As we approach cooler weather and the holiday season – the time of year when most home fires occur – the National Fire Protection Association (NFPA) reminds us to be prepared in the case of fire. The group’s annual Fire Prevention Week, Oct. 8-14, focuses on steps consumers nationwide can take to prevent fires, and to stay safe if one occurs.
Installing a residential fire alarm is a key step to preparing for a potential fire. But, as Beasley Allen previously reported, not all alarms are equal, and some do not always offer the best protection.
The NFPA explains that there are two types of alarms: ionization and photoelectric alarms. Ionization alarms better detect flaming fires, while photoelectric alarms detect smoldering fires more quickly. Because housing materials are now created with materials that produce fewer ions when they are burned, it is difficult for the alarms to detect the smaller amounts of ions. Additionally, alarms are typically placed up high, and ion particles are usually too large and heavy to rise high enough to be detected.
A more effective approach is to use both types of alarms, according to the NFPA. The ions that escape detection by an ionization alarm, because they are too cool and heavy, can be detected by a photoelectric alarm. Photoelectric alarms detect smoke instead of ions. So, when smoke scatters a light beam in the detector, the alarm sounds.
Still, some alarms combine elements from both devices. However, two other fire safety organizations – the International Association for Fire Fighters and the World Fire Safety Foundation – recommend the use of photoelectric fire alarms, rather than the ionization fire alarms or combination fire alarms.
Manufacturers of ionization fire alarms have misled the public with marketing schemes that imply the alarms will keep them safe. Approximately 90 percent of American homes use ionization alarms, but consumers should be aware that they do not actually detect smoke, and are known to not function effectively during a smoldering fire – a common form of fire.
Ionization alarms are identifiable by the small amount of radioactive material on the outside, or possibly on the inside, of the detector. Consumers can view more fire prevention and smoke alarm tips on the NFPA’s website.
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National Fire Protection Association