CENWAT Safety Devices and Regulations 2 — Questions and Answers
Question 1: Under Building Regulations, what is the requirement for carbon monoxide alarms when installing a new or replacement gas boiler?
- CO alarms are recommended but not required
- A CO alarm must be fitted in the same room as the boiler (Correct answer)
- CO alarms are only required in bedrooms
- CO alarms are only required for oil-fired boilers
Correct answer: A CO alarm must be fitted in the same room as the boiler
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?
- Light a match at the burner while slowly turning on the gas
- Open all downstream appliance valves and purge at a suitable point, ensuring adequate ventilation (Correct answer)
- Simply turn on the boiler and let it self-purge
- There is no need to purge a new gas installation
Correct answer: Open all downstream appliance valves and purge at a suitable point, ensuring adequate ventilation
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?
- 0.002
- 0.004
- 0.008 (Correct answer)
- 0.012
Correct answer: 0.008
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?
- Water spilling from the condensate pipe
- Whether combustion products are spilling from the draught diverter into the room (Correct answer)
- Gas leaking from the pipework
- Overflow on the feed and expansion cistern
Correct answer: Whether combustion products are spilling from the draught diverter into the room
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?
- Level with the ridge
- At least 600mm above the roof penetration point (Correct answer)
- 300mm above the roofline
- No specific requirement
Correct answer: At least 600mm above the roof penetration point
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.
Question 6: What is the engineer obligation under Gas Safe Register requirements regarding reporting of Immediately Dangerous situations?
- No notification is required, only the customer needs to be informed
- The engineer must report any Immediately Dangerous situation to Gas Safe Register within 28 days (Correct answer)
- Only fatalities need to be reported
- Only situations involving carbon monoxide poisoning need reporting
Correct answer: The engineer must report any Immediately Dangerous situation to Gas Safe Register within 28 days
Gas Safe registered engineers are required to report any Immediately Dangerous classified situation to Gas Safe Register within 28 days using the Gas Safe notification system. Gas Safe Register then reports to HSE. Failure to report can result in disciplinary action.
CENWAT Safety Devices and Regulations 2
Under Building Regulations, what is the requirement for carbon monoxide alarms when installing a new or replacement gas boiler?