Carl Edison 2016-12-28 11:00:00
The easiest and most effective way to prevent residential fires and stay safe is to install smoke detectors in every room of your house. A properly installed and maintained smoke detector works for 24 hours a day to scan for smoke or fire.
The two main types of smoke detectors for your home have either photoelectric or ionization sensors. Each detects different types of fires, so dual sensor alarms have grown more popular, making there three types of residential smoke alarms.
There are two primary parts to a smoke detector: a sensor and an alarm. They can be either hardwired into your house current or run off of a nine-volt battery. The backup batteries in your hardwired system, or main battery or batteries should be tested regularly and replaced at least twice a year, typically when the clocks change in Spring and Fall. Learn more about the different types of fire alarm systems at the Chubb Edwards website.
Some smoke alarms offer vibrations and strobe lights to alert people with hearing disabilities.
These types have a light source in a light-sensitive electric sensor. These are positioned at 90-degree angles to each other. When everything is normal, light from the light source goes straight across and misses the sensor. When smoke enters the chamber, it makes the light scatter, hitting the sensor and triggering the alarm.
These alarms tend to respond faster to a fire in its early stage before the source of fire bursts into flame. They are more sensitive to the larger particles that are given off during slow and smouldering fires, which typically occur at night when people are asleep.
Ionization smoke detectors have americium-241 in an ionization chamber. An electric current goes between two metal plates and when this is disrupted by smoke entering the chamber, an alarm is sounded. Ionization smoke alarms quickly detect small amounts of smoke that are produced by fast-flaming fires like those fuelled by flammable liquids or paper, or cooking fires.
This kind of smoke detector is commonly used in kitchens but tends to be set off by smoke from an overheated pan or burnt dinner, or what fire prevention safety people call “nuisance alarms.” People tend to disable these alarms, which makes them useless.
Dual smoke detectors have both photoelectric and ionization sensors so they can adequately alert homeowners of a fire with active flames, or of a smouldering fire. Some fire safety experts have recommended these types since they cover a broad range of fire types. There is no industry standard for setting the individual sensor sensitivity in these types of detectors, which means that a dual sensor with a non-functioning ionization sensor will still meet the national standards as long as the photoelectric sensor works.
The International Association of Fire Fighters recommends photoelectric smoke detectors, and in 2008, said that dual sensor alarms aren’t acceptable. The reasoning to support photoelectric sensors was because the tech in ionization sensors doesn’t give a warning soon enough when the fire is smouldering, which leads to a greater loss of life. Further, ionization detectors don’t work as well in high airflow environments.
Photoelectric smoke detectors are less susceptible to nuisance alarms and are much more effective at warning people of smoke from smouldering fires.
The IAFF and several other safety organizations have recommended that homeowners replace all of their unknown, dual sensor, and ionization alarms with photoelectric smoke detectors.