Part 7 - LPG Installations

Introduction to the subject matter covered by the checks in Part 7

LPG (Liquefied Petroleum Gas) is kept under pressure as a liquid and when released, becomes a highly flammable gas that is much heavier than air. The gas industry also knows it as one of the most searching of gases, that is, it can escape through gaps that would hold water and other gases.

This Part explains how to minimise the risk of LPG escaping into the boat's interior, where it could quickly build up from the bottom of the boat forming an explosive 'mix' of gas and air. Therefore, this part covers how to store LPG, how to arrange the gas supply system and how to protect the gas supply installations from heat and impact damage.

It also covers the need for shut-off valves and appliance isolation valves to control the LPG supply, and the importance
of having the system installed in a way that minimises risk.

In the context of gas safety requirements it should be noted that the BSS strongly recommends that any work on LPG systems be carried out by a suitably competent person.

The BSS requirements associated with LPG installations and storage:

  • 18 All LPG systems must be designed, installed and maintained in away that minimises the risks of explosion or of fire starting and spreading.
  • 19 All LPG containers and high-pressure components must be secured in a position where escaping gas does not enter the interior of the vessel.
  • 20 All LPG systems must be designed, installed and maintained to ensure gas-tight integrity.
  • 21 All LPG system connections and flexible hoses must be accessible for inspection.SS Essential Guide
  • 22 All LPG control and shut-off devices, or the means to operate them must be readily accessible.
  • 23 LPG shut-off valves, or their means of operation, must be marked when not in clear view or when their function is not clear.
  • 24 All LPG systems must have a suitable means to test that the system is gas-tight.

Notes on the qualities of fuels that have a bearing on the nature of the Requirements and the Examination Checking Procedures

On boats, the Liquefied Petroleum Gases in common use are, 'commercial butane', and 'commercial propane'. They exist as gases at normal temperatures, but become a liquid under moderate pressure.

Propane turns into gas at a lower temperature than butane, so the storage pressure for liquid propane is slightly higher than butane.

One volume of liquid butane or propane produces approximately 250 volumes of gas and thus a leak of liquid is a grave hazard, especially on a boat. Since LPG vapour is denser than air, leaked LPG vapour will fall and flow along cockpit floors, bilges, etc and the vapour may travel some distance. The LPG will build up in low-lying parts of a boat and it may persist for some time.

Concentrations of 2-10% LPG in air create a flammable mix. In a boat, a flammable mix will explode if ignited. It is also possible for gas/air mixtures from leaks or other causes to be ignited some distance from the point of leakage and the flames travel back to the source before exploding.

Notes onLPG installation testing

All LPG installations must meet the gas-tightness testing requirements of PD 5482-3. Meeting these requirements will give an assurance that the installation is gas-tight at the time of the test.

However, to minimise the risks of gas leaks into your boat, it is also critical that all maintenance and changes to LPG installations are carried out competently.

At the time of examination, it is very important to ensure that all appliances to be tested are in working order and that a boat has enough gas, water and electrical power on board for testing to take place.

If appliances cannot be tested, the examination will be incomplete and, where this relates to a requirement, no certificate can be issued.

The proposals

The revised version of the ECPs can be read from a pdf format file by clicking the link on the image on the right below.

The orginal version of the Checking procedures can be read by clicking on the link on the left-hand image. This will launch the chapter of the BSS Guide that also contains all the relevant guidance and descriptions which may offer a more whole perspective.

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ECP Cover 300x200

Click on this image to see original ECPs and notes  Click on this image to see Proposed revisions