REPUBLIC OF IRAQ
GENERAL DIRECTORATE FOR WATER
BAGHDAD - IRAQ
VOLUME 1
GENERAL SPECIFICATION
FOR
ELECTRO – MECHANICAL
AND
CIVIL WORKS
Index to Clauses - Technical and Civil Works Specification Clauses
Clause No. Title Page
One Standard specifications 4
Two Clarifying tanks 7
Three Sludge pit and main sludge pipes 11
Four Alumina dosing apparatus 12
Five Chemical disinfection equipment 13
Six Filters 15
Seven Ground filtered water storage tanks 21
Eight Pumping s e t s 23
Nine Switch board and control panels 28
Ten Sub-stations 35
Eleven Power house 39
Twelve Cables 49
Thirteen Lighting 50
Fourteen Building works 53
Fifteen Environmental services 75
Sixteen Water services 85
Seventeen Steel E. T. S. With foundations 88 Eighteen Structures: Suction well, Suction and Intake 91
Nineteen Pipe work and fittings 95
Twenty Workshop building 115
Twenty – One Overhead travelling cranes 116
Twenty - Two Water meters 117
Twenty - Three Sewage disposal system 118 Twenty- Four Corrosion protection and Painting 121 Twenty - Five Safety rules and regulations 12 Twenty- Six Packing and protection during Transports shipping and storage 129
Twenty -Seven Engineers house 131
Twenty –Eight Operators house 132
Twenty - Nine Fencing with guard room 133
Thirty Roads and foot paths 134
Thirty - one General site development works 135 Thirty - two Surveillance and security system 136
Thirty - Three Spare parts 137
Thirty- four Tools 142
Thirty - Five Furnishings 144
Thirty -Six Water sample testing equipment 146 Thirty - Seven Operation and maintenance instruction 151 Thirty -Eight Plant operation and training of operators 152
Note:
The general conditions of tender, general conditions of contract, general and civil works specification, technical specification with bill of quantities and form of summary of tender shall form part of the tender documents.
Technical and Civil Works Specification
To be observed in the execution of work comprised in the construction of certain water work the subject of the contract.
CLAUSE ONE
STANDARD SPECIFICATIONS
1.
A. Except when otherwise stated in the relevant clauses of specification all materials and equipment used in the Plant shall in case be inferior to those specified in British Standard Specification (BSS), when no IOS (Iraqi Organization of Standards) or ISO (International Standard Organization) specification is applicable (for all standard the last edition). They shall pass the test mentioned in the relevant standard. All welded steel elevated service tanks shall conform in general to the requirements of the A.W.W.A.D-100. All electrical equipment shall be in accordance with the latest IEC. All switchboards must be IP56. Any material or equipment found to be inferior to that specified in the above mentioned standard will be rejected.
All water retaining structures (clarifiers, ground storage tanks, filters) should be designed without expansion joints in walls and foundations
Reinforced concrete should be designed according to CP 8110 or ACI 2002.
Retaining structures should be designed according to BS 8007.
All valves and gates inside the treatment plant shall be electrically actuated with manual override except clarifiers and ground storage tanks.
The GDW (General Department of Water) shall have the right to appoint an inspector to inspect and test the goods before shipment.
The Inspector is required to indicate in each of his certificates:
• To which standard the inspected material and equipment comply giving the name and number of the Standard.
• That material and equipment inspected is in no way inferior to that specified in the above mentioned standard
B - Standard design for treatment plants as shown below Capacity of H.L pumps m3/hr Capacity of L.L pumps m3/hr No of filters and area m2 No of clarifiers inside dia. of flocculation tank (m) inside dia. of sedimentation Tank (m) 1. 400 420 4x20 2 7 20 2. 600 630 6x20 2 7 20 3. 800 840 8x20 2 10 26 4. 1000 1050 10x20 2 10 26 5. 1500 1575 8x40 2 12 34 6. 2000 2100 10x40 3 12 34 7. 3000 3150 16x40 3 14 38 8. 4000 4200 20x40 4 14 38 9. 6000 6300 30x40 6 14 38 10. 8000 8400 40x40 8 14 38 11. 10000 10500 40x50 10 14 38 12. 20000 21000 80x50 20 14 38
Note: The effective side depth of water in sedimentation tank shall be
4.0m
2. Materials and Workmanship
All plant and materials employed in the finished construction of the works shall conform to the individual IOS or British Standard Specification or approved equal of such plant and materials and of the current issue where such Specification is in force. Where no IOS or British Standard Specification is available, the best water supply practice should be selected. Provided that in the use of all materials of local production they shall be of the best quality.
All materials which in the judgment of the Engineer are of an inferior quality or improper to be used in the works shall be removed by and at the expense of the Contractor and likewise all inferior workmanship and finish shall be amended to the satisfaction of the Engineer.
3. Drawings to be Supplied
Drawings showing clearly the plant and appurtenances for the complete installation included in t h e Contract shall be submitted by the Contractor. The drawings shall give all necessary leading dimensions including the clearance between the pumps and th e walls. On notice of the acceptance of the Tender the Contractor shall submit, within six months complete signed working drawing of the general arrangement of all details of the complete plant apparatus and appurtenances and elevated service tank for the full information and approval of opinion on the part of the Engineer as; to the efficiency or strength of any part of the plant and appurtenances or in any way reliving the Contractor from his responsibilities and obligations under the Contract. Within two weeks after notification of approval of the drawing the Contractor shall supply a further four sets of complete drawing linen backed for use by the representative of the Engineer on sites of works and for office record.
Literature, pamphlets of machineries with names and numbers of different parts as well as chlorinators etc, and operation instruction complete with linen backed drawings are to be supplied in triplicate by the Contractor before starting the work. The price of supplying the drawings shall be included in the total price of the Scheme.
During the period of maintenance, the Contractor shall supply to the Engineer, record drawing to a scale approved by the Engineer showing layout of the complete treatment plant and all details of the equipment, writing, cables, pipelines etc. The record drawings shall furthermore show all branches and connections left for future extensions. One ink tracing and five paper prints are to be supplied for each such drawing with 2 (CD) for final drawing.
Note: All mechanical & electrical drawing must be submitted before civil
CLAUSE TWO
CLARIFYING TANKS A- Circular Type
The clarification of the raw water shall primarily be undertaken in single stage comprising flocculation and settlement. The tanks employed in those operations shall be of Nos. indicated in Basic Data and shall be constructed in vibrated reinforced concrete of 1:1½:3 mixtures. All inside surfaces shall be smoothly finished and the tanks must be watertight. They shall be equipped with electrically driven (peripheral drive) revolving sludge scrapers and provided with scum collecting channels with discharge common with overflow. The drive shall be equipped with an overload device to stop the drive meter when the overload becomes excessive. The sludge shall be scraped into a central hopper from which it shall be discharged to the river under the hydraulic head to be obtained in the tanks through a common sludge main with tidal flap out falling 50m downstream of the intake work when the highest water level in the source permits that and with bypass arrangement to sludge pit if the highest water level does not permit that the slope of the floor on which the sludge is scraped shall not be less than 8%. The rim of the tank which forms the track for the outer end of the scraper bridge shall be made to correct level throughout and shall be plastered with wood polished concrete plaster. However the scraper mechanism should be able to tolerate 0.1% inaccuracy in the track level. Each scraper shall be provided with a single rubber wheel. The wheels shall have high quality polyurethane or Duthene tiers suitable for humid and hot climate and shall be set radially true. The scraper bridge shall extend from the wall of the tank to a point beyond the center pier to provide convenient access to the flocculators drive. The bridge shall not be less than 0.7m in width and shall be surfaced with chequer plate flooring of not less than 6mm in thickness. The bridge shall have double rail hand railing to both sides, the rail being tubular 30mm minimum outside diameter. Stanchions shall be of cast steel at not greater than 1.6m centers and the finished height of the hand railing shall not be less than 0.7m above the walkway. All steelwork shall be painted in accordance with the specification (clause 24).
