Section 2 Fuel oil - General requirements

2.1.1 The flash point (closed cup test) of fuel oil for use in ships classed for unrestricted service is, in general, to be not less than 60°C. For emergency generator engines a flash point of not less than 43°C is permissible.

2.1.2 The use of fuel oil having a flash point of less than 60° but not less than 43° may be permitted for emergency generators, emergency fire pumps, engines and auxiliary machines which are not located in machinery spaces subject to the requirements of Pt 5, Ch 14, 4.19 Arrangements for fuels with a flash point between 43°C and 60°C.

2.1.3 The use of fuel having a lower flash point than specified in Pt 5, Ch 14, 2.1 Flash point 2.1.1 or Pt 5, Ch 14, 2.1 Flash point 2.1.2 may be permitted in cargo ships provided that such fuel is not stored in any machinery space and the arrangements for the complete installation are specially approved.

2.1.4 Fuel oil in storage tanks is not to be heated to a temperature exceeding 10°C below its flash point. Higher temperatures will be considered for fuel oil stored in settling and service tanks where:

1. The tanks are vented to a safe position outside the engine-room and, as in the case of all fuel oil tanks, the ends of the ventilation pipes are fitted with gauze diaphragms.

2. Openings in the drainage systems of tanks containing heated fuel oil are located in spaces where no accumulation of oil vapours at temperatures close to the flash point can occur.

3. The length of vent pipes from such tanks and/or a cooling device is sufficient for cooling oil vapours to below 60°C, or the outlet of the vent pipes is located at least 3 m from sources of ignition.

4. There is no source of ignition in the vicinity of openings in the drainage systems.

5. There are no openings from the vapour space of the fuel tanks into machinery spaces other than bolted manhole covers.

6. Enclosed spaces are not located directly over such fuel tanks, except for vented cofferdams.

7. Electrical equipment is not fitted in the vapour space of tanks unless it meets the requirements of Pt 6, Ch 2, 14.3 Selection of equipment for use in explosive gas atmospheres 14.3.4 for electrical equipment in zone 0 explosive atmospheres.

2.1.5 The temperature of any heating medium is not to exceed 220°C.

2.2.1 When it is desired to carry a quantity of fuel having a flash point below 43°C for special services, e.g. aviation spirit for use in helicopters, full particulars of the proposed arrangements are to be submitted for special consideration. For helicopter refuelling, as a minimum, the requirements of SOLAS 1974 as amended II-2/G, Regulation 18 - Helicopter facilities will apply.

2.2.2 For the burning of gas fuel in liquefied gas tanker/carriers, see the Rules and Regulations for the Construction and Classification of Ships for the Carriage of Liquefied Gases in Bulk, July 2022 (hereinafter referred to as the Rules for Ships for Liquefied Gases).

2.2.3 Where it is proposed to use fuel for main or auxiliary engines in ships other than given in the Rules and Regulations for the Construction and Classification of Ships for the Carriage of Liquefied Gases in Bulk, July 2022, the relevant requirements of the Rules and Regulations for the Classification of Ships using Gases or other Low-flashpoint Fuels, July 2022 are to be complied with. Full particulars of the proposed arrangements are to be submitted for special consideration. Attention is to be given to any relevant statutory requirements of the National Authority of the country in which the ships are to be registered.

2.3.1 Sampling points are to be provided within the fuel oil system. The design and location of sampling points is to enable samples of fuel oil to be taken easily and in a safe manner.

2.3.2 The position of a sampling point is to be such that the sample of the fuel oil is representative of the fuel oil quality at its location within the system, e.g. by ensuring steady state flow past the sampling point.

Note Samples taken from sounding pipes and tank drain cocks are not considered to be representative of the tank’s contents.

2.3.3 Sampling points are to be located so as to reduce the possibility of fuel oil coming into contact with any heated surface or electrical equipment under reasonably foreseeable operating conditions and therefore shall be positioned as far away as possible from such surfaces or equipment. Where contact is still likely, positions are to be shielded from any heated surface or electrical equipment. The shielding shall be sturdy enough to endure leaks, splashes or spray under design pressure of the fuel oil supply line.

2.3.5 The sampling arrangements within the machinery space are to be capable of safely providing samples when the machinery is running and are to be provided with isolating valves and cocks of the self-closing type.

2.4.1 The spaces in which the fuel oil burning appliances and the fuel oil settling and service tanks are fitted are to be well ventilated and easy to access.

2.5.1 The boilers are to be suitably lagged. The clearance spaces between the boilers and tops of the double bottom tanks, and between the boilers and the sides of the storage tanks in which fuel oil and cargo oil is carried, are to be adequate for the free circulation of the air necessary to keep the temperature of the stored oil sufficiently below its flash point.

2.5.2 Where water tube boilers are installed, there is to be a space of at least 760 mm between the tank top and the underside of the pans forming the bottom of the combustion spaces.

2.5.3 Smoke-box doors are to be shielded and well fitting, and the uptake joints made gastight. Where the surface temperature of the uptakes may exceed 220°C, they are to be efficiently lagged to minimise the risk of fire and to prevent damage by heat. Where lagging covering the uptakes, including flanges, is oil-absorbing or may permit penetration of oil, the lagging is to be encased in sheet metal or equivalent. In locations where the Surveyor is satisfied that oil impingement could not occur, the lagging need not be encased.

2.6.1 Dampers which are capable of completely closing the gas passages are not to be fitted to inner funnels of ships equipped for burning fuel oil only. In ships burning oil or coal alternatively, dampers may be retained, if they are provided with a suitable device whereby they may be securely locked in the fully open position.

