade temperatures shall be kept on site together with a summary of the weather conditions.

40. Samples of Finished Concrete

Prior to the commencement of the actual concreting work, a trial mix of the required concrete, as described herein shall be made by the Contractor's expense, in order to check and establish the actual working crushing strength of the required concrete mix.

The total water content in the mixture determines its consistency and once a consistency of a trial mix has been approved it must remain constant throughout the Contract.

In order to held the concrete maintain the desired consistency the slump of an approved trial mix shall be measured; thereafter all mixes must give the slump as the approved trial mix. The slump shall be determined by test as described in BS 1881 Parts 102, 104, 106, 107 and DD 83 Part 2. In general the approved slump shall be in the order of 74 mm for hand compacted concrete and 35 mm for vibrated concrete. The slump test shall be made on concrete actually being placed in the works at the commencement of each period of concrete placing and at such other times as instructed.

The proportions of materials to be used for the preliminary cube tests, and subsequent batching, shall be ascertained by calculation from the results of the aggregate grading tests carried out by the Nominated Testing Authority.

Preliminary concrete cubes shall be made by the Contractor on site, as required by the Project Supervisor’s Representative, and tested by the Nominated Testing Authority. As a result of these tests definite weights of each material for batching shall be ascertained and agreed with the Project Supervisor’s Representative. Thereafter these proportions shall be adhered to throughout the works and may be varied only by instructions given by the Project Supervisor’s Representative.

The weights of damp aggregates must be adjusted to take into account the weight of water in the aggregates, and this in turn will affect the amount of water to be added to the mix.

Throughout the carrying out of the Contract, "Works Cube Tests" are to be made from concrete drawn from newly laid concrete or concrete about to be placed in position, such cubes being made when directed by the Project Supervisor’s Representative and in his presence. Such cubes shall be made in 150 mm cube steel or cast iron moulds and shall be marked and cured strictly in accordance with the Appendices of the Code of Practice, and shall be forwarded carriage paid in

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time for testing at the required age to a testing laboratory to be nominated by the Project Supervisor’s Representative.

Four cubes shall be made on each occasion, concrete for each cube being from a different batch. Two cubes shall be forwarded in time for testing at the age of seven days from casting and two cubes in time for testing and distinctive reference number in accordance with a system agreed by the Project Supervisor’s Representative.

A record shall be kept of the position from which the concrete for each set of cubes was drawn, or to which it was about to be placed.

At least three sets of cubes shall be cast during each week concrete is being cast including sets of cubes for each quality of concrete used during the period.

The moulds for test cubes shall be of metal and true to shape to give a 150 mm cube and shall be well oiled before filling. The mould shall be filled with concrete taken from that actual ly placed in the works, the concrete being selected by the Project Supervisor’s Representative from a point as near as possible to the position of placing. The filling of the moulds shall be done immediately after the selection of the sample concrete and in such a way that the concrete in the moulds be truly representative of that in the works.

The concrete shall be placed in the moulds in three layers of equal thickness, each layer being rammed with 25 strokes of a steel bar 40 mm diameters, (or equivalent), weighing 2 kg. If the concrete in the works be consolidated by mechanical vibration, the test cube moulds shall be likewise vibrated after filling. Each cube shall be inscribed with the date of manufacture and identification mark.

A record shall be kept for each batch of cubes showing the position in the works which the con-crete represents, the date of manufacture, the mixture and slump of the concrete, particulars of the cement and aggregate used, a statement of whether or not the cubes are vibrated and other information relating to the subsequent history of the cubes.

The moulds containing the test cubes shall be stored for 24 hours on the site in a damp place free from vibration. At the end of this period the cubes shall be taken from the moulds and stored in damp sand for 20 days if they are to be tested at 28 days, or for 4 days if they are to be tested at 7 days.

The Contractor shall be instructed about the despatch of the cubes to an approved laboratory and will pay all costs relating to the tests. A set of four cubes will be required for not more than ever 60 cubic metres of concrete placed in the works.

The mix proportions shall be modified to increase the strength if, in the first and consecutive (but not overlapping) sets, of any of the following conditions are not satisfied:

Not more than 1 of 20-cube test result should fall below the specified works cube strength.

No value of the range in any set should exceed 4 times the designed standard deviation.

Not more than one set should have any average, which is less than the specified strength plus 11/3 times the designed standard deviation.

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No value of the average for any set should be less than the specified strength plus the designed standard deviation.

After 5 consecutive sets of results have been obtained the overall average and the standard deviation of the 20 results shall be calculated and any appropriate modifications made.

Subsequently, if any of the foregoing conditions are not satisfied, the overall average and the standard deviation of the previous results, including the non-complying sets, should be calculated and the appropriate steps taken if the overall average strength minus twice the standard deviation is less than the specified works cube strength.