The tanks shall be additionally provided with a special arrangement for continuous sludge bleeding. This shall be in the form of adjustable overflow permitting continuous sludge withdrawal at a slow rate under minimum hydrostatic head.
The diameter of the sludge outlet pipe from each clarifying tank shall be as indicated in Basic Data and that of the common sludge main shall be as indicated in Basic Data. There shall be an inspection chamber at the outlet of the sludge pipe for each tank and shall be located in such a way that the operator could inspect the sludge while operating the
sludge valve. The direction of discharge shall be parallel to the line of motion of the river. An arrangement for flushing the sludge pipes from the pumping main of the high lift shall be provided.
The diameter of the flushing pipe shall not be less than 200mm. The main sludge pipe for the scheme shall be extended from clarifying tanks and filters to sludge pit then to river. The inside diameter of each clarifier shall be as indicated in Basic Data and inside diameter of each flocculator also as indicated in Basic Data. The minimum side effective depth of water in the clarifying tanks shall be 4m.
The tanks will normally be operated in parallel but shall be made capable of being independently operated for the purpose of overhaul and maintenance of the mechanical equipment and when the degree of turbidity of the raw water so permits. The sludge pipes should be located at a depth capable to empty each clarifier completely.
Consideration should be given to the manner of draw-off as locality is subject to intense dust storms which will deposit a layer of impalpable dust on the surface of the water and all care shall be taken to insure that the settled water will be collected at equal rate from all the sides of the tanks. The clarified water shall be collected at adjustable weir along the periphery of the basin. The settled water from each clarifier shall be connected with control chamber by ductile pipes with sluice valve.
The flash mixer(s) shall be constructed in a separate concrete chamber each having a retention period of one minute pumping capacity with shaft driven by electric motor. The shafts of the flocculation tanks also shall be driven by electric motors. The motors driving the mechanical equipment shall be of the totally enclosed weather proof squirrel cage type and be suitable for operation at 400V, 3-phase, 50Hz with output for continuous rating and shall conform to BSS 2613 with windings of Class F tropical proof insulation and with limits of temperature rise of 10°C less than those permitted under the BSS. The motor shall be fully equipped in accordance with the Regulations for the Electrical Equipment of Buildings of the Institution of Electrical Engineers, England and shall be housed in an approved manner in protection against inclement weather and the effect of the direct rays of the sun. Where the power of the motors exceeds 7.5KW Star / delta type starters shall be provided. The flash mixers and the flocculators shall be of approved efficiency in their respective performance of thorough pervasion of the chemical and agglomeration of the flocculators. There should be a distribution chamber of a volume as indicated in Basic Data to which the raw water pipes will be connected. Then from this well the raw water will be distributed to each flash mixer. The overflow of clarifying system should be constructed at this structure a control chamber of a volume as indicated in Basic Data to which settled water should be collected before going to the fitters should be provided. The tanks shall be embanked with well compacted good earth to a height of 0.9m below their upper periphery and sown with
suitable grass. The top of the embankment shall be 1.2m wide and the side slope shah be 1:1 level with the top of the embankment, a reinforced concrete 1 meter wide footpath around the tanks and attached to the tank walls shall be provided to allow access for inspection and operation of the tanks. Necessary valves shall be supplied for isolating each clarifier from others during maintenance period.
B- Rectangular Type
The concrete tacks to be employed in the preliminary treatment of the raw water shall be of the upward flow type, a flocculator shall be incorporated in the tanks.
The retention period in the flocculation compartment shall not be less than 20minutes, at a rate of full flow per hour and 1½ - 2 hour in each sedimentation tank. The tank shall be constructed with vibrated reinforced cement concrete 1:1½:3. The sludge shall be discharged to river under the hydraulic head to be obtained in the tanks through a sludge main with tidal flap valve out falling 20m downstream of the point of intake of tile low lift pumps direction of the charge shall be parallel to the line of motion of canal. The surface load in the tanks when both in operation shall not be more than 1m3/m2/hr and the water depth in the
tanks shall not be less than 3.0m excluding sludge hopper space and the freeboard which shall not be less than 50cm. The bottom of the tanks shall be in a form at a paramedic hopper or hoppers at not less than 45° slopes with a sludge draw-off from the invert of each hopper. The tanks shall be provided with scum collecting channels with discharge common with the overflow and with gangways and with access ladders, the tanks shall be provided with suction tanks for the high lift pumps of capacity not less than 5m3. The dia. of sludge pipe for each tank shall be not less than
100mm, and the common sludge main shall be not less than 150mm. To increase the surface area of these tanks we can use lamella (inclined plate) which shall be rigid self supporting lift table steel from for easy cleaning and maintenance.
The plates shall be instilled in the upper half of the tank and arrange 55° degree angle, the plates shall be arrange for easy removal and washing with lifting device. The lamellas plates shall be used for extension the treatment plant only with more filters added for these purposes.
The flash mixing shall be done in separate cement concrete chambers having a retention period of two minutes pumping capacity with shaft driven by electrical motor. There shall be an inspection chamber at the outlet of the sludge pipe for each tank shall be located in such a way that the operation can inspect the sludge while operating the sludge valve, the clarified water shall be draw off through perforated collecting pipes or channels spaced 1.0m centers across the tank .
The diameter of the pipe connecting the flocculation tank and each sedimentation tank shall not be less than 200mm.
The motors are used in the tanks they shall be of the totally enclosed squirrel cage output for continuous rating and shall conform to BSS 2613 with windings of class F Tropical proof insulation and with limits of temperature rise of equipped in accordance with the (Regulations for the Electrical Equipment of Buildings) of the institution of Electrical Engineers, England and shall be housed in an approved manner in protection against inclement weather and effect of the direct raves of the sun. Where the power of the motor exceeds 18.5KW star / Delta type starters shall be provided.
The flocculator shall be of proved efficiency in its performance of through pervasion of the chemical and agglomeration of the flocs.
Due consideration shall be given to the effective depth of the tanks the number of inlets and the manner of the draw off of the clarified water in their bearing on the optimum operation of the tanks and moreover to the consequence of the locally experienced intense dust storms which will deposit a layer of impalpable dust on the surface of the water. The Contractor shall include in his Tender for the professional fees for the design of the complete tanks and documents with fully detailed drawing.
