ACS Tightness Testing & Purging

Question 1

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

Accepted Answer

U-gauge manometer

Answer

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

Question 2

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

Accepted Answer

Working pressure (approximately 21 mbar)

Answer

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

Question 3

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

Accepted Answer

2 minutes

Answer

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

Question 4

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

Accepted Answer

No pressure drop at all

Answer

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

Question 5

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

Accepted Answer

To allow temperature and pressure to equalise

Answer

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

Gas Safe ACS Practice Test