The Irish Department of Transport, Tourism & Sport issued a marine notice, providing guidance on the use of liquefied petroleum gas (LPG) installations on merchant vessels, fishing vessels, pleasure craft and other marine craft.
When handled incorrectly, the dangers associated with LPG systems include fire, explosion, burns and asphyxiation due to gas leakage from the system or accumulation of gas following flame failure in an appliance. Such incidents have caused loss of life and material damage.
The scope of recommendations includes:
Installation and Testing: To help prevent accidents with LPG systems, such systems should be installed at least in accordance with the International Standard ISO 10239:2014 (Small craft – Liquefied petroleum gas (LPG) systems). It is recommended that an inspection and test of such systems and associated alarm systems be carried out at least monthly to ensure correct operation.
Ventilation: As with any open flame type appliance, there is risk of asphyxiation due to oxygen depletion of the atmosphere and carbon monoxide poisoning where an open flame LPG appliance is operated in an area with inadequate ventilation, or where combustion is incomplete. It is dangerous to sleep in spaces where open flame type appliances are operated. Heaters without flues should not be sited in sleeping quarters, adjoining spaces or in any unventilated spaces.
Marking and Storage: LPG is supplied in pressurised cylinders and is usually propane, butane or a mixture of the two gases. Cylinders must be clearly marked with their contents. LPG has a stenching agent added to enable the presence of gas to be detected by smell, even when its concentration in air is below its lower explosive limit. Butane systems operate at final pressure of 28 mbar and propane systems at 37 mbar. Appliances should be checked to verify which gas they consume. Natural gas appliances are not suitable for use with LPG.
Propane cylinders should be stored outside in a cylinder housing, whilst butane cylinders may be located in a cylinder housing or a cylinder locker. All cylinders must be stored and used upright. LPG systems draw off the vapour phase of the gas from the top of the cylinder whilst the liquid phase remains in the bottom of the cylinder.
LPG is heavier than air and any leakage will tend to fall to the bottom of a compartment. Gas may travel some distance like this and may form an explosive mixture with the air in the compartment. A spark as small as the static discharge from clothing may ignite such a mixture.
Gas detection and alarm system: In conjunction with any LPG system, the provision of an automatic gas detection and alarm system of a reliable type is strongly recommended and is required when a LPG appliance is installed in spaces below decks. It is essential that any electrical equipment associated with the gas detection alarm and shutoff system is not a potential source of ignition and is ignition protected in accordance with ISO 8846.
Read the guidance note in full: Use-of-LPG-installations