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An Introduction to the Various Types of Available Smoke Alarms

Debopriya Bose Dec 03, 2018
The risk that fire poses to life, makes installing smoke alarms very important. There are various types available in the market for you to choose from. Here is a brief introduction to a few varieties.
One of the most important installations in buildings for safety against fire are the smoke alarms. They became widely available in a huge variety in the United States since the 1970s. Once they were generally available, prices fell and their sale also increased rapidly.
By 1991, almost 88% of the houses in the US had smoke alarms or fire alarm systems. Since then the number of fatalities due to fire related accidents have dropped by half.
Smoke alarms are self-contained devices that can detect fire or smoke and set out an alarm as a warning for the occupants of a building to evacuate its premises. They detect fire at an early stage. This gives occupants ample time to evacuate the building that has caught fire.
Hence, installing these alarms helps reduce the number of casualties to a large extent and ensures fire safety. Also known as smoke detectors, they are typically enclosed in a circular disk-like plastic enclosure and are fitted to the ceiling. However, the shape may vary according to the make and the company.

Types of Smoke Alarms

Ionization Type

These alarms are sensitive to small particles of smoke.These sense smoke particles that are too small to be detected, like from fast burning fires like oil or fat fires, and set out an alarm much before the smoke gets too thick. However, they are less sensitive to slow and smoldering fires that give off lots of smoke before the flaming fires are caused.
They are the most widely available varieties and are also inexpensive. However, they are quite prone to setting off false alarms.

Optical Alarms

These alarms are slightly more expensive. However, their advantage is that they are less prone to sending out false alarms. They do not react to steam or cooking fumes produced in the kitchen or to the steam in bathrooms.
They are effective in detecting smoke particles produced by slow, smoldering fires, that may be caused due to burning of foam-filled upholstery or PVC wiring insulation. However, optical alarms are slower in detecting fast flaming fires.
Combined: As the name suggests, these alarms use the technology of both the ionization as well as optical alarms. Hence, they can detect a fast-flaming as well as a slow, smoldering fire.

Additional Features

To prevent the setting off of false alarms, certain models have a provision of a 'silencing' button. Once pressed, there is some sort of indication like a small red light glowing to let the user know that it is in the 'silent mode'. However, once there is thick smoke due to fire, these alarms come out of their silent mode and the ring out loud.
Some are interconnected so that smoke detected by one alarm in one room activates the ones installed in other areas of the house. There are smoke alarms for people with special needs. For example, for people with hearing disabilities, there are alarms with emergency lights that flash once they detect smoke.

Power for Smoke Alarms

Smoke alarms run on batteries, mains electricity, or by a combination of both. The batteries need to be replaced every year. However, there are some that come with batteries that can last for almost 10 years. Although these are more expensive than the others that run on ordinary batteries, they can save the cost and trouble of replacing batteries each year.
Although a mains-powered alarm eliminates the use of batteries, it is important to install one that has a power back up so that you are informed of fire even when there is a power cut. Also, get a qualified electrician to fit such alarms.
Smoke alarms are an important component of home security systems. There are many different types to choose from. Installing the right kind depends upon the type of fire that is most likely to be expected in the different rooms of a home or building. However, what is most important is to ensure that they are always in proper working condition.