Cube tests proving unsatisfactory, the work represented shall be immediately liable to rejection. The Contractor may, however, be given the option of cutting three specimens from the com-pleted work subject to the direction of the Project Supervisor’s Representative, and preparing there from test cubes or cores which shall be sent to the Testing Laboratory for testing as for Works Cube Tests.

Should the average strength of these specimens attain the specified minimum twenty-eight day strength, the work will, subject to the Project Supervisor’s Representative's discretion, be accepted. Alternatively, the Project Supervisor’s Representative may instruct the Contractor to make a loading test as described hereinafter. The cost of all cutting, preparation of specimens, testing and making good the portions of the structure affected shall be borne by the Contractor. The cost of all delays on site due to concrete not attaining the desired strength, or cause by investigation of defects, cutting away and making good, shall be entirely the Contractor's responsibility.

The Project Supervisor’s Representative shall instruct that a loading test be made on the works, or any part thereof, if the opinion is that such a test is deemed necessary for one or more of the following reasons.

The site made concrete test cubes failing to attain the specified strength.

The shuttering being prematurely removed.

Overloading during construction of the works, or part thereof.

Concrete improperly cured.

Any other circumstances attributable to alleged negligence on the part of the Contractor which, in the opinion of the Project Supervisor’s Representative, may result in the works, or part thereof, being less than the required strength.

If the loading test be instructed to be made solely, or in part, for one or more of the reasons mentioned above, the test shall be made at the Contractor's own cost. If a test is instructed to be made for any reason than specifically stated above, the Contractor shall make the test and shall be reimbursed for all costs relating thereto.

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If the result of the loading test be not satisfactory, the Project Supervisor’s Representative shall instruct that the part of the works concerned shall be taken down or removed and reconstructed to comply with this specification, or that such other remedial measures shall be taken as to make the works secure.

If the test be instructed to be made for one or more of the reasons hereinbefore specified, the Contractor shall take down or remove and reconstruct the defective work, or shall take the remedial measure instructed, all at his own cost.

42. Programme and Details of Contractors Plant

Before construction commences the Contractor shall supply to the Project Supervisor’s Representative his detailed programme showing the methods and order of procedure proposed for the structural work. The Contract shall also submit to the Project Supervisor’s Representative for his approval details showing the general arrangement of his concreting plant systems of formwork and all other devices, which he proposes to use for the construction of the structural framework.

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Part IV: Steel Work

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Part IV: Steel work

1. General Requirements

The whole of the structural steel work and testing shall comply with the relevant clauses of BS 449 (Part 2) and BS 5950.

The whole of the fabrication testing and erection of the steel work shall be carried out in accordance with BS 449 Part 2.

The steel work may be constructed by a subcontractor. Before an order is placed by the Contractor, the subcontractor shall be approved by the Project Supervisor’s Representative.

The Contractor shall include for the preparation of all shop details from the drawings supplied by the Project Supervisor’s Representative. All such details shall be approved in writing by the Project Supervisor’s Representative before the work is put in hand. Every drawing shall show the number and sizes of all bolts, complete details of welds, type of electrodes, welding procedure, whether the welds are to be made in the shop of elsewhere and any other relevant information.

The Contractor shall be responsible for the correctness of the shop details, for shop fittings and site connections.

The Contractor shall submit to the Project Supervisor’s Representative for approval, drawings showing the proposed erection scheme, together with all calculations for erection stresses, etc. The approval by the Project Supervisor’s Representative will not absolve the Contractor in any way from responsibility.

2. Copies of Orders

A copy of all orders for materials shall be supplied by the Contractor to the Project Supervisor’s Representative at the time of ordering, for identification purposes.

3. Damage

Any damage to materials on the site due to inadequate precautions being taken during the erection of the steel work shall be made good to the satisfaction of the Project Supervisor’s Representative at the Contractor's expense.

4. Quality of Steel

All structural mild steel shall comply with BS 449 and BS 4360 Part 2.

All structural steel tubes shall comply with BS 6323 and BS 449 Part 2.

Hot rolled sections shall comply with BS 4, part 1. Hot rolled hollow sections with BS 4, Part 2. Tubes (other than circular hot rolled hollow sections) shall comply with BS 1775 and shall be of the type of steel and method of manufacture described.

Mild steel and medium tensile steel electrodes for metal-arc welding shall comply with the requirements of BS 639.

High strength friction grip bolts and washers shall comply with BS 4395 part 1.

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For the purpose of measurement, the weight of mild steel shall be as given in BS 648. The weights per metre given on the drawings do not include shelf angles affixed to webs, nor plates affixed to flanges of Universal beams or other sections.

All surfaces of steel work shall be clean, free from loose millscale and rust.

Each piece of steel shall be legibly marked with the maker's name or trade mark and with cast numbers or identification marks.

