Carbon monoxide poisoning

What is it ?

Carbon monoxide is a poisonous gas. It can be given off by appliances that burn fossil fuels such as gas, coal, wood or oil, if they're not working properly, if the flue is blocked in any way, or if the room is not properly ventilated.

Why is it so dangerous ?

Carbon monoxide is odourless, colourless and tasteless, which makes it difficult to detect. However its effects are deadly. On average, 50 people a year are killed by carbon monoxide poisoning due to faulty heating appliances.

What are the main causes of carbon monoxide poisoning ?

Most cases of carbon monoxide poisoning are due to inadequate ventilation or poor maintenance of appliances, blocked or leaky flues and chimneys. Chimneys can become blocked for various reasons. It could be as a result of birds nesting on the chimney, or possible degradation of the flue. A blocked flue can lead to carbon monoxide leaking into your home.

Who is most at risk ?

Some people mistakenly think that it is only gas fuelled heating systems which can cause carbon monoxide poisoning - in fact, it can happen with any fossil fuel system if the system, which included both the appliance and the flue, is faulty or the room is not properly ventilated. Also, some people associate carbon monoxide poisoning with rented accommodation - in fact, more people are killed in owner occupied rather than rented properties.

Carbon monoxide poisoning

A typical scenario is a living room with a solid fuel heater. The windows and doors have been draught proofed and the permanent ventilation has been blocked up (by the victim) to prevent draughts. The chimney and flue have not been swept for years. The victim may not have carried out the regular maintenance of their appliance, like cleaning the throat plate monthly, let alone had the appliance serviced professionally. There may be soot deposits at the appliance outlet, or bits of the flue lining may have broken away and tumbled down to the appliance outlet. The weather is cold and the fire is not drawing well, so the victim opens the fire door to get more heat. This compounds the problem. The victim becomes drowsy, falls asleep, and doesn't wake up again.

The danger signs

Carbon monoxide may be present if there are any of the following danger signs:

  • Gas flames that normally burn blue burn orange or yellow instead.
  • Sooty stains appear on or just above appliances, regardless of the fuel being burnt.
  • Coal or wood fires burn slowly or go out.
  • The fire is difficult to light.
  • The room is not properly ventilated.
  • The chimney or flue is blocked - watch out for smoke in the room.
  • You develop the following unexplained symptoms:
    • tiredness
    • drowsiness
    • headaches
    • dizziness
    • chest pains
    • nausea

Key Safety Messages & Facts

Carbon monoxide can result from burning all fossil fuels - not just gas fires and boilers.

It is important to ensure rooms are ventilated - never block vents. If double glazing or draught-proofing is fitted, make sure there is still enough air circulating for any heaters in the room.

Portable heaters do not need a flue, but they still need good ventilation.

Make sure that all chimneys and flues are regularly swept by a competent sweep and kept clear. This includes chimneys being used as flues for gas fires, but is particularly important for solid fuel appliances.

Boilers and heating systems and appliances should be installed, maintained and regularly serviced by a competent engineer (make sure they are CORGI-registered for gas appliances).

If you have recently moved, check when your boiler or heating appliances were last serviced.

Gas flames burning orange or yellow instead of blue may indicate the presence of carbon monoxide.

Carbon monoxide detectors should comply with British Standard BS 7860 - but remember they are only warning devices. Never rely on them entirely and do not use them as a substitute for regular servicing.

Never cook on a barbecue indoors - the charcoal gives off carbon monoxide.

If you develop any of the following unexplained symptoms - drowsiness, headaches, chest pains, giddiness, sickness, diarrhoea, stomach pains - you could be suffering from carbon monoxide poisoning. Switch off your appliances and see your doctor at once.

Safety Warnings

If your fire starts to burn more slowly than usual or fumes and smoke start to build up in the room instead of going up the chimney, open doors and windows and let the fire go out. Seek professional advice before relighting.

Safe use of gas fires

Gas appliances operate safely when they are installed, operated and maintained correctly.

It is best only to buy appliances from reputable dealers. Make sure they meet the appropriate British or European Safety requirements. Avoid buying second-hand appliances if you can. If you do buy second-hand, choose appliances that have been tested for safety. Insist on a written guarantee from the dealer and a copy of the user instructions. Never install or reconnect a gas appliance yourself.

By law, gas appliances must be fitted and maintained only by an installer who is registered with CORGI (Council for Registered Gas Installers). If the appliance is fitted to an existing chimney, this should first be swept. Any newly installed appliance in a bathroom must be of the room-sealed type.

When installing a gas fire of 14 kilowatts input or less in a bedroom it must either have a spillage safety device or be room-sealed. If it is larger than 14 kilowatts input it must be room-sealed.

Have all your gas appliances serviced regularly by a Corgi registered installer - once a year for gas fires and boilers. Ensure this includes a safety check to make sure flues are working properly.

