Carbon Monoxide Awareness Week

Carbon Monoxide – What, where, how?

Carbon monoxide (CO) is a colourless, odourless, tasteless, poisonous gas produced by incomplete burning of carbon-based fuels, including gas, oil, wood and coal.

Anything that burns with a yellow flame produces Carbon Monoxide; fires, faulty gas appliances, candles, etc. Boat engines and generators also produce Carbon Monoxide.

CO can also be produced from the ashes from your fire, please ensure ashes are stored outside away from vents in a suitable container with a lid. Please see this form the BBC; Carbon monoxide warning over ash from stoves


Ensure all appliances are suitable and well maintained.

Sweep/clean flues regularly.

Ensure adequate ventilation.

Fit a suitable CO alarm, should conform to BS EN 50291-2 (BS EN 50291-1 alarms are not suitable for the marine environment).


Choosing the right Carbon Monoxide alarm? from Boat Safety Scheme on Vimeo.


Urban Myths

Carbon Monoxide is heavier than air.

NO, carbon monoxide is slightly lighter than air, Carbon monoxide is 28.01 g/mol and air varies from 29-32 g/mol, depending many factors including composition, temperature, elevation, humidity.  However two things to consider, firstly it is usually produce by fuel burning appliances, they produce hot gasses, hot air rises, second, it has been found that carbon monoxide mixes very well in air, with drafts etc. and will equalise throughout the boat.

It is CO (Carbon Monoxide) not CO2 (Carbon Dioxide).

Many people mix them up, CO2 can be dangerous at high quantities and is not good for the environment, but is generally harmless.

I don’t have any fuel burning appliances, i’m fine.

You can still get Carbon monoxide in you boat from you neighbours boat, engine, generator, etc.

All my appliances are Balanced flue (room sealed).

These type of appliances are safer than flue less or open flue, but only if maintained and checked regularly.

Symptoms of carbon monoxide poisoning

The symptoms of carbon monoxide poisoning are not always obvious, particularly during low-level exposure.

A tension-type headache is the most common symptom of mild carbon monoxide poisoning.

Other symptoms include:

  • dizziness
  • feeling and being sick
  • tiredness and confusion
  • stomach pain
  • shortness of breath and difficulty breathing

The symptoms of exposure to low levels of carbon monoxide can be similar to those of food poisoning and flu.

If you think you have been exposed to CO please seek medical advice from your GP or call 101, or you think you have been exposed to high levels go to your local A&E.

The Symptoms of Carbon Monoxide Poisoning from Boat Safety Scheme on Vimeo.


Positioning of a carbon monoxide alarm

For the best protection, follow the alarm manufacturer’s installation instructions as far as the space and nature of the boat allow.

But if the placement directions are difficult to meet on your boat, these are the ‘best practice’ points

Try to place the alarm:

  • in living quarters between 1m and 3m (on plan view) from the appliance
  • in living quarters fix alarms high up on a wall, but at least 150mm from the ceiling and where the indicator lights can be seen
  • in sleeping quarters have the alarm in the “breathing zone”, i.e. near the bed head
  • before fixing, test that you can hear an alarm from any position in the boat (or buy an additional alarm)

Don’t Forget to test them regularly, If it doesn’t work it can’t save your life!

This not meant to be a definitive guide to all things Carbon Monoxide, it is just to raise awareness.  This has been prompted by the numerous post I have recently seen on Facebook that could lead to a danger from Carbon Monoxide.

Please go to the Boat Safety Scheme website HERE. They have compiled wealth of information related to boats and CO from many expert organisations.