Section 4 Fuel oil pumps, pipes, fittings, tanks, etc.

4.1.1 Where a power driven pump is necessary for transferring fuel oil, a standby pump is to be provided and connected ready for use, or, alternatively, emergency connections may be made to one of the unit pumps or to another suitable power driven pump.

4.2.1 The power supply to all independently driven fuel oil transfer and pressure pumps is to be capable of being stopped from a position outside the space which will always be accessible in the event of fire occurring in the compartment in which they are situated, as well as from the compartment itself.

4.3.1 All pumps which are capable of developing a pressure exceeding the design pressure of the system are to be provided with relief valves. Each relief valve is to be in closed circuit, i.e. arranged to discharge back to the suction side of the pump and effectively to limit the pump discharge pressure to the design pressure of the system.

4.4.1 Valves or cocks are to be interposed between the pumps and the suction and discharge pipes, in order that any pump may be shut off for opening up and overhauling.

4.5.1 Pipes conveying oil under pressure are to be of seamless steel or other approved material having flanged or welded joints, and are to be placed in sight above the platform in well lighted and readily accessible parts of the machinery spaces. The number of flanged joints is to be kept to a minimum.

4.5.2 Where pipe systems convey heated oil under pressure and include flanged joints, the flanges and joints are to be suitable for a design pressure of at least 13,7 bar (14 kgf/cm²) or the design pressure, whichever is the greater and a design temperature of 150^oC or the design temperature whichever is the greater. They are to comply with a relevant and acceptable National or International Standard, and the requirements of Vol 2, Pt 7, Ch 1 Piping Design Requirements at the defined temperature and pressure. Materials for the pipes, flanges and gaskets are to be suitable for the conveyed medium at the defined temperature and pressure.

4.5.3 The short joining lengths of pipes to the burners from the control valves at the boiler may have cone unions, provided these are of specially robust construction.

4.5.4 Flexible hoses of approved material and design may be used for the burner pipes, provided that spare lengths, complete with couplings, are carried on board.

4.5.5 For requirements relating to flexible hoses, see Vol 2, Pt 7, Ch 1, 13 Flexible hoses.

4.6.1 Transfer, suction and other low pressure oil pipes and all pipes passing through oil storage tanks are to be made of steel, having flanged joints suitable for a working pressure of not less than 6,9 bar. The flanges are to be machined and the jointing material is to be impervious to oil. Where the pipes are 25 mm bore or less, they may be of seamless copper or copper alloy, except those which pass through oil storage tanks. Oil pipes within the engine and boiler spaces are to be fitted where they can be readily inspected and repaired.

4.6.2 For requirements regarding bilge and dewatering pipes in way of double bottom tanks and deep tanks, see Vol 2, Pt 7, Ch 2, 7.7 Bilge and dewatering pipes in way of double bottom and deep tanks.

4.7.1 Valves, cocks and their pipe connections are to be so arranged that oil cannot be admitted into tanks which are not structurally suitable for the carriage of oil or into tanks which can be used for the carriage of fresh water.

4.7.2 All valves and cocks forming part of the fuel oil installation are to be capable of being controlled from readily accessible positions which, in the engine and boiler spaces, are to be above the working platform. See also Vol 2, Pt 7, Ch 2, 2.3 Valves - Installation and control.

4.7.3 Every fuel oil suction pipe from a double bottom tank is to be fitted with a valve or cock.

4.8.1 Every fuel oil suction pipe from a storage, settling and daily service tank situated above the double bottom, and every fuel oil levelling pipe within the boiler room or engine room, is to be fitted with a valve or cock secured to the tank.

4.8.2 The valves and cocks mentioned in Vol 2, Pt 7, Ch 3, 4.8 Valves on deep tanks and their control arrangements 4.8.1 are to be capable of being closed locally and from positions outside these spaces. The remote controls are to be accessible in the event of fire occurring in the deep tank's space. Instructions for closing the valves or cocks are to be indicated at the valves and cocks and at the remote control positions.

4.8.3 The control for remote operation of the valve on the emergency generator fuel tank is to be in a separate location from the controls for the remote operation of other valves for tanks located in machinery spaces.

4.8.4 In the case of tanks of less than 500 litres capacity consideration will be given to the omission of remote controls.

