FUEL STORAGE AND SUPPLY SYSTEM
10.1 SERVICE FUEL TANK
A service fuel tank (or fuel tank) shall be supplied and installed within the generator room at a location to be agreed by the S.O.’s representative. Service fuel tank shall have a capacity for a minimum of 8 hours continuous operation at full load or 1000 litres capacity whichever is larger supported by suitable hot-dip galvanised angle iron supports to permit gravity feed to the engine fuel injection pump. Service fuel tank shall comply with BS 799-5, fabricated from 2.5 mm thick mild steel sheet construction, not galvanised but painted inside and outside with oil resistant prime and externally finished with undercoat and topcoat. A dial type level indicator calibrated in litres shall be provided. A breather is to be provided. The breather opening must be adequate to vent gases and air from the service fuel tank without back pressure. The fuel injection pump suction line shall pick fuel about 30 mm from the bottom of the service fuel tank complete with fuel strainer. The fuel return line shall be so located so as to allow separation of the fuel and vapour or gases in the expansion space above the normal fuel level and shall be pointed away from the breather and suction area. A drain valve complete with padlock shall be provided at a low point in the service fuel tank in an accessible location to allow periodic removal of water condensation and sediment. A spill tray shall be provided beneath the drain valve. If more than one generator set are installed in the generator room, a common service fuel tank may be used. The common service fuel tank shall be of sufficient capacity to run the generator sets simultaneously for minimum 8 hours continuous operation at full load. Under this Contract the Electrical Contractor shall supply a full tank of fuel at the time of handing over. The Electrical Contractor shall also supply all fuel required for carrying out all tests including site tests. This shall be in addition to the full tank of fuel mentioned above.
10.2 BULK STORAGE FUEL TANK
A bulk storage fuel tank in the form of skid tank shall be supplied and installed if specified in the Bills of Quantities. The skid tank shall be installed at the location indicated by the S.O.’s Representative. Unless otherwise specified elsewhere, the capacity of the skid tank shall be 9000 litres. Generally the skid tank shall be fabricated in accordance with the standard design and specification of oil companies in Malaysia compliance with BS 2594. The skid tank shall include a permanent steel ladder providing access to the manhole at the top of the skid tank. Drain pipe with shut-off cork complete with padlock shall be provided at the tank bottom. Fuel level sighting gauge shall also be included. A filler pipe shall be installed to facilitate the filling of the skid tank from a road fuel tanker. An efficient approved method of sealing this pipe to prevent ingress of moisture shall be provided. A filler coupler to suit and in accordance with the requirement of oil companies in Malaysia shall be provided. All material and steel plates used shall be new and free from rust. Minimum sizes of steel plates shall be 7.9 mm thick for the end plates and 6.3 mm for the shell. Tank plates
and structural steel shall be of carbon steel plates complying with of BS 1449–1.1. Only welded construction complying with the requirements of BS EN 1011 shall be used. Tank is to be hydrostatically tested at a hydrostatic pressure of 103 Kn per sq. m. for a period of 20 minutes. All rust, scale, oil or grease on the surface of the tank must be removed thoroughly before painting of the skid tank. Immediately all rust is removed, one prime coat of bituminous solution shall be applied on the surface, followed by two coats of bitumen emulsion paint and finished with two coats of bituminous aluminium paint. Interior of the skid tank shall be thoroughly cleaned of dirt such that it can be put into immediate used. An accurately calibrated brass dip stick graduated in litres at intervals of 200 litres up to save contents of tank shall be supplied with the skid tank. A concrete foundation for the skid tank shall be constructed and erected. The area approximately 500 mm wide around and below the skid tank shall be covered with cement to 50 mm thickness. Spillage containment area and fire walls compliance with the requirements of Jabatan Alam Sekitar (JAS) and Jabatan Bomba dan Penyelamat Malaysia respectively shall be constructed. The cost for the construction of spillage containment and fire walls is deemed to be included in this Contract. Under this Contract the Electrical Contractor shall supply a full tank of fuel at the time of handing over. The cost of supply the fuel shall deem inclusive in the Contract.
10.3 FUEL TRANSFER SYSTEM
Fuel transfer system for transferring fuel from drums into the service fuel tank shall be supplied and installed. The fuel transfer system shall consist of hand-operated pump installed in parallel with an electric motor-driven pump. A filler pipe shall be installed from the inlet point of the service fuel tank to the outlet point of the fuel transfer pumps. A suitable length of flexible transparent oil resistant hose shall be connected from the inlet of the fuel transfer pumps for off-loading from drums. Fuel transfer from the drum into the service fuel tank shall stop automatically by stopping the electric motordriven fuel transfer pump controlled by means of high fuel level sensor in the service fuel tank.
