Kenninghall Creations

Did you know smoke detectors expire? It was news to me.

At 10pm last night two of my smoke detectors started chirping intermittently. Figuring the batteries needed changing since I missed doing it last time we changed the clocks, I went to get my step stool. Normally I would use my step ladder, but I didn’t want to wake the kids lugging it up the stairs and surely bashing into something. The ceiling upstairs is high enough that I could just reach the detector, but I wasn’t able to grip and remove the batteries. I could reach with a screw driver, so I loosened the screws and took it down. When I removed the batteries I saw some text embossed in the plastic of the battery compartment that said: “Detector to be replaced no later than 2003.” Usually I wouldn’t be able to see the text when changing the batteries at arms length, so it was fortunate I did it this way this time.

I haven’t found a definitive explanation of why the detectors expire. I’ve seen references to expiry ranges of 7 to 10 years and possibly less if your detectors are in hasher environments: heat, cold, humidity, dust, etc. The most common explanation that has come up is a concern over the electronics functioning properly after running constantly for so many years. I’m wondering if the radioactive component that many detectors contain has decayed after many years and doesn’t do its job any more, but that’s just speculation I haven’t found any support for yet.

Anyways, no matter why they expire, it looks like I’ll be shopping for some new detectors this weekend.