4.8.5 Every fuel oil suction pipe which is led into the engine and boiler spaces, from a tank situated above the double bottom outside these spaces, is to be fitted in the machinery space with a valve controlled as in Vol 2, Pt 7, Ch 3, 4.8 Valves on deep tanks and their control arrangements 4.8.2, except where the valve on the tank is already capable of being closed from an accessible position on the damage control deck.

4.8.6 Where the filling pipes to deep oil tanks are not connected to the tanks near the top, they are to be provided with non-return valves at the tanks or with valves or cocks fitted and controlled as in Vol 2, Pt 7, Ch 3, 4.8 Valves on deep tanks and their control arrangements 4.8.2.

4.9.1 Settling tanks and service tanks are to be provided with means for removing water from the lowest point in the tank.

4.9.2 If settling tanks and service tanks are not provided, the fuel oil storage tanks are to be fitted with means for removing water from the lowest point in the tank.

4.9.3 Open drains for removing the water from oil tanks are to be fitted with valves or cocks of a self-closing type, and suitable provision is to be made for collecting the oily discharge.

4.10.1 Relief valves are to be fitted on the oil side of heaters and are to be adjusted to operate at a pressure of 3,4 bar above that of the supply pump relief valve, see Vol 2, Pt 7, Ch 3, 4.3 Relief valves on pumps. The discharge from the relief valves is to be led to a safe position.

4.11.1 Filling stations are to be isolated from other spaces and are to be efficiently drained and ventilated.

4.11.2 Provision is to be made against overpressure in the filling pipelines. Where any relief valve(s) are fitted for this purpose, they are to discharge to an overflow tank or other safe position.

4.11.3 The arrangements for filling fuel oil tanks are to be such that the tanks will not be subject to a pressure in excess of that for which they were designed. Maximum filling rates are to be stated in the ship’s Operations Manual.

4.12.1 Provision is to be made for the transfer of fuel oil from any fuel oil storage or settling tank to any other fuel oil storage or settling tank in the event of fire or damage.

4.13.1 Where it is intended to carry fuel oil and water ballast in the same compartments alternatively, the valves or cocks connecting the suction pipes of these compartments with the ballast pump and those connecting them with the fuel oil transfer pump are to be so arranged that the oil may be pumped from any one compartment by the fuel oil pump at the same time as the ballast pump is being used on any other compartment.

4.13.2 Attention is drawn to regulations that may be specified by the Naval Administration in connection with the International Convention for the Prevention of Pollution of the Sea by Oil, 1973/78.

4.14.1 In the case of deep tanks which can be used for the carriage of fuel oil or water ballast, provision is to be made for blank flanging the oil and water ballast filling and suction pipes.

4.15.1 Pipes in connection with compartments used for storing fresh water are to be separate and distinct from any pipes which may be used for oil or oily water, and are not to be led through tanks which contain oil, nor are oil pipes to be led through fresh water tanks.

4.16.1 Two or more filters are to be fitted in the fuel oil supply lines to the main and auxiliary engines, and the arrangements are to be such that any filter can be cleaned without interrupting the supply of filtered fuel oil to the engines.

4.17.1 Where separate fuel oil tanks are permitted, their construction is to be in accordance with the requirements of Vol 2, Pt 7, Ch 3, 4.17 Independent/separate fuel oil tanks 4.17.2 to Vol 2, Pt 7, Ch 3, 4.17 Independent/separate fuel oil tanks 4.17.6, see also Vol 2, Pt 7, Ch 3, 2.9 Precautions against fire 2.9.1and Vol 2, Pt 7, Ch 3, 2.9 Precautions against fire 2.9.2.

4.17.2 In general, the minimum thickness of the plating of service, settling and other oil tanks, where they do not form part of the structure of the ship, is to be 5 mm, but in the case of very small tanks, the minimum thickness may be 3 mm.

4.17.3 For rectangular steel tanks of welded construction, the plate thicknesses are to be not less than those indicated in Table 3.4.1 Plate thickness of separate fuel oil tanks. The stiffeners are to be of approved dimensions.

4.17.4 The dimension given in Table 3.4.1 Plate thickness of separate fuel oil tanks for the breadth of the panel is the maximum distance allowable between continuous lines of support, which may be stiffeners, washplates or the boundary of the tank.

4.17.5 Where necessary, stiffeners are to be provided, and if the length of the stiffener exceeds twice the breadth of the panel, horizontal stiffeners are also to be fitted, or, alternatively, tie bars are to be provided between stiffeners on opposite sides of the tank.

