Lifetime battery in Smoke Detector
- Thread starter mlnk
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First Alert. But 'lifetime' of any smoke is only 10 years.
Rewire
Senior Member
- Location
- Lake of the Ozarks
We started putting these in hard to reach places like 20ft vaulted ceilings
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
My understanding is that the smoke detector itself has an expected sensor life of 10 years.
The 'lifetime' smoke detectors have a relatively large lithium battery that is permanently soldered down, and expected to run the detector for 10 years of normal use. When the battery is dead you throw the detector away and get a new one.
-Jon
The 'lifetime' smoke detectors have a relatively large lithium battery that is permanently soldered down, and expected to run the detector for 10 years of normal use. When the battery is dead you throw the detector away and get a new one.
-Jon
ultramegabob
Senior Member
- Location
- Indiana
I happen to have a Kidde smoke detector with a 10 year battery right on my desk, lol...
peter d
Senior Member
- Location
- New England
And where does one dispose of a smoke detector properly? :roll:
Oh yeah, in the trash.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
Given that the detector element is in fact radioactive, I would have thought that special disposal was required.
I had to dispose of a bunch last year, so going from memory: Manufacturers are no longer required to accept 'spent' detectors (some still will, as long as the detector is still in the warranty period). I brought a detector to my local household hazardous waste station ('Portland Metro') where I was told that it should go in the regular household trash.
-Jon
I had to dispose of a bunch last year, so going from memory: Manufacturers are no longer required to accept 'spent' detectors (some still will, as long as the detector is still in the warranty period). I brought a detector to my local household hazardous waste station ('Portland Metro') where I was told that it should go in the regular household trash.
-Jon
This is funny. First Lithium would be the battery of choice for smoke detectors.
The exposure you receive from a smoke detector is considerably less than the dirt in your front yard. Most smoke detectors use of about 2 microcuries of americium-241, which is used to make the air in the detector's "ionization chamber" electrically conductive. If smoke enters the chamber, it inhibits the flow of electricity, which causes the alarm to sound.
Americium-241 half life is about 10-years which is why smoke detectors last only 10-years. After that the radioactive material has decayed and is harmless.
The exposure you receive from a smoke detector is considerably less than the dirt in your front yard. Most smoke detectors use of about 2 microcuries of americium-241, which is used to make the air in the detector's "ionization chamber" electrically conductive. If smoke enters the chamber, it inhibits the flow of electricity, which causes the alarm to sound.
Americium-241 half life is about 10-years which is why smoke detectors last only 10-years. After that the radioactive material has decayed and is harmless.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
The half life of Americium-241 is more like 430 years, not 10 years. At the 'end of life' of a smoke detector, it is almost as radioactive as when manufactured.
( http://www.epa.gov/radiation/radionuclides/americium.html#properties )
However the amount of Americium-241 in a smoke detectors is quite small, on the order of 1 microcurie (http://home.howstuffworks.com/home-improvement/household-safety/fire/smoke2.htm). Comparing this to 'natural' sources, this is about the same total radioactivity as found in 2 cubic feet of average soil ( http://www.physics.isu.edu/radinf/natural.htm )
Given that the Americium-241 in a smoke detector is pretty well stabilized into a metal foil, I am comfortable disposing of it in the ordinary trash...but I am surprised that I am permitted to do so.
-Jon
( http://www.epa.gov/radiation/radionuclides/americium.html#properties )
However the amount of Americium-241 in a smoke detectors is quite small, on the order of 1 microcurie (http://home.howstuffworks.com/home-improvement/household-safety/fire/smoke2.htm). Comparing this to 'natural' sources, this is about the same total radioactivity as found in 2 cubic feet of average soil ( http://www.physics.isu.edu/radinf/natural.htm )
Given that the Americium-241 in a smoke detector is pretty well stabilized into a metal foil, I am comfortable disposing of it in the ordinary trash...but I am surprised that I am permitted to do so.
-Jon
Ok so will it down to your kids, it will still work with fresh batteries.
however from the NRC in your link quotes;The Nuclear Regulatory Commission, which regulates the radioactive material in smoke detectors, permits their disposal as ordinary trash.
Which is the point I was making, its funny.
Last edited:
Jimtheboat
New member
Only for Ionization type Detetors
Only for Ionization type Detetors
The previous post(s) are true only as follows:
They are true only for ionization type of detectors using radioactive Americium. They are not true for photoelectric type which operate on completely different principle of light transmission.
If ionization type detectors are based on the ability of the radioactive substance to ionize the air and hence aid the transmission of electrical properties, why doesn't the ionization type detector alarm continuously when the half-life time is reached? Could it be that this ability of ionizing the gas is not completely destroyed after the first half-life, but the standard has a built in safety factor?
Only for Ionization type Detetors
The previous post(s) are true only as follows:
They are true only for ionization type of detectors using radioactive Americium. They are not true for photoelectric type which operate on completely different principle of light transmission.
If ionization type detectors are based on the ability of the radioactive substance to ionize the air and hence aid the transmission of electrical properties, why doesn't the ionization type detector alarm continuously when the half-life time is reached? Could it be that this ability of ionizing the gas is not completely destroyed after the first half-life, but the standard has a built in safety factor?
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