# Fire Alarm Again! - Radioactive! What?!?



## Starbuck88 (Nov 12, 2013)

Well the fire alarms all just went off again.

Managed too see this time which one set them off, the one that did made an extra weird beep.

However, could not get the buggers to turn off, pressing the button on them all, turned the mains off and kept pressing the buttons.

The one on the ground floor, managed to turn it off, but the mid floor and top floor could not get them to turn off.

It was the top floor that set them off. So I had to get it off the ceiling.

I pulled off the cover but it was just like a cover that covered the internals, was absolutely shocked to see on a metal cage it said radioactive material?!?!?!!?!?!?

I looked in the metal cage and there's like a circular thing, I guess that's the detector with the radioactive stuff in it? (I didn't even touch the metal cage in case) but surely you can't just touch radioactive stuff by taking off the outer plastic cover. Americium 241 0.9 Microcuries it says.

Well then I could see the 2 clips to take it off the ceiling and disconnect it from the mains. Once off the middle floor one stopped and once I took the battery out....silence thank god!

Just paranoid about the radioactive thing, jesus. 

Will ring TW in the morning and get them to come and put a new one in, surely they do it for free, only lived in here for 6 months.


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## chp (Jul 22, 2011)

Ionisation-type smoke alarms do indeed contain a minute amount of the radioactive element americium-241. (Interestingly this is made in nuclear reactors from the decay of plutonium!) The radioactivity provides the ion source that the alarm uses to detect combustion products.

The radioactive source is contained within the detection chamber. You are completely safe if you simply remove the cover of the alarm. As you said, you can't inadvertently come into contact with the radioactive source unless you start trying to disassemble the detector apparatus. If you did somehow come into contact with it, it would be pretty harmless unless it was ingested, and even then you would only receive a very small radiation dose as the americium compound in smoke alarms is insoluble and would pass straight through the gut.


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