Appendix N: Specifications

1 DCOM Standard Specifications

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TABLE OF CONTENTS

#	Title	Page
1	GENERAL REQUIREMENTS	1
2	DIN SPECIFICATIONS	20
3	EARTHWORKS	21
4	CONCRETE, REINFORCEMENT, FORMWORK AND JOINTS	36
5	MASONRY AND PLASTER WORK	61
6	EARTHWORKS	66
7	TIMBER AND GLAZING	79
8	MISCELLANEOUS BUILDING WORKS	86
9	ENGINEERING METALWORK	95
10	PAINTING AND PROTECTIVE COATING	95
11	PIPELINES	95
12	SITEWORKS	119

2 STANDARD SPECIFICATION FOR CIVIL WORKS

2.1 GENERAL REQUIREMENTS

1.1 Permissions being obtained by the Employer

The Site of the Permanent Works is shown on the drawings accompanying these Employer’s Requirements. The Employer shall have obtained (or shall obtain) the planning, zoning or similar permission for the Permanent Works. 1.2 Plan of operations and temporary works

The Contractor shall in accordance with the Conditions of Contract, and before commencing on site, submit to the Engineer a fully detailed programme showing the order of procedure and methods by which he proposes to carry out the construction and completion of the Works, and particulars of the organisation and staff proposed to direct and administer the performance of the Contract.

The Works shall be carried forward to completion with the greatest possible expedition, to the satisfaction of the Engineer, in accordance with the programme. The information to be supplied to the Engineer shall include drawings showing the general arrangement of the temporary offices, camps, storage sheds, buildings and access roads, and details of Contractor’s Equipment and Temporary Works proposed.

1.3 Standard Specification

For convenience, and in order to establish the necessary standards of quality, reference will be made to specifications issued by national or other widely recognised bodies. Such specifications shall be referred to as "Standard Specifications" and shall be the latest editions of such Standard Specifications issued prior to the issue of the Tender Dossier, together with such additions and amendments as may have been issued prior to the same date. For all paving and roadworks the ‘Standard Specifications for Road Works’ by the Ministry of Works of the United Republic of Tanzania shall apply. Subject to the written approval of the Engineer, any other internationally accepted Standard, which requires an equal quality of work, may be used. If the Contractor proposes to use a Standard Specification other than that specified, three copies of the proposed Standard Specification, in the English Language, shall be submitted to the Engineer not less than twenty eight days before approval of the Standard Specification is required. In referring to Standard Specifications, the following abbreviations are used: BS British Standard BSCP British Standard Code of Practice DIN Deutches Institut für Normung ISO International Organisation for Standardisation. 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. 1.4 Units

In this Specification, on the Drawings, and in the Bill of Quantities, the metric system of dimensioning has been adopted except where it is understood that suppliers and manufacturers are not yet able to provide materials in metric sizes. Where dimensions are given in metric units for materials which are only available in Imperial system dimensions, and vice versa, the Contractor may, subject to his obtaining the prior approval of the Engineer, substitute the nearest equivalent available standard size in the other system. 1.5 Contractor’s Documents

The Contractor shall, in accordance with the General Conditions of Contract submit to the Engineer for approval the Contractors Documents. These documents shall amongst others include the following: a) Designs of any approved alternatives; b) Construction Report; c) Concrete mix designs; d) Falsework and centering designs; e) Cathodic protection system designs; f) Pipe specials and fitting designs; g) “As Built” documents; h) Operation and Maintenance manuals; Any other designs necessary for the construction works but not specifically mentioned. 1.6 Setting out points, lines and levels of reference

It shall be the responsibility of the Contractor before commencing work to obtain from the Engineer in writing the values and locations of the benchmarks to be used in these Works. All temporary benchmarks shall be referred thereto. The Contractor shall construct such temporary benchmarks as the Engineer may direct and shall agree the levels thereof with the Engineer. The establishment of such temporary benchmarks shall be deemed part of the Contractor's responsibility in setting out the works. 1.7 Setting out

The Contractor shall appoint and employ the necessary qualified and experienced staff to set out the Works accurately.

The Contractor shall establish and locate all lines and levels and be responsible for the correct location of all works.

Where directed by the Engineer, the Contractor shall take such levels and dimensions as may be required for the purposes of measurement before disturbance of the ground.

These shall be agreed between the Contractor and the Engineer in writing before any ground surface is disturbed or covered up. Any work commenced without taking the said levels and dimensions shall be measured on the Engineer’s reckoning of their values before disturbance. The Engineer’s decision on this matter shall be final. 1.8 Construction and checking of work

The Contractor shall be solely responsible for and shall provide all labour, tools, lifting tackle, and other equipment required for the construction and checking of the works.

No operative shall be allowed to execute any type of work which is normally carried out by a skilled trades man, unless the operative is thoroughly experienced and proficient in the trade concerned. Foremen and operatives may be required to demonstrate their proficiency or produce certificates of competence to the satisfaction of the Engineer.

