Smoke Alarms and radiation from them

In summary: They called around home around 8 months ago and replaced our two, free of charge, and disposed of the radioactive source onesin a safe manner.Yes, I've heard of this happening in the US. They call around and offer to replace them for free if you have them.
  • #1
Happy Days2021
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Why are smoke detectors with Americium exempt from leak testing when there are ones in older houses maybe 30 years old and one needs to open them up to change the battery. Surely the Americium could leak out over time from the ionisation chamber?
 
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  • #2
"surely"??
The Americium wouldn't be in the form of a powder. Afaik, most sources are encapsulated in matrix of glass or ceramic which would stay intact for thousands of years if it were not roasted or dissolved income strong acid.
 
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  • #3
Happy Days2021 said:
Summary:: Smoke Alarms and radiation from them

Why are smoke detectors with Americium exempt from leak testing when there are ones in older houses maybe 30 years old and one needs to open them up to change the battery. Surely the Americium could leak out over time from the ionisation chamber?
It is not in the form of a gas or a powder.
https://hps.org/publicinformation/ate/q7445.html
Please be aware that there is a very small amount of 241Am, ~33.3 kBq in a smoke detector. This form of 241Am is embedded (fused) onto a layer of foil and does not pose any danger to you or your family; it cannot be wiped off, nor can it leach off. This is one of the reasons NRC originally authorized its use in the 1970s.
 
  • #4
Why then do smoke detectors need leaked tested in schools as radiation sources and also solid sealed sources need leak tested in labs?
 
  • #7
No I don't think my previous thread addressed how or why they could leak?
 
  • #8
Happy Days2021 said:
No I don't think my previous thread addressed how or why they could leak?
We may end up merging your two threads. The Mentors are discussing it now...
 
  • #9
Happy Days2021 said:
Why then do smoke detectors need leaked tested in schools as radiation sources and also solid sealed sources need leak tested in labs?
Do you have a source for this requirement? I'm not familiar with it.
 
  • #10
Yes, in England all schools must leak test sealed sources including smoke detectors used in Physics experiments
 
  • #11
Happy Days2021 said:
Yes, in England all schools must leak test sealed sources including smoke detectors used in Physics experiments
No, a source. A link to a description of the requirement.

...also, if you already know the test protocol I don't understand why you would be asking about test instruments in the other thread.
 
  • #12
I know they need tested, but I don't know the how you actually do it part
 
  • #13
Happy Days2021 said:
I know they need tested, but I don't know the how you actually do it part
Well, since you said the UK I was able to find this (but you should really be doing your own homework here):
http://science.cleapss.org.uk/Resou...active-Substances-in-Schools-and-Colleges.pdf

I don't have time right now to dive into it, but the testing requirement and protocol are in there. But as a starting point, since this is the source of your concern it should be what frames your investigation.
 
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  • #14
Happy Days2021 said:
Yes, in England all schools must leak test sealed sources including smoke detectors used in Physics experiments

russ_watters said:
Well, since you said the UK I was able to find this (but you should really be doing your own homework here):
http://science.cleapss.org.uk/Resou...active-Substances-in-Schools-and-Colleges.pdf
excellent info, but I didnt seen any mention of smoke detectors in there

reading through this thread, I continue to wonder if the OP has some misunderstanding on what is being referred to.
@Happy Days2021 you still haven't given an information source relating specifically to testing smoke detectors.
And since radioactive source smoke detectors have been made obsolete in most 1st world countries, I still can't help but wonder
why you are so fixated with them ??

Dave
 
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  • #15
davenn said:
excellent info, but I didnt seen any mention of smoke detectors in there
Page 32, but more broadly the entire document is about radiation sources used in school labs. If there were an unspecified one, the requirements would still apply.
davenn said:
And since smoke detectors have been made obsolete in most 1st world countries...
What?!
 
  • #16
russ_watters said:
Page 32, but more broadly the entire document is about radiation sources used in school labs. If there were an unspecified one, the requirements would still apply.

