CCN1 Flue Systems and Chimneys 2

Question 1

What is the minimum distance a balanced flue terminal must be from an opening window, air vent, or other opening into a building?

Accepted Answer

300 mm

Answer

100 mm

Answer

200 mm

Answer

600 mm

Question 2

What material is commonly used for flexible flue liners in gas installations within masonry chimneys?

Accepted Answer

316 grade stainless steel

Answer

Plastic PVC

Answer

Aluminium alloy

Answer

Galvanised mild steel

Question 3

When installing a vertical flue from a gas boiler through a flat roof, what is the minimum height the flue terminal must extend above the roof surface?

Accepted Answer

600 mm

Answer

150 mm

Answer

300 mm

Answer

At least 250 mm above the highest point of the roof penetration

Question 4

What is the purpose of a flue gas analysis test carried out during commissioning of a gas boiler?

Accepted Answer

To measure the carbon monoxide, carbon dioxide, and flue gas temperature to verify safe and efficient combustion

Answer

To check the gas supply pressure

Answer

To test the condensate drainage system

Answer

To verify the electrical connections are correct

Question 5

When a chimney serves an open-flued gas fire, what test must be carried out to confirm the chimney is safe to use?

Accepted Answer

A smoke test (flue integrity test) and spillage test

Answer

A pressure test at 200 mbar

Answer

An electrical continuity test

Answer

A water flow test

Question 6

What component must be fitted where a gas flue pipe passes through a combustible material such as a timber floor or wall?

Accepted Answer

A fire-resistant sleeve with a minimum 25 mm air gap

Answer

A gas isolation valve

Answer

A condensate trap

Answer

A pressure relief valve