As each part of the work is carried out, it shall be subject to the approval of the Engineer. 1.9 Supervision and labour

The Contractor will be required to maintain a competent supervising engineer and staff on Site throughout the construction period until completion of the Works, and thereafter as may be required during the Defects Liability Period. The Engineer shall give prior approval to the appointment of this supervising engineer and shall have the authority to withdraw this approval at any time in accordance with the Conditions of Contract.

1.10 Subcontractors

Where subcontractors are not nominated, the Contractor shall appoint specialist subcontractors for any sections of the Works described herein in which he is not himself an experienced, recognized and approved operator.

A subcontractor nominated by the Employer or the Engineer will be required to hold the Contractor indemnified against all claims, accidents, damage or loss occasioned by any act of the subcontractor in the performance of the sub-contract.

The Contractor shall allow for phasing the work to meet the requirements of subcontractors and for varying his programme, or otherwise, to comply with the programme of the subcontractors. 1.11 Environmental constraints 1.11.1 Environmental Control Officer (ECO)

An Environmental Control Officer (ECO) will be appointed by the Employer to ensure and monitor the implementation of the Environmental Management Plan (EMP) where applicable. The ECO will have the following responsibilities:

i. To advise the Engineer on the interpretation and enforcement of the environmental requirements; ii. To supply environmental information; iii. To undertake regular inspections and submit reports on the Contractor’s compliance with the environmental requirements; these reports shall be copied to the Contractor and Engineer;

iv. To demarcate particular sensitive areas and pass instructions through the Engineer concerning works in these areas. 1.11.2 Responsibilities of the Contractor

The Contractor shall:

i. Comply with the environmental requirements contained in this document;

ii. Be familiar with the EMP; iii. Notify the ECO and Engineer immediately in the event of any accidental infringements of the environmental requirements to enable appropriate remedial action to be taken; iv notify the ECO and Engineer, at least ten working days in advance, of any activity he measures may be implemented timeously; iv. Ensure environmental awareness among his employees and subcontractors so that they fully aware of, and understand, the environmental requirements and the need for them; v. undertake rehabilitation of all areas affected by construction activities to restore them to their original states, as determined by the Engineer; vi. Undertake the required works within the designated working areas. 1.11.3 Responsibilities of the Engineer

The Engineer shall:

i. be familiar with the contents of the EMP; ii monitor the Contractor’s compliance with the environmental requirements on a daily basis and enforce compliance; iii communicate to the Contractor the advice of the ECO and the contents of the ECO reports and issue site instructions giving effect to the ECO requirements where applicable; iv communicate to the ECO, at least ten working days in advance, any proposed actions which may have negative impacts on the environment; v designate all working areas;

vi communicate to the ECO any infringements of the environmental requirements and accompany the ECO during site inspections; vii maintain a record of complaints from the public and communicate these to the Employer and Contractor; viii. facilitate communication between all roleplayers in the interest of effective environmental management; ix monitor the compliance of the Contractor through the ECO reports. 1.11.4 Working areas

The Contractor shall only conduct construction activities in designated working areas. Limitation of construction activities to specific working areas minimises the impact on the natural environment and facilitates control of the works. Sites shall be divided into working areas and “no-go” areas:

Working areas are those areas required by the Contractor to construct the works and as approved by the Engineer. These areas include the area of permanent works, borrow areas and haul roads between site and borrow areas. If necessary, the working areas may be demarcated during the construction period. The Contractor shall not be permitted beyond the designated working areas

“No-go” areas are those areas outside of working areas.

The Contractor will not be allowed to quarry or remove stones from the surrounding hills as these are mostly of a fossil nature. Permission to quarry needs to be acquired from the relevant authorities.

1.11.5 Protection of flora, fauna, natural features and archaeological material

The Contractor shall protect natural features, flora and fauna in the vicinity of the project works and prevent or minimise damage or disturbance, specifically:

i. no plant species may be removed unless agreed by the Engineer or unless they are listed as invasive/alien species; ii. all fauna (including domestic livestock) within and surrounding the site shall be protected; they shall not be caught or killed; ii. natural features shall not be defaced or painted or otherwise tampered with, even for survey purposes, unless agreed by the ECO. Any features defaced by the Contractor iii. It is foreseen that a dredging operation will be required from the raw water pumping station to the position of the new intake works in order to be able to lay the intake pipe below the lake bottom in firm soils. Extreme care has to be exercised in order not to disturb the adjacent areas during this exercise and to minimise the impact of the operation. 1.11.6 Conservation and stockpiling of topsoil

Topsoil shall be excavated from the following areas no longer than five days before the start of construction:

i. all areas to be excavated for the construction of the Permanent Works; ii. areas to be occupied by roads, including temporary roads; iii. areas for the storage of fuels and oils; iv. areas to be used for batching/mixing of concrete; v. areas for stockpiling of construction materials; vi. areas for Contractor’s camps.

