Tightness testing & Purging

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When should a tightness test be carried out

When a gas pipe has been installed or where work has been carried out that could affect its integrity.
Permissible pressure drop allowed on new pipework.

There should be no perceptible pressure drop.
Permissible pressure drop allowed for existing installations with appliances connected.

A maximum pressure drop is allowed dependent on the meter and pipe size of installation. There must be no smell of gas.
Low pressure meter procedure
- let by of ecv 7 to 10mbar 1 minute
- stabilisation 20 to 21mbar 1 minute
- tightness test 20 to 21mbar 2 minutes
- LDF test point
Medium pressure meter procedure
- let by of ecv 7 to 10mbar 1 minute
- let by of regulator 7 to 10mbar 1 minute
- stabilisation 20 to 21mbar 1 minute
- tightness test 20 to 21mbar 2 minutes
- LDF test point
Maximum permissible pressure drop on a E6 meter installation or an installation with no meter up to 28mm pipe

8 mbar
Maximum permissible pressure drop on a U6 or G4 meter installation up to 28mm pipe

4 mbar
Maximum permissible pressure drop on a U16 or G10 meter installation up to 28mm pipe

1 mbar
Purge Volume of either a E6, U6, or G4. Up to 28mm pipe.

0.01m3
Purge Volume of U16 or G10. pipe work larger than 28mm

1.5 IV
When should purging be carried out.

Immediately after a tightness test.

Test > Make safe > Purge

Or whenever a new installation has been installed or the pressure in an existing pipe has dropped down to atmospheric pressure.
Purging procedure
- Notify responsible person.
- Extinguish sources of ignition and ventilate area.
- Purge at end of pipe run.
- Test the purge point with LDF if necessary
- Check minimum purge volume has passed through the meter.
- Purge each branch in the pipework as above ensuring all appliances have been re-lit and a stable flame is achieved at each.

Author

zenken79

313262

Card Set

Tightness testing & Purging

Description

Tightness testing

Updated

2015-12-15T15:24:51Z

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