Safety must always come first when any work is carried out to the building infrastructure. Combustion appliances, for example, contain a real risk of carbon monoxide (CO) poisoning which can lead to death. Real fire risks depend on factors such as the fuel used for burning and the supply control to the flames; appliance type and efficiency; how often it is used and keeping it properly maintained. Fire regulations to handle appliances safely are not ‘over the top’. They prevent serious injury or death if such rules are respected. It is also important that chimney sweeping is carried out by a certified and professional chimney sweep – or the consequences could be fatal.
Risk factors can be numerous. The build-up of heat into the floor through the back of a fireplace or floor under a gas fire are two examples. Or imagine a tar build-up which keeps burning inside a chimney for a few hours with a temperature of more than 1000°C. It can make bricks and cement disintegrate and any nearby steel metal pipes glow red. Even normal flue fires carry safety risks and so the building regulations give advice on placing flue pipes near flammable materials; recommended hearths to install and fireplace walls.
(CO), mentioned above, is commonly known as the silent killer, and it represents a lethal risk to households. It is a difficult gas to detect with no odour or colour. CO is a product of carbon-based fuels including oil, gas, coal and wood. Oxygen levels in the blood of a human being can be pushed dangerously low by a bond between CO and haemoglobin (part of red blood cells) when CO is inhaled. Carboxyhaemoglobin – the bond between CO and haemoglobin – eventually kills the oxygen. This is known as CO poisoning. Even low levels of exposure to CO can cause damage as oxygen is slowly starved. Vital organs in the human body will stop working such as the brain. If CO is inhaled for a short time, recovery is possible if the patient is quickly taken to a CO-free room. However if exposure is long enough, the person will die because oxygen is not taken around the body.
Factors influencing carboxyhaemoglobin damage to the human body:-
Carbon monoxide in air inhaled into the lungs.
The length of time a person is exposed to the toxic air.
A person’s activity in the contaminated environment e.g. working causes.
Higher levels of inhaled air leading to an increased CO poisoning rate.
Existing health conditions or vulnerable people e.g. older folk, pregnant women, patients with heart or lung complaints.
Symptoms of CO poisoning
Symptoms of CO poisoning depend on the amount of blood contamination. Flu-style signs are an early warning of low level poisoning and later indications are confusion, weakness, muscle waste and memory loss. Sometimes, in 50 per cent of cases, a victim’s skin has gone pink in colour. A CO poisoning victim is likely to feel better away from home than when they return. If more than one person in a household suffers such symptoms – that is another warning sign. Always be safe and get immediate medical advice, if in doubt.
Where does carbon monoxide come from? CO is found in a number of sources in a property – coal, oil, gas and oil. Cigarette smoke is another cause. Any portable paraffin or gas heaters can create high CO levels if a room is not properly ventilated. Dangerous CO levels will also be present if any fires, room heaters, oil, cookers and boilers fuelled by natural gas; or liquid petroleum gas are not given efficient air supply.
Gas from solid fuels (wood, coal and smokeless fuels) contain dangerously high levels of CO because these fuels do not mix with oxygen. So a properly working flue or air vent is essential to transport these fumes to the outside atmosphere. It is vital, and potentially life-saving, for these flues/air vents to be unblocked and in proper working order – maintained on a regular basis by a certified and professional chimney sweep.
Oxygen is essential for the combustion of any fuel but modern building techniques mean there are less draughts in a home – so building regulations also give information on getting fixed air vents installed.
A number of solid fuel open fires, usually with an underfloor draught set-up, draw upon outside air to feed the flames via the under-grate area. However it amounts to just 10 per cent of the total air needed for combustion – the other 90 per cent is required for ventilation purposes, especially as a lot of air is directed by the fire up the chimney. If there is not enough ventilation air, the combustion products will go up the flue at a slower pace and leave soot; or even cause smoke to come back down the chimney, with a greater risk of CO poisoning.
Any stoves and open fires alight with their doors open will need more air for ventilation than combustion. Larger fireplaces will require air replacement several times in just a single hour.
HETAS is an example of Building Regulations which make sure the professional who installs solid fuel chimneys and appliances is a bona fide qualified tradesman. He or she can install these types of appliances as long as building control approval is given before the work begins. Chimney systems and liners can be included under this competent person’s scheme, not just flexi stainless steel linings. If you employ a HETAS member, they could also be registered to install other systems such as prefabricated chimney set-ups and cast in situ or sectional lining works. This type of work does not need previous building control permission. However, if foundation work is needed to build or repair a chimney – note that building control permission is always needed first, regardless of the qualifications of the tradesman doing the work.
HETAS is also responsible registering tradesmen with the National Association of Chimney Engineers (NACE) and overseeing the quality-control scheme provided by the association. This means that scheme members can complete certain chimney work under their registration framework.