Topsoil shall be excavated to the base of the A-Horizon or approximately 150mm, whichever is deeper, and stockpiled in the area designated by the Engineer. Topsoil shall be stored in piles less than 1m in height. This soil is valuable for its humus and seed content and shall be used for rehabilitation purposes. Grass shall not be removed prior to stripping of the topsoil.

Topsoil shall not be mixed with any other material and erosion of the topsoil stockpiles shall be prevented.

1.11.7 Erosion control

No erosion will be tolerated on the Site. The Contractor shall take all reasonable measures to prevent soil erosion resulting from a diversion, restriction or increase in the flow of stormwater or river flow caused by the presence of temporary/permanent works, operations and activities. Erosion prevention measures must be implemented to the satisfaction of the Engineer.

Areas affected by construction related activities must be monitored regularly for evidence of erosion. Areas particularly susceptible to erosion are: areas stripped of topsoil, soil stockpiles and slopes steeper than 6%.

Where soil erosion does occur, the Contractor shall reinstate such areas and areas damaged by the erosion to the satisfaction of the Engineer. 1.11.8 Prevention of pollution

Pollution could result from the release, accidental or otherwise, of chemicals, oils, fuels, sewage, waste water containing kitchen waste, detergents, solid waste and litter, etc. The Contractor shall ensure that pollution of the ground or water does not occur as a result of any activities on Site. 1.11.9 Dust control

Dust is regarded as a nuisance when it reduces visibility, soils private property and is aesthetically displeasing. Dust reduces the palatability of grazing grasses and may retard plant growth.

The Contractor shall be responsible for the control of dust arising from his operations and activities. Control measures could include regular spraying of working / bare areas with water, at an application rate that will not result in soil erosion. 1.11.10 Noise control

The Contractor shall familiarise himself with the legislation pertinent to noise generation. The Contractor shall take measures to limit noise levels during construction, taking into account the rural setting of the project. 1.11.11 Traffic control

Increased traffic, especially heavy vehicle traffic, has the potential to draw complaints from nearby residents. The Contractor shall address any complaints received.

The Contractor shall comply with all the applicable Laws with regard to road safety and transport. He shall instruct his drivers and equipment operators that vehicles will be expected to comply with all road ordinances, such as speed limits, roadworthiness, load securing and covering. 1.11.12 Fire prevention and control

The Contractor shall take all the necessary precautions to ensure that uncontrolled fires are not started as a consequence of his activities on Site. The Contractor, subcontractors and all employees are expected to be conscious of fire risks. The Contractor shall hold fire prevention talks with staff to create an awareness of the risks of fire. Regular reminders to his staff on this issue are required.

The Contractor shall ensure that there is adequate fire-fighting equipment on site.

The Contractor shall be liable for any expenses incurred by any organisations called to assist with fighting fires and for costs involved in rehabilitation of burnt areas/property/persons, shall the fire be the result of the activities of the Contractor. 1.11.13 Social disruption

The Contractor’s Personnel shall in no way be a nuisance to nearby residents. Any complaints received by the Engineer will be addressed and the relevant persons will be removed from the Site.

The Contractor shall give at least seven days notice to the residents in the vicinity of the construction activities of his intention to begin construction activities in their area. The Engineer may request a representative to be available to discuss issues raised by residents and make information available to them on construction activities.

The Contractor shall ensure that access to property is not unreasonably disrupted.

Where construction activities require the removal of fences from around private land, the Contractor shall warn occupants at least three days in advance. The Contractor shall reinstate these fences/boundary markers as soon as construction is complete. 1.11.14 Protection of the public

The Contractor shall be responsible for the protection of the public, and public property, from any dangers associated with construction activities, and for the safe and easy passage of pedestrians and traffic in areas affected by project activities.

The Contractor shall employ competent watchmen and guard the Works both by day and by night.

Any excavations, material dumps, spoil dumps or other obstructions likely to cause injury to any person or thing shall be suitably fenced off and at night marked by red warning lights.

Fences shall consist of at least three 15mm diameter hemp ropes or 4mm diameter wires, or more if required, stretched tightly between poles, and standards securely planted in solid ground, well clear of the excavation. The poles and standards shall not be more than three metres apart, and where circumstances require, they shall be placed closer. Ropes or wires shall be stretched tight approximately 0.4m, 0.8m and 1.2m above the ground. The Engineer may accept banks of spoil instead of fencing, if of suitable height and form. 1.11.15 Vehicles and access roads

Site vehicles shall be permitted only within the demarcated construction sites or on existing roads, as would be required to complete their specific tasks. Vehicles are not permitted on re-vegetated areas and site traffic shall be limited to prevent unnecessary damage to the natural environment. 1.11.16 Stockpiling of materials

All stockpiling sites are subject to the approval of the Engineer. The stockpiles shall be located in demarcated construction sites, or areas such as exhausted borrow pits/quarries. Material stockpiled shall be done so in such a way as to minimise the spread of materials and the impact on the natural vegetation. The Contractor shall ensure that no materials creep into “no-go” areas.