5. Standard Dimensions

The dimensions and allied requirements of all structural rolled sections shall comply with BS 4 Part 1 and BS 4848. The dimensions, weight, tolerances, etc., of all bolts, nuts, studs, etc., shall conform to the following standards:Black bolts, nuts, studs, lock nuts and washers shall comply with the requirements of BS 916 for dimension and screw threads, or with BS 1580 for unified black bolts, etc.

Turned bolts shall have the shank turned to the specified diameter allowing only a minus tolerance up to 0.13 mm.

6. Painting

Surface cleaning and painting/metal spraying shall preferably be done in a shop or in a tent to enable control of the conditions for application.

Before coating starts, written procedures shall be approved by the Project Supervisor’s Representative. The procedures shall include procedures for painting as well as for repairing damaged areas, information on trade names on all coating materials, and required coating equipment as well as measures to maintain all safety and environmental requirements.

When blasting on site, bolted parts, pumps, gaskets, instruments, valves and other sensitive equipment shall be covered and taped to avoid ingress of blasting material. Likewise surfaces, which are not to be coated at that time, shall be protected during painting. This includes stainless steel pipes and components, instruments, identification plates etc.

All mechanical damages to pipes or components shall be brought to the attention of the Project Supervisor’s Representative.

Prior to blasting or grinding, the surface shall be free of water soluble salts, oil and grease, and recently welded steel shall be free of alkalies originating from welding fumes. Salts shall be removed by water rinsing, preferably with hot water or condensing steam. Degreasing may be carried out by means of steam, emulsifiers or by high-pressure water jetting.

All bolt holes shall be solvent-cleaned prior to blast cleaning. All sharp edges shall be removed.

Millscale, rust, corrosion products, paint or any other foreign matter, welding slag and flux residue shall be removed by blast cleaning to the grade specified below.

Blast cleaning shall not be conducted when the temperature is less than 3o C above dew point of the surrounding air or when the relative humidity of the air is greater than 85%. The Contractor shall furnish a humidity meter to determine the relative humidity and the dew point.

The blast-cleaned surfaces shall be carefully cleaned to remove all traces of blast-cleaned products from the surface or from pockets and corners.

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Surface finish after blasting shall be min. Sa 2½ to ISO 8501-1.

Sa 2½ corresponds to BS 4232 "second quality".

The surface profiles shall correspond to patterns shown in ISO 8503-1, comparator G. The roughness shall be between segment 2 and 3.

Where blast cleaning is impossible, cleaning to white metal by grinding may be used.

Brush cleaning can only be used if approved by the Project Supervisor’s Representative.

Particular care shall be taken to prevent rusting and/or contamination of cleaned surfaces.

For joints with high strength friction grip bolts the contact surfaces shall be left unpainted but special care shall be taken after assembly to paint all edges and corners near the joints together with bolt heads, nuts, washers to prevent the ingress of moisture. For joints made with other bolts the contact surfaces shall each be given a coat of priming paint and for shop connections the contact surfaces shall be brought together while the paint is still wet.

For welded connections where the contact surfaces are not completely sealed the contact surfaces shall be painted to within 50 mm of the edges that are to be welded.

The primer shall be touched up with similar primer if damaged by subsequent handling.

Application shall be strictly in accordance with the paint manufacturer's recommendation.

The paint system shall be Amercoat or equivalent:

Amercoat 305 1 x 50 =50 microns

Amercoat 450 2 x 75 =150 microns

Total 200 microns

Colours: Service Gray

The final paint system shall be free from obvious defects and shall be tested as follows:

The film thickness shall be checked with calibrated film thickness gauges. The gauges shall be calibrated at least twice daily in accordance with the manufacturer's recommendations. If the film thickness does not meet the specified value, additional coat(s) shall be applied.

The adhesion of the coating shall be examined by making a V-shaped cut through the oating with a sharp knife. The adhesion is satisfactory if the film cannot be peeled by the knife, either from the substrate or between the coats. Excessive force to the extent of coating rupture should leave portions of the film adhering tightly to the surface.

Prior to final acceptance of the paint work the Contractor shall prepare an inspection report. The report shall state the amount and the location of the test carried out and the result of the tests.

The Project Supervisor’s Representative will make spot checks on the paint work carried out, and if he finds consistency with the statements of the inspection report, he will sign the report.

The Project Supervisor’s Representative will also check the correct shade of colour, degree of gloss, and the overall quality of the work.

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7. Hot-dip Galvanizing

Galvanized shall be carried out by complete immersion in one operation and excess carefully removed, all in accordance with ISO 1459 & 1461 Class B.

The finished surface shall be clean and uniform.

The Contractor shall document that the zinc thickness of the hot-dip galvanized items complies with the requirements of ISO 1461.

The hot dipped galvanizing shall be done to the finished structural components of steel members. No drilling, cutting, bending etc shall be done after parts have been galvenized.

8. Smithing

All smithing and bending shall be soundly and neatly executed, care being taken not to overheat.

