Sunday, October 5, 2014

Smoke detectors

"The alpha particles from the smoke detector do not themselves pose a health hazard, as they are absorbed in a few centimetres of air or by the structure of the detector.
The radiation dose to the occupants of a house from a domestic smoke detector is essentially zero, and in any case very much less than that from natural background radiation. The small amount of radioactive material that is used in these detectors is not a health hazard. On the other hand, the ability of domestic smoke detectors to save life and property has been demonstrated in many house fires.
Even swallowing the radioactive material from a smoke detector would not lead to significant internal absorption of Am-241, since the dioxide is insoluble. It will pass through the digestive tract, without delivering a significant radiation dose. (Americium-241 is however a potentially dangerous isotope if it is taken into the body in soluble form. It decays by both alpha activity and gamma emissions and it would concentrate in the skeleton.)
...Disposal of individual units can be in normal household garbage which goes to landfill."
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About thirty years ago I had a smoke detector that came with information that said something like, 'you could put a smoke detector against your skin for 10,000 years and not one isotope would enter your body.' So I haven't worried much about them since. But I have some old ones to dispose of and wanted to double-check the disposal rules, as I'd read you can just put them into the household trash.
I have two really old detectors I'll pitch, but several that are 11 years old. The recommendation is to replace detectors after ten years. Instead, I'll get all new ones, but keep the old ones for back up. For example, in the hallway I'll put one over each bedroom door, as well as a new detector in each bedroom. Yesterday, for the first time ever, I gently vacuumed the inside of the detectors, as per instructions.

18 comments:

Eric the Fruit Bat said...

However, it's a proven scientific fact that granite counter tops cause cancer of the fingertips, . . .

so don't ever touch one!

Christy said...

Americium is a delicious word. Obviously named after America, but it's pronounced so very differently. Am er EE cee um. Some combine the last two syllables as "shum." Not that it's a word one hears much in conversation.

Funny, isn't it, that an isotope with a >400 year half life is used in a device that wears out in 10 years?

deborah said...

"Funny, isn't it, that an isotope with a >400 year half life is used in a device that wears out in 10 years?"

Nice catch. What would wear out in ten years that a unit change is warranted?

chickelit said...

What would David Hahn do?

chickelit said...

Glenn T Seaborg et al. "discovered" Plutonium (Element 94). Next came Americium (95), then Curium (96), and then back to place names for Berkelium (97) and Californium (98). At the time that the latter two were named, The New Yorker sarcastically remarked that the Berkeley group had missed an opportunity by not naming the prior two elements "Universitatium" and "Ofium" first.

chickelit said...

What would wear out in ten years that a unit change is warranted?

I was going to suggest oxidation and disintegration of Americium, but it's used in detectors as the oxide.

So probably other circuitry. Maybe something is damaged by close contact to alpha particles?

chickelit said...
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Methadras said...

Eric the Fruit Bat said...

However, it's a proven scientific fact that granite counter tops cause cancer of the fingertips, . . .

so don't ever touch one!


Foowey!!! Who needs granite when you can get a beautiful CeaserStone counter top. Better than granite imho.

Trooper York said...

It is a proven scientific fact that if you touch a homeless guy in Dallas you will get the Ebola.

Unknown said...
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Unknown said...
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Unknown said...

Good to know about the gentle vacuuming.

If you ride around in a car in West Africa with a load of people who are all oozing ebola and are all about to drop dead with ebola, you'll be fine. Just fly to America. Joe Biden will greet you.

Trooper York said...

It is a proven fact that if you are a busy body politically correct judge you can be exposed to Ebola and not wear any protective gear because only racists can get Ebola which is why they are so afraid.

Unknown said...

That's all true, Troop. Only racists can get ebloa.

deborah said...

That Hahn story is so sad.

Eric the Fruit Bat said...

Jessica?

Couldn't agree more.

chickelit said...

deborah said...
That Hahn story is so sad.

I agree. He was talented and motivated. He just needed guidance and little oversight.

chickelit said...

"a little oversight."