The Contractor shall reinstate areas used for stockpiling upon completion of the project. 1.11.17 Site camp

Where site camps are to be established, the feasibility of removing topsoil from the site, before site establishment, shall be investigated. Removed topsoil shall then be stockpiled for use in rehabilitation of the site camp.

The site camp shall not be located in an environmentally sensitive area. The site shall be located greater than 20m from a watercourse/wetland. Runoff from site must be prevented from entering any water bodies; all water requiring discharge shall be discharged in a manner approved by the Engineer.

The Contractor shall maintain all site camps and surrounds in a clean, tidy and orderly condition at all times. 1.11.18 Prevention of oil and fuel spills

The Contractor shall take all measures necessary to protect surface and groundwater from contamination by fuels and lubricants. He shall:

i. bund all tanks for fuels, oils etc. to contain any possible spills; ii. provide spill mitigation equipment including absorbents, foam cover spraying equipment and oil skimmers; iii. establish and maintain an emergency preparedness programme. 1.11.19 Refuse and litter

The Contractor shall keep the Site clean and litter free. The Contractor shall provide refuse bins at the work sites and shall be responsible for the disposal of all litter generated by all staff in an approved manner. 1.11.20 Drinking and construction water

Water for drinking and construction purposes shall be obtained from an approved source. 1.11.21 Concrete batching

Concrete batching/mixing equipment shall be located greater than 200m from the nearest watercourse/wetland. The batching site must be bunded with earth berms or sandbags to prevent runoff escaping. Contaminated water shall be allowed to soak away in a soak pit. Waste concrete and cement sludge shall be scraped off the site and disposed of in an approved landfill site. 1.11.22 Existing services and infrastructure

The Contractor shall ensure that existing services are not disrupted or damaged, unless required by the contract and with the permission of the Engineer. 1.11.23 Alien vegetation

Alien species of vegetation shall be removed from any working areas and the site camp(s). Alien vegetation species shall also be eradicated when they begin to establish themselves in disturbed areas (disturbance of the natural vegetation will encourage the establishment of invasive species). In order to discourage the spread of alien species, soil shall not be moved from one part of the site to another without the consent of the ECO.

The ECO will assist in the identification and eradication of alien species. Methods or removal / eradication usually involve hoeing by hand or, in some cases, herbicides. 1.11.24 Work stoppage

The Engineer shall have the right to order work to be stopped in the event of significant infringements of the environmental requirements, until the situation is rectified. In this event, the Contractor shall not be entitled to claim for delays or incurred expenses. 1.11.25 Monitoring of compliance with the environmental requirements

The Engineer will monitor the Contractor’s performance in relation to the environmental requirements on a daily basis. He will be assisted in his monitoring by the ECO.

The ECO shall inspect the site on a regular basis. After such visits a report will be submitted to the Engineer and the Employer. The reports will contain any infringements of the environmental requirements. The reports may also aim at anticipating problems and so alert the Contractor to potential environmental risks and the appropriate action that may be taken. The Engineer will make the content of these reports known to the Contractor.

The ECO may undertake an Environmental Audit of the works. 1.12 Contractor’s site offices, workshops, storage and working areas

The Contractor shall be allocated an area for his site offices, stores, and working areas.

The Contractor shall be responsible for providing all buildings, fences, etc. that he may require and on completion of the Works shall be required to remove the same and restore the land to its original condition to the satisfaction of the Engineer.

The location of all offices, stores and the like shall be to the approval of the Engineer. 1.13 Access, electricity, water, gas and other services available on the Site 1.13.1 Access roads to site

The Contractor shall maintain access road(s) to sites to be passable all the year round. 1.13.2 Water

The Contractor shall be solely responsible for the location, procurement and maintenance of a water supply adequate in quality and quantity to meet his obligations under the Contract. The Contractor shall be solely responsible for the transporting of water from its source to the point at which it is required for construction purposes. A package water treatment plant for potable water will be required to service the staff houses and office facilities for the duration of the contract. 1.13.3 Power

The Contractor shall make his own arrangements for power supplies required for the completion of the Works and supply to the supervisory staff houses and offices. However, a standby generator of may be required for the permanent works. The Contractor may use this generator during the construction period to supply electricity to the staff houses and offices as required. Should the Contractor elect to use the generator for this purpose, he will service the generator and ensure that it is in an acceptable running condition.

1.13.4 Fuel

The Contractor shall arrange for obtaining, storing and distributing all fuel oils required for the completion of the works.