Thanks for finding the bit about smoke detectors on page 31, I missed that :smile:

russ_watters said:
What?!

yup, here and in NZ at least ... the fire service will actively replace all radioactive source smoke detectors with the newer type
They called around home around 8 months ago and replaced our two, free of charge, and disposed of the radioactive source ones
in a safe manner.
Sorry of you Americans are behind the times :wink:

Dave
 
  • #17
davenn said:
yup, here and in NZ at least ... the fire service will actively replace all radioactive source smoke detectors with the newer type
They called around home around 8 months ago and replaced our two, free of charge, and disposed of the radioactive source ones
in a safe manner.
Sorry of you Americans are behind the times :wink:
Ok, you're talking about the radioactive type, not smoke detectors in general. That's not what you said. :wink:
 
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  • #18
Awesome list
have several of them ( as ticked) always looking for more sources for the collection
Most of my sources are radioactive rocks, currently have ~ 15 samples with various mineral compositions

Cruising the old "op shops" ( second hand and antique shops) with my Geiger counter, which I need to do again,
been a while, brings up watches, clocks, occasional cup or plate.
The "hottest " natural source I used to be able to get to see what a thumb sized hunk of pitchblende
in the geology dept. where I did my studies. Even through the 1" think lead crucible it was still detectable
radioactive sources1.JPG
my 2 current detectors are these ...

one of these ( from China) ...

CAJOE Geiger counter.jpg

and 2 of these (from the Ukraine - sold like hotcakes during the Chernobyl chaos)

Bella Dosimeter.jpg


cheers
Dave
 
  • #19
russ_watters said:
Ok, you're talking about the radioactive type, not smoke detectors in general. That's not what you said. :wink:
I said radioactive type :wink: :smile:

edit, ohhh maybe you were referring to post #14 ... I will edit
 
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  • #20
davenn said:
They called around home around 8 months ago and replaced our two, free of charge, and disposed of the radioactive source ones
in a safe manner.
I read somewhere that they actually donated them to school science labs...

:wink:

Well, to schools in other countries of course...
 
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  • #21
The standard for UK schools it says this:
The residual risk is low with the control measures in place.
Note: these control measures are not required for smoke alarms when used in the home, as
they are extremely unlikely to suffer damage in the normal position, fixed to the ceiling.
So they are basically saying that they don't leak in normal use, but you never know what might happen if you let school kids abuse them.
 
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  • #22
russ_watters said:
but you never know what might happen if you let school kids abuse them.
I'm imagining the old American Tourister ads.

davenn said:
And since smoke detectors have been made obsolete in most 1st world countries
russ_watters said:
What?!
You didn't hear? Building fires have been banned.
davenn said:
And since radioactive source smoke detectors have been made obsolete in most 1st world countries

The US is, last I checked, the 1st world. You can even get Vegemite if you know where to look. Not sure why anyone would want to.

According to Home Depot, ionization (they never say "radioactive source") detectors are the most popular. I'm not surprised. They are safe, inexpensive and effective.

They used to be uniformly superior to photocell detectors. Photocells are getting better, thanks to two developments: cheap computation, and blue LEDs. Photodetectors were less accurate - less sensitive at the same threshold, or if you lowered the threshold, more prone to false alarms. Shorter wavelengths help, comparing responses at different wavelengths helps, looking at the time profile helps, and tiny little DSP chips put it all together. And while in principle CO detection is independent of smoke sensor type, if you already are going to put some intelligence on your smoke detector, you can combine the information from the smoke detection with CO and do a better job on both fronts.
 
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  • #23
Vanadium 50 said:
Vegemite if you know where to look. Not sure why anyone would want to.
It's very yummy :smile:
 
  • #24
davenn said:
It's very yummy :smile:
Nothing like as nice as the sharper taste of Marmite. I feel sorry for Aussies, in that respect. They seem to think that the poor relative is as good.
 
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  • #25
davenn said:
Thanks for finding the bit about smoke detectors on page 31, I missed that :smile:
yup, here and in NZ at least ... the fire service will actively replace all radioactive source smoke detectors with the newer type
They called around home around 8 months ago and replaced our two, free of charge, and disposed of the radioactive source ones
in a safe manner.
Sorry of you Americans are behind the times :wink:

Dave

We're "behind the times" when it comes to guns too, dave.

Anyway, it's unbelievable to me that such a dangerous radioactive alpha-particle-emitting material (americium) was ever approved for use in these things which are in tens of millions of homes in this country.
 
  • #26
meb68 said:
Anyway, it's unbelievable to me that such a dangerous radioactive alpha-particle-emitting material (americium) was ever approved for use in these things which are in tens of millions of homes in this country.
It's about understanding and properly mitigating risk. It just isn't that high even if described in scary sounding terms.
 
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  • #27
Typical radiation doses from smoke detectors is the same as eating 0,1-0.5 bananas per year.

An interesting question would be if the Amerecium is the most radioactive part of the smoke detector, or which has more radiation at a distance of, say 1 meter: ionization or photodetection. The answer is not obvious.
 
