Each year, a theme is selected for Fire Prevention Week, which this year occurs Oct. 5-11. For 2014, the theme is “Working Smoke Alarms Save Lives. Test Yours Every Month!” It is important for the fire service to get this message out, because it not only saves lives, it also makes our job easier.
The smoke alarm was introduced to the general public in the early 1970s. Since then, the technology of smoke alarms has been enhanced to provide better warning and ease of maintaining. Along with that, loss of life due to smoke inhalation has been dramatically reduced because of the early warning smoke alarms provide.
It is important that every firefighter knows the different types of smoke alarms, how they operate, how they should be installed and how they should be maintained. In addition, fire personnel should also instruct people on what to do when the smoke alarm sounds.
Types of alarms
There are two different types of smoke alarms: ionization and photoelectric. In the ionization smoke alarm, there is a chamber that contains a substance called Americium-241 and two metal plates called electrodes that are connected to a battery. The Americium-241 converts air molecules into positive and negative ions. In the chamber, negative ions are attracted to the positive plate and positive ions are attracted to the negative plate. When smoke enters the chamber, the ions bond with the smoke. This reduces the attraction process, which then sets off the alarm. The photoelectric smoke alarm uses a light source, so when smoke enters the smoke alarm, it obscures the path of the light, which sets off the alarm. Ionization smoke alarms work best for hot, fast-moving fires whereas the photoelectric smoke alarm works better with slower, cooler, smoldering fires.
It is recommended by several fire safety organizations that smoke alarms that use both technologies in the same smoke alarm be used. These are commonly known as dual-sensor smoke alarms.
Two power sources are available for smoke alarms: battery operated and AC house current. It is recommended that both be used. For older homes, the battery operated unit works best. There are now some smoke alarms available that have a 10-year-life battery available.
Smoke alarms should be installed in each room where people sleep, one in the hallway outside each sleeping area, one between the kitchen and sleeping area and one on each occupied level of the home.
For best protection, smoke alarms should be interconnected so if one activates, it activates all the other units at the same time, which gives faster notification. For wired in units, there is an extra wire for this purpose. For battery-operated smoke alarms, new wireless technology is now available that activates all the smoke alarms together when one detects smoke. Some smoke alarms now have a voice module that works in conjunction with the beeps.
Smoke alarms should be tested once each month by depressing the test button. This shows that the unit is in operational condition.
Battery-operated smoke alarms and AC-powered smoke alarms with a battery backup should have the battery replaced once each year. The easiest way to remember is to change the batteries in the smoke alarms on the weekend when clocks are placed back to standard time in the fall. (“Change Your Clock – Change Your Battery”).
Many smoke alarms have a “hush” option (check the package for this information). This is where the button can be depressed to silence the smoke alarm for nuisance alarms such as cooking. This option may discourage people from removing the battery in the smoke alarm closest to the kitchen, the place where many fires occur. Smoke alarms should be replaced once every 10 years or if they do not pass the monthly test.
Correct terminology
The correct terminology is “smoke alarm.” “Smoke detectors” are devices that detect smoke such as in an office building or school. When the detector is activated, it sounds an alarm that is usually on a wall with an audible device or light advising people to evacuate. Because both the detection device and alarm are both in one unit, it is known as a smoke alarm. As a fire service professional, you should use the correct terminology as much as possible.
Once the smoke alarm activates, people should be told to evacuate as quickly as possible. This is why it is important for people to know two ways out of every room, to crawl low to the floor under the smoke while escaping and to go to a safe meeting place outside before calling for help. Encourage people to practice fire drills in the home at least twice a year.
For more information and tips about fire prevention week check out the Fire Prevention Week website of the National Fire Protection Association www.fpw.org.