9. Forging

All straps, bolts and similar work shall be forged neat and clean from the anvil.

10. Welding

The word 'welded' is to be understood to include the normal trade methods of jointing metals using an oxyacetylene torch, rod and flux. The joints shall be made so that they will transmit the loads and resist the stresses to which they will be subjected.

All excess metal is to be filed down and smoothed off to a finish to the approval of the Project Supervisor’s Representative. The materials employed in welding shall be selected with due regard to the character of the rework and the metals being connected.

All welded members, which are to be galvanized, shall be galvanized only after all fabrication and welding is complete.

The welding of steel to BS 4360 Part 2 must conform to BS 5135 -"General requirements for the metal-arc welding of mild steel" as applicable. For welding any particular type of joints the Contractor shall provide evidence acceptable to the Project Supervisor’s Representative that the welder has satisfactorily completed the appropriate tests as described in BS 449, Part 2

11. Joints and Connections

No variation of the number, type or position of the joints or connection shown on the drawings shall be made without the consent of the Project Supervisor’s Representative. If such consent is desired the Contractor shall submit detailed drawings of the proposed joints for the approval of the Project Supervisor’s Representative and no extra cost incurred by reason of such additions or alterations will be allowed to the Contractor.

12. Quality Control

Manufacturer's Mill Test certificates for all structural steel shall be supplied to the Project Supervisor’s Representative as and when required. Where and when directed by the Project Supervisor’s Representative, the Contractor shall take and deliver samples of structural steel for testing to a testing facility nominated by the Project Supervisor’s Representative. Should the results of any test be unsatisfactory the whole consignment of steel, which the sample represents,

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shall be rejected and shall be replaced by other material of proper quality at the expense of the Contractor.

Any portion of the work which, in the opinion of the Project Supervisor’s Representative is not in accordance with the drawings or specification shall be rejected whether before or after delivery and must be removed, from the site if delivered, within 24 hours from receipt of such notice of rejection at the Contractor's expense. Any delay caused by such rejection will not in any way relieve the Contractor from his responsibility with regard to the provision of the Contract. If any welding is found to be defective the cost of all remedial measures shall be borne by the Contractor, including the cost of re-testing. The Contractor is responsible for the good quality of all welding work and no exceptions will be made on the grounds that the Project Supervisor’s Representative or his representative have inspected any part or parts of the work at some stage during production. Steel work shall be in accordance with the approved drawings. The Contractor shall give four days clear notice of steel work ready for inspection at the manufacturer’s works to facilitate inspection before delivery.

Any welder's tests shall be made at the Contractor's expense and shall include the cost of any fees incurred by the Contracting Authority for witnessing of, or making such tests. The right is reserved to make non-destructive tests on the welding to determine if the welding conforms to the standards laid down in BS 5135 as applicable.

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Part V: As Built Documentation

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Part V: As-Built Documentation

1. Scope

The As-built Documentation include the Construction documentation, Supplier Documentation Packages for supplies purchased by the Contractor, and Operation and Maintenance Manuals

The Contracting Authority will collect vendor documentation for supplies purchased by the Contracting Authority.

The Contractor shall prepare as-built documentation as specified in this Specification and the other Technical Specifications as well as the contract documents, and hand it over to the Project Manager.

During the construction phase the Contractor shall update working drawings and collect vendor documentation such as test certificates, manuals etc.

2. Codes and standards

The following standards form an integral part of the requirements for the preparation of the as-built documentation: IEC 113: Preparation of Drawings, Diagrams, Charts and Tables.

- IEC 617: Graphic Symbols for Diagrams.

- IEC 750: Item Designation in Electro-technology.

- ISO 31: General Principles concerning Quantities, Units and Symbols.

- ISA-S5.1: Instrumentation Symbols and Identification.

- ISA-S5.4: Instrument Loop Diagrams

3. Units

SI units shall be used unless otherwise specified in the Data Sheets, Drawings, Schedules, etc.

4. As-Built Documentation

The Contractor shall provide the as-built documentation as specified below and in the following sections.

The Contractor is obliged to prepare the revisions and detailing deemed necessary to ensure a complete documentation.

The as-built documentation shall be delivered to and accepted by the Project Manager before handing over of the installation can take place.

The Contractor shall deliver one AutoCAD original diskette of each as-built drawing. Each original diskette shall be suitable for printing. The Contractor shall further deliver 4 copies of the individual packages as stated below.

- As-built drawings and "Construction Documentation Package" – A1 Size

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- "Supplier Documentation Packages"

- Operation and Maintenance Manuals

"Construction Documentation Package" includes all documentation required in the Technical Specifications to prove that the work has been completed, checked, examined and tested to the extent required, and that the results meet the requirements of the Specifications.

"Supplier Documentation Packages" includes any type of certificates required in the Specifica-tion, e.g. material certificates, Ex-certificates, Suppliers test certificates etc.

