Gas Safe ACS - Accredited Certification Scheme Chimney and Flue Systems Questions and Answers

Question 1

An engineer is installing a new, room-sealed, fanned-draught boiler.
According to BS 5440-1, what is the minimum horizontal distance required between the centre of the flue terminal and an opening window on the same wall?

Accepted Answer

300 mm

Answer

600 mm

Answer

150 mm

Answer

1200 mm

Question 2

When performing a spillage test on a conventional open-flued appliance, after allowing it to operate for an initial period, what is the minimum duration the smoke test should be observed at the draught diverter opening?

Accepted Answer

2 minutes

Answer

30 seconds

Answer

5 minutes

Answer

Until the smoke pellet is fully extinguished

Question 3

An engineer is assessing a masonry chimney for use with a new inset live fuel effect gas fire. Which of the following is a primary requirement before the appliance can be installed?

Accepted Answer

The chimney must be swept, and its integrity and suitability confirmed, being lined if necessary.

Answer

The chimney must be fitted with a specific anti-downdraught cowl.

Answer

The top of the chimney stack must be at least 1 metre higher than any neighbouring property's roof.

Answer

The chimney must have a minimum internal diameter of 200 mm throughout its entire length.

Question 4

While servicing a condensing boiler, an engineer finds that the plastic flue pipe runs through an unheated loft space but has not been insulated. What is the primary safety concern associated with this installation fault?

Accepted Answer

Condensate within the flue could freeze, leading to a blockage and appliance shutdown or malfunction.

Answer

The flue pipe may become brittle and crack due to UV light exposure.

Answer

The uninsulated pipe will cause excessive heat loss from the property.

Answer

The noise of the condensate running down the pipe will be unacceptably loud.

Question 5

An engineer is called to a property where the homeowner reports fumes from an open-flued gas fire. The engineer finds the flue is completely blocked by a bird's nest. How should this situation be classified according to the Gas Industry Unsafe Situations Procedure (GIUSP)?

Accepted Answer

Immediately Dangerous (ID)

Answer

At Risk (AR)

Answer

Not to Current Standards (NCS)

Answer

Requires Specialist Investigation (RSI)

Question 6

What is the defining characteristic of a 'room-sealed' gas appliance?

Accepted Answer

Its combustion circuit (air intake and flue outlet) is sealed from the room it is installed in.

Answer

It must be installed in a room with a permanent, sealed air vent to outside.

Answer

All of its external joints and seams are sealed with a high-temperature waterproof sealant.

Answer

It can only be installed in rooms with a volume greater than 10 cubic metres.

An engineer is installing a new, room-sealed, fanned-draught boiler.According to BS 5440-1, what is the minimum horizontal distance required between the centre of the flue terminal and an opening window on the same wall?

An engineer is installing a new, room-sealed, fanned-draught boiler.
According to BS 5440-1, what is the minimum horizontal distance required between the centre of the flue terminal and an opening window on the same wall?