CLAUSE THREE
SLUDGE PIT AND MAIN SLUDGE PIPES
The wash water overflow and drain from all parts of the plant shall be discharged directly to the river by a common sludge pipe under the hydraulic head to be obtained from the respective units and discharged to the river. A sludge pit with sludge pumps for pumping the sludge to the river shall be provided. A bypass from the sludge main to the pit shall be provided with the necessary control valve for diverting the sludge to the pit whenever it is necessary and vice versa. The pit shall be made of reinforced concrete (1:1½:3) and shall be of capacity as indicated in basic Data the slope of the pit floor shall not be less than 25% towards the suction pipes of the sludge pumps. All inside surface of the pit shall be smoothly finished and the pit shall be provided with hand railing of not less than 0.75m in height above ground level.
The sludge shall be pumped to the river by triplicate unshakeable, self-priming pumps (one as stand by). The pumps shall be provided with a level control to stop and start the pumps when the liquid level reaches predetermined maximum and minimum levels in the pit, t h e pumps shall be positive head. The starters shall be fitted with suitable adjustable time relay device so that there is no possibility of more than one motor starting in the station at one time. The pumps control shall be arranged with probe-type metal electrodes, which uses the liquid as an electrolyte to complete the electrical circuit and operate a magnetic relay.
The pumps shall be housed in a suitable building which shall be built in accordance with the pumps and filter house building. A monorail should be provided to lift the pumps and accessories from the building for maintenance purposes.
Note: Over flow pipe of the GST will be connected to the sludge pit
according to hydraulic head and the capacity of the sludge pumps shell be calculated according to this note.
General details of the sludge pit and detailed specification of the sludge pumps shall be submitted with the offer.
CLAUSE FOUR
ALUMINA DOSING APPARATUS
The raw water will be dosed with a solution of kibbled sulphate of alumina in the process of the precipitation of the suspended matter and for this purpose tanks complete with stirrers driven by electric motor, air ejector, regulators and flow indicators shall be provided. The flow indicators shall be calibrated in both liter/hr of solution and in mg/liter (ppm) for 10% solution in accordance with the pumping rates.
The capacity of each tank shall be sufficient for 10% solution to does the water with alum at a rate of 100ppm at a pumping rate of the raw water of the scheme for 8 hours operation.
All surfaces of the apparatus and equipment in contact with the sulphate of alumina solution shall be resistant to the corrosive attack by this chemical using acid resistance tiles. The tanks must be ROBUST and if made of concrete (RCC of 1:1½:3 mixtures) provision shall be made in the system of supply for the facility of removing any part for clewing in the event of deposit building up. The solution shall be fed by dosing pumps to each flash mixing chamber. The dosing pumps shall be operated, started up and stopped under control of the raw water pumps.
An arrangement for flushing the pipe connecting the dozer to the point of application shall be made from the service pipe iron the plant. There shall be an electrical hoist with runway of 0.25 Ton capacity to lift the kibbled sulphate to the solution tanks a platform not less than one meter wide with handrails shall be provided in front of the tanks to facilitate their operation and inspection. The drain pipe for this apparatus shall be connected to the drain pipe for the Plant.
A 0.5 Ton platform weighing scale shall be provided for weighing the alum before charging it in to the solution tanks.
Should the Contractor desire to tender for a dosing apparatus other than the aforesaid type, it should be submitted a n d priced as an alternative.
General design details of the apparatus must be submitted with the offer.
CLAUSE FIVE
CHEMICAL DISINFECTION EQUIPMENT
The filtered water shall be disinfected by chlorine and for this purpose chlorinators shall be provided to dose the effluent of the filters with chlorine. The No. and the dosing of each chlorinator shall be according to Basic Data. All chlorinators shall be of pedestal cabinet
form and of the automatic type and suitable for injection feed. The
injection units shall be operated by pressure water obtained from the ground storage tanks provided by means of three booster pumps (two as stand by) which shall be for this purpose. An ivorine plate with dose chart consistent with the High Lift pumping rates shall be fitted to the Panel of each apparatus.
Automatic devices with indicating lights and gas pressure gauges shall be supplied at site of waterworks for charging the flow of chlorine gas for each set of drum (each set at least two drums) to the other when one set of drum gets empty. The maximum limit of chlorine gas pressure shall not be less than 200psi in addition shut-off valves and pressure gauges shall be provided for manual change over when the automatic device is out of order. The chlorine stores shall be provide with an electric type hoist of 2tons capacity with two 2tons weighing scales with suitable top monorail and cross girders with arms and hooks to lift the chlorine drums and putting them in position. Suitable truncheons seating the chlorine drums shall be provided and fixed to the floor of chlorine store. The general arrangement of drums and the electric hoist in the chlorine store shall be similar to that shown in the typical drawing in the Appendix. One set of chlorine leak detection equipment shall be provided in each of the chlorine room and the chlorine store and they shall be of the type that gives a warning sound when the chlorine concentration in the atmosphere becomes dangerous. The Contractor should submit with the tender all details for these sets. Two 50cm Plastic axial fan ventilators to be located in the chlorine room 1ft (30cm) above floor level under the window shall be provided. They must be suitable for chlorine contact. A similar four fans ventilator shall be provided for chlorine store. Four No. makes suitable for protection against the chlorine gas each packed and a suitable wooden box shall be provided. The walls and floor of chlorine room shall be covered with acid resistance tiles and the same for the store except the floor should have heavy paint of acid resistance. Two rubber suits complete with breathing device and oxygen cylinder and all accessories must be provided and four pairs of glove. A wall mounted chlorine fume detector capable for determining in a i r concentrations to a sensitively of 0.1micro-liter/liter shall be provided and installed one in chlorine store and one in chlorine room. It shall have alarm contact for operator at
5micro-liter/liter to bring up a warning light within the chemical attendant room with repeat indication on the main water supply control panel. The detector shall have a further set of heavy contact to operate at a level of 15micro-liter/liter.
At this level an audible alarm and warning light it in chemical attendant room together with a repeat alarm indicating on the main water supply control panel shall be initiated and operate the exhaust fans automatically.
The contractor shall make allowance for all measures necessary to prevent leakage of chlorine gas from pipe work connection between the liquid chlorine gas.
These measures shall include:
1- A pictorial representation of the procedure for changing liquid chlorine containers with written instructions where necessary in Arabic and on plastic covered card mounted on a board fixed to the inside wall of the chlorine store. All tools necessary for changing the containers shall also be clipped to this board.
2- All necessary washers and couplings required when changing containers sufficient for five years operation.
3- A water spray bar to provide a water curtain fixed externally over the chlorine store and connected via solenoid operated valve direct to the delivery main from pumping station. The solenoid valve shall operate automatically at chlorine gas concentration within the chlorine store of 15micro-liter/liter. This system must be provided with manual starting from outside the room for emergency The dosing location for the chlorinators shall be:
B. Inlet channel of G.S.T. C. Outlet channel of G.S.T. D. Each flash mixer.
The system shall be provided with necessary valves to choose the required location.
Detailed drawing for the arrangement of the chlorine room, chlorine store and the electric hoist complete with working drawing shall be supplied together with installation instruction and well covered operation and maintenance instruction in accordance with clauses of this specification.
A Similar arrangement shall be provided for Boosting Station if required according to Basic Data.
CLAUSE SIX
FILTERS
a) Rapid Gravity Filters
The filters shall be rapid sand gravity type comprised in a battery of total effective filtering area in comport with a filtering rate of 5m3/m2/hr.
The No. of filters and the effective area of each filler shall be as shown in Basic Data.
