CENWAT Safety Devices and Regulations 2

Question 1

Under Building Regulations, what is the requirement for carbon monoxide alarms when installing a new or replacement gas boiler?

Accepted Answer

A CO alarm must be fitted in the same room as the boiler

Answer

Under the Building Regulations Approved Document J, a carbon monoxide alarm must be fitted in the same room as any new or replacement fixed combustion appliance (excluding gas cookers). The alarm must comply with BS EN 50291 and be positioned as per manufacturer instructions.

Question 2

What is the safe procedure for purging air from a gas installation before commissioning?

Accepted Answer

Open all downstream appliance valves and purge at a suitable point, ensuring adequate ventilation

Answer

Gas installations must be purged of air before commissioning by opening a suitable purge point downstream and allowing gas to displace the air. This must be done in a well-ventilated area with no ignition sources present. The volume of gas used for purging should not exceed 0.02 cubic metres.

Question 3

What is the maximum permissible CO/CO2 ratio from a natural gas appliance measured during combustion analysis?

Accepted Answer

0.008

Answer

The maximum permissible CO/CO2 ratio for a natural gas appliance is 0.008. If this ratio is exceeded, the appliance is not burning gas safely and must be investigated. If the fault cannot be corrected, the appliance must be classified under the GIUSP as either At Risk or Immediately Dangerous.

Question 4

What does a spillage test check for when commissioning an open-flued gas appliance?

Accepted Answer

Whether combustion products are spilling from the draught diverter into the room

Answer

A spillage test checks whether combustion products are being safely carried up the flue or are spilling into the room from the draught diverter. The test uses a smoke match held at the draught diverter after the appliance has run for approximately 5 minutes. If smoke is drawn into the flue, the test passes.

Question 5

What is the required clearance for a conventional open-flue terminal above the roof penetration point?

Accepted Answer

At least 600mm above the roof penetration point

Answer

An open-flue terminal must terminate at least 600mm above the roof penetration point. It must also be positioned with adequate clearance from the ridge. If within 1.5 metres horizontally of the ridge, it must be at or above ridge height. These requirements ensure adequate dispersal of flue products.

ACS CENWAT Practice Test

ACS CENWAT Practice Test

CENWAT Safety Devices and Regulations 2