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Selecting the right fire extinguisher for your home

Different types of fire extinguishers

There are three basic types of fire extinguishers. Each type of extinguisher may be rated for one or more classes of fire. In some cases, particular extinguishers are not only considered ineffective against certain classes of fire, they can be dangerous if used in those circumstances.

Firstly, you have the water-based fire extinguisher. These are filled with pressurised water, and are made to put out type A fires from combustible materials, such as rubbish, clothing, wood and papers.

Secondly, you have dry chemical extinguishers. Dry chemical fire extinguishers are by far the most common fire extinguishers in the home. They can handle up to three types of fires. Type A: combustible solids like wood or paper, Type B: combustible liquids like gasoline or grease, and Type E: electrical fires.

Thirdly, you have carbon dioxide fire extinguishers. A carbon-dioxide fire extinguisher works by eliminating oxygen and replacing it with carbon dioxide. This is most commonly used to extinguish type E fires, electrical fires.

In addition to these three, you also have foam extinguishers and wet chemical extinguishers.

These different types of extinguishers are not interchangeable. In fact using the wrong fire extinguisher could make matters a lot worse. For instance, using a water-based extinguisher on a type B fire will only make it worse. A dry chemical extinguisher will put out a type E fire, but it will leave a sticky or corrosive residue that can damage the surface on which it has been sprayed. Moreover, for Type F fires, cooking oil and fat fires, a fire blanket must be used and not a fire extinguisher. The pressurised force from a fire extinguisher onto burning oil and fat could blow and spread it and make it worse.

For most homes, it will be more than sufficient with a combination of dry chemical extinguishers and fire blankets in addition to smoke alarms.

Carbon Monoxide- the Silent Killer

What is carbon monoxide, and how does it affect humans?

Carbon monoxide is a gas found in air. It is a colourless, tasteless and odourless compound produced by incomplete combustion of carbon-containing materials. High levels of carbon monoxide are poisonous to humans and, unfortunately, it cannot be detected by humans as it has no taste or smell and cannot be seen. It is also difficult to treat once the damage is done, carbon monoxide is known as the silent killer.

Carbon monoxide affects healthy and unhealthy people. Increased levels of carbon monoxide reduce the amount of oxygen carried by haemoglobin around the body in red blood cells. The result is that vital organs, such as the brain, nervous tissues and the heart, do not receive enough oxygen to work properly.

For healthy people, the most likely impact of a small increase in the level of carbon monoxide is that they will have trouble concentrating. Some people might become a bit clumsy as their coordination is affected, and they could get tired more easily.

People with heart problems are likely to suffer from more frequent and longer angina attacks, and they would be at greater risk of heart attack. Children and unborn babies are particularly at risk because they are smaller and their bodies are still growing and developing.

How does carbon monoxide detectors work?

Carbon monoxide detectors sound an alarm when they sense a certain amount of carbon monoxide in the air over time. Different types of alarms are triggered by different types of sensors.

  • Biomimetic sensor: A gel changes colour when it absorbs carbon monoxide, and this colour change triggers the alarm.
  • Metal oxide semiconductor: When the silica chip’s circuitry detects carbon monoxide, it lowers the electrical resistance, and this change triggers the alarm.
  • Electrochemical sensor: Electrodes immersed in a chemical solution sense changes in electrical currents when they come into contact with carbon dioxide, and this change triggers the alarm.

Once the alarm sounds, the carbon monoxide detector must be in a carbon monoxide-free environment to reset itself.

Carbon Monoxide is released as a by-product of a combustion (burning) process. Any household appliance that burns natural gas, coal, oil, bottled gas, paraffin, wood, petrol, diesel or charcoal will produce some levels of CO. The level produced will vary depending on the type of fuel being burnt and the quality of the service and maintenance of the appliances.

  • Always fit a CO alarm in rooms with fuel burning appliances
  • Fitting at least 2 interconnected alarms will:
    • Enhance early detection of CO
    • Raise the alarm sound levels throughout the house
  • If there is only one appliance in the house, consider fitting an additional alarm in the bedroom area.
  • CO alarms must always be fitted in conjunction with a standard smoke alarm they are not intended to be used as the sole detection device.

Where should you place carbon monoxide detectors?

  • Living rooms with high occupancy
  • Bedrooms above or adjacent to room with appliance
  • Rooms with chimney breasts passing through them, e.g. upstairs bedroom
  • Rooms with portable gas / oil heaters
  • Parking garages