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  • #28
I ws originally thinking about glass and potassium-40. But...

Now that I think of it, ionization-type may actually reduce radiation exposure. By ionizing dust, it will collect on surfaces rather than stay in the air (kind of the point). Mineral dust contains radioisotopes - uranium, thorium and polonium. In principle, an ionization smoke detector will reduce exposure to some natural radioactivity.

In practice, this effect is surely too small to detect. But my point is that it's not immediately obvious even in which direction the sign is.
 
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  • #29
Are we getting this into a proper perspective? The possible risk of death in a house fire is what needs to be compared with very low risks of radiation damage from the 'offending' detectors.
I read a few web documents which were of varying degrees of quality but the opinion seems to be that a functioning smoke detector in a home is likely tohttps://www.health.ny.gov/prevention/injury_prevention/children/toolkits/fire/smoke_alarms_effective_preventing_deaths.htm. The actual statistics is obviously complicated but that link suggests that 890 deaths would be avoided (in US?) per year if everyone had a functioning detector. How many deaths, on the other hand, have been caused by damaged detectors due to escape of radioactive materials? This link suggests the exposure is less than the background radiation levels.
Thing is, radiation, like flying, has a very high perceived risk and we tend to overestimate the dangers associated with both.

PS the number of deaths due to using wood fires in cooking in developing countries is pretty vast. This link has evidence that 3.8M deaths are caused through the use of wood fires in cooking. Scary but not a simple problem to solve in developing countries. (Barbecues?!)
 
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  • #30
meb68 said:
Anyway, it's unbelievable to me that such a dangerous radioactive alpha-particle-emitting material (americium) was ever approved for use in these things which are in tens of millions of homes in this country.

You are really not understanding how low the risk is. They are incredibly low level sources
The ones I have played with, with a Geiger counter, were not even detectable from 1m away.

Alpha particles do not travel very far ... they are a Helium nucleus and will pic up a couple of free electrons very quickly and become neutral
 
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  • #31
Some of you guys must think we live in a perfect world when it comes to handling dangerous radioactive material like americium.

In this piece from 2017, Lyman writes about some Japanese nuclear workers who were accidentally exposed to high levels of "extremely hazardous" plutonium-239 and americium-241...

https://allthingsnuclear.org/elyman...1 was present as,of the isotope plutonium-241.

The most heavily exposed worker inhaled about 360,000 becquerels (Bq) of plutonium-239, and 220 Bq of americium-241.

As he states, "The mass equivalent of 360,000 Bq of Pu-239 is about 150 micrograms."

150 micrograms is just 0.00015 grams.

In other words, if inhaled, incredibly tiny amounts of radioactive alpha-particle-emitters like plutonium-239 and americium-241 are sufficient to eventually cause a fatal cancer.

Now, does anyone seriously believe that these ionization smoke detectors can be manufactured by humans in facilities that are so perfect and pristine that there is absolutely no chance that this "extremely hazardous" americium could contaminate the plastic housing, any other part of the device, or even possibly get on packaging material?
 
  • #32
meb68 said:
Some of you guys must think we live in a perfect world when it comes to handling dangerous radioactive material like americium.

In this piece from 2017, Lyman writes about some Japanese nuclear workers who were accidentally exposed to high levels of "extremely hazardous" plutonium-239 and americium-241...

https://allthingsnuclear.org/elyman...1 was present as,of the isotope plutonium-241.

The most heavily exposed worker inhaled about 360,000 becquerels (Bq) of plutonium-239, and 220 Bq of americium-241.

As he states, "The mass equivalent of 360,000 Bq of Pu-239 is about 150 micrograms."

150 micrograms is just 0.00015 grams.

In other words, if inhaled, incredibly tiny amounts of radioactive alpha-particle-emitters like plutonium-239 and americium-241 are sufficient to eventually cause a fatal cancer.
Perhaps smoke detectors should come with a warning label that says you shouldn't grind them up and smoke them?

It doesn't need to be just less than "perfect". It would take real effort to get cancer from smoke detectors(if even possible - looks like the dose from that accident was like 50,000x what is in a smoke detector).

You're really not listening and actually analyzing risk, but instead still making scary sounding false equivalences. The amount those workers were exposed to is vastly more than you could get from a smoke detector yet still only a "maybe" cancer risk.

[Edit] Ok, I'm barely trying, but if my math serves me: if you're a pack a day smoker and you roll your own cigarettes you could disassemble and grind up the Am source from one smoke detector in each cigarette to get the equivalent dose those workers got in about four years. Not including the radiation dose from the tobacco itself, which is of a similar order of magnitude.
 