2.7.1 Where steam is used for heating fuel oil, cargo oil or lubricating oil, in bunkers, tanks, heaters or separators, the exhaust drains are to discharge the condensate into an observation tank in a well lighted and accessible position where it can be readily seen whether or not it is free from oil, see Pt 5, Ch 15, 6.4 Heating circuits.

2.7.2 Where hot water is used for heating, means are to be provided for detecting the presence of oil in the return lines from the heating coils.

2.7.3 Where it is proposed to use any heating medium other than steam or hot water, full particulars of the proposed arrangements are to be submitted for special consideration.

2.7.4 The heating pipes in contact with oil are to be of iron, steel, approved aluminium alloy or approved copper alloy, and, after being fitted on board, are to be tested by hydraulic pressure in accordance with the requirements of Pt 5, Ch 12, 8.1 Hydraulic tests before installation on board.

2.7.5 Where electric heating elements are fitted means are to be provided to ensure that all elements are submerged at all times when electric current is flowing and that their surface temperature cannot exceed 220°C.

2.8.1 Tanks and heaters in which oil is heated are to be provided with suitable means for ascertaining the temperature of the oil. Where thermometers or temperature sensing devices are not fitted in blind pockets, a warning notice, in raised letters, is to be affixed adjacent to the fittings stating `Do not remove unless tank/heater is drained'.

2.8.2 Controls are to be fitted to limit oil temperatures in oil storage and service tanks in accordance with Pt 5, Ch 14, 2.1 Flash point 2.1.4 and in oil heaters to the maximum approved operating temperature, see Pt 6, Ch 1 Control Engineering Systems.

2.9.1 Fuel oil tanks and fuel oil filters are not to be situated immediately above boilers or other highly heated surfaces, see also Pt 5, Ch 1, 4.6 Fire protection.

2.9.2 Fuel oil pipes are not to be installed above or near high temperature equipment. Fuel oil pipes should also be installed and screened or otherwise suitably protected to avoid oil spray or oil leakages onto hot surfaces, into machinery air intakes, or other sources of ignition such as electrical equipment. Pipe joints are to be kept to a minimum, and where provided are to be of a type acceptable to LR. Pipes are to be led in well lit and readily visible positions, see also Pt 5, Ch 2, 8 Piping.

2.9.3 Pumps, filters and heaters are to be located to avoid oil spray or oil leakages onto hot surfaces or other sources of ignition, or onto rotating machinery parts. Where necessary, shielding is to be provided and the arrangements are to allow easy access for routine maintenance.

2.9.4 The design of filter and strainer arrangements is to be such as to avoid the possibility of them being opened inadvertently when under pressure. This may be achieved by either mechanically preventing the pressurised filter from being opened or by providing pressure gauges which clearly indicate which filter is under pressure. In either case, suitable means for pressure release are to be provided, with drain pipes led to a safe location.

2.9.5 The arrangement and location of short sounding pipes to oil tanks are to be in accordance with Pt 5, Ch 13, 12.13 Short sounding pipes. For alternative sounding arrangements, see Pt 5, Ch 13, 12.11 Sounding arrangements.

2.9.6 Water service pipes and hoses are to be fitted in order that the floor plates and tank top or shell plating in way of boilers, fuel oil apparatus or deep storage tanks in the engine and boiler spaces can at any time be flushed with sea-water.

2.9.7 So far as is practicable, the use of wood is to be avoided in the engine rooms, boiler rooms and tunnels of ships burning fuel oil.

2.9.8 Drip trays are to be fitted at the furnace mouths to intercept oil escaping from the burners, and under all other fuel oil appliances which are required to be opened up frequently for cleaning or adjustment.

2.9.9 Oil-tight drip trays of ample size having suitable drainage arrangements are to be provided at pipes, pumps, valves and other fittings where there is a possibility of leakage. Valves should be located in well lighted and readily visible positions. Drip trays will not be required where pumps, valves and other fittings are placed in special compartments either inside or outside the machinery space with approved overall drainage arrangements or for valves which are so positioned that any leakage will drain directly into the bilges, see Pt 5, Ch 14, 2.9 Precautions against fire 2.9.2.

2.9.10 Where drainage arrangements are provided from collected leakages, they are to be led to a suitable oil drain tank not forming part of an overflow system.

2.9.11 Separate fuel oil tanks are to be placed in an oil-tight spill tray of ample size having drainage arrangements leading to a drain tank of suitable size, see Pt 5, Ch 14, 4.17 Separate fuel oil tanks.

2.9.12 Where level switches are used below the tank top, they are to be contained in a steel enclosure or other enclosures which provide equivalent protection against fire.

2.10.1 The materials and/or their surface treatment used for the storage and distribution of fuel oil are to be selected such that they do not introduce contamination or modify the properties of the fuel. The use of copper or zinc compounds in fuel oil distribution and utilisation piping is not permitted except for small diameter pipes in low pressure systems, see Pt 5, Ch 14, 4.6 Low pressure pipes 4.6.1.

2.10.2 For prevention of ingress of water into fuel oil tanks via air pipes, see Pt 5, Ch 13, 12.5 Termination of air pipes 12.5.4.

2.10.3 The piping arrangements for fuel oil are to be separate and distinct from those intended for lubricating oil systems to prevent contamination of fuel oil by lubricating oil.

2.10.4 Piping arrangements or alternative means are to be provided to ensure that distillates (i.e. gas oils/diesel grades) are to be kept separate and distinct from residual grades, up to the service tanks required by Pt 5, Ch 14, 4.18 Fuel oil service tanks, in order to prevent cross-contamination. Cross-connection is permitted between separate arrangements in the event of failure of a designated item of equipment.

2.11.1 Tanks containing fuel oil are to be separated from passenger, crew and baggage compartments by a division of all-welded steel construction capable of withstanding a head of water at least 1,5 m greater than the maximum service head or by a cofferdam.