Carbon Monoxide.

Original Article
November 10th, 2019


Carbon monoxide is tasteless, odourless and colourless, but it can cause danger and even kill. In recent news it has been reported that footballer Emiliano Sala, who tragically died when the plane he and pilot David Ibbotson were on crashed whilst flying over the Channel Islands, had high levels of carbon monoxide in his blood after toxicology tests were carried out. Experts suggest it is likely he was unconscious before the plane crashed, and it is likely pilot David, whose body has not yet been found, was also exposed to high levels of the toxic gas. In this article, we will review the dangers of carbon monoxide, what appliances in our homes could potentially pose a risk, and the relevant building regulations.

An overview 

Carbon monoxide (CO) is produced from partial oxidation of carbon containing compounds, including when fuels such as wood, coal, oil or natural gas are burned. It is present in the air around us because of the activities we carry out such as driving or for heating or cooking and even from smoking. Out in the open air, the level of CO is less concentrated and therefore not as dangerous, but high, concentrated levels in enclosed spaces pose a dangerous risk to humans and animals.

When inhaled, carbon monoxide will attach itself to the molecule (haemoglobin) that usually carries oxygen to our blood and vital organs – the more CO that is inhaled, the bigger the build-up of CO and the more we are deprived of oxygen, resulting in asphyxiation which can lead to unconsciousness and even death.

According to the National Office of Statistics, in 2017 there were 59 deaths in the UK due to accidental carbon monoxide poisoning. This is an increase compared to 49 in 2016 and 53 in 2015.

Symptoms of CO poisoning can include:

•          Tension-type or dull headache (common in mild cases)

•          Dizziness

•          Feeling and being sick

•          Tiredness and confusion

•          Stomach pain

•          Shortness of breath and difficulty breathing

•          Blurred vision

CO dangers in the home

As we burn fuels in our homes, there are appliances that could pose a risk to occupants. In our previous technical bulletin, we included an article on dangerous gas appliances and how to identify them which you may find useful (read here). Boilers, gas and solid fuel fires, woodstoves, gas or kerosene heaters, water heaters, gas or charcoal stoves or grills or gas tumble dryers could potentially have a carbon monoxide leak and therefore could be a danger in the home. Tell-tale signs that an appliance is faulty are:

•          A yellow/orange colour flame as opposed to a crisp blue flame

•          Soot or yellow/brown stains around the appliance

•          Flickering or frequently blowing out pilot lights

•          Condensation on windows (a higher amount than usual)

Regulations and requirements

As professionals in the property industry, we have a duty of care to tenants and owners of the properties we inspect. It is, therefore, important to understand the laws and regulations around health and safety requirements to ensure the correct information is shared to those who may be at potential risk.

Building Regulations

Carbon monoxide is considered in Part F (ventilation) and Part J (combustion appliances and fuel storage systems) of the Building Regulations.

Part F lists the performance criteria for buildings which includes the levels that exposure to carbon monoxide should not be exceeded – see figure 1.

Figure 1

In Part J, an addition was made in 2010 to include a new requirement, “Warning of release of carbon monoxide”, which states, “Where a fixed combustion appliance is provided, appropriate provision shall be made to detect and give warning of the release of carbon monoxide.” It’s noted that whilst carbon monoxide alarms are required for solid fuel appliances, alarms can still reduce the risk of poisoning from other types of appliance.

Requirements of Gas Safe professionals 

Appropriately qualified professionals in the industry are also required to follow various legislation such as The Gas Safety (Installation and Use) Regulations and the Gas industry unsafe situations procedure, which we touched on in our previous article. The latter is a useful document in terms of referencing and advising on appropriate actions when faced with potential carbon monoxide poisoning. Incidentally, regardless of whether you are a Gas Safe professional or not, in the event that you are faced with a situation which you suspect may be creating spillage of the products of combustion into a living area, then you should immediately cut off the gas supply from the emergency control (with the occupier’s permission), evacuate the premises immediately to a safe, open-air environment and inform the gas transporter on 0800 111 999.


When renting out properties, landlords need to ensure they meet the minimum requirements. They must ensure gas appliances are in a safe condition, fitted or repaired by a Gas Safe engineer and checked every 12 months by a Gas Safe registered engineer. This includes pipework, boilers, fires and water heaters as well as cookers. Whilst tenants are responsible for any gas appliances they own, the landlord will be responsible for any flues, pipework or the chimney they may be connected to. The landlord is responsible for installing carbon monoxide detectors in rooms with a coal fire or wood burning stove at the start of the tenancy. Following this, the tenant is responsible for checking they are working after the tenancy has started and must notify the landlord if they stop working, who will then arrange for replacement batteries or a new detector.


For a condition survey, surveyors are required to report on heating and the gas supply if applicable, so surveyors should become familiar with the requirements necessary to report appropriately within the limits of the survey type commissioned.

If the surveyor has not seen and taken evidence of a recent gas safety certificate for the property, the gas should automatically be given a condition rating 3, advising the client that a recent gas safety certificate should be obtained by an appropriately qualified professional to ensure the gas appliances are safe.

With regards to carbon monoxide alarms, although it is not a mandatory requirement to have a carbon monoxide detector where gas appliances are present, it is recommended. It would, therefore, be advisable to include in the survey if no carbon monoxide detectors could be seen during the inspection. You should also be aware of the British Standards which relate to installed CO detectors:

BS EN 50292:2013 states that carbon monoxide alarms should be:

•          Placed in the same room as fuel-burning appliances (either wall or ceiling mounted), such as an open fire, gas cooker or boiler

•          Fitted in rooms where people spend the most time, such as living rooms

•          Located in bedrooms in addition to the above, relatively close to the breathing zone of the occupants

•          Fitted in any room that has a flue running through it

•          Placed at least 300mm from any wall (for ceiling mounted alarms)

•          Placed at least 150mm from the ceiling, above the height of any door or window (for wall mounted alarms)

•          Between 1 and 3m (measured horizontally) from the potential source of CO

The British Standard EN 50292 also recommends that an alarm is not fitted:

•          Where it can be obstructed

•          In an enclosed space

•          Directly above a sink

•          Next to a door, window, extractor fan, air vent or similar ventilation opening

Here are some examples showing appliances with signs of spillage of the products of combustion:

Figure 1 – signs of spillage on the fireplace mantle 

Figure 2 – signs of spillage above the open fireplace

Figure 3 – yellow flame indicates a combustion issue

In 2006 a 14-year-old girl from Cwmbran in Wales and the family dog tragically died following the installation of a flueless gas fire. The installation was carried out by a CORGI-registered engineer; however, he was not appropriately qualified to install that particular appliance. The court heard that the engineer failed to check that the gas pressure on the appliance was set to the correct level, resulting in a leak. Two days after the appliance was installed, the teenager’s mother returned home from work and found their dog had died in the hallway and her daughter had died in her bedroom. Both deaths were the result of carbon monoxide poisoning.

To take away

Although carbon monoxide detectors are not required by law for every property, there still seems to be a lack of awareness from the public about the potential danger carbon monoxide can bring, and how it can become present in a property. If a carbon monoxide detector is not present, there is no harm in bringing this to the occupier or future occupier’s attention and, of course, appropriate advice should be given regarding gas safety checks. We strongly feel that any professional working in the property industry must not only understand the requirements but also the dangers of carbon monoxide poisoning and how tragedies such as the case mentioned can be avoided by following simple steps, relaying the appropriate information and educating those around us.