CCN1 Pipework Installation & Tightness Testing 2

Question 1

What is the purpose of a gas meter bypass?

Accepted Answer

It is not a legitimate installation component — a bypass around a gas meter is illegal as it allows gas use without metering

Answer

There is no legitimate purpose for a bypass around a gas meter in a domestic installation. Creating or using a meter bypass is a criminal offence as it enables theft of gas and creates serious safety risks.

Question 2

What is a 'pressure governor' (regulator) in a domestic gas installation and where is it located?

Accepted Answer

A device that reduces the high pressure from the gas main to the lower working pressure (typically 20-21 mbar) required by domestic appliances — located at or in the meter assembly

Answer

The pressure governor (regulator) is part of the meter assembly. It reduces the gas supply pressure from the higher distribution main pressure to the lower working pressure (approximately 20-21 mbar) required by domestic appliances.

Question 3

What must a Gas Safe engineer check when installing new gas pipework?

Accepted Answer

That it is correctly sized, properly supported, uses approved materials and jointing methods, is tested for tightness, and is correctly identified

Answer

New pipework installation requires correct sizing, proper mechanical support at specified intervals, use of approved materials and jointing methods, a tightness test of the completed pipework, and correct identification (labelling or marking).

Question 4

What is the correct jointing method for copper gas pipework?

Accepted Answer

Compression fittings or capillary (solder) fittings approved for gas use — never push-fit plastic fittings

Answer

Copper gas pipework may be joined with compression fittings or capillary solder fittings that are approved for gas use. Push-fit plastic fittings approved for water are NOT suitable for gas. Approved fittings must carry the relevant British Standard marking.

Question 5

At what intervals must copper gas pipework be supported (clipped) in a domestic installation?

Accepted Answer

Every 1.2 metres for horizontal runs and every 1.8 metres for vertical runs (15 mm copper) — per BS 6891

Answer

BS 6891 specifies support intervals for domestic gas installations. For 15 mm copper pipe, supports are required at maximum 1.2 m intervals on horizontal runs and 1.8 m on vertical runs. Correct support prevents sagging and joint stress.

ACS CCN1 Practice Test

ACS CCN1 Practice Test

CCN1 Pipework Installation & Tightness Testing 2