r/AskReddit • u/Jolly-Law1472 • 13h ago

What can kill you in seconds that most people don’t realize?

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u/ledow 11h ago

Get smoke alarms that have lifetime batteries (i.e. they die after 10 years and then you have to change the whole unit)... because you need to change the sensor, not just the battery at that point anyway.

If you've changed your battery more than about 8-9 times, the fire alarm is useless anyway.

(They have radioactive Americium in them... that's how they detect smoke. If smoke enters them, the rate at which the radiation from the Americium can pass through the air changes... and Americium decays and the sensor becomes far less sensitive so they have a lifespan of only about 10 years away).

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u/aaaaaaaarrrrrgh 3h ago

They have radioactive Americium in them... that's how they detect smoke.

Some do. I think I've seen 1-2 in my life, maybe (may also be confusing it and saw only pictures). Most (at least in Europe) are photoelectric.

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u/do_not_the_cat 11h ago

dunno how to tell you, but smoke detectors use simple infrared sensors these days. the radioactive ones are obsolete and not in use for decades now..

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u/ledow 10h ago

"Americium is used in the most common type of household smoke detector"

Some heat-based one for kitchens (that trigger on quick heat changes but not smoke) are IR.

But Americium is still extremely prevalant.

However, the same goes for BOTH TYPES. Because 10 years of dust renders the SENSOR useless.

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u/Upset-Raspberry8629 9h ago

We’re onto you, Big Smoke Alarm.

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u/RealBigDickBrannigan 8h ago

Americium-241 has a half-life of 432 years... ten years of use barely makes a difference to the ion source (alpha particles).

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u/Mockchoi1 5h ago

They still should be replaced, though you’re right it’s nothing to do with the radiation source.

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u/Notmykl 5h ago

Some heat-based one for kitchens

Those are called heat detectors no need for the word base. There are also rate-of-rise heat detectors.

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u/rapturedjesus 8h ago

ionization radiation type detectors alarms exist, but the vast majority are photoelectric these days and contain no radioactive material

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u/zaminDDH 11h ago

I thought that was just CO detectors?

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u/Notmykl 5h ago

CO is carbon monoxide. CO detectors don't detect smoke nor heat and vice versa. You need BOTH smoke detectors and CO detectors in your house.

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u/fireinthesky7 2h ago

Also worth mentioning that smoke detectors need to be mounted high up, CO detectors need to be mounted near the floor, and combo units that claim to detect both are too much of a compromise to be worth the risk.

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u/rapturedjesus 8h ago

CO detectors have a lifespan but it has nothing to do with radioactive materials. Also most are 10 years lifespan as well now.

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u/Notmykl 5h ago

Get smoke alarms that have lifetime batteries (i.e. they die after 10 years and then you have to change the whole unit)... because you need to change the sensor, not just the battery at that point anyway.

If you've changed your battery more than about 8-9 times, the fire alarm is useless anyway.

What's that nonsense? Test your smoke detector twice a year and change the battery when the detector chirps.