Operation and Maintenance Manuals includes all types of instructions from suppliers, e.g. a general description of the components, components drawings(s) with bill of material, spare part lists including indication of which are recommended to be stored on the depot, instructions for testing, calibration, operation and maintenance.

All the documentation shall be collected under the tag numbers specified. Where tag numbers have not been stated the documentation shall be collected under an agreed equipment designation.

The complete documentation shall be supplied in ring binders (loose leaf binders) with a divider for each tag number/equipment designation. Construction documentation, which refers to drawing numbers or line numbers, shall be arranged in accordance with these references.

For all as-built documentation prepared on AutoCAD, the Contractor shall hand over one set of compatible 31/2" diskettes with AutoCAD R14 – 2000.

Unless anything else is stated in the specifications, the following guidelines for use of text language must be adhered to:

- Text on drawings shall be prepared in English.

- Text for other as-built documentation shall be prepared in English.

The Contractor is responsible for the correct translation of any documentation.

For translated documents also the original document shall be included.

For equipment/components supplied and installed by the Contractor, attention shall be paid to the handling of documents required in the relevant specifications or by the authorities. The Contractor shall check the completeness of all certificates and documents before handing over it to the Project Manager.

5. Piping and Mechanical Equipment

The documents of the individual packages to be provided by the Contractor, includes the following:

- Isometric drawings

- Pipe log

- As-built piping arrangement drawings and schedules

- Manuals and spare parts lists

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- Functional test reports

- Calibration certificates

- Material certificates

- Welding documentation

- Strength and tightness test certificates

- Other certificates/reports

Isometric drawings

The Contractor shall prepare, update and issue as-built isometric drawings.

The isometric drawings shall identify the exact location of welds and items shown and shall state piping class and reference no. to pipe log.

Pipe log

The Contractor on pipe record forms shall state the information required to supplement the as-built isometric drawings.

Piping layout drawings and Schedules

The contractor shall mark up the following drawings.

- Piping Lay-out Drawings

- Line Lists

- Mechanical Equipment List

Manual and spare parts lists

For each component and equipment supplied and installed by the Contractor, operation and maintenance manuals shall be provided/prepared.

The operation and maintenance manuals shall include sufficient documentation to ensure safe operation and maintenance procedures.

The documentation in the operation and maintenance manuals shall as a minimum include the following items which shall be specified in the purchase requisitions:

- Description, including manufacture, model, type no., supplier in Tanzania or abroad.

- Brochure/catalogue sheets with marking of the specific item or alternatively drawing.

- Complete technical data, including dimensions, weight, capacity, performance curve, electrical data, materials, etc.

- Erection/installation instructions including instruction for start-up.

- Complete parts list with description of all parts.

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- Detailed user's Instruction.

- Detailed instruction for dismantling and assembling. Operation instruction, including description of items to be inspected regularly, frequency of lubrication, type of lubricant, amount of lubricant, possibilities for setting and adjustment, etc.

- Faultfinding schedule, including description of typical faults with causes and including activ-ities required to remedy the fault(s).

- Maintenance schedule, including specification of checking activities required during operation with description of frequency (daily, weekly, monthly, etc.) of the checking activities and frequency of service from supplier, if necessary.

- Emergency procedures required in case of abnormal operation etc.

- List of operation spare parts, recommended tools, lubricants, etc.

Functional test reports:

Functional test reports for site tests performed by the Contractor and duly signed by the Project Manager shall be supplied.

Calibration certificates:

Calibration certificates for Contractor supplied items and for test instruments used by the con-tractor shall be supplied.

Material certificates:

Where specified in the contract documents, the Contractor shall provide material certificates for all components supplied by the Contractor.

Welding documentation:

The Contractor shall enclose Welding Procedure Specifications (WPS) and Procedure Qualification Records (PQR).

Non-destructive examination documentation shall include all radiographic films and non-destructive evaluation reports.

Strength and tightness test:

The Contractor shall enclose:

- Pressure test certificates for spools and equipment completed in shop.

- Pressure and tightness test certificates for the completed sections of storage tanks or plant piping

The Contractor and the Project Manager shall duly sign the certificates.

Other certificates/reports:

The Contractor shall supply other approvals and certificates as stated in Technical Specifications.

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6. Electrical and Instrumentation Equipment

The documents to be provided by the Contractor shall include:- As-built drawings- Manuals and spare parts lists- Other certificates- Factory acceptance test documents - Functional test reports- Other reports/notes etc.

As-built drawings:

The Contractor shall revise all relevant project drawings and issue as-built drawings.