The filters are in the form of rectangular tanks and shall be constructed from vibrated reinforced cement of 1:1½:3 and shall be made perfectly water-tight with fair faced internal surface.
The filter under drainage system should consist of a manifold made of reinforced concrete or well protected steel and perforated pipe lateral made of either copper or appropriate plastic material. The lateral end should be supported by a concrete block with 7.5cm in height, allowing the laterals to collect the filtered water from the gravel and also distribute the wash water during the washing process, the cross sectional area of the manifold should preferably be 2-3 times the total area of the laterals in order to minimize friction losses and give the best distribution. The perforations or orifices in the laterals should be directed downward with 150° either clockwise or anticlockwise from the vertical axis of the lateral. The ratio of the final area of the perforations or orifices to the filter bed area should be between 0.2% to 0.5%.
Each filter shall be cleaned by an upward wash waters in conjunction with agitation by pressurized air and for this purpose a suitable rotary air blowers complete with an air filter and a silencer, isolation valves, non return valves, pressure gauges and air flow meters shall be provided. An oil interceptor shall also be provided to make sure that no oil goes to the filters. Air blowers shall be provided, to provide the necessary a i r to the filters. The capacity of each blower shall be as indicated in Basic Data. The units shall be containerized to lower the noise level to 20 db. The common delivery pipe supplied with non return valve and relief valve also each delivery pipe from the air blower shall be equipped with a sluice valve. A bypass arrangement shall be provided with necessary valves for emergency use between the sets,
The wash water shall be obtained from the storage tank below the pumps the effective size of this tank shall be according to Basic Data or from GST. The wash water pumps shall be mixed flow type, or horizontal split case.
The bottom of the wash water troughs must be kept at least 5cm. above of the surface of the expanded sand and the top edge of the
troughs shall not be more than 60cm above the top of the filter bed. The top of the troughs shall be leveled, and the capacity of the troughs shall be such that they will carry the maximum rate of wash water with a minimum freeboard of 5 cm. Lateral travel to the wash water overflowing into the troughs should be between 1.0m to 1.5m (i.e. the clear distance between troughs is hold to be between 2m to 3m), the troughs should discharge into a gullet, the capacity of the gullet be such that it will carry the maximum coming water from the troughs.
The filtering material shall be clean silica sand acid washed, there should be no reaction where the sample of the filter medium is placed in diluted hydrochloric acid and when immersed in concentrated hydrochloric acid, the sand shall not lose more than 2% of its weight.
The sand shall be compounded pure quartz sand having a depth of not less than 70cm, having an effective size from 0.60mm to 0.650mm and with a uniformity coefficient of not greater than 1.5. A sample of the sand and its size distribution shall be submitted for approval before being used. The gravel supporting the sand should be hard, rounded and durable, be free from flat, thin or long pieces and containing no loam, sand, clay, shells or other foreign materials, grading and layer thickness shall be approximately as follows:
Gravel size Depth 50 to 38 mm 10 cm 38 to 13 mm 10 cm 13 to 9.5 mm 10 cm 9.5 to 6.5 mm 15 cm 6.5 to 2,5 mm 15 cm
Testing procedure for filter media 0.6mm to 0.6mm filter sand particle sizing by sieve analysis
1) Sieves: 200mm diameter test sieves to BS 410 sieve size
Metric ASTM BS 1.4 14 12 1.18 16 14 1.00 18 16 0.85 20 18 0.71 25 22 0.60 30 25 0.50 35 30 0.425 40 36
PAN PAN PAN
2) Sample Charge: Obtain a representative sample of the media through suitable sub-division. The sample weight should be minimum 200g maximum 500g. Sample should be dry or free flowing.
3) Sieving: Selected sieve stack should be placed on suitable sieving machine and vibrated for 5min after introducing selected representative sample into top sieve.
4) Results: The particles retained on each sieve should be accurately weighed and tabulated to produce a cumulative weight retained on each sieve. Cumulative percentage retained should then be calculated for each sieve and resultant percentage plotted against sieve sizes to produce a graph curve for the media. The effective size should then be obtained from the plotted graph and uniformity coefficient calculated.
5) Effective Size: Particle size for 90% retained.
6) Uniformity Coefficient: Particle size for 40% retained divided by particle size for 90% retained to conform to contract specification the effective size should lie between 0.6mm and 0.65mm and the uniformity coefficient should be less than 1.5.
ACID SOLUBILITY
1) Sample weigh: Obtain a representative sample of the media through suitable sub-division. The sample weight should be minimum 100g after rinsing with distilled water.
2) Testing: The rinsed representative sample should be placed in contact with 10% V/V hydrochloric acid at room temperature for 24 hours. Any initial effervescence and color of the supernatant liquor at the end of the test should be noted. After 24 hours the sample should be washed in distilled water, dried at 105°C maximum and re weighed.
3) Results: Loss in weight of the sample should be calculated and tabulated as a percentage figure to conform to the contract specification the loss in weight should be less than 5% V/V.
ORGANIC CONTENT
Minimum sample weight 5g loss in weight on ignition at 350°C for 1hr should be less than 5% w/w. The depth of water on the surface of the sand shall be not less than 1.50m. The elevation of water on the filter shall be at least 3.00m higher than the minimum water level in the clear well. The water level in the filter must be below the filter operating floor. Provision must be made for draining the filtered water to waste, the drain valve may be a hand operated valve, and need not be controlled from an operating platform. All other valves shall be electrically operated from a steel controlling desk of attractive appearance to be installed next to each filter.
The desk shall comprise:
1) Head -lose gauge with warning light indicator, indicating when the filter ought to be washed.
2) Rate of flow indicator.
3) Control tight indicating the state of filter (filtering, washing, stop). 4) All push buttons to operate the filter valves, with indicating light. 5) Switches to start and stop the air blowers and washing filter pump
from G.S.T. with light indicating their position (ON & OFF). 6) Push button for all lamp testing.
The waning light shall operate at a predetermined loss of head between 1.2m to 1.8m at which the filter should be washed. The inlet to the filters shall be arranged in such a way as to ensure equal distribution of settled water between the filters. A control of filtered water rate by a weir shall be incorporated in the outlet of each filler to ensure a minimum of 10cm depth of water above the sand bed and a maximum of 1.5m. In this way the filtration rate will only depend on the amount of settled water
coming to the filters. When submitting his offer the Contractor shall give full details of the fillers control arrangement to ensure this. The diameter of each pipe connecting the sedimentation tanks and filters should be as indicated in Basic Data and the diameter of common wash water outlet should be connected to the sludge pit. Overflows shall be provided in the inlet channel of the filters.
All care shall be taken that the pipe arrangement shall be easy to install, maintain and operate.
The entire area of the filters shall be covered by a superstructure, with sufficient headroom not less than 3.5m to permit inspection and operation for filter beds.
The minimum depth of a filters bed shall not be less than 3m. A curb must be provided around the filter to prevent floor wash from entering. Filter effluent pipes in the clear well should be trapped to prevent air from entering the bottoms of the filters, the wash water from the filter shall be discharged to sludge pit.
