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7. Carbon Monoxide Information
Those involved in the installation or use of wood burning Stoves, should take the risk of carbon
monoxide poisoning seriously; otherwise the results can be dangerous.
All fuels used for heating or cooking consist primarily of hydro-carbons, that is they are predominantly made
up of trapped carbon and hydrogen atoms in either solid, liquid or gaseous form.
Air consists of about 79% nitrogen and 21% oxygen. Nitrogen does nothing to aid combustion, in most cases
it just gets in the way, which is why a considerable amount of “excess” air is needed to make sure that
sufficient oxygen is supplied to enable the fuel to burn. For combustion to occur as completely as possible,
an abundant supply of oxygen has to be given sufficient time to be vigorously mixed with the combustible fuel
elements and at a temperature at which combustion can be maintained. This applies to any fuel, be it Wood,
Solid Fuel, Gas, Oil, and even rubbish!
Carbon Monoxide is a very poisonous gas. When inhaled, it seriously interferes with the process which
carries oxygen via the red blood cells to the body tissues, including the heart and brain. If affected, the
symptoms can include nausea, headaches, drowsiness, sickness, diarrhoea, stomach cramps and feeling
generally unwell - symptoms which are often attributed to common ailments including influenza and food
poisoning. In cases where extremely high doses of carbon monoxide are inhaled, unconsciousness and
DEATH can follow in as little as 1 to 3 minutes. The maximum recommended exposure to CO is 35 parts per
million, (PPM), over an 8 hour period. When exposed to levels greater than 200 PPM for 2 to 3 hours, the
symptoms start. More information can be seen in the Table below.
It is therefore very important that users of wood burning and solid fuel burning appliances are aware of the
dangers to ensure that such equipment is correctly and safely used.
Particular attention should be given to the Building Regulations which relate to the correct application of all
flue and chimney products and in particular to the requirements which dictate the legally required permanent
provision of combustion air supply to the appliances served by the chimneys. Although, as mentioned in the
section on Ventilation on page 4, Building Regulations state that n
If insufficient
combustion air is unable to be obtained by the appliance, - and it is one of the chimney’s functions to provide
the draught to do just that where solid fuel or wood is burned, Carbon Monoxide, (and usually a lot of soot), will
be produced. For that reason, installers and customers should be aware of the potential dangers of closing
off or blocking combustion air openings into rooms where any type of combustion equipment is installed.
o purpose provided ventilation is required
for stoves rated under 5KW, it does not mean that combustion air is not needed and it may still be necessary to
provide a deliberate opening for combustion air provision if circumstances so demand.
Carbon Monoxide is a colourless
poisonous gas which has no smell,
which is why it is often referred to
as the “silent killer”. It is created
when any fuel is incompletely
burned. Incomplete combustion is
usually caused by an inadequate
supply of oxygen, or because the
released gases are not subjected
to a high enough temperature to
enable them to ignite.
CO is the abbreviated term
because one molecule of Carbon
Monoxide consists of one atom of
carbon (C) combined with one
atom of oxygen (O).
If an abundant supply of oxygen
(O) is supplied resulting in the
complete combustion of all the
carbon (C) in the fuel, a
substantial amount of the
combustion gases released will
be harmless Carbon Dioxide,
one molecule of which consists
of one atom of carbon (C) and
two atoms of oxygen (O). That
is why CO is the abbreviated
2
t e r m . W h i l s t c o m p l e t e
combustion is the target, it is
s e l d o m a c h i e v e d , a n d
particularly so with domestic
heating appliances.
The other predominant
compound released during
the combustion process is
H O, which is just a harmless
2
combination of two hydrogen
atoms and one oxygen atom,
otherwise known as water!
We recommend the installation of a SmartSense Carbon
Monoxide Alarm which may be wall or ceiling mounted
and which will provide an effective warning of the presence
of carbon monoxide. SMART
SENSE
Carbon Monoxide - CO Carbon Dioxide - CO2Water H O
2