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  • #33
meb68 said:
Some of you guys must think we live in a perfect world when it comes to handling dangerous radioactive material like americium.

I handle ( with respect) material much more radioactive than those tiny Americium samples in S.A's

one of my latest mineral samples is Torbernite Cu(UO₂)₂(PO₄)₂ · 8-12 H₂O

My Geiger count goes absolutely berserk in the presence of this mineral sample

Torbernite sm.jpg


not my sample ... am not at home at the moment to retrieve my photo
this one looks pretty much like my samplecheers
Dave
 
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  • #34
New PSA needed: "Granite Countertops: The Silent Killer".
 
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  • #35
meb68 said:
Some of you guys must think we live in a perfect world when it comes to handling dangerous radioactive material like americium.

In this piece from 2017, Lyman writes about some Japanese nuclear workers who were accidentally exposed to high levels of "extremely hazardous" plutonium-239 and americium-241...

https://allthingsnuclear.org/elyman/cancer-risk-for-japanese-exposed-to-plutonium/#:~:text=For isotopes such as plutonium,will cause a fatal cancer.&text=Americium-241 was present as,of the isotope plutonium-241.

The most heavily exposed worker inhaled about 360,000 becquerels (Bq) of plutonium-239, and 220 Bq of americium-241.

As he states, "The mass equivalent of 360,000 Bq of Pu-239 is about 150 micrograms."

150 micrograms is just 0.00015 grams.

In other words, if inhaled, incredibly tiny amounts of radioactive alpha-particle-emitters like plutonium-239 and americium-241 are sufficient to eventually cause a fatal cancer.

Now, does anyone seriously believe that these ionization smoke detectors can be manufactured by humans in facilities that are so perfect and pristine that there is absolutely no chance that this "extremely hazardous" americium could contaminate the plastic housing, any other part of the device, or even possibly get on packaging material?
Im sure your laptop/desktop gives off more harmful things, than a smoke detector. Are you dying after typing? No. So relax a bit...
 
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<h2>1. How does a smoke alarm detect smoke?</h2><p>A smoke alarm uses a small amount of radioactive material, usually Americium-241, to ionize the air inside the alarm. When smoke particles enter the alarm, they disrupt the ionization and trigger the alarm to sound.</p><h2>2. Is the radiation from a smoke alarm harmful?</h2><p>The amount of radiation emitted by a smoke alarm is very low and poses no harm to humans. In fact, the radiation levels are so low that they are considered safe even for pregnant women and children.</p><h2>3. How long does a smoke alarm's radioactive material last?</h2><p>The half-life of Americium-241 is approximately 432 years, meaning it takes that long for half of the material to decay. However, the amount used in smoke alarms is so small that it will last for the lifetime of the alarm.</p><h2>4. Can smoke alarms cause false alarms due to radiation from other sources?</h2><p>No, smoke alarms are specifically designed to detect the ionization caused by smoke particles and are not affected by other sources of radiation such as cell phones or microwaves.</p><h2>5. Are there any alternatives to using a radioactive smoke alarm?</h2><p>Yes, there are photoelectric smoke alarms that use a light beam to detect smoke particles. These alarms do not use any radioactive material and are a safe alternative for those concerned about radiation exposure.</p>

1. How does a smoke alarm detect smoke?

A smoke alarm uses a small amount of radioactive material, usually Americium-241, to ionize the air inside the alarm. When smoke particles enter the alarm, they disrupt the ionization and trigger the alarm to sound.

2. Is the radiation from a smoke alarm harmful?

The amount of radiation emitted by a smoke alarm is very low and poses no harm to humans. In fact, the radiation levels are so low that they are considered safe even for pregnant women and children.

3. How long does a smoke alarm's radioactive material last?

The half-life of Americium-241 is approximately 432 years, meaning it takes that long for half of the material to decay. However, the amount used in smoke alarms is so small that it will last for the lifetime of the alarm.

4. Can smoke alarms cause false alarms due to radiation from other sources?

No, smoke alarms are specifically designed to detect the ionization caused by smoke particles and are not affected by other sources of radiation such as cell phones or microwaves.

5. Are there any alternatives to using a radioactive smoke alarm?

Yes, there are photoelectric smoke alarms that use a light beam to detect smoke particles. These alarms do not use any radioactive material and are a safe alternative for those concerned about radiation exposure.

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