Gas Systems - Page 1 2 3 4

Liquid petroleum Gas (LPG) Systems


LPG installations are covered by BS 5482: parts 1,2 &3.

LPG is stored in tanks that range in size from domestic ˝ tonne to commercial 1,3,5,7 and 12 tonne tanks. Another method of sizing tanks is to use their water capacity i.e. 450 litres.

The diagram below shows a typical schematic layout of a LPG system.











































Installation Notes


1.        A prime requirement is that storage vessels must not be installed within buildings particularly basements, LPG being heavier than air.

2.        Storage pressure for propane is 6.9 bar.

3.        This is reduced to about 0.70 bar at the first stage regulator, which supplies the primary distribution main running up to the outside of the building.

4.        A second stage regulator fitted on the outside wall of the building will have an output pressure of 0.037 bar (37 millibar) to suit the standard low pressure rating of appliances such as cookers, boilers,etc.



Notes from ‘The storage of LPG fixed installations’ Guidance note CS5 from the Health & Safety Executive.


1.       At normal temperature commercial propane has a vapour pressure of about 7 bar.

2.       LPG vapour is denser than air.

3.       All piping over 13mm should be made of steel.

4.       Copper piping should be seamless and only used under 13mm diameter.

5.       LPG tanks over 9000 litres water capacity should be enclosed by a 1.8metre fence.

6.       Tanks should be installed with pressure relief valve, drain, contents gauge, and if the tank is over 2250 litres water capacity, a pressure gauge.

7.       All connections should have a shut-off valve.


Notes from ‘Installation notes for Liquefied Petroleum Gas plants’ Shell-Mex and BP Gases Ltd.


1.        Tanks up to 1 tonne product capacity must be sited at least 3 metres (10 feet) away from any building.

2.        Tanks greater than 1 tonne capacity must be sited at greater distances from buildings.

3.        Special jointing compound for pipe fittings should be used.

4.        Special P.T.F.E. tape may be used.

5.        For most cases pipework from the first stage of pressure regulation is of heavyweight class ‘C’ galvanised steel.

6.        12.5mm water gauge (0.5 in. w.g.) pressure drop is the maximum permitted pressure drop on pipelines.

7.        A shut-off valve must be positioned in the gas line immediately before it enters a building and a second isolating valve should be installed before second stage pressure regulation.


Gas Systems - Page 1 2 3 4