1.14 Communications

The Contractor shall obtain suitable means of communications during the course of the Contract. The use of radio communications may be permitted, but the Contractor shall be responsible for obtaining all the necessary permits and licenses. 1.15 Sanitation

The Contractor shall provide adequate sanitation and refuse collection and disposal facilities complying with the laws and local by-laws for all houses, offices, workshops, and the like erected on the Site, all to the satisfaction of the Engineer. The Contractor shall warn his employees and subcontractors that any employee found fouling the site will be removed from the site immediately. 1.16 Interference with existing works

The Contractor shall not interfere in any way, with any existing works, be it the property of the Employer or of a third party, whether such works has been shown to the Contractor by the Engineer, except where such interference is specifically described as part of the Works, either in the Contract or in instructions from the Engineer to take over such Works. 1.17 Materials for the Works

All materials shall comply with the appropriate Standard Specifications unless otherwise required hereinafter.

The Contractor, shall, before placing any order of materials, manufactured articles or machinery for incorporation in the Works, submit for the approval of the Engineer the names of the suppliers from whom he proposes to obtain such materials, manufactured articles or machinery, together with a list of the same, giving the origin, quality, weight, strength, description and other relevant details. No materials, manufactured articles or machinery shall be ordered or obtained from any suppliers not approved in writing by the Engineer.

All materials shall be delivered to the Site a sufficient period of time before they are required for use in the Works, to enable the Engineer to take such samples as he may wish for testing and approval.

Notwithstanding the fact that approval has been given to the source of supply, the Engineer may forbid the use of any materials if, upon delivery, they are found to be defective, or he considers them unsuitable for incorporation in the Works. Such rejected materials shall be removed from the site forthwith.

The Contractor may propose alternative materials of equivalent quality to those specified, and subject to the Engineer's approval, such materials may be used in the Works.

The Contractor shall have no claim against the Employer in respect of any financial loss which he may suffer as a result of the rejection of any such materials, and he shall also bear the cost of removing them from the Site.

The Engineer shall have the right to inspect materials and plant for the permanent Works during the course of manufacture. The Contractor shall arrange for the right of access to manufacturing premises for the Engineer and his staff during normal working hours. The Contractor shall give the Engineer sufficient notice to allow him to observe the testing of any materials for the works at the place of manufacture. The Engineer shall also be given the opportunity to inspect any material or plant in their completed state before packing for transport to the site.

If requested by the Engineer, the Contractor shall provide the Engineer with copies of orders for the supply of goods or materials required for the Works. 1.18 Dust, insect and vermin proofing

All materials supplied under this Contract shall be dust and vermin proofed where no protection is afforded in its normal manufactured form to ensure that no mechanical breakdown or excessive wear shall occur due to interference or damage by dust, insects or vermin.

All materials used in the works shall be resistant to attack by insects, microbiological life or other local fauna. 1.19 Rejected materials and defective work

Materials or work which, in the opinion of the Engineer, do not comply with the Specification, shall be classified as rejected materials or defective work, and shall be cut out and removed. 1.20 Employer’s equipment and free issue material

The Employer shall not make any Employer’s Equipment available for the use of the Contractor.

The Employer shall not supply any “free-issue materials”. 1.21 Criteria for design personnel

The design personnel shall be registered or chartered professional engineers with at least fifteen years experience of the design of similar works. 1.22 Factory inspections

During the course of supply and procurement of process, mechanical and electrical equipment for the contract, the Employer and Engineer will require to witness equipment supply, manufacture, corrosion protection and testing before shipment to site. The Contractor must propose a schedule and meet all costs associated with such visits to the manufacturers’ yards for three persons during the manufacturing and procurement stages. 1.23 Alternatives

The Contractor's main Tender shall comply fully with the Specification. The Contractor is however at liberty to include alternative materials, items of Plant or methods of construction for which he claims advantages to those indicated in the Specification and Drawings, provided the modes of operation and methods of construction are fully described and are at least equal to those shown on the Drawings or implied in the Specification.

The Contractor shall submit manufacturer's detailed descriptions of alternatives and he shall draw attention to any aspect of each component that does not fully comply with the requirements of this Specification. These detailed descriptions, including any departure from the requirements of the Specification may, after approval by the Engineer, be included among the Contract documents and each item shall be in accordance with it’s description. Approval of a manufacturer's description shall not include approval of any departure from the requirements of the Specification unless the Engineer specifically approves the departure in writing.

Where materials, plant or methods of construction differ from those specified, the Contractor shall submit with his Tender drawings showing any amendments of system design necessary to suit the alternative. The Engineer will either approve these drawings or issue others if he approves the components concerned.

The Engineer however, may not necessarily accept any alternative put forward. 1.24 Existing works and services

The Contractor shall acquaint himself with the positions of all existing works and services including water mains, sewers, storm water drains, cables for electricity, and lighting poles before any excavation is commenced.

