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Smoke alarms

March 2010

Smoke alarms are designed to give you an early warning of a fire in your home. They make good safety sense, giving you and your family valuable time to act and escape.

But a recent national survey on smoke alarm ownership found that more than 300,000 households in Ireland do not have any smoke alarms installed and 82% of fires resulting in fatalities had no working smoke alarm.

Besides saving lives, smoke alarms could save you money too - consumers who install smoke alarms (or burglar alarms) should always check if their insurance policy gives a discount for having them.

But what type of alarms should you look for, how many should you buy, and how do you get the best value?

Which types

There are three main types of smoke or heat detector:

  • Ionisation smoke alarms - these are the cheapest and most common type of alarm. They are sensitive to small particles of smoke from "flaming" fires such as chip pans, and will detect this type of fire before the smoke gets too thick.
  • Optical smoke alarms - these are slightly more expensive but more effective at detecting larger particles from "slow burning" fires such as smouldering foam or PVC wiring. This kind of alarm is best suited for a kitchen type area, as they are not so sensitive to small particles of smoke such as smoke from toast cooking or minor oven smoke.
  • Heat detectors - these detect heat but not smoke or fumes, so they can be used in areas where there could be false activations due to steam, burnt food, car fumes etc.

Generally speaking, the most effective alarm systems will run off a wired power supply as well as having battery back-up in case of a power cut.

Standalone alarms that just run on batteries will tend to be cheaper. Ten-year ionisation or optical smoke alarms are available which are fitted with a long-life lithium battery or a sealed power pack that lasts for 10 years.
How many to get

The Department of the Environment, Heritage and Local Government recommends that four detectors should be installed in the average home.

In a standard two-storey house, for minimum protection against fire you will need smoke detectors at least on each landing and in the living room, plus a heat detector in the kitchen.

For maximum protection, you should have a smoke alarm in every room (except the bathroom and garage), every hall and landing, as well as a heat alarm in the kitchen.

Remember, the more correctly fitted and maintained smoke alarms you have in your home, the quicker any fire will be detected - and the quicker you and your family can safely evacuate.

Which standard

As with most products, you should shop around for the smoke alarms and heat detectors that offer the best value. A cheap alarm may be a false economy if it doesn't conform to the most widely recognised safety standards and doesn't do the job. CE mark

Domestic type smoke alarms should meet Irish Standard IS 409;1988, British Standard BS 5446 (Part 1) or the equivalent.

These standards should be clearly identified on the alarm or its box/packaging. Also look for the CE Mark (pictured above) and/or the British Standard Kitemark.

Remember, while buying several smoke alarms may seem expensive in the short term, if they alert you to a potentially serious fire, then their value for money is arguably priceless.

How to look after them

There is no point in buying an alarm if it isn't in full working order or properly positioned:

  1. Make sure that each alarm is properly installed and maintained - follow the manufacturer's instructions carefully
  2. Fit them on the ceiling as close to the centre of the room as possible
  3. While domestic alarms should be easy to install, if in doubt you should consult a qualified electrician or the supplier
  4. Make sure that you can still hear the smoke alarm at night with the doors closed
  5. Make sure the batteries are working, and replace them twice a year (or every 10 years if they are long-life lithium batteries)
  6. Test each alarm once a week by pushing and holding the test button until it activates
  7. Vacuum and brush the casing every six months so that dust doesn't build up and affect performance

Remember, a working smoke alarm is only an early warning system to alert you to a possible danger in the home. To further protect yourself from the dangers of fire, exercise the other golden rules of fire safety in the home:

  • Make an escape plan and practise it often
  • Check for fire dangers in the home and correct them
  • Carry out a "last thing at night" routine, including emptying ashtrays, putting up a fireguard, switching off appliances and electric blankets, making sure escape routes are clear etc

Learn more

Read the Department of the Environment's guides on fire safety