Liquefied Natural Gas (LNG) or Liquefied Petroleum Gas (LPG) is commonplace on board the modern yacht, for your stove, your barbeque and perhaps also your water heater. I'll never forget walking down the pier in Penryn, Cornwall, past an old barge with the back end blown apart in a gas explosion. The family with 2 children had all been killed in the blast. Whilst instances remain relatively rare, do yourself a favour and run through your own system to make sure you have all the bases covered.
Types of Liquefied Natural Gas (LNG) & Liquefied Petroleum Gas (LPG)
LNG/LPG is most commonly supplied as Propane (orange bottles familiar to the US) or Butane (blue bottles familiar to the EU). Both are gaseous at room temperature, but turn to liquid under pressure.
Propane turns into gas at a slightly lower temperature than Butane, and is therefore stored at a slightly higher pressure, however both can change from 1 volume of liquid into approximately 250 volumes of gas at room temperature. LPG is considerably heavier than air and escaped gas therefore drops to the lowest part of a boat and spreads throughout the bilges for a considerable period of time. It also known as a “searching” gas as it can find exits from spaces that would normally hold air or water.
In the Caribbean, LPG is simply sold as “Cooking Gas” and can be propane, butane (normal butane and/or iso-butane), or a mix of propane and butanes.
LPG is highly flammable at concentrations of 2 to 10% in air and, once ignited, flames can travel back along pipework to source before exploding.
Recommended Safety Standards
Vessels operating commercially, whether for charter or sailing school, have an obligation to meet the regulations of their flag state in order to be eligible for a commercial licence and relevant insurance. Private vessels should consider the commercial regulations as best practice guidance, although there is no legal obligation to comply unless stipulated by an insurance company.
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| From BSS Guide Chapter 7 |
Guidelines for safe gas installation on small vessels (less than 24 metres) are given in the following documents. The guidance you should follow depends on the flag state of your vessel, however there is an exercise underway to harmonise the manufacturing standards for sea-going vessels, in Europe and worldwide.
Official guidance is generally NOT available free; most of the following safety standards must be purchased from publishers (unless indicated):
British (and dependent territory) registered vessels (clearly explained by the Boat Safety Scheme - BSS):
- Statutory Instrument SI 1998 No 2451 "Gas Safety (Installation and Use) Regulations 1998" (GSIUR) forms the backbone of legislation in the UK (free).
- For vessels built within the United Kingdom, PD 5482-3:2005, which supercedes BS 5482-3:1999 (now withdrawn). This is the code of practice for installations in boats, yachts and other vessels of lengths up to 24 metres.
- For vessels CE marked to the Recreational Craft Directive, which may be imported, the builder may have chosen to apply the standards within BS EN ISO 10239:2008.
European flagged vessels:
US (and dependent territory) registered vessels:
- A-1 (ANS) — Marine Liquefied Petroleum Gas (LPG) Systems, as supplemented by
- ABYC A-22, Marine Compressed Natural Gas (CNG) Systems
- ABYC A-3, Galley Stoves
- ABYC A- 26, LPG and CNG Fuelled Appliances
The subsequent information given in my blog posts concerning gas installations references the British Small Boat Safety Scheme Chapter 7 and their leaflet "Avoiding Fire Afloat - Safe Use of LPG" both of which is available as a pdf online. Whilst aimed boats sailing on British Inland Waterways, this document takes into account the guidance given in a number of relevant manufacturing standards and is therefore an excellent source of information for those not needing to splash out on the full safety standard.
Commercially operating vessels should ensure that they meet the latest official standards as per the links above.
Part 2: Gas Bottles & Bottle Storage
Part 3: Gas System Components
Part 4: Leak Detection & Management
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