During the construction phase, the Contractor shall prepare different working drawings. The Contractor shall revise the working drawings and issue as-built drawings, which, as a minimum shall include the following types of drawings:

- Installation plans

- Erection and installation details

- Cable routing plans with measurement to fix points

- Circuit diagrams

- Load schedule

- Single-line diagrams

- Cable schedules

- Termination drawings

- Other relevant drawings

EEx Certificates:

For all electrical equipment suitable for use in explosive atmospheres, or part of Exi circuit (intrinsically safe) the Contractor shall provide EEx approval and conformity certificates.

Manuals and spare parts list:

For each exchangeable item supplied and installed by the Contractor, operation and maintenance manuals shall be provided/prepared.

The operation and maintenance manuals shall include sufficient documentation to ensure safe operation and maintenance procedures.

The documentation in the operation and maintenance manuals shall include the following items, which shall be specified in the purchase requisitions:

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- Description, including manufacture, model, type no., supplier in Tanzania or abroad.

- Brochure/catalogue sheet with marking of the specific items, alternative drawings.

- Complete technical data, including measurements, weight, capacity, performance curve, electrical data, materials, etc.

- Erection/installation instructions, including instruction for start-up.

- Complete parts list with description of all parts.

- Detailed User's Instruction.

- Detailed instruction for dismantling and assembling.

- Operating instruction, including description of items to be inspected regularly, frequency of lubrication, type of lubricant, amount of lubricant, possibilities for setting and adjustment, etc.

- Faultfinding schedule, including description of typical faults with causes and including activities required to remedy the fault(s).

- Maintenance schedule, including specification of checking activities required during operation with description of frequency (daily, weekly, monthly, etc.) of the checking activities and frequency of service from supplier, if necessary.

- Emergency procedures required in case of abnormal operation etc.

- Complete list of operation spare parts, recommended tools, lubricants, etc.

Calibration certificates:

The Contractor shall provide calibration certificates for measuring instruments, transducers, etc.

supplied by the contractor.

Other certificates, test etc.

The Contractor shall provide other certificates, test such as:

- Calibration certificates for test instruments used by the Contractor during the construction period.

- Factory acceptance test documents.

- Functional test reports for site tests performed by the Contractor and duly signed by the Project Manager shall be supplied.

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Other reports, notes etc

Other documentation generated during the construction such as reports, approval, notes, etc., shall be handed over to the Project Manager.

7. Structural Work

The documents to be provided by the Contractor shall include:

- As built drawings.- Material certificates.- Welding documentation.- Other certificates/reports.

Material certificates:

The Contractor shall provide material certificates for all materials supplied by the Contractor.

Welding documentation:

The Contractor shall enclose Welding Procedure Specifications (WPS) and Procedure Qualification Records (PQR).

The Contractor shall enclose all radiographic films and non-destructive evaluation reports.

Other certificates/reports:

The Contractor shall supply other approvals and certificates as stated in Specifications.

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PRICED SCHEDULE/BILLS OF QUANTITIES

I. PREAMBLETenderers must price each item in the price schedule separately and follow the instructions regarding the transfer of various totals in the summary.

The price schedule must be read with all the other contract documents and the Contractor shall be deemed to have thoroughly acquainted himself with the detailed descriptions of the works to be done and the way in which they are to be carried out. All the works must be executed to the satisfaction of the project supervisor.

1.1. Quantity of itemsThe quantities set forth against the items in the price schedule are an estimate of the quantity of each kind of the work likely to be carried out under the contract and are given to provide a common basis for bids. There is no guarantee to the Contractor that he will be required to carry out the works indicated under any one particular item in the price schedule or that the quantities will not differ from those stated.

When pricing items, reference should be made to the conditions of contract, specifications and and drawings relating to the management and description of the works and materials involved.

The quantities given in the price schedule are provisional and reflect the estimates made at the time of approval to provide a basis for this dossier and tenders. Tenderers must consider every aspect of the dossier carefully.

Any comments concerning the quantities must be made in the form of an attachment, following the system of itemisation, quoting the codes and giving brief descriptions, as in the present documents, including the rates and prices.

Save where the technical specifications or the price schedule specifically and expressly state otherwise, only permanent works are to be measured. Works will be measured net to the dimensions shown on the drawings or ordered in writing by the project supervisor, save where described or prescribed elsewhere in the contract.

In adjusting extras or variations on the contract, works will be measured on the same basis as that on which the quantities were prepared. All works not specifically mentioned in the price schedule will be taken as included in the prices of various items.

Where, in the opinion of the project supervisor, extra works cannot be properly measured or estimated, the Contractor may, if so directed by the project supervisor, carry out the work at the daywork rates shown in the schedule of day-work. All completed daywork sheets must be signed by the project supervisor on or before the end of the week in which the works are executed.

No allowance will be made for loss of materials or volume thereof during transport or compaction.

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1.2. Units of measurementThe units of measurement used in the annexed technical documentation are those of the International System of Units (SI). No other units may be used for measurements, pricing, detail drawings etc. (Any units not mentioned in the technical documentation must also be expressed in terms of the SI.)