Should the Contractor desire to tender for filters arrangement other than the aforesaid arrangement it should be submitted and priced as an alternative. After the maintenance period the loss of depth of the sand must not exceed 3.5cm and the contractor shall supply the required lost quantity. If the loss exceed 15cm all the sand must be replaced be new sand on Contractors account.
b) Pressure Filters (for each unit)
The settled water shall be pumped from (Intermediate Tank) to ground storage tank pressure filters (Horizontal types), each filter shall be in 20ft (6m) container. Each filter shall have the following requirements:
1. Wall thickness not less than 10 mm 2. Dished ends not less than 12mm 3. Nozzle floor not less than 16mm
4. Number of nozzles shall not be less than 500 No. per filter
5. Rate of filtration when all filters working shall not be more than (6-8) m3/m2/hr
6. Filter media shall be provided for each filter with spare filter media for complete one filter in suitable sacks 50kg, the sand shall be pure quartz sand having depth less than 60cm, having an effective size of from 0.60 to 0.65 and having a uniformity coefficient of not greater than 1-5 and gravel will be
9.5 - 13 10 cm
9.5 - 6.5 10 cm
7. Back washing of filters as follows:
a) Air for agitation using duplicated air blower (1+1 capacity each 600 m3/hr.
b) Water (through other filters and air).
c) Water (through other filters only arrangement) for automatic operation and manual operation for back wash sequence. 8. Differential pressure gauge with warning light (sound and light) for
filter back wash shall be provided in main control panel.
9. Each filter shall be supplied with two inspection manhole at the top and one at the bottom.
10. Air relief valve of 2 inch diameter the filter shall be seated on reinforced concrete saddles of 1:2:4 mixture and surrounded with a strip around roofing or other suitable semi-plastic material where they pass through the walls of the filter corridor.
CLAUSE SEVEN
GROUND FILTER WATER STORAGE TANKS
The ground filter water storage tanks shall be constructed in vibrated reinforced cement concrete of 1:1½:3 mixture and the tanks shall be made perfectly water-tight with smooth internal surfaces. The capacity of the tank shall be as indicated in Basic Data excluding freeboard inlet and outlet channels. The water depth in the ta n k shall be as indicated in Basic Data and the tank shall be divided into two or four equal separate cells or compartments according to Basic Data for independent operation. The tank shall be covered with reinforced concrete (1:2:4) roof and shall have over flow washout, manholes ventilators etc. with necessary valves, One 100mm dia. ventilator shall be provided for every 100m2 of roof area or equivalent. The ventilators shall be provided with outer ends fitted with removable weir wool strainers or other suitable device for the purpose of arresting the entry of dust in the normal breathing of the tanks at times of prevailing dust storms. In order to avoid stagnation, horizontal circulation of water (by means of partitions) shall be arranged. Filter water from the rapid gravity filters shall flow into each cell or compartment of the tank and suction pipes of the high lift pumps shall be connected to suction compartment. The max water level of the tanks shall be not more than the level of reformed ground level at site of water work. After testing the tanks shall be embanked with good earth of 60cm thickness with side slopes (1:1½) and sown with suitable grass. There shall be indicators in the pump and filter house building to show the water levels in each cell or compartment of the tank. Max water level at the tank shall at least 2.5m lower than Max water level at filters.
There shall be movable pumping arrangement to pump out to sludge pit impure water from the tank if the tank cannot be dewatered completely. The invert of the suction such compartments of the tank to which the suction pipes of the high lift pumps shall be connected shall not be less than 1.5m below the invert of the tank. The over flow pipe should be extended to the river. Drain pipe shall be provided for each cell or compartment and the common sludge pipe shall be connected to the overflow pipe or sludge pit. An arrangement shall be provided to prevent any backflow of sludge to the tank. The tank must be separate from pump filter house building. An arrangement for removing any foot valve and strainer without having to empty the tank and stopping the plant shall be provided. One monorail above the suction compartment shall be provided for lifting strainers fitting from the tank.
The contractor shall supply and install level transmitter in each compartment of the tank and digital type recorded and indicator shall be installed in instrument panel.
A bypass arrangement shall be provided between the inlet compartment to the tanks and suction compartment of the pumps using a ductile iron pipe with valve to bypass the tank if the tank is four cell or more. Float valve with electrical butterfly valve shall be installed in the inlet pipe of GST of Boosting Station. Overflow system for GSTs in Boosting Station should be according to Basic Data.
CLAUSE EIGHT
PUMPING SETS
A) Horizontal Split Case Pumps
The pumps shall be of the single or double entry Horizontal split case type positive suction and of a speed not exceeding 1500rpm when performing their normal duty at maximum efficiency and shall each be driven through a flexible coupling by AC motor. The impellers of the pumps shall be of bronze for High Lift Pump and stainless steel material for Low Lift Pump with passages finished to a perfectly smooth and true surface and shall be keyed to stainless steel shafts and be in static and dynamic balance. They shall be fitted with renewable eye rings neck bushes and shaft sleeves and all internal bushes secured.
The glands shall be provided with split bronze lantern rings and filtered water lubricated with sealing device to preclude the admission of air. The pump house floor shall be kept dry by fitting small diameter (not less than 20mm) drain pipes from the gland of each pump to discharge to waste. All ball or roller or grease lubricated bearings shall be arranged for grease gun lubrication and 2 No. suitable grease guns provided. A pressure and pressure vacuum gauge of Bourdon type, priming funnel cock and air cock shall be fitted to each pump. The pressure gauge shall be calibrated in meter head of water and Kg/cm2. Sluice valves with hand wheels shall be non return valves with bypasses. The sluice valves on the suction branches shall be water sealed in preclusion of air being drawn in during pumping operation. The non return valve shall be installed between the pump and the delivery sluice valve so that it can be isolated for cleaning when necessary. The sluice valve should preferably be installed with their spindle vertical. The sluice valves, non return valves and pressure gauges shall be of the best quality and from reputable manufacturer, where tapers are employed in the connections of the pumps to the suction main they shall be of the flat topped type with the flat surface on the upper side. All care shall be taken that the pumping arrangement for the pumps shall be easy to install, maintain and operate. All fitting used in the piping arrangement shall be standard fittings. All pipe work within the building shall be supported on fair faced concrete stools or on wall brackets, maximum spacing for supports is 1.8m on horizontal runs and 3.0m on vertical runs. Each of the high lift pumps shall have a separate suction from the clear water storage tank. The motors driving the pump shall be suitable for operation at 400V, 3-phase 50Hz up to 500KW, 11KV for larger motors with output continuous rating and shall be of the squirrel cage induction protection IP55 minimum type with fan cooling and shall conform to BSS 2613/1971 with windings of
class F tropical insulation and with limits of temperatures rise of 10°C less than those permitted under this specification. They shall be fully equipped in accordance with the Regulations for Electrical Equipment of Buildings of the Institution of Electrical Engineers, England. They shall be able to work under voltage variation of 5% occasionally, under 10% during short periods, without developing damageable heat rating of No for must be operate (55°C).
Air break automatic starter with push button ON/OFF with under voltage overload relay (MCCB) molded case circuit breaker shall be provided with each motor. The starting equipment shall be of the star delta starter. The starter shall be located at the side of each pump if the starter located in the upper floor a local ON/OFF must be provided near each pump.
