Smoke Alarms

Smoke Alarms - The various types, how to install and maintain them and why we should use them

In 2006 over two and half thousand Americans died in fires. Figures for the UK are just as shocking. In the twelve month period between June 2006 and June 2007 there were 467 fire deaths.

The following article examines the types of smoke alarm available and provides advice on how to install and maintain them.

An Introduction to Smoke and Heat Alarms

"You are twice as likely to survive a house fire if you have a working smoke alarm". source: UK Government 'Firekills' campaign.

"Approximately half of home fire deaths in the US occur in homes without smoke alarms" source: US National Center for Injury Prevention and Control (NCIPC)

Whilst the benefits of an early warning system are obvious, these statistics brings into sharp focus the importance of those vital few extra minutes that a smoke alarm affords those escaping a fire, particularly of course at night. There are two main types of smoke alarm, Ionisation and Optical.

Ionisation Smoke Alarms In simple terms Ionisation alarms work by monitoring the quality of the air. Detecting tiny particles of combustion that cannot be seen or smelt, they respond very quickly to hot, fast flaming fires, such as those caused by fires in chip pans. Ionisation smoke alarms, are however susceptible to false alarms since they will detect dust, small insects and steam. Though some would consider this a small price to pay for early fire detection.

Optical Smoke Alarms Optical smoke Alarms work by 'seeing' the smoke, using an emitter to direct a tiny Infra red beam onto a receiving photocell. As the smoke particles enter the detection chamber the infra red beam is interrupted, breaking the circuit and thus activating the alarm. They are more effective at detecting slow-burning fires during which more smoke is generated. This type of condition is common to the smouldering of foam filled furniture or overheated wiring. They are less prone to false alarms than Ionisation smoke alarms, but, if mounted in the kitchen will be activated by the smoke of burning toast.

Heat Alarms Requiring less maintenance, as they are less sensitive to dust, heat alarms are ideal for use in kitchens. Smoke alarms are rarely mounted in kitchens as they are prone to false alarms. However, since roughly 40% of all house fires develop in the kitchen this is the very zone requiring most attention.

There are two basic types of heat alarm: 'Fixed Temperature' and 'Rate of Rise'. Fixed temperature alarms tend to activate at around 58°C (136°f). Rate of Rise alarms, which as the name suggests, measure changes in temperature as opposed to absolute temperature, are not generally recommended for domestic use as the steam from kettles and the heat from opened oven doors can activate them.

Which Alarm Should I Use?

Both slow and fast burning fires are equally common, and since it's impossible to know which might strike it is recommended that a mix of both type of smoke alarm is used.

Growing in popularity, 'interconnected alarms' which may use a combination of Ionisation, optical, heat or even CO2 alarms, are linked in one unified system. In the event that one of the units detects fire it will send a signal via radio frequency to all the other units, which will sound simultaneously.

This system obviously comes into its own in larger dwellings where individual alarms in the affected area may not be heard and where those in other areas are not activated until the fire has really taken hold.

Battery powered smoke alarms fitted with a long life battery of 5 or 10 year life will provide basic protection, but a mains powered smoke alarm with battery backup is the better option. In the event that the wiring is affected by the fire, or indeed if the fire occurs because of an electrical fault, the battery backup maintains both detection and warning capability. Examples of this type of alarm are the Firex 4870 and Aico EI161RC.

Strobe light and vibrating pad alarms are also available for homeowners with impaired hearing or as a complement to existing alarms giving warning of fire using means other than sound.

Whatever type of alarm you chose be sure that it has the British Standard Kitemark. The Firex and Aico smoke alarms listed above all conform to this standard.

Fitting and Maintaining your Fire Alarms

A fire alarm will work only as well as it is fitted, and will only work as long as it is maintained.

"Nationally 80 per cent of homes now own smoke alarms but in 12% of house fires attended by fire and rescue services the smoke alarm failed to work, mainly due to flat or missing batteries" source: UK 'Firekills' campaign

Both the UK Fire Service and US Fire administration recommends that alarms are fitted on every level of the home. Smoke alarms should be fitted in bedrooms if there is a TV or other large electrical appliance. If you have only one smoke alarm and two floors, it should be installed where it can be heard when asleep - in the ceiling at the top of the stairs leading to the bedrooms, is usual. Although ionisation and optical alarms are equally effective, optical alarms may be preferred in this particular situation as they are especially good at detecting slow-burning, smouldering fires.

Smoke alarms usually mount onto bases which are simply screwed into the ceiling. They should be fitted as close to the centre of the room as possible, but at least 30 centimetres (12 inches) away from any wall or light fitting. You should always make sure that your alarm is fitted in a place where it can be heard throughout your home - particularly when you are asleep. If your home is on one level, you should fit the alarm in the hallway between the living and sleeping areas.

It is strongly recommended by all manufacturers and fire prevention bodies that the following points should always be followed when installing and maintaining your smoke alarm:

1. The manufacturers' instructions should be followed at all times 2. Mains powered alarms should always be installed by a qualified, registered electrician 3. Smoke alarm batteries are tested once a week and changed once a year. 4. Clean your smoke alarm regularly, by removing dust or cobwebs with a vacuum cleaner and moist cloth.

Darren Gilbert writes for Gil-lec Electrical Wholesale and kindly asks that all links are retained should you wish to publish this article.
www.gil-lec.co.uk
www.gil-lec.co.uk/smoke_alarms

The Popularity of Pellet Stoves

There isn't any question in my mind why pellet stoves are so popular with homeowners. First is that you can save a lot of money burning efficient wood pellets and use your high cost gas, oil or electric heat as a secondary source of heat. Wood pellets burn CO2 neutral, which is better for the environment. They're made from by products of wood production, also good for the environment. Also, a ton of wood pellets has a burn time similar to a cord and a half of wood.

When you go to look at pellet stoves you'll see several types, freestanding and fireplace inserts. Freestanding, as the name implies, stand freely. You can place them anywhere in your home. Experts suggest that they go into the center of the largest room you want to heat. Of course you will have to have the floor underneath the stove protected against potential burns. A pellet stove insert fits into your conventional mortar fireplace.

You'll find many different fine manufacturers such as Enviro, Whitfield, Breckwell, QuadraFire and Englander just to name a few. Some of these manufacturers have been in business for generations. Depending on where you live you may have a wider selection of stoves. Use the great resources on the internet to do research on different pellet stove manufacturers. Talk with family and friends who may be using pellet stoves to get their opinions. Talk with the salespersons in the store, listen closely and carefully to what they have to say.

One of the most important questions they should ask is how much square footage do you want to warm with your pellet stove. This is a very important question because pellet stoves come in a wide variety of sizes. The professional may suggest a stove that has more heating capacity than you're looking for, and if you an afford the increase this is generally a good idea.

Another question the salesman should ask you is what the construction of your home is and how well insulated it is. These are all important facts that go into the equations of buying a pellet stove.

You'll find lots of specifications when looking for wood pellet stoves, such as BTU/hour input, heating capacity, feed rate and hopper capacity. You will also find overall efficiency ratings. Pay attention to these specifications, they're important.

In order for you to be happy with your pellet stove you're going to have to have realistic expectations. However, you're sure to find that most homeowners who burn wood pellets are hapilly saving lots of money on the cost of home heating.