Tightness Testing & Purging Flashcards

Which instrument is typically used to perform a tightness test on a domestic gas installation?

Answer: U-gauge manometer

A U-gauge manometer is used because it can detect very small pressure changes that would indicate a gas escape from the installation.

At what pressure should a tightness test be conducted on a domestic natural gas installation?

Answer: Working pressure (approximately 21 mbar)

Tightness tests are performed at working pressure (approximately 21 mbar for natural gas) to replicate actual operating conditions.

How long should the final tightness test period last after stabilisation for a standard domestic installation?

Answer: 2 minutes

The final test period is 2 minutes after the stabilisation period, as specified in IGEM/UP/1B for standard domestic installations.

What constitutes a satisfactory result during a domestic gas tightness test?

Answer: No pressure drop at all

A satisfactory tightness test requires zero pressure drop, as any fall in pressure indicates gas is escaping from the installation.

What is the purpose of the stabilisation period before the final tightness test reading is taken?

Answer: To allow temperature and pressure to equalise

The stabilisation period allows temperature-related pressure fluctuations to settle so that accurate and reliable readings can be taken.

What position should all appliance isolation valves be in during a tightness test?

Answer: Closed, isolating all appliances from the pipework

All appliance isolation valves must be closed so the tightness test checks the integrity of the pipework only, not the internal components of appliances.

Which of the following would indicate a failed tightness test?

Answer: The U-gauge shows a pressure drop during the test period

A pressure drop on the U-gauge during the test period indicates gas is escaping from the installation, meaning the tightness test has failed.