The Contractor will be held responsible for any damage, however caused, in the course of the execution of the Works, to such existing works and services. Any damaged caused shall be made good at the Contractor’s expense.

Such existing works and services, where exposed by the execution of the works, shall be properly shored, hung-up and supported to the satisfaction of the Engineer and of the authority concerned. The Contractor shall exercise special care when refilling trenches or other excavations around such existing services. Stop cock boxes, water meters and the like shall not be covered up.

Poles supporting cables and the like adjacent to the Works shall be kept securely in place until the Works are completed and shall then be made as safe and permanent as before.

Notwithstanding the foregoing requirements and without lessening the Contractor's responsibility, the Contractor shall inform the Engineer immediately any existing works have been exposed and shall comply with any requirements of the authority concerned.

Only when and as directed by the Engineer shall the position of existing works or services be changed by the Contractor to meet the requirements of the proposed work.

The Contractor shall make adequate provision so that when carrying out his work, no interference, damage or pollution is caused to highways and footpaths, or to any mains, drains, sewers, and the like or other parts of the Works.

Wherever loads have to be carried over ground in which pipes, valves, culverts, and the like are buried, the Contractor shall take all precautions including where necessary, the provision and use of sleepered roads, light gauge railways or other means to prevent damage occurring to such underground works. The Contractor shall not store any plant or materials or spoil heaps over existing water mains, or in such positions that interference with access to the mains, control valves and the like, is created. Approval by the Engineer to the means of protection employed shall not relieve the Contractor of any responsibility in respect of damage occasioned by his operations.

The laying of pipework, ducts, drains and the like shall be arranged so as to cause as little disruption, to traffic or public movement as possible with the smooth operation of existing works.

When breaking out and making good existing structures, the Contractor shall disturb the existing structures as little as possible. All structures shall be made good with materials similar to those used in the existing works, or such materials which are considered by the Engineer to be of similar appearance and suitable in all other respects. 1.25 Overhead power lines

Where work is being carried out in the vicinity of overhead power lines, the Contractor shall be responsible for ensuring that all persons working in such areas are aware of the safe working distances in the vicinity of high voltage over head power lines especially when cranes or other large masses of steel are in the vicinity of the power lines.

The Contractor's attention is drawn to BS 162, which gives safe clearance for various voltages.

The Contractor shall take all necessary precautions to ensure the safety of his employees and all other persons where work is being carried out near overhead power lines. 1.26 Excavation across roads and tracks

Before excavating across any public or private road or track, the Contractor shall give the Engineer ten days notice of his intention to excavate and shall include, in writing, the precautions he proposes to take for the continuance of passage and safety of traffic, and details of the warning signs and lights to be provided and operated. The excavation shall not commence until the written approval of the Engineer has been given. 1.27 Liaison with police and other officials

The Contractor shall keep in close contact with the police and other officials in the areas concerned regarding their requirements for the control of workmen, movement of traffic, or other matters and shall provide all assistance and facilities which may be required by such officials in the execution of their duties. 1.28 First aid and medical services

The Contractor shall provide and maintain all equipment necessary to render first aid in case of accidents, snakebites or other emergencies. This equipment shall be kept in readiness at the sites of the works, at camps and wherever the Contractor's staff may regularly live and work. The Contractor shall ensure that there are persons available at all such places with knowledge of simple first aid procedures and able to administer snakebite treatment. 1.29 Health checks

Every employee whom the Contractor intends to engage on the Works shall successfully undertake a test for typhoid and paratyphoid at an approved hospital or medical centre. The medical certificate for each employee shall be submitted to the Engineer before the employee will be allowed on Site. 1.30 Inspections by the Engineer during the Defects Liability Period

The Engineer will give the Contractor due notice of his intention to carry out any inspection during the Defects Liability Period. The Contractor shall, upon receipt of such notice, arrange for a responsible representative to be present at the times and dates named by the Engineer.

This representative shall render all necessary assistance and shall take note of all matters and things to which the Engineer shall direct his attention. 1.31 Health and safety 1.31.1 General

The Occupational Health and Safety Act (OSHA) of 2003, OSH Policy of 2010 and subsequent OSH Rules of 2015, 2017 and 2018 guide the health and safety issues in the project.

The Contractor shall use his best endeavour to ensure, so far as is reasonably practicable and to the satisfaction of the Engineer, the health, safety and welfare at work of his employees, including those of his Subcontractors, and of all other persons on the Site. His responsibilities shall include:

i. provision and maintenance of safe and properly illuminated Contractor’s Equipment; ii. establishment of safe and well-illuminated systems of working; iii. provision of protective clothing and equipment; iv. establishment of first aid stations, staffed and equipped to provide information, instruction, training and supervision on all aspects of safety and health on site; v. appointing as Safety Officer one of his senior staff who shall have specific knowledge vi. provision of adequate sanitary facilities and maintenance of these in a clean and hygienic state for use by all persons employed by the Beneficiary, Engineer, Contractor or other contractors on the Site; vii. measures to control flies, mosquitoes and pests in both working and recreational areas including chemical spraying, if necessary, in compliance with the rules and regulations of the Beneficiary; viii. reporting details of any accident to the Site Safety Officer as soon as possible after its occurrence ix reasonable prevention of non-site personnel from entering the work areas.

