© Crown Copyright
Code of Practice
ANNEX 3
OPEN FLAME GAS INSTALLATIONS
1 General Information
1.1 Possible dangers arising from the use of liquid petroleum gas (LPG) open flame appliances in the marine environment include fire, explosion and asphyxiation due to leakage of gas from the installation.
1.2 Consequently, the siting of gas consuming appliances and storage containers and the provision of adequate ventilation to spaces containing them is most important.
1.3 It is dangerous to sleep in spaces where gas-consuming open-flame appliances are left burning, because of the risk of carbon monoxide poisoning.
1.4 LPG is heavier than air and, if released, may travel some distance whilst seeking the lowest part of a space. Therefore, it is possible for gas to accumulate in relatively inaccessible area, such as bilges, and diffuse to form an explosive mixture with air, as in the case of petrol vapour.
1.5 A frequent cause of accidents involving LPG installations is the use of unsuitable fittings and improvised "temporary" repairs.
2 Stowage of gas containers
2.1 Gas containers should be stowed on the open deck or in a gas-tight enclosure opening on to the deck, so that any gas which may leak can disperse overboard.
2.2 Stowage should be such that containers are positively secured against movement in any foreseeable event.
2.3 In multiple container installations, a non-return value should be placed in the supply line near to the stop valve on each container. If a change-over device is used, it should be provided with non-return valves to isolate depleted containers.
2.4 When more than one container can supply a system, the system should not be used with a container removed.
2.5 Containers not in use or not being fitted into an installation should have the protecting cap in place over the container valve.
3 Fitting and pipework
3.1 Solid drawn copper ally or stainless steel tube with appropriate compression or screwed fittings are recommended for general use for pipework in LPG installations.
3.2 Aluminium or steel tubing or any materials having a low melting point, such as rubber or plastic, should NOT BE USED.
3.3 Lengths of flexible piping (if required for flexible connections) should be kept as short as possible and be protected from inadvertent damage. Also, the piping should conform to an appropriate standard.
4 Open-flame heater and gas refridgerators
4.1 When such appliances are installed, they should be well secured so as to avoid movement and, preferably, be of a type where the gas flames are isolated in a totally enclosed shield where the air supply and combustion gas outlets are pipe to open air.
4.2 In refrigerators when the burners are fitted with flame arrestor gauzes, shielding of the flame may be an optional feature.
4.3 Refrigerators should be fitted with a flame failure device.
4.4 Flueless heaters should be selected only if fitted with atmosphere-sensitive cut-off devices to shut off the gas supply at a carbon dioxide concentration of not more than 1.5 per cent by volume.
4.5 Heaters of a catalytic type should not be used.
5 Flame failure devices
A gas consuming device should be fitted, where practicable, with an automatic gas shut-off device which operates in the event of flame failure.
6 Gas detection
6.1 Suitable means for detecting the leakage of gas should be provided in a compartment containing a gas-consuming appliance or in any adjoining space or compartment into which the gas (more dense than air) may seep.
6.2 Gas detectors should be securely fixed in the lower part of the compartment in the vicinity of the gas-consuming appliance and other space(s) into which gas may seep.
6.3 A gas detector should, preferably, be of a type which will be actuated promptly and automatically by the presence of a gas concentration in air of not greater than 0.5 per cent (representing approximately 25 per cent of the lower explosive limit) and should incorporate an audible and a visible alarm.
6.4 When electrical detection equipment is fitted, it should be certified as being flame-proof or intrinsically safe for the gas being used.
6.5 In all cases, the arrangements should be such that the detection system can be tested frequently whilst the vessel is in service.
7 Emergency action
7.1 A suitable notice, detailing the action to be taken when an alarm is given by the gas detection system, should be displayed prominently in the vessel.
7.2 The information given should include the following:-
.1 The need to be ever alert for gas leakage; and
.2 When leakage is detected or suspected, all gas-consuming appliances should be shut off at the main supply from the container(s) and NO SMOKING should be permitted until it is safe to do so.
.3 NAKED LIGHTS SHOULD NEVER BE USED AS A MEANS OF LOCATING GAS LEAKS.