A monitoring ammeter shall be installed on the starter such that the operator can watch the rise of motor current while loading. The couplings between the motors and pumps shall be of the flexible rubber bush and steel pin type and shall be turned to ensure perfect balance and bored to the shaft gauge and securely keyed and fitted to the shaft. Each unit shall be mounted on a common base plate of substantial casting with machined surfaces for the feet of the pump and motor and with planed underside and shall be erected on fair faced concrete foundation. The pumps motors, starters and their accessories shall be of the best quality of reputable manufacturer. The characteristics of the pumps shall be stable. The horse power of the motors shall be such as will provide a margin of 10% over and above the required in their stated parallel operation. The overall efficiency of the pumping units shall be guaranteed not less than 70%.
Each pumping unit shall be provided with the following protections: • Protection against uprising and priming and dry running. • Protection against mono phase driving.
• Protection against stator healing.
• Protection against bearing excess heating.
Three sets of characteristic curves for each set of pumps shall be provided for office record and three sets of complete instruction for operation and maintenance of the plant shall be supplied. A complete set of wiring diagram for all electrical equipment shall be provided on suitable and durable material and fixed to the wall of the motor room for easy reference. The floor shall be sloped (about 1 in 100 minimum) towards a sump from which the drainage should be pumped by twin electric pump which shall be provided for this purpose to waste for alternative operation. The floor of all pumps pits shall be covered with suitable best quality tiles. Walkways shall be provided for all pumps pit in order that all
the windows could be open.
b) Mixed Flow Pumps
Mixed flow pumps shall be close coupled vertical suspended pumps. The pump and drive unit shall be close coupled and mounted in correct alignment. The casing shall be split at the suction flange to permit withdrawal of impeller after dismantling of suction pipe work. The material of the casing shall be close grained cast iron minimum Grade 260 to BS 1452 free from blowholes and other defects. Lifting rings shall be provided on the pump and drive unit casing to permit lifting of complete pump unit including bed plate.
The impellers shall be stainless steel. The shaft shall be manufactured from high tensile steel minimum with renewable phosphor bronze or stainless steel sleeves of large bearing surface where the shaft passes through the seal housing.
The shaft bearing and seals should be oil water lubricated type or dry type. The motor specifications shall be according to horizontal split case pumps but vertically mounted.
C) Submersible Pumps General Description
The pump and electric motor drive shall be directly coupled and shall form a single vertical unit freestanding within the sump on a combined base and suction strainer.
Materials of Construction
Materials of construction shall be as follows:
Pump casing and stator housing close grained cast iron free from blowholes and other defects. Renewable phosphor bronze case wear ring shall be fitted at both suction and delivery. A separate oil filled casing shall be provided between the pump and motor casing to lubricate and tool the seals. A strainer shall be provided at the base of the unit.
All connecting bolts and nuts shall be of stainless steel. Impeller stainless steel, non clocking type machined to a smooth and accurate profile to discourage aversion of fibrous matter and provide for passage of solids. The impeller and shaft assembly shall be statically and dynamically balanced as a whole unit.
Shaft: Stainless steel renewable sleeves of large bearing surface where the shaft passes through the seal housing.
Bearing: A heavy duty tapered roller bearing and a heavy duty ball bearing shall be provided.
Seals: Shaft seals shall be of the mechanical type with tungsten carbide interfaces and of well proven design and backed by a lip seat.
A separate oil filling casing shall be provided between the pump and stator casing to lubricate and cool the seals. An oil reservoir level indicator shall be provided at a convenient level above the pumps. The seal housing shall be provided with a plug to enable checking of the oil level and condition to be carried out, motor work at 400V, 3 phase, 50Hz, IP68, class F insulation.
Accessories and Fittings
The following accessories and fittings shall be provided:
Reflux valve and wedge gate valve on delivery main, level electrodes for stop, start and emergency low level alarm, holder for level electrodes suitable for wall mounting complete with intermediate supports.
Cables for power required (Dol or Y/D) with control cables for float switch.
D) Sludge Pumps
End suction centrifugal pumps with non-clocking stainless steel impeller, rpm not exceeding 1000rpm, the pump and motor must be designed to handle heavy slurry suspended materials.
Other specifications are as for horizontal split casing.
E) GENERAL
1- Cooling of Motors
The cooling of all motors exceeding 500KW shall be either by means of pipe ventilation with dueled discharge of warm air to the exterior of the building and with efficient air fillers on the inlet apparatus to prevent airborne dust entering the enclosure, or alternatively by a closed air circuit and water cooled system including all necessary external ventilating and ducting. A thermometer shall be fitted to indicate the bearings temperature and a visual indicator shall be fitted in the cooling circuit to show that the fluid is flowing. A temperature sensor shall be fitted to operate an alarm on the station alarm panel if bearing should get over heated. Temperature sensors embedded in the motor windings shall also be indicated to stop motor and to give alarm indication if the windings are too hot (for all motors). All valves inside the plant shall be electrically operated with indicator.
2- Characteristic Curves and Performances
Characteristic curve of the pumps shall be submitted with the Tender including curves of total head capacities BHP at coupling and overall efficiencies. The efficiencies of the low lift pump units should cover the range of static lift or head between the lowest low water, and highest high water at the source of supply.
The performance of the pumping units as specified when operating at the imposed head comprised in their sequence of operation shall be submitted in the following form:
PERFORMANCE OF PUMPS AT WORKS PUMPING STATION
1 2 3 4 5 6 7 Static head in m. Total imposed head in m. on pump Discharge in m3 per minute Water Horse Power as calculated from columns 1 & 3 W.H.P. as calculated from columns 2 & 3 B.H.P. at pump coupling % Pump efficiency W.H.P X 100 B.H.P.
A further triplicate copies of the characteristics curves of all pumps included in the plant should be submitted for record before handling over the plant.
CLAUSE NINE
SWITCHBOARD AND CONTROL PANELS
The main switchboard to be mounted in special room next to the pump house building shall be of cubical type and shall comprehend the required No. of panels. An electric clock with 300mm diameter suitable for operation at 1.5VDC (dry battery) shall be mounted in the center panel. The equipment of the panel shall comprise:
Main Switchboard
Two incoming supply main each contains:
1. One No. air circuit breaker motorized type draw out type with thermal overload, magnetic short circuit and earth leakage protection and single phasing protection for incoming power and adjustable for ±25% each rated 1.25 full load of the plant with capacity (1.5) times of rated current and breaking capacity 70KA and above.
2. Three No. Ampere meter for - ditto- 144mm diameter
3. One No. Voltmeter 0-500V with six position selector switch and protection fuse. KWH meter with 3 current transformers suitable for unbalanced load.
4. One No. CB on each side parallel to each incomer for supply from the diesel generator with mechanical find electrical interlocking system.
5. One No. 3-phase auto CB with full protection for lighting supply connected before the main CB.
6. Phase sequence meter and 3 No. indicating lamps (one per phase). 7. Lamps testing push button.
BUS - Coupler
1. One No. automatic air circuit breaker draw out type with thermal and magnetic protection as bus - coupler.
2. Bus coupler indicator ON/OFF defect (Red/Green/Amber) neon lamps.
Motor - Distribution Section
1. One No. Ammeter for each motor 144mm diameter 2. One No. Working hour meter for each motor
3. One No. automatic air circuit breaker with full protection feature with draw able type for each motor
4. Read/Green/Amber pilot lamps to indicate On/Off/Defect positions of each motor circuit.
Auxiliaries
1. One No. ammeter for each auxiliary unit including filter load center flocculators load centers, chemical building, workshop, administration building, houses load center other small distribution boards.
