【正文】 the load and each charger to be isolated from the battery. The battery charger should be a proven standard type in pliance with NFPA 20 and listed for fire pumps. Battery chargers should be provided with blocking diodes(????????) in the output DC circuit to protect the battery system from back feeding the charger circuit in the event of internal fault in the charger circuit. During normal operation, the battery should be floating online with battery chargers connected. The normal steadystate loads should be supplied by the battery charger. The following indicators and meters should be provided on the front of the charger panel (all indicators light should be cluster LED type):? . power on indicator? Float charge indicator? Boost charge indicator? . voltmeter with at least 2 percent accuracy? Float and boost charger selector switch? Ammeter Chargers should incorporate extensive fault monitoring and should give a local alarm for :? DC Over Voltage? DC Under Voltage? +ve Ground Fault? ve Ground Fault? AC Power Trip? DC Power Trip A mon alarm from each charger should as a minimum give an alarm on the firepump controller. Cooling Unless specifically indicated otherwise on the data sheet, all engine cooling duties should use shell and tube coolers, as required by NFPA 20.14 / 32 The seawater/jacket water cooler should be constructed to TEMAC requirements and should be the AEM type where thermal expansion permits. Alternatively, the cooler should be the AET type. The minimum allowable tube diameter is 5/8, and 10% spare surface area, or 5 spare tubes, whichever has the largest area, should be provided. Tube holes should have two grooves. Bolting should not be smaller than 1/2 diameter. The entire cooler should be manufactured from 90/10 coppernickel material, or a similar alloy suitable for hot seawater. Local temperature indicators, bimetal dial type, should be provided at the seawater cooler39。 ABBREVIATIONSCNOOC China National Oil Offshore Company, the CompanyANSI American National Standards Institute5 / 32API American Petroleum InstituteASME American Petroleum InstituteESD Emergency ShutdownNFC National Fire CodeNEMA National Equipment Manufacturers AssociationNFPA National Fire Protection AssociationIMO International Maritime OrganisationSOLAS Safety of Life at Sea3 FIRE WATER PUMPS CapacityGenerally at least two fire water pumps with independent driven power should feed the fire water system. Each fire water pump should be capable of delivering 100% of the calculated demand. This demand should normally prise the maximum fire zone fire fighting requirement (deluge, or foam generation, etc) plus 2 fire hydrants or hosereels (with minimum capacity 25 m3/h 700 kPaG at inlet) or, one fire water monitor and one hydrant or hosereel while maintaining a minimum pressure 700 kPaG at fire water monitor inlet. In addition, where a foam system is provided, for example the foam system for helideck or the foam hosereel, the pump should be capable of maintaining at least a pressure of 700 kPaG at the foam installation.Fire water pumps should be designed in accordance with NFPA 20 with 150% of design capacity at no less than 65% of design pressure and the shutoff pressure (no flow) should not exceed 120% of the rated pressure for horizontal centrifugal pumps or 140% of the rated pressure for vertical centrifugal pumps.The discharge pressure should be measured at the pump discharge head flange with a pumping water level as specified. The total discharge head and performance curves should include all internal losses in the pumps (including column pipes).At least one of the two fire water pumps should always be ready for use.In case of a large offshore facility requires the fire pump with large capacity, the individual pump’s capacity should not exceed 1200 m3/h unless it should be demonstrated that the integrity of the fire water distribution system cannot be impaired by the surge effect during transient flow regimes. In such case, the configuration of the pump station can be: 3 x 50 %, each pump having a minimum capacity of 50 % of the maximum fire water requirement.6 / 32As a general rule, fire water pumping capacity must be achieved with dedicated fire pumps. However the use of cooling water pumps for fire water service may be envisaged if they have adequate characteristics (flow and pressure) and if it is demonstrated that they should ensure a reliable fire water supply in all circumstances, even in case of loss of all utilities. The decision to proceed along this configuration should be subject to a special study and specific approval by COMPANY. Pump characteristics LocationThe fire pumps should be located in the nonhazardous area or away from hazard.The two fire water pumps should be segregated such that a single incident occurring at one pump can not impair the functionality of both pumps. The segregation can be reached by installing the pumps in different decks, or at same deck however with adequate distance (at least 5 m) or a steel wall or equivalent. Submerged vertical type fire water pumps should be of installed in a pump caisson posed of a steel pipe securely attached to the platform for protection against wave action and mechanical damage. Where practicable, the pump caisson should be located where it will be protected by the platform framing to minimise the risk of mechanical damage by boats. The pumps should be located away from lay down areas and, more generally, should be protected against the fall of heavy loads. The upper extremity of the pump caisson should be located above the air gap.The pumps should also be located near the platform hosting equipment or provided with an alternative method of retrieving the pump for maintenance.Pump minimum submergence should be at least 3 m from the