Conducting a tightness test on gas pipework is essential as part of general health and safety when working with gas appliances. Your first step before beginning any tightness testing is ensuring that the appliance you are working on is turned off and that any gas isolation valves are set to open.
How can you conduct a tightness test
You'll need to connect up a U-Gauge to your gas meter in order to conduct any relevant tests. The U-Gauge itself must be equipped with a hose that can be connected to the test nipple on your gas meter.
Step 1: Switch off your Gas supply via the Emergency Control Valve (ECV) located on your meter.
Step 2: Unscrew the test nipple and connect the U-Gauge hose
Step 3: Test for for let-by. To do this you'll need to:
- Pull the ECV bar up so that the level on your U-Gauge reads between 7-10 millibar
- Monitor for 1 minute to ensure that water within the gauge doesn't rise or fall.
If the water rises this would suggest there is let-by. Ensuring that you have some Temporary Continuity Bolts (TCP) connected to the unit, you would need to use Leak Detection Fluid (LDF) around the meter and pipes to test for leaks. If fluid is applied and you can see bubbles, this would then need to be looked at by your Gas Transporter.
If the water drops this would suggest a gas leak somewhere in the property, which would need tracing and repairing.
Step 4: Conduct a temperature stabilisation
- Raise the ECV bar up to 20 millibar
- Leave for 1 minute.
- If the water in the U-Gauge rises or falls during the minute, just adjust the ECV bar to bring the level back to 20 millibar.
Step 5: Continue with the tightness test once temperature stabilisation is complete. Over a 2 minute period this will involve checking and monitoring the whole installation inside the house while appliances are connected. Depending on the type of gas meter installed, you should do the following.
Tightness test with a G4 Gas Meter: Ensure that the U-Gauge doesn't drop by more than 4 millibar from 20 and check for smell of gas.
Tightness test with a E6 Gas Meter: Ensure that the U-Gauge doesn't drop by more than 8 millibar from 20 and check for smell of gas.
Step 6: Return ECV to off and reattach test nipple. Finish by spraying the meter and pipework with LDF before switching the gas back on.
Our Knowledge Hub video below provides a practical demonstration of the steps highlighted in this article.
