Ionization vs Photoelectric smoke alarms
What's the difference, and which one should I have?
Smoke detectors are an essential part of any home’s safety system. There are two main types of smoke detectors: photoelectric and ionization. Understanding the differences between the two can help you make an informed decision when it comes to choosing the right smoke detector for your home.
Photoelectric: These are generally more expensive and more responsive to fires that begin with a long period of smoldering also known as “smoldering fires”. This type of smoke detector uses a light source that is aimed into a sensing chamber at an angle away from the sensor. When smoke enters the chamber, it reflects light onto the light sensor, triggering the alarm.
Ionization: These are generally less expensive and more sensitive to large-flame, small smoke fires. This type of smoke detector uses a small amount of radioactive material to detect smoke particles. When smoke particles enter the chamber, they disrupt the flow of the radioactive material, triggering the alarm.
So which type of alarm should you choose? Studies have shown that photoelectric alarms will detect a slow smoldering fire up to 50 minutes faster than an Ionization alarm! Conversely, a photoelectric alarm is only slightly slower at detecting a large-flame fire than an ionization alarm (about 30-90 seconds). In my opinion, due to the fact that most fire related fatalities are caused by smoke inhalation as would be present with a smoldering-type fire while occupants are asleep, and the fact that a photoelectric alarm is only slightly slower at detecting a large-flame fire, photoelectric alarms are the clear choice in my mind.
A photoelectric alarm is likely all you need based on the research. Still, it is important to note that many experts still suggest that both types of smoke detectors should be installed in your home for maximum protection. No matter the type, it is important to regularly test and replace your smoke detectors to ensure they are working properly. You should replace smoke detectors before they are older than 10 years.
Are there dual sensor alarms utilizing both technologies in one unit? Yes, however, the jury is still out on these a little bit. Initially, these were manufactured to only go off when both the ionization and photoelectric sensors tripped. That has been changed, but some still worry that users are more likely to disarm a dual sensor alarm due to higher nuisance tripping associated with ionization technology. For example from burning toast in the toaster etc.
Finally, how can you tell what type of alarm you have? Most of the time, the type of alarm will be clearly stated on the back, as is the case in the picture that accompanies this blog post. In the picture, it clearly states "Ionization smoke alarm" at the top. If no such labeling is present, there are a couple of other tricks to help identify the type. First, either an i or a p will be embossed on the front of the alarm, depending on the type. If you can't find that, ionization alarms will always have a statement about containing a small amount of radioactive material on the back of the alarm.
That's it, until next time!
Sources:
2.https://blog.koorsen.com/what-is-the-difference-between-ionization-and-photoelectric-smoke-alarms