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Why Is The FRS Moving Away From Ionisation Alarms? – An Interview

Posted | 06-Mar-2018 09:27:00

Mark Hazelton has worked for the fire service for more than 20 years in various roles, including Station Officer and Community Safety Development Manager for London Fire Brigade. Previously, Mark was a firefighter for 11 years at several stations in Kent. He is the National Fire Chiefs Council’s ( NFCC’s) Lead for Smoke and Carbon Monoxide Detection.

What type of smoke alarms do London Fire Brigade fit during their Home Fire Safety Visits/ recommend fitting?

London Fire Brigade do over 80,000 home fire safety visits every year. During these we give all sorts of advice, but we also fit smoke detection where needed.

We recommend fitting multi-sensor detectors in the home. We’ve moved away from ionisation detectors (normally the cheapest detectors sold) as these will work to detect fires, but can be over-sensitive. Hence they will often cause spurious (false) alarms if toast is burnt, for example. In fact, cheap ionisation alarms are largely responsible for the public believing fire detectors are “annoying” devices rather than an essential piece of protective technology.

We’d also recommend not installing fire detectors with a replaceable battery. Quite often these batteries are taken out to be used for another device or, when the alarm makes a low battery chirp, they are removed to stop it sounding. Then they don’t replace it. Therefore we’d recommend alarms with fixed term batteries - when these have a low battery, you have to replace the whole detector. This also ensures the detector head (the bit that detects the smoke) will be renewed, ensuring it has not worn out or deteriorated.


What are the benefits of multi-sensor technology?

There are different types of fires in the home. These can be fast-burning fires (e.g. a flammable liquid) which will be fast-spreading, produce a lot of heat and have a relatively ‘clean burn’ (not so much soot), or you can get smouldering fires. These fires are the kind produced when a cigarette is dropped down the back of a sofa, where the fire ‘smoulders’ for a long time before the fire really emerges. Hence, this type of fire produces a lot of particles, but not as much heat or energy as fast-flaming fires.

Multi-sensor detectors are also beneficial as they cater for all types of fire - they work to detect different elements of fire in a combined alarm. They also avoid the false alarms you can get in single detector types.


What are the issues with ionisation alarms?

There are two real issues with ionisation alarms:

1. They are oversensitive

With reference to the old-fashioned cheaper ionisation alarms, these are over-sensitive to spurious sources e.g. dust, toast, insects that can cause false alarms. As a result, we often find that people take out the ionisation alarm batteries, or physically break them, when they are sound erroneously.

2. Disposal issues

The other issue is the environmental issue. They are very small, so there is only a small radiation source within them, but if many of these alarms are disposed together, this could pose an environmental risk. Nowadays we are much more conscious of recycling, rather than just disposing.


Where should you fit smoke alarms in the home?

Fit them everywhere a fire can start.

We would never advise fitting smoke alarms in the kitchen because normal cooking fumes will typically set them off . Have a heat alarm in the kitchen, and smoke alarms everywhere else, primarily bedrooms and halls. The 2 exceptions are the bathroom and toilet as these are unlikely to be the source of the fire.

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It is important to note that behaviours and lifestyles are changing. There is now a lot more electrical equipment around us, which present a fire risk when left unattended (e.g. charging a phone). You may think white goods/domestic appliances are safe, but occasionally these too can develop a fault and cause a fire. Fires started by cigarettes are also the biggest causes of fatalities, so we’d advise smoking outdoors.


How should people look after their smoke alarms?

Firstly: Read the instructions that come with the alarm (we’ve undertaken approx. 80,000 visits and hardly anyone has read the instructions!)

Secondly: Test it regularly. At least monthly or weekly so that people recognise the sound of it and people know what to do should it go off in a real life situation.

Thirdly: Make sure you vacuum it at least once a year to get rid of any dust.

Finally: Make sure you take action as soon a low battery is detected. Don’t ignore it, but replace it as soon as possible.

Make sure you get carbon monoxide alarm too. Carbon monoxide, known as the “silent killer”, is a toxic gas that you can’t see, smell or taste and people don’t recognise the symptoms of CO gas in the home. If you have any fuel burning appliance e.g. coal, wood, oil, or paraffin, make sure you have a CO detector in the room with that appliance. Also ensure that these are serviced annually, in addition to making sure your flue is cleaned on a regular basis.

 Kitchen Fire Safety


Topics: Fire Safety News & Interviews

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