CCN1 Pipework and Fittings

Question 1

What is the standard working pressure for natural gas supplied to domestic properties in the UK?

Accepted Answer

21 mbar

Answer

11 mbar

Answer

35 mbar

Answer

75 mbar

Question 2

When carrying out a tightness test on a domestic gas installation, how long must the test be conducted for using a U-gauge?

Accepted Answer

2 minutes

Answer

30 seconds

Answer

1 minute

Answer

5 minutes

Question 3

What is the maximum permissible pressure drop on a let-by test of a gas meter?

Accepted Answer

Zero — no drop is acceptable

Answer

0.5 mbar

Answer

1 mbar

Answer

2 mbar

Question 4

What material is most commonly used for domestic gas installation pipework in the UK?

Accepted Answer

Copper to BS EN 1057

Answer

Plastic PVC

Answer

Stainless steel

Answer

Cast iron

Question 5

When installing gas pipework, what is the minimum distance it should be kept from electrical cables where they run parallel?

Accepted Answer

25 mm

Answer

10 mm

Answer

50 mm

Answer

150 mm

Question 6

What type of joint is NOT permitted for use on gas pipework concealed within a wall cavity?

Accepted Answer

Compression joints

Answer

Soldered capillary joints

Answer

Brazed joints

Answer

Welded joints