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Last edited 07 Jan 2019
Carbon monoxide in buildings
Carbon monoxide (CO) is a colourless, tasteless and odourless gas that is highly poisonous. It can cause serious damage to health if inhaled over a long period, and can quickly cause neurological damage, paralysis or death. Carbon monoxide poisoning is estimated to kill approximately 40 people a year in the UK, and to result in 1,100 hospital admissions, with children most at risk.
When carbon monoxide gas is breathed in it gets into the blood stream and behaves like oxygen, attaching itself to red blood cells which can then no longer carry oxygen. This leads to oxygen starvation and causes the cells and tissues to die.
Symptoms of carbon monoxide poisoning can include:
- Drowsiness, dizziness or loss of consciousness.
- Nausea or vomiting.
- Stomach or chest pains.
- Visual problems.
- Flu-like complaints.
Carbon monoxide is produced when a combustion appliance, such as a boiler, heater, oven, and so on, does not completely burn a carbon-based fuel. This might include fuels such as; gas, oil, paraffin, coal, wood or charcoal. Typically, fuel might not be completely burned if an appliance has been incorrectly installed or maintained or if vents chimneys or flues are blocked. It may also enter a property through shared chimneys or flues.
It is important to ensure that appliances are properly installed by suitably qualified installers (such as a HETAS approved installer or a Gas Safe Registered engineer), and that they are regularly serviced and maintained. Landlords are required to maintain gas appliances and to have annual gas safety checks carried out. The fire service recommend that householders do not use appliances such as paraffin heaters, BBQ’s or cabinet heaters in their homes.
- Increased levels of condensation.
- Problems with pilot lights.
- Soot or yellow-brown staining on or around appliances.
- Yellow or orange flames rather than blue flames.
In addition, the presence of carbon monoxide can be identified by carbon monoxide detectors. These can be standalone units, or combined units that also operate as smoke detectors. Typically, an audible alarm is sounded if carbon monoxide is detected.
For more information, see Carbon monoxide detector.
From 2010, the building regulations have required carbon monoxide alarms when solid fuel burning appliances are installed. In 2015 the government introduced new regulations requiring private rented sector landlords in England to have a carbon monoxide alarm in any room used as living accommodation where solid fuel is used. Detectors must be tested at the start of each tenancy, and penalties for failure to comply can be up to £5,000.
Detectors should have a EN 50291 mark and a British Standards' Kitemark (or equivalent European mark). They should be installed in accordance with manufacturers’ instructions, typically at head height in each room with a combustion appliance. They should be tested regularly, and batteries replaced as required. Ideally they should give a warning when batteries are approaching the end of their life.
In April 2018, the government announced it was undertaking a review of rules that require carbon monoxide alarms to be fitted in homes across England when solid fuel appliances such as wood burning stoves and boilers are installed.
The review will examine the regulations to establish whether they remain fit for purpose and will consider new research into the number of carbon monoxide poisonings and whether the rate of installation is being affected by the cost of alarms.
 Find out more
 Related articles on Designing Buildings Wiki
- Carbon dioxide.
- Carbon monoxide detector.
- Combustion appliance.
- Fire and rescue service.
- Fire dampers.
- Fire detector.
- Fire detection and alarm system.
- Fire door inspection scheme.
- Fire protection engineering.
- Gas Safe.
- Heat alarm.
- Intruder alarm.
- Ionisation smoke alarm.
- Multi-sensor alarm.
- Nitrogen dioxide.
- Project SHOUT.
- Smoke damper.
- Smoke detector.
- Types of domestic boiler.
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