In the case where the skid tank is provided in the Bill of Quantities, a fuel transfer system for transferring fuel from the skid tank into the service fuel tank shall be provided and installed. The fuel transfer system shall consist of hand-operated pump installed in parallel with an electric motor-driven pump. Fuel transfer from the skid tank into the
service fuel tank shall be controlled by means of high and low fuel level sensors in the service fuel tank and the skid tank respectively by stopping and starting the electric motor driven fuel transfer pump automatically. The delivery branch pipelines shall include both non-return valves and shut-off valves that have padlocking facility. Overflowing fuel from the engine shall be fed back to the service fuel tank by means of fuel pipe complete with non-return valve near the service fuel tank. Full-flow duplex fuel filters of the replacement type shall be provided at the entry to the service fuel tank and a full flow single fuel filter with impregnated paper element of the replacement type shall also be provided at the entry to the engine. Spill trays shall be provided beneath the filters. ‘Fail-Safe’ quick closing emergency valves shall be provided at the fuel entry to the engine in the fuel transfer system to shut-off the fuel supply in the event of engine fuel pump runaway and/or fire. Similar emergency valve shall also be provided at the fuel
entry to the service fuel tank from the skid tank if the skid tank is installed. Flow meters calibrated in litres with accuracy of ± 1% or better shall be fitted in the supply lines from the skid tank to the service fuel tank if skid tank is installed, from the service fuel tank to the engine and from the off-loading fuel drum to the service fuel tank. The fuel transfer pumps shall be installed as close to the service fuel tank as possible but the exact location shall be decided by the S.O.’s representative on site. The electric motor-driven fuel transfer pump shall be of the self-priming type and
shall have sufficient suction lift to deliver a transfer rate of 50 litres per minute. The pump shall be suitable for operation from single phase, 240 V, 50 Hz supply. The Electrical Contractor shall carry out wiring in galvanised steel conduit from the electric starter point on nearby wall to the electric motor-driven pump.
10.4 FUEL SUPPLY PIPING
All rigid fuel pipes and fittings shall be of carbon steel. All valves shall be cast steel and designed for the duty they are required to perform. All flexible fuel pipes for connection to the engine fuel inlet and return outlet shall be of seamless synthetic rubber, flame retardant, armoured type with cone connections at both ends. The diameter of the pipe shall be as recommended by the generator set manufacturer. Care must be taken to keep the number of bends to a minimum. Fuel pipes shall be brown as a basic identification colour in compliance with BS 1710. Flow direction markers shall also be provided. Fuel supply pipelines inside the generator room shall be installed in the concrete
trench covered with hot-dip galvanised checker steel plate of sufficient thickness. Outside the generator room fuel supply pipelines shall be in containment ducting buried 750 mm directly in ground with protective covers laid above the whole length of the pipelines. Pipeline markers shall be at both ends of the pipelines and at every change in direction of the pipeline routes. At road crossings and concrete pavements, fuel supply pipelines in containment ducting shall be protected by galvanised steel pipes. No fuel supply piping shall be installed in the cable trench.
All fuel supply piping shall be hydrostatically tested at a hydrostatic pressure recommended by the manufacturer for a period of 20 minutes.
10.5 FUEL LEVEL SENSOR SWITCHES
Fuel level sensor switches shall be provided in the skid tank, viz.: –
Stage 1: Low fuel level – warning.
Stage 2: Low fuel level – stop the electric motor driven fuel pump
from transferring the fuel from the skid tank into the service fuel tank. For the service fuel tank, fuel level sensor switches shall be provided for:-
Stage 1: High fuel level – stop electric motor driven fuel pump from transferring the fuel from the skid tank or the fuel drum into the service fuel tank.
Stage 2: Low fuel level – start the electric motor driven fuel pump transferring the fuel from the skid tank into the service fuel tank (if skid tank is provided).
Stage 3: Low fuel level – warning.
Stage 4: Low fuel level – stop generator set operation. The fuel level sensor switches shall be of hermetically sealed reed switch with float type suitable for oil and gas application. As the float rises and falls with the level of the fuel, the reed switch is activated by means of magnet.
Padlocks shall be provided as specified in Section 7.1 – Service Fuel Tank and Section 7.2 – Bulk Storage Fuel Tank, as the case may be. Padlocks shall also be provided for the opening cover of the service fuel tank and the manhole cover of the skid tank. Padlocks shall be of high quality water resistant non spring type for outdoor use and the shackles shall be of hardened stainless steel. Master-key system shall be provided for the all padlocks used for shut-off valves of the fuel supply pipes and drain valves of the service fuel tank and the skid tanks. Three (3) sets of master keys and individual keys for the padlocks shall be provided. All keys shall be properly labelled.