An Introduction To Carbon Monoxide

Carbon Monoxide has been part of a Gas Safe Awareness campaign in the news recently as “the silent killer” but what exactly is it and what can you do for your customers?

What is Carbon Monoxide?

Carbon monoxide (CO) is a tasteless, colourless, odourless,poisonous gas produced when burning fossil fuels such as gas, oil, wood and coal.

Normally most of the CO is burnt off but if the fuel does not burn properly excess CO is produced.

CO has no smell or taste and cannot be seen but it is poisonous as when it enters the body it prevents your blood from getting oxygen to your cells tissues and organs.

Although it is a killer even in low levels that do not kill it can cause serious harm to health when breathed in over a long period of time.

Some long term effects of exposure include Paralysis and brain damage.

However even short term inhalation include –

  • headaches
  • dizziness
  • nausea
  • breathlessness
  • collapse
  • loss of consciousness

Carbon monoxide symptoms are very similar to flu, food poisoning, viral infections and simply tiredness.

What can I do for my Customers?

Gas Safe and the Health and Safety Executive both advise 2 steps your customers should take to reduce the risk of CO poisoning –

1. Making sure that fossil fuel burning appliances (and flues) are regularly checked by competent engineers which should be you.

2. And secondly fitting a CO alarm near the appliance and/or flue.

Interesting note – In Northern Ireland fitting a CO alarm is mandatory however in England and Wales only the 2010 Building Regulations Part J states carbon monoxide alarms need only be fitted in the same room as new or replacement solid-fuel heating appliances. 

What is a CO Alarm?

A CO Alarm is similar to a smoke alarm except that it alerts you to the presence of carbon monoxide (a smoke alarm will alert you to smoke and NOT carbon monoxide).

They are small battery operated units normally with a guarantee of 5 years which are mounted or sit near a gas appliance.

They only need to be periodically checked to make sure the battery is still operating, just like a smoke alarm.

What alarm should I fit for my customers?


Gas Safe Register recommends the use of audible carbon monoxide alarms.

It should have the British Standards’ Kitemark or another European approval organisation’s mark on it and be marked to EN 50291 standards.

We supply the leading brands such as Honeywell XC70 or Fire Angel which are both rated at and above the relevant standards.

Next time you are in the shop, pop-in and we can show you the units and prices.

Where should the Co alarm be fitted?

The recommendation is to fit an alarm in each room with a gas appliance and to always follow the alarm manufacturer’s instructions on siting, testing and replacing the alarm.

It is important to choose an alarm that will wake your customers up if they’re asleep, or they may not be aware of early CO symptoms until it is too late.

Is there anything I can do now that might indicate potential problems?

There are signs that you can ask your customers that could point to carbon monoxide poisoning if they feel unwell and

  • Their symptoms only occur when you are at home
  • Their symptoms disappear or get better when they leave home and come back when they return
  • Others in their household are experiencing symptoms (including your pets) and they appear at a similar time

What can I advise to my customers if they experience any symptoms of carbon monoxide poisoning?

  1. Get fresh air immediately. Open doors and windows, turn off gas appliances and leave the house.
  2. See your doctor immediately or go to hospital – let them know that you suspect carbon monoxide poisoning. They can do a blood or breath test to check.
  3. If they think there is immediate danger, call the Gas Emergency Helpline.

AND – Get you to inspect their gas appliances and flues to see if there is a dangerous problem.



  1. Meet Honeywell's newest CO Alarm. - Stevenson Sales - April 22, 2015

    […] A few months ago I introduced the hazards and dangers of Carbon Monoxide in my post imaginatively titled – An Introduction to Carbon Monoxide. […]

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