2. One No. air circuit breaker with full protection features for each unit as per item (1) above with indicating lamps.
3. Two No. air circuit breaker each rated 100A, 3 phase, fixed on the side of the panel.
The panels shall be of attractive appearance and complete in every respect. The frame shall be efficiently earthed and rubber mats provided there to with 10 pairs of rubber gloves for each station. The Board shall be protected according to IP56. The inside of the panel shall be supplied with anti-condensation heater as well as 24 VDC lighting fitting with the required battery and battery charge.
NOTES
1. If the L.L. is separate site a separate board should be provided as above with a power building.
2. Similar board should be provided for each Boosting Station (if any). 3. Standby supply for schemes with more than 2 Transformers will be
connected on the 11KV side.
Chemical Load Center
The Contractor shall supply, install and test a complete load center in the chemical building to feed a l l the mixers, dosing pumps, lighting, hoist and crane comprising of:
Panel No .1
1. One No. 3-phase automatic air circuit breaker with overload earth fault and single phase protection.
2. Three No. ammeters 144mm dia.
3. One No. voltmeter 144mm with selector switch.
PANEL No. 2 and No. 3
1. One No. automatic Star/Delta (for motors larger than 18.5 KW) or direct on line start (for motors less than 18.5 KW) swing out type backed up overload contractor and fuses, with ON/OFF switch interlocked with the cover. The front cover contain (Name and Number) of the motor (in Arabic) indicating lights for ON/OFF/FALLT state of each motor. One No. ammeter 75mm with START/STOP/REST push buttons.
2. One No. automatic circ ui t breaker 3 phase for lighting. 3. One No. A.C.B, 3 phase 30A spare.
4. Two Nos. earthing point connected to the a.m. center load with the required cabling.
5. One No. A.C.B. 3 phase for laboratory.
Administration & Filter Centers
Same as (above) to cover the supply to all control valves as well as lighting and heating and cooling of the administration and filter centers, air blower, wash water pumps, houses, guard room, workshop will be fed from administration building center. In case the filters building is separated from the administration building, each building will have its own load center and the filter building load center will be similar to the main switchboard in general features.
Control Panel Instrument Panel
This panel will be floor mounted and contain the following instruments: 1. Red warning light for each filter.
2. Water level indicator for each compartment of G.S.T with audio warning for low depth and over flow in the treatment plant.
3. Digital recorder with indicator and integrator to water meter specified in clause (22) Water Meter.
meter.
5. Water pressure indicator and chlorine residual indicator for each rising main.
6. Direct reading pH meters for raw and filtered water. No display instrument or light shall be installed less than one meter above floor level.
Control Desk
The control desk shall be constructed of 2.5mm thick sheet steel, with structural frame primed and suitably indicated and fully accessible and finished in suitable color, all control compartments installed in the cabinet shall be factory prewired. Terminal blocks shall be provided for simple connection to remotely located equipment and sensors.
All switches, push buttons, control lights, recorders, totalizer and meters, gauges and indicators shall be located on the desk face, mounted flush with the surface. The operation and malfunction indicating lights diode shall be incorporated into the complete flow diagram or ounliti color plastic on the desk. The desk layout and flow diagram shall be subject to approval prior to construction (2x3m).
The following components shall be included in the cabinet: 1) Alarm System
a. The system No. 1 shall be powered by AC supply and initiated by failure of equipment with AC powered control system high and low level etc. as follows :
- Pressure vessels - High water level - low water level. - Duty main pump failure.
- Standby main pump running. - Duty low demand pumps failure. - Standby low demand pumps running. - Duty air compressors failure.
- Standby air compressor running. - Pump well flooded.
- Pump reflux valves jammed. - Reservoir high water level. - Reservoir low water level. - Chlorine residual high.
- Chlorine residual low. - Duty chlorinator failure.
- Standby chlorinator operating. - Duty booster pumps failure. - Standby booster pumps running. - Chlorine lock alarm.
- Chlorine leak alarm. - ph high.
- ph low.
b. Alarm system No. 2 shall be powered by DC supplied from heavy duty batteries and shall be initiated by failure associated with diesel driven standby generator and maim supply. The Contractor shall detail the alarm indication considered necessary for diesel engine and the associated alternator, but they shall include:
- Alternator protection trip.
- Alternator air temperature high. - Diesel lubricating oil pressure low, - Diesel generator running.
- Diesel generator trip.
The audible alarm shall sound for five minutes and provision shall be included for automatic re-setting.
The visual alarms shall operate continuously until canceled manually. 2) Ammeter for each low lift, high lift, back wash water and air
blowers.
3) Any additional operating information that may be necessary for plant operation and maintenance which is characteristic of the pumping and water treatment plant.
4) 300 mm dia. quartz clock operated from 1.5 volts DC supply.
5) Call system with the required desk type microphone and suitably distributed loud speakers in the low lift, clarifier, high lift, filters, administration building, chemical building, guard room, engineers house, operators houses and workshop.
6) Digital camera for each building as well as the purification system with monitor in control room
NOTE: 1A and 1B may be combined in one control panel, and this panel
must be located in control room, in high lift pump, the contractor will be responsible for furnishing the control room, and supply it with air condition unit.
The Contractor shall supply and install wireless system with UPS power supply units (DC & AC) in the control panel for transmitting speech signals between Treatment Plant & all ESTs and the Directorate of water.
Water level indicators for each G.S.T. outside the treatment plant with full scale deflection with min and max audio alarm must be transmitted by means of multi core armored cabl e laid in suitable PVC conduits along the pumping mains, also for the use for communication plus 3-spare pairs.
Spare parts for five years and all necessary test a n d maintenance tools, fault location equipments, 500m of cable and different types of joint boxes and compounds should be supplied with the offer.
Telephone System
The telephone installation shall be the type generally known as the "Private Automatic Branch Exchange" (PABX) with facilities for initiating the receiving external as well as internal calls at all instruments. All internal calls shall capable of being dialed directly and shall be independent of the operator. The switch board shall be capable of accommodating all extension mentioned below, it shall be possible to restrict outside access to any selected extension.
The telephone system shall consist of an automatic switchboard of 30 internal and two external lines and shall be installed in the control room. The switchboard shall be complete with 220V, 50Hz supply unit and emergency battery supply (12hr) and to board the following telephone apparatus shall be connected and it will be provided with special desk.
a. One No. desk telephone in each of the following rooms: • Chief Engineers room.
• Engineers rooms. • Laboratories. • Operator’s rooms. • Control rooms. • Engineers houses. • Operator’s houses. • Lecture rooms.
• Meeting rooms. • Workshop.
• Booster Station or Low Lift site: in each operator houses and guard room and pumping station.
NOTE: For booster station, there, must be special arrangement to
connect all line with one external line coming from Treatment Plant also Low Lift site.
b. One No. wall mounted with 100mm bell in: • Raw water pumps area.
• Treated water pump area. • Workshop.
• Guard room. • Chemical building. • Filter control gallery. • Filter operator room.
• Power houses (Low Tension switch board room). • Guard Posts.
c. One No. weather proof (cabinet and door made of aluminum alloy) with 100mm bell in:
• Suction Structure. • Flash mixers.
