nocturneYSK Your smoke detectors should be replaced every 7-10 years
GorkThis is only true for the Americium based smoke detectors. The newer photoelectric cell fire detectors don’t decay like Americium detectors, and as long as you replace the battery it’ll be good for however long it’s internal components (capacitors and whatnot) will last.
Technology Connections has a good video about this subject:
There are two types of smoke alarm. One of 'em ain't so good.
The half life for americium 241 is like 450 years. The 10 year replacement has nothing to do with decay. It’s just a non specific safety in case any of the electronics or board etc start to fail. Photoelectric detectors have the same 10 year recommendation as a max.
It’s actually recommend by many organizations (like the NFPA) to replace photoelectric detectors more often than ionization detectors, if anything.
I know exactly how they work. I’m a firefighter and a hazmat technician. Plus I work on and repair electronics as a hobby. Your smoke detector failing after 10 or 30 years has zero to do with radioactive decay. It’s from contamination (dust) and sensor degradation. Once the metal plates inside get enough buildup from dust (like smoke dust and regular dust) and contamination from humidity, the charge that’s supposed to be detected between those plates from the ionization stays lower all the time. That means less actual “smoke” is needed to drop it below the threshold. This happens MUCH faster than radioactive decay reducing what it will ionize.