4.17.6 On completion, the tanks are to be tested by a head of water equal to the maximum to which the tanks may be subjected, but not less than 2,5 m above the crown of the tank.

4.18.1 A fuel oil service tank is a a fuel oil tank which contains only the required quality of fuel ready for immediate use.

4.18.2 Two fuel oil service tanks, for each type of fuel used on board, necessary for propulsion and generator systems, are to be provided. Each tank is to have a capacity for at least eight hours operation at sea, at maximum continuous rating of the propulsion plant and/or generating plant associated with that tank.

4.18.3 A greater or lesser period than the 8 hour period specified in Vol 2, Pt 7, Ch 3, 4.18 Fuel oil service tanks 4.18.2 may be considered in conjunction with the operational requirements of the ship and any assigned Service Restriction.

4.19.1 The use of water compensated fuel oil tanks is to be avoided whenever practicable and attention is drawn to regulations that may be specified by the Naval Administration in connection with the International Convention for the Prevention of Pollution of the Sea by Oil, 1973/78.

4.19.2 Where the ship design considerations require the inclusion of sea-water compensated fuel oil tanks the arrangements are to comply with the requirements inVol 2, Pt 7, Ch 3, 4.19 Water compensated fuel oil tanks 4.19.3. Acceptance of water compensated fuel oil tanks is subject to the provision of alternative fuel oil storage and usage arrangements that do not rely only on the use of water compensated tanks and that permit fuel oil to settle before use. The arrangement and capacity of fuel oil in tanks that do not have sea-water compensation arrangements are to recognise the service profile required by Vol 2, Pt 1, Ch 3, 3.3 Calculations and specifications 3.3.1

4.19.3 Tank types to be used as sea-water compensated fuel tanks are listed in order of preference below. Preference is based on tank shape and the ability to readily pump out the contents:

1. Wing or deep tanks.

2. Wing double bottom tanks.

3. Flat double bottom tanks.

4.19.4 The tank design is to limit the oil/water interface to reduce mixing to the minimum.

4.19.5 The internal structure of tanks is to allow free drainage to the lowest part of the tanks.

4.19.6 The tank internal preservation is to be suitable for both sea-water and fuel oil and capable of resisting microbiological contamination, specifically sulphate reducing bacteria.

4.19.7 All tanks are to have vertical longitudinal partitions (either of the fixed structural or flexible membrane type) with provision for sequential displacement of fluids in partitioned sections. The partitioned section furthest from the suction is to be provided with a suitable air pipe.

4.19.8 Means are to be provided to detect the fuel/water interface to allow accurate detection of remaining fuel in tanks.

4.19.9 The piping arrangements at the filling and discharge points are to be designed to minimise fluid turbulence.

4.19.10 The design fuel oil filling and sea-water discharge flow rates are to be specified by the Naval Administration. The fuel oil filling rate is to be achieved by use of filling trunks or other regulating method that will always provide sufficient head of oil to displace water from the water compensated fuel tanks and prevent a tank being subjected to a pressure greater than that for which it has been designed.

4.19.11 The discharge of sea-water is to be via either:

1. A high level discharge point above waterline for discharge to shore or lighter.

2. Low level discharge just below waterline for discharging at sea.

Means are to be provided to ascertain actual discharge of sea-water at a position close to the ship-side discharge valve.

4.19.12 Header tanks for supply of sea-water to water compensated fuel oil tanks are to be provided with level indication that can be readily sighted. Where the HP seawater main is used to supply the header tanks, arrangements are to be made to prevent the oil tanks being subject to a pressure that exceeds the design pressure. Arrangements are also to be made to ensure that oil does not enter a header tank.

4.19.13 Where a water compensated fuel oil storage system is required to be capable of displacing fuel oil direct to a service tank in the event of a transfer pump or centrifuge failure, testing is to be carried out to demonstrate that the specified transfer rate can be achieved.

4.20.1 Fuel oil tanks other than those in double bottom compartments are to be located outside Category A machinery spaces, see also Vol 1, Pt 3, Ch 2, 4.9 Separation and protection of tanks.

4.20.2 Provisions are to be made for the measurement of fuel oil temperature at the pump suction pipe.

4.20.3 Stop valves are to be provided at the inlet and outlet side of fuel oil strainers.

4.20.4 Pipe joints are to be either welded or spherical type union joints.