The contractor shall make all the required study for the required area for installing the above mentioned control and instrument panel.
BOOSTER STATIONS
Same as above
a. Water level in each • EST s
• Ground Storage Tanks.
b. Pressure gauges of 150mm dia. on each pumping main with rate of flow.
c. Working hour meter for each pump.
CLAUSE TEN
SUB – STATIONS
The supply voltage will be either 33KV or 11KV. The breaking capacity shall be 1500MVA and 750MVA respectively. If the power required is more than 4MVA or there is no 11KV supply from the national network a 33KV to 11KV or 33KV to 400V station should be supplied and erected according to the state organization of electricity requirements and specifications and the contractor is responsible to get their approval for that.
1) 11/0.400 KV Sub Stations
The Contractor shall supply, install and test the following equipment for each sub – station, The Contractor may separate the power supply for the low lift pump house as well as the L.T. switchboard (with a typical sub-station) and build a suitable building for the transformer and switchgear (if required). The same shall be applicable for Boosting Stations.
a) Take - off Points
Consist of 2 x 10m tubular steel poles, brackets, pin insulators, lightning arrestors, hand operated three pole H.T. link switch, H.T. link fuses of the suitable rating, cable boxes and H.T. cables (XLPE).
The take - off points will be fixed near the guard room. In case of 33KV sub-station this will be eliminated and it will be connected directly from sub-station to H.T. switchboard.
b) H.T. Switchboard
The switchboard shall comprise five No. panels each housing an automatic CB of the draw out type with skeleton compartment for future extension. The circuit breaker shall be according to BS 116 latest Edition having breaking capacity 750MVA at 11KV and impulse level of 75KA and CB will be vacuum or SF6 type. The 11KV system is un earthed but all allowances must be taken and required equipment should be supplied for converting the system to an earthed systems. In case there is more than two transformers within the site the required panel should be supplied within this switchboard.
Panels No. 1 for incoming supply
• The CB shall be rated 630A • 3 No. 144mm ammeter
• No. 144mm voltmeter and selector switch
• No. Current transformers for operating t h e protection and instrumentation
• 1 No. T.P. isolating voltage transformers.
• 1 No. 1 DTH over current and earth fault relay with over current and earth fault settings.
• 1 No. 1 DMT under voltage relay for supply failed alarm. • 1 No. test terminal block.
• 1 No. healthy trip lamp and push button. • 1 No. 110 DC shut trip and auxiliary switch.
• 1 No. Set of spare auxiliary switches 3 normally open and 3 normally closed.
• 1 No. unit cable sealing for box for 3 -core incoming cable. • 1 No. pilot cables terminating box.
• 1 No. alarm disconnecting relay with indicating lamp and reset button.
• 1 No. alarm bell remotely mounted (operated from battery system).
• 1 No. discrepancy switch, incorporating indicating lamps.
Panel No. 2 -Transformer No. 1 - FEEDER
- Same as Panel No. 1 except that: - CB rate 400A.
- 1 No. Bochloz relay with 2 elements for "surge trip" and gas "alarm".
- 1 No. excess oil temperature trip relay with the elements for "alarm" and "trip" stages.
Panel No. 3 Transformer No. 2 - Feeder
- Same as Panel 2
Panel No. 4, Panel No. 5 for automatic power factor correction
c) DCs Supply
Complete set of DC supply consist of nickel alkaline type with required electrolyte and distilled water, crater, stands, stand insulator, inter-cell and inter raw connection, battery charger, panel for battery ,panel for DC feeders, accessories and spares (2 hydrometers, 2 thermometers to read 0°C - 70°C, 2 large containers for mixing the electrolyte, 2 moving voltmeters 3-0-3 volts, complete set of maintenance equipment, one complete of spare part.
d) Two No. oil immersed transformers each rated 1.25 of full load of the plant 11/0.4KV Vector Group DY 11 with L.T. neutral brought out and solidly earthed, ONAN type, off load tape charger +4.5% +5% - on the 11KV side, rating plate bi-directional mending temperature indicator with centigrade pointer and indicating maximum pointers each indicating pointer having two sets of adjustable contacts, oil temperature indicator same as above, thermometers pocket with captive cap, explosion vent of double diaphragm type with portholes type sight bath type, gas, actuated relay, double float, drain valve complete with sampling cock, vacuum valve, filter valve, conservator, terminal boxes on H.T. and L.T. sides.
e) The 0.4KV side of each transformer shall connected by means of bus bars inside suitable conduit to CBs in the main distribution switchboard all the H.T. cables from the take off point to the transformers shall be (XLPE) type.
f) At least 4 earthing points are required to earth the neutral point of the transformers with all the necessary cables and electrodes.
The Contractor shall supply the low lift pump house and filter building with separate transformers if required and build suitable rooms if it is necessary. H.T. switchgear should be in the same H.T. board for main pump house.
NOTES: Iraqi standard transformers (11/0.4KV) are: 1000KVA, 630KVA,
400KVA, 250KVA & 100KVA.
2) H .T. LINES
The Contractor shall include in his price to supply and erect an over head H.T. or ground cable between treatment plant and low lift pump house if required. The poles will be tuber steel 10m high and conductors of copper. All technical specification will be according SOE requirements.
The contractor is required to survey the rout along the raw water delivery pipe. In case that the low lift station or other stations are within the site, a ring system by means of cables should be provided.
3) 33/11KV or 33/0.400KV step Down Sub Station
The Contractor shall supply a complete step down intermediate sub-station 33/11KV or 33/0.400KV complete from take off points to 11KV or 400V. Feeders out door type CBs will have vacuum or S.F.6 type. Breaking capacity of the system will be 1500MVA and all the
system equipment shall be in accordance to SOE requirement and there approvals. Each station will be equipped with 33KV, 11KV CB as spare. The Contractor is responsible for civil works for the control room, and fence of 50x50 meters, will all required cables near the fence up to each 11KV or 400V transformer site and feeding point for low lift, filters building and workshop transformers.
CLAUSE ELEVEN POWER HOUSE
Stand by generator sets site of Treatment Plant or any site
1) Scope of Supply
The object of this tender is to supply and install diesel generating sets of stationary design in quantities and capacities as in Basic Data. These generation sets shall be used to operate these water treatment plants at 100% of pumping capacity plus 100% services during periods of complete electricity mains shut down. These sets shall be erected and connected parallel to the mains system. All sets shall be designed for manual and automatic start and shall incorporate all necessary equipment like with automatic change over switches for emergency to permit feeding the consumer either from the mains or from the emergency diesel sets at any time. All water treatment plants are connected to the electricity mains national grid.
2) Capacity of Generating Sets
All generating sets shall be designed to have continuous net site rating output under the following site conditions:
Ambient temperature 55°C in the shade Altitude above sea level 1000 meters Relative humidity 80%
Every generating set shall be able to run at 10% overload for a period of one hour after working on full load for 12 continuous hours. The results shall be within the normal limits of the working conditions of the set. All generating sets shall be designed for 50Hz 3-phase, 0.8 P.f. generated voltage shall be 11KV or 400V with step-up transformers to 11KV. All sets shall be equipped with synchronizing devices allowing the operated in parallel of two or more sets. All generating sets shall be skid mounted installed in suitable building.
3) Description of Engine & Auxiliaries 3.1) General
