Smoke Alarms

What is a smoke alarm?

A smoke alarm is a self-contained warning device, designed to activate an alarm sound upon detection of smoke. It may be battery operated or 120 Volt AC hard wired.

Will a smoke alarm really protect me?

People with working, properly installed smoke alarms have nearly a 50% better chance of surviving a fire.

What is the life expectancy of a smoke alarm?

The effective life expectancy of a smoke alarm is 10 years. Even if it appears to work when tested it should be replaced to reduce the potential for failure.

Is there only one type of smoke alarm?

The two types of smoke alarms are the ionization type and the photoelectric type.

The ionization type alarm uses “ions” or electrically charged particles to detect smoke in the air. Smoke particles entering the sensing chamber change the electrical balance of the air. The greater amount of smoke the higher the electrical imbalance. The alarm will sound when the electrical imbalance reaches a preset level.

The photoelectric type alarm uses a beam of light and a light sensor in its sensing chamber. The sensing chamber is designed so that the light beam does not strike the sensor, but smoke particles entering the chamber deflect the light onto the sensor. The greater the amount of smoke entering the chamber, the more light will be deflected onto the sensor. The alarm sounds when the amount of light hitting the sensor reaches a preset level.

Which smoke alarm will give me the earliest warning?

A fire that generates a lot of small smoke particles (hot flaming fire) will cause an ionization smoke alarm to sound sooner than a photoelectric. The time delay between the two is very small. A fire with a lot of large smoke particles (smouldering fire)will cause a photoelectric smoke alarm to sound sooner than an ionization type.

If you want the advantages of both you can install one of each type everywhere a smoke alarm is required or recommended or you can buy combination smoke alarm units which contain both sensing types.

Install smoke alarms according to the manufacturers’installation instructions that are provided in the smoke alarm packaging

When and how should I test the smoke alarm?

Smoke alarms should be tested monthly by pressing the test button. Never use real smoke, as residue may coat the sensing chamber and make the unit inoperable.

How should I maintain my smoke alarm?

Replace batteries once a year. Pick a date to remember. Some newer smoke alarms come with a ten year battery.

Vacuum over and around the smoke alarm regularly to keep dust and debris out of the unit.