Ventilation is vital. All fuel uses up fresh air as it burns and gives off waste gases. Gas appliances need fresh air to burn properly. Never block or obstruct any vent. If your appliances are fitted with balanced flues, make sure the grille outside is kept clear. Where appliances require flues, removal of waste gases is essential.

Safe use of portable gas heaters

Cylinder gas (liquefied petroleum gas/LPG) is used to fuel powerful domestic heaters in houses, boats, caravans and mobile homes. Portable heaters do not need flues but they do need a lot of air. They should not be used in confined spaces with poor air circulation.

All new portable cabinet heaters made to British Standards BS 5258 Parts 10, 11 and BS EN449 are fitted with a special safety device that cuts off the gas supply if the room gets too stuffy. Other portable heaters, designed for outdoor activities, have no such device and must not be used in confined spaces.

  • Choose an appliance that meets the British or European safety standard.
  • Avoid buying secondhand.
  • Get Corgi-registered installer to install and check new appliances.
  • Follow the manufacturer's instructions.
  • Have your appliances regularly serviced by an engineer who is registered with CORGI.
  • Make sure there is enough air coming into the room - by not blocking or obstructing vents.
  • Keep portable heaters clear of furniture, bedclothes and curtains.
  • Do not use a portable heater for drying clothes.

Changing gas cylinders:

  • Do it in the open air. If this is not possible, open windows and doors to increase ventilation. Never change the cylinder on a stairway or other escape route.
  • Extinguish all sources of ignition such as cigarettes and pilot lights. If you are indoors, turn off other heaters and electrical appliances.
  • Make sure the valve on the empty cylinder is closed before disconnecting the heater. Do not open the valve on the new cylinder until the connection to the heater is secure.
  • Look for any gas leaks by brushing soapy water onto the flexible hose and fittings and looking for bubbles. If you find a leak, take the heater and cylinder into the open air, and do not use either until the faulty part is replaced.
  • Store spare cylinders upright, and outside wherever possible. Never store them in basements, near drains, under the stairs or in a cupboard containing electricity meters or electrical equipment.

Safe use of paraffin heaters

Paraffin heaters are safe when used properly and sensibly. Choose a new heater that meets British or European safety standards. Wherever possible avoid buying second-hand.

  • Follow the manufacturer's instructions carefully.
  • Never refill with paraffin while the heater is alight.
  • Make sure there is plenty of air coming into the room.
  • Keep heaters away from doors and direct draughts.
  • Check all parts regularly and remove any build-up of dust, which could restrict the air flow.
  • Check regularly to make sure the wick has not become choked or dirty. When necessary, trim it with the special wick cleaner provided. If you do not have one, ask at the shop where you buy your wicks.
  • When buying paraffin, look for the special symbol with the number BS 2869 CI on the pump or tank. Using this paraffin will help to ensure that your heater works safely.

When refilling the heater:

  • Extinguish the heater and let it cool first.
  • Where possible, refill the tank outside.
  • Refill to just below the maximum level, to allow for expansion when the paraffin warms up.
  • Never allow the paraffin to overflow or drip onto the floor - clear up any spills immediately.
  • Before lighting, make sure the heater is standing level, preferably on a non-combustible base, and away from draughts.
  • Store spare fuel outside the home, and try not to store more than 9 litres (2 gallons). Keep the fuel in purpose-made containers away from sources of heat.

Safe use of oil-fired heaters

Oil-fired heaters with chimneys or flues need air to allow them to work properly. Make sure that air can enter the room.

  • Get a reputable company to install your oil-fired heater or boiler.
  • Read and follow the manufacturer's instructions.
  • Get your appliance serviced regularly by an experienced engineer. This should include a safety check to make sure that chimneys and flues are not blocked.
  • Do not try to adjust gauges and instruments yourself.

Safe use of wood-burning stoves and boilers

Wood-burning stoves and boilers should only use the right quality of wood. They need to be properly maintained and regularly serviced.

  • Get a competent person to install the stove or boiler, following the manufacturer's instructions and the building regulations and code of practice.
  • Make sure there is enough air coming into the room.
  • The wood should be dry and well seasoned - this usually takes about two years. A well-seasoned log has drying out splits in the ends. Never use wet or newly felled wood as this can cause tar or creosote to form in the wood burner and chimney.
  • If the wood burner has been used slowly (overnight, for instance), this should be followed by a period of faster burning to dry out any creosote and to warm up the chimney again.
  • Get the chimney cleaned at the end of each heating season and at least once during the heating season. Get it inspected regularly.

Portable heaters

Place heaters where they will not be knocked or tripped over. Do not put them where objects will fall on them.

  • Make sure heaters are well clear of curtains, furniture and bedding.
  • Do not move a heater while it is alight and switched on.

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