1.31.2 Safety equipment and training

The Contractor shall provide: i. all necessary breathing apparatus, gas testing equipment, safety harnesses and any other equipment required to ensure safe working of all his personnel on Site; ii. test certificates for all safety equipment; iii. proof that all relevant personnel have received appropriate training. 1.31.3 Health and safety plan

The Contractor is required to produce a health and safety plan covering the hazards that may apply during the Contract, the rules and standards to be used in assessing risk and in undertaking work and the methods that he will employ to ensure compliance with his plan.

The Health and Safety Plan shall include details of the following:

i. details of all potential risks and the proposals for dealing with such hazards; ii. controls to regulate risks that occur during all construction, testing and commissioning activities; iii. measures to avoid health risk in connection with the use, handling, storage and transportation of hazardous and harmful substances; iv. safety equipment and training proposals in respect of equipment referred to above.

1.31.4 HIV/AIDS awareness

The Contractor shall implement an HIV/AIDS awareness programme for his Personnel. 1.32 Work in confined spaces 1.32.1 General

The procedures for working in confined spaces before completion of the Works and after completion differ and are defined below. 1.32.2 Procedure for working in confined spaces prior to the completion of the Works

The danger shall be under the Contractor’s control. The construction of the Works may result in the creation of hazardous confined spaces.

The Contractor shall:

i. produce and conform with a set of rules for working in confined spaces when carrying out work associated with the Contract; ii. ensure that any person requiring working access to confined spaces under the Contractor’s control shall comply with the Contractor’s safety rules; iii. advise the Engineer in writing of his authorised person responsible for supervision of work in confined spaces who will be subject to the Engineer’s approval; iv. submit to the Engineer a copy of his Practise for Working in Confined Spaces; v. maintain on site copies of all issued Permits to Work; vi. issue Permits to Work to other contractors and the Employer’s Personnel as necessary. 1.32.3 Procedure for working in confined spaces after taking over by the Employer

The danger shall be under the Employer’s control. The Site shall be regarded as an operational site. The Employer shall notify the Contractor of his representative responsible for the Site.

When the Contractor undertakes remedial work or modification work on the Site, he shall comply with the Employer’s procedures for Working in Confined Spaces and the following procedures:

i. the Contractor shall sign to certify that the procedure for Working in Confined Spaces shall be brought to the attention of, read to and understood by all his employees, subcontracted employees and all other persons under his contractual control required to work on the Site; ii. no work shall be undertaken on any plant under the control of the Employer unless the iii. the Contractor must give reasonable notice to the Employer and Engineer of intended visits to Site and to programme the works to allow for the preparation of appropriate written instructions and authorisations.

1.33 Sign boards

Before the erection of any signboards or posters by the Contractor, the Contractor shall obtain the approval of the Employer and the Engineer to the size, location and wording of such sign boards or posters.

1.34 Contractor’s tracked equipment

The Contractor's tracked equipment may not be run on any public or private road without the written permission of the owner or authority concerned. Tracked equipment shall not cross railway lines. 1.35 Site meetings

The Contractor shall be obliged to attend all site meetings at the appointed time. 1.36 Abbreviations 1.36.1 The following abbreviations have been used for units and for other words or phrases as indicated. 1.36.2 Units of length

μm micrometre, 10-6 m mm millimetre m metre km kilometer 1.36.3 Units of area

m2, sq.m square metre ha hectare, 104 m2. 1.36.3 Units of volume

l litre m3, cu. m cubic metre 1.36.4 Units of time

s second min minute h hour wk week 1.36.5 Units of mass

gm gramme kg kilogramme t tone 1.36.6 Units of weight and force

N Newton kN kiloNewton

1.36.7 Units of pressure and stress

N/m2 Newtons per square metre Pa Pascals, equal to Newtons per square metre kN/m2 103 Newtons per square metre kPa kiloPascals, 103 Newtons per square metre bar 105 Newtons per square metre MN/m2 106 Newtons per square metre N/mm2 106 Newtons per square metre MPa MegaPascals, 106 Newtons per square metre 1.36.8 General abbreviations