Abbreviations used in the price schedule are to be interpreted as follows:mm means millimetrem means metremm² means square millimetrem² means square metrem³ means cubic metrekg means kilogramto means tonne (1000 kg)pcs means piecesh means hourf means lump sumkm means kilometrel means litre% means per centDN means nominal diameterm/m means man-monthm/d means man-daynr means number

II. TERMS RELATING TO PAYMENTS1. The method of measurement of the completed works for payment shall be as specified in the

relevant parts of the Tender dossier (General Conditions of Contract and Special Conditions) and in accordance with the following:

a. All work completed under the contract will be measured by the Project Supervisor Representative, using the International System of Units.

b. The method of measurement and computations to be used in determination of quantities of material furnished and of work performed under the contract will be those methods generally recognized as conforming to good engineering practice. The quantities will be computed net.

Use, in whole or in part, of the provisional sums in the price schedule must be at the discretion of the Project Supervisor’s Representative.

Each item in the price schedule for which payment is to be made in a lump sum, and for which no payment schedule is provided, must be paid after the work covered by the lump sum has been completed to the satisfaction of the project supervisor.

2. Unless otherwise specified, longitudinal measurements for area computations will be made horizontally, and no deductions will be made for individual fixtures (or leave-outs) having an area of one square meter or less. Unless otherwise specified, transverse measurements for area computations will be the net dimensions shown on the drawings or ordered in writing by the Project Supervisor’s Representative.

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3. The rates for electrical and mechanical work shall be deemed to include for all necessary temporary works, lighting, access and staging, supply and installation of permanent works. The rate for supply, installation and commissions of electrical installation shall be deemed to include removal of existing equipment and disposal off site to the approval of the Project Supervisor’s Representative and luminaries, switches, cabling, tray work, fixtures and fittings.

4. In-situ concrete shall be measured as the net volume shown on the drawings or variation to the drawings as directed by the Project Supervisor’s Representative, but no deductions shall be made for small chamfers, steelwork, reinforcement, bolt holes or fitting required to be built-in, nor shall extra volume be measured for splays or fillets. Deduction will only be made for openings with a cross-sectional area exceeding 0.1 m2.

5. The rates for in-situ concrete shall include all necessary construction joints and shrinkage joints unless they are measured under separate items, stop ends, building in fittings, joints, pipes, conduits, bolts and the like and forming all small holes, apertures and other features which although not specifically mentioned in the Contract Documents, or shown on the drawings, can reasonably be inferred from the drawings and the Project Supervisor’s Representative instructions.

6. Where no separate quotes/measurement are provided in the Bills of Quantities, the rates for all concrete shall include the supply of all materials including admixtures, mixing, transport, placing, compaction, curing, sampling and testing of concrete as specified.

7. Formwork shall be measured as the net area in contact with the finished concrete surface. No measurement will be allowed for any temporary construction such as props, struts, stays, wedges, etc. The rates for formwork shall be deemed to include bolts, form oil, all types of cutting, raking, forming splays to arises, waste, etc

8. Formwork incorporating holes, fillets, chamfers, grooves drip-chases, joints for any other appurtenances required shall be measured as if these features are not present. Deductions will only be made for openings with an area exceeding 1.0 m2. Formwork will be measured as inclined when the angle of inclination to the vertical lies between 10 and 850.

9. Unless otherwise specified, all contract items which are measured by the linear metre such as excavation, pipe laying, pipe culverts, under drains, and similar items shall be measure parallel to the base or foundation upon which such items are placed.

10. Valve chambers shall be measured by number. The price for valve chambers shall include excavation, construction of valve support, foundation concrete, concrete/brickwork walling and cover as per the drawings, and backfilling around the chamber.

11. Thrust blocks shall be measured by number. The rate quoted shall include variation in pipe diameter leading to automatic fluctuations in volumes of concrete.

12. When a complete structure or structural unit (in effect, “Lump Sum’’ Work) is specified as the unit of measurement, the unit will be construed to include all necessary materials, fittings and accessories.

13. Rental of equipment will be measured by time in hours of actual working time and necessary traveling time of the equipment within the limits of the work.

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14. When standard manufactured items are specified such as fence, wire, plates, rolled shapes, pipe, etc, and these items are identified by gauge, unit weight, section dimensions, etc, such identification will be considered to be nominal weights or dimensions. Unless more stringently controlled by tolerances in cited specifications, manufacturing tolerances established by the industries involved will be accepted.

15. When the estimated quantities for a specific portion of the work are designated as the pay quantities in the contract, they shall be the final quantities for which payment for such specific portion of the work will be made, unless the dimensions of said portions of the work shown on the plans are revised by the Project Supervisor’s Representaive . If revised dimensions result in an increase or decrease in the quantities of such work, the final quantities for payment will be revised in the amount by the authorized changes in the dimensions.

