For best protection, it is recommended both (ionization and photoelectric) technologies be used in homes. In addition to individual ionization and photoelectric alarms, combination alarms that include both technologies in a single device are available.
Over 90% of house smoke alarms are ionization detectors. Learn more about the difference between each type and the benefits of installing an ionization alarm in your home.
Ionisation smoke detectors, also known as ionization smoke detectors, were traditionally used throughout properties however, ionisation smoke alarms contain a tiny radioactive source in the sensor chamber, and due to this, these types of smoke alarms are getting phased out.
Determining which type of smoke alarm you currently have can be difficult. If you find anything mentioning radioactive materials, a model number with an “I” or any mention of Americium-241 on the alarm's label, it is an ionization alarm. If you find a “P,” it is a photoelectric alarm.
Cons of Ionization Smoke Detectors
This can often lead to false alarms. Ionization detectors can also be triggered by cooking smoke or steam from the shower. Although this usually isn't an issue in public and commercial buildings, it can lead to annoyed homeowners disabling smoke detectors.
An ionization detector can quickly sense fast-moving fires, but has huge shortcomings in detecting smoldering, slow moving fires; such fires can go completely undetected by an ionization alarm.
Most smoke detectors use americium-241 as their source. Some early models used radium-226, and commercial smoke detectors and some residential units used nickel-63. The types of radiation from these sources cannot make anything else radioactive.
Since no one can predict what type of fire might start in their home, the U.S. Fire Administration recommends that every home and place where people sleep have: Both ionization AND photoelectric smoke alarms, OR. Dual-sensor smoke alarms, which contain both ionization and photoelectric smoke sensors.
Ionization alarms have about a 55% failure rate to save people in home fires.
Install smoke alarms inside each bedroom, outside each sleeping area and on every level of the home, including the basement. On levels without bedrooms, install alarms in the living room (or den or family room) or near the stairway to the upper level, or in both locations.
Please note: Ionisation smoke alarms are now being phased out across the entire fire safety industry in favour of optical smoke alarms due to manufacturing, transportation, and disposal concerns around the radioactive material that ionisation smoke sensors rely on. Why are ionisation smoke detectors being phased out?
Optical smoke detectors may respond slightly slower to fast, flaming fires compared to ionisation detectors. While they are excellent for smouldering fires, their response time might be marginally delayed in situations where rapid flame detection is crucial.
Iowa and Vermont have passed similar laws banning ionization smoke detectors as stand-alone smoke alarms. Vermont went a step further than Massachusetts by requiring photoelectric-only-type smoke detectors in dwellings.
Can I install a hardwired smoke detector myself? While it is technically possible, it is not recommended. Working with your home's electrical system can be dangerous and complex, best left to a qualified electrician.
Dust and other particles can easily build up in the ionization chamber, causing false alarms. Insects and pests can also find their way into the chamber, disrupting the flow of ions and triggering the alarm. Moisture is another common cause of false alarms.
Potential for False Positives in Dusty Environments
While photoelectric detectors are generally less prone to false alarms, they can still be triggered in dusty environments. Particulate matter in the air, such as dust or insect debris, may scatter light and lead to false positives.
An ionization smoke alarm is generally more responsive to flaming fires (imagine a fire where you can see the flame), while a photoelectric smoke alarm is generally more responsive to smoking, smoldering fires (such as a cigarette).
Most detectors are certified for a useful life of ten years. Check the expiration date on your smoke detector when you replace the batteries. Throw away outdated ionization smoke detectors. Your community may have a separate recycling program for them.
The amount of radioactive material contained in ionization smoke detectors is so small it does not pose a risk to human health. However, some municipalities prohibit the disposal of ionization detectors in the municipal waste stream.
Overall, we recommend the First Alert SA3210 because it combines photoelectric and ionization sensors that detect low and smoky fires as well as high flames. It's also battery-operated, so it's easy to install. If you're looking for a bargain, the Kidde I9030 is a basic smoke detector that does the job at low cost.
Test smoke alarms every month by pressing their test buttons. If your alarms use regular batteries, swap in fresh batteries at least once a year. A “chirping” sound means that it's time to change batteries. Because alarm sensors wear out, replace each alarm at least every 10 years.
The risk of dying in a home fire is cut in half in homes with working smoke alarms. There are two types of smoke alarm technologies on the market, ionization and photoelectric. The most commonly available is the inexpensive battery-powered ionization-type smoke alarm.
Photoelectric smoke detectors use a light and sensor to detect smoke and do not contain radioactive material. Many smoke detectors may use both ionization and photoelectric features to achieve maximum detection.
Request a Quote for Americium-241
Currently, the NIDC has Am-241 available for purchase with an isotopic purity exceeding 99% and a plutonium content of less than 1%. For further inquiries on Am-241 contact the NIDC at [email protected] or click the link below to request a quote.
If you are unable to return your smoke detector containing Americium-241 to the manufacturer, contact your local transfer station for other options. It is legal to dispose of smoke detectors in a landfill because they are not considered hazardous waste.