Carbon Monoxide Detectors

We all know it makes sense to have carbon monoxide detectors fitted; it’s one of those jobs on the to-do list that all too often gets forgotten.

Carbon Monoxide is produced when fuels such as gas, oil, coal and wood do not burn fully. Burning charcoal, running cars and the smoke from cigarettes also produce carbon monoxide.

Gas, oil, coal and wood are sources of fuel used in many household appliances including:

  • boilers
  • gas fires
  • central heating systems
  • water heaters
  • cookers
  • open fires

The main causes of carbon monoxide poisoning are outlined below.

Poorly installed or maintained appliances

Incorrectly installed and badly maintained household appliances, such as cooking and heating devices, are the main cause of accidental exposure to carbon monoxide. Correctly fitted and well maintained appliances should produce very little CO gas. Damaged appliances can also produce higher levels of CO gas than normal and become dangerous.

Blocked flues and chimneys

Blocked flues and chimneys can stop CO gas escaping, allowing it to build up to dangerous levels in a room.

Enclosed or unventilated spaces

Burning fuel in an enclosed or unventilated space increases the risk of CO poisoning. For example, a car engine left running inside a garage or a faulty heating boiler in a poorly ventilated kitchen can emit potentially lethal levels of CO gas.
A car left running in a closed garage will take around 10 minutes to build up a lethal level of CO gas.

What the Regulatory Bodies have to say about carbon monoxide detectors…

Picture1Gas Safe Register recommends the use of audible carbon monoxide alarms marked with British Standard EN 50291. It should also have a British or European approval mark, such as a Kitemark.



HSE strongly recommends the use of audible carbon monoxide (CO) alarms as a useful back-up precaution but they must not be regarded as a substitute for proper installation and maintenance of gas appliances by a Gas Safe Registered engineer.



Building Regulations Approved Document J requires a CO alarm to be installed when a new solid fuel appliance is installed or when an existing one is replaced



Picture4Building Regulations Technical Booklet L requires the installation of a CO alarm when any fuel burning appliance is installed






Example 1 of a Carbon Monoxide Tragedy


  • Gas boiler failed to ignite and build up of gas in firebox.
  • Boiler ignited, a small explosion resulted in the flue being displaced.
  • Exhaust gases escaped into the boiler room
  • Fumes leaked into two bedrooms above
  • One man died and there was also a near miss.

A CO alarm would almost certainly have saved them.

Example 2 of a Carbon Monoxide Tragedy

  • A flue leading from a boiler had been fixed just below the bathroom
    window of a seaside hotel bedroom.
  • The window had been screwed down but was later undone – fumes entered the bedroom
  • 1 man died from CO poisoning
  • Flue and terminal were installed in the wrong place and in the wrong way.
  • Two employees of the installer company were charged with manslaughter and received fines.
  • Statements from family included …“We hope everyone who reads this will buy a carbon monoxide alarm and pass the message on.”

Carbon Monoxide Poisoning…. why risk a tragedy?

You can arrange the installation of carbon monoxide detectors for when our engineers are onsite carrying out another service. This way it’s cheaper and means another job gets ticked off the ‘to do list’!

We have a range of detectors, from mains wired to battery and battery with radio link. In some cases we can add detectors to your building’s fire alarm.

Contact us and speak to a member of the team, to discuss your requirements and arrange installation.