% per cent ‰ per mille AV air valve AWWA American Water Works Association BS British Standard BSPT British Standard pipe thread (i.e. threaded to BS 21) ch chainage (distance in metres) cif cost, insurance and freight DI ductile iron dia diameter DIN Deutches Institut für Normung DN nominal bore Do ditto eo extra over fob free on board GMS galvanised mild steel GRP glass reinforced plastic HYS high yield steel ISO International Organisation for Standardisation m amsl metres above mean sea level max maximum mh manhole min minimum ne not exceeding No number Nr number (in bill of quantities) P. Sum Provisional Sum PCC precast concrete PE polyethylene PN pressure rating in bar SV sluice valve Tshs Tanzanian Shillings uPVC unplasticised polyvinyl chloride WO washout

1.37 Factory inspections

During the course of supply and procurement of process, mechanical and electrical equipment for the contract, the Employer and Engineer will require to witness equipment supply, manufacture, corrosion protection and testing before shipment to site. The Contractor must propose a schedule and meet all costs associated with such visits to the manufacturers yards for three persons during the manufacturing and procurement stages. 1.38 Operational training for the Employer’s Personnel 1.38.1 General

The Water Treatment Works and other structures shall be operated and maintained by the Contractor for a period of three months, before commissioning of the works. During this period, the Employer's operators are to be trained by the Contractor in all aspects of the operation and maintenance of the Works. 1.38.2 Operational aspects

The works shall be operated in accordance with the Operation and Maintenance Manual, supplied under this Contract, and as updated and agreed by the Engineer.

The Contractor is to provide the following services:

• Operate the works to produce the quantity of water required, to the required standard, as set out in Part C of the works requirements.

• The operator(s) provided by the Contactor shall have a certificate of competence in the operation of a water treatment works, and shall be fully conversant with all aspects of the processes employed, the plant and associated controls and instrumentation, and shall be capable of training the Employer's operators. He shall also have at least 10 years working experience in the operation of a treatment works at a level where he was responsible for all aspects of running a similar plant.

• The Contractor shall have in place the resources and administration system to provide the necessary, store, control and use consumables for the running of the plant, and to ensure timeous payment for the consumables, electricity, wages etc.

• The provision of consumables, including all chemicals, stationary, etc

• A stock of consumables for between four and six months (at average rate of use) shall be stored on site. The same stock shall be held after the 12 month operation of the plant.

• Transport for his staff (light delivery vehicle for transport of small items of equipment)

• A monthly report, providing full details of the operation of the works, is required. The information required is to include generally the requirements of the Tests and Monitoring of Performance as set out in Particular Specifications of these Employer’s specification and the following:

i. Water Quality analysis results. ii. Graphs drawn from the information gathered by the data capture system. iii. Result of routine tests iv. Full details of power used v. Full details of staff utilization vi. Full details of sludge wastage and drying vii. Full details of sludge disposal viii. Full details of consumables used. ix. Full details of all maintenance carried out on plant, and electrical works. 1.38.3 Power requirements

(a) kVA demand

The operation of the works shall be such as to limit the kVA demand to not exceed the value given in the Data Schedules that form part of the accepted tender.

(b) kWh

The power required for the operation of the works at full capacity shall not exceed the value given in the Data Schedules that form part of the accepted tender, when averaged over a week. Should the flow be less than the design capacity, 25% will be assumed to be fixed while the remaining power usage will be assumed to be in proportion to the volume of water treated. 1.38.4 Staff Requirements

During the operation and maintenance period, the Contractor shall provide supervisory and specialized personnel, skilled and experienced in all aspects of the operation and maintenance of the works. The Contractor's staff shall be sufficient in number to operate the works by day and by night. The contingent of staff may be reduced after 2 months of operation providing the Employers staff had gained enough competence to take over certain functions from the Contractor. This will be done in conjunction with the Engineer and the Employer. Under no circumstances may the plant be left short of operators. 1.38.5 Training of Employer's Personnel

The Employer may deploy operating personnel at the works 3 months before project completion.

The Contractor shall propose 6 months before the scheduled start of the operation and maintenance period, a schedule of permanent operations staff positions to be filled, together with the qualifications and experience required. This is to be in line with the staffing requirements indicated on the Data Schedules that forms part of the accepted tender. Once approved by the Engineer and the Employer, suitable staff will be appointed by the Employer to fill these posts for full time training from the start of the operation and maintenance period.

The Contractor shall train these individuals generally in all aspects of the operation and maintenance of the works as appropriate, and for the specific tasks associated with these positions. 1.38.6 The Contractor shall train these personnel for the full duration of the one-year operation and maintenance period. The Employer may deploy operating personnel at the works 3 months before project completion.

The Contractor shall propose 6 months before the scheduled start of the operation and maintenance period, a schedule of permanent operations staff positions to be filled, together with the qualifications and experience required. This is to be in line with the staffing requirements indicated on the Data Schedules that forms part of the accepted tender. Once approved by the Engineer and the Employer, suitable staff will be appointed by the Employer to fill these posts for full time training from the start of the operation and maintenance period.

The Contractor shall train these individuals generally in all aspects of the operation and maintenance of the works as appropriate, and for the specific tasks associated with these positions.