16. Payment to the Contractor of Bill Items relating to Performance Bond and insurances shall be the actual sum expended by the Contractor as substantiated by receipts/invoices. However, in each case such a sum shall not exceed the sum inserted by the Contractor against the corresponding item in the Bill of Quantities.

17. The rates quoted for reinforced concrete/ reinforced concrete blockwork shall be deemed to include all reinforcements embeded in respective structure as per provided drawings. No separate payment will be made for reinforcements in reinforced concrete.

18. The rates quoted for all items under construction of pump house shall be deemed to include elevation of both the pump house and its compound for the areas exposed to floods.

19. The rates quoted for all items under construction of storage tank shall be deemed to include soil investigation prior to the construction of respective storage tank.

20. Day work schedule

Day work – Labor

i. In calculating payments due to the Contractor for the execution of day works, the hours for labor will be reckoned from the time of arrival of the labor at the job site to execute the particular item of day work to the time of departure, but excluding stand down time, meal breaks and rest periods. Only the time of classes of labor directly doing work ordered by the Project Supervisor’s Representative and for which they are competent to perform will be measured.

ii. The contractor shall be entitled to payment in respect of the total time that labor is employed on day work, calculated at the rates entered by him in the Day work Schedule.

iii. The said rates shall be deemed to include due and complete allowance for wages and allowances paid to such labor, transportation time, overtime, subsistence allowance, sums paid to or on behalf of such labor for social benefits in accordance with the Tanzanian Law; Contractor’s profit, overheads, superintendence, liabilities and insurances, timekeeping, clerical and office work, the use of consumable stores, water, lighting and power; use and repair of staging, scaffolding, workshops and stores, portable power tools, manual plant and tools; supervision by the Contractor’ staff, foremen and other supervisory personnel; and all charges incidental to the foregoing.

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Day work – Materials

The contractor shall be entitled to payment in respect of materials used for day work, at the basic rates entered by him in the Day work Schedule, together with an additional percentage payment on the basic rates to cover overhead charges and profit, as follows:

a. The basic rates for materials shall be calculated on the basis of the invoiced price, freight, insurance, handling expenses, damage, losses, etc, and shall provide for delivery to store or stockpiling at the Site. The basic rates shall be stated in local currency but payment will be made in the currency or currencies expended upon presentation of supporting documentation.

b. The additional percentage payment to be quoted by the Tenderer and applied to the equivalent local currency payments made under (a) above shall be deemed to cover the Contractor’s profit, overhead, superintendence, liabilities and insurances and charges incidental to the foregoing. Payment under this item will be in local and foreign currency as applicable.

c. Unless specifically scheduled the cost of hauling materials for use on work ordered to be carried out as day work from the store or stockpile on the Site to the place where it is to be used will be paid in accordance with the terms of Labour and Equipment in this Bill.

Day work – Equipment

The Contractor shall be entitled to payments in respect of Contractor’s Equipment already on Site and employed on day work at the basic rental rates entered by him in the Day work Schedule.

The said rates shall be deemed to include due and complete allowance for depreciation, interest, indemnity and insurance, drivers, operators and assistants, repairs, maintenance, supplies, fuel, lubricants, and other consumables and all overheads, profit, supervision and administration costs related to the use of such equipment.

In calculating the payment due to the Contractor for Equipment employed on day work, only the actual number of working hours as determined by the Project Supervisor’s Representative will be eligible for payment, except that where applicable and agreed with the Project Supervisor’s Representative, he ravelling time from the part of he Site where the Equipment was located when ordered by the Project Supervisor’s Representative to be employed on day work and the time for return journey thereto shall be included for payment. Payment for this item will be in local and foreign currency as applicable.

III. PRICINGThe prices and rates inserted in the price schedule are to be the full inclusive values of the works described under the items, including all costs and expenses which may be required in and for the construction of the works described together with any temporary works and installations which may be necessary and all general risks, liabilities and obligations set forth or implied in the documents on which the tender is based. It will be assumed that establishment charges, profit and allowances for all obligations are spread evenly over all the unit rates.

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The rates and prices tendered in the price schedule will be quoted at the rates current prior to the date of submission.

Rates and prices must be entered against each item in the price schedule. The rates will cover all taxes, duties and other liabilities which are not stated separately in the price schedule and the tender.

IV. TAXESVAT and other taxes are not payable on funds originating in the European Union and the Kingdom of Belgium. However, separately, tenderers must quote, in national currency, the taxes, customs and import duties applicable at the time of submission.

V. COMPLETING THE PRICE SCHEDULEIn the price schedule, rates and prices will be entered in the appropriate columns in national currency.

Errors will be corrected as follows:

a) where there is a discrepancy between amounts in figures and in words, the amount in words will prevail; and

b) where there is a discrepancy between the unit rate and the total amount derived from the multiplication of the unit price and the quantity, the unit rate as quoted will prevail.

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