Smoke Alarms and radiation from them

[Happy Days2021]

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?

 

[sophiecentaur]

"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.

 

[anorlunda]

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.

 

[Happy Days2021]

Why then do smoke detectors need leaked tested in schools as radiation sources and also solid sealed sources need leak tested in labs?

 

[berkeman]

Why then do smoke detectors need leaked tested in schools as radiation sources and also solid sealed sources need leak tested in labs?

Wasn't this already covered in your previous thread?

https://www.physicsforums.com/threads/radiation-leak-test-instruments.1002498/

 

[sophiecentaur]

Wasn't this already covered in your previous thread?

https://www.physicsforums.com/threads/radiation-leak-test-instruments.1002498/

Keep asking the same question until you get the answer you want, perhaps.

 

[Happy Days2021]

No I don't think my previous thread addressed how or why they could leak?

 

[berkeman]

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...

 

[russ_watters]

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.

 

[Happy Days2021]

Yes, in England all schools must leak test sealed sources including smoke detectors used in Physics experiments

 

[russ_watters]

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.

 

[Happy Days2021]

I know they need tested, but I don't know the how you actually do it part

 

[russ_watters]

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.

 

[davenn]

Yes, in England all schools must leak test sealed sources including smoke detectors used in Physics experiments

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

 

[russ_watters]

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.

And since smoke detectors have been made obsolete in most 1st world countries...

What?!

 

[davenn]

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

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

Dave

 

[russ_watters]

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

Ok, you're talking about the radioactive type, not smoke detectors in general. That's not what you said.

 

[davenn]

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

my 2 current detectors are these ...

one of these ( from China) ...

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

cheers
Dave

 

[davenn]

Ok, you're talking about the radioactive type, not smoke detectors in general. That's not what you said.

I said radioactive type

edit, ohhh maybe you were referring to post #14 ... I will edit

 

[berkeman]

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...

Spoiler

Well, to schools in other countries of course...

 

[russ_watters]

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.

 

[Vanadium 50]

but you never know what might happen if you let school kids abuse them.

I'm imagining the old American Tourister ads.

And since smoke detectors have been made obsolete in most 1st world countries

What?!

You didn't hear? Building fires have been banned.

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.

 

[davenn]

Vegemite if you know where to look. Not sure why anyone would want to.

It's very yummy

 

[sophiecentaur]

It's very yummy

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.

 

[meb68]

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

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.

 

[russ_watters]

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.

 

[Vanadium 50]

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.

 

[Vanadium 50]

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.

 

[sophiecentaur]

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?!)

 

[davenn]

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

 

[meb68]

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?

 

[russ_watters]

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.

 

[davenn]

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

not my sample ... am not at home at the moment to retrieve my photo
this one looks pretty much like my samplecheers
Dave

 

[russ_watters]

New PSA needed: "Granite Countertops: The Silent Killer".

 

[MidgetDwarf]

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...

 

[Drakkith]

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?

I'm not concerned, for two reasons. First, because the different components of the smoke detectors are manufactured in entirely different plants and are then shipped to where they will be assembled. There is simply no way for contamination to occur to such an extent as you are worried about because the components are never in a situation where that could happen.

In addition, the americium is itself mixed with gold, which is then plated with layers of gold and silver, to form a small piece of 'foil' that has two 5mm discs cut out that are inserted into the detector casing or circuit board. Alloying the americium with gold virtually assures that a person won't get contaminated, as gold is an extremely malleable metal that is very difficult to fracture by accident. It doesn't shatter into many tiny shards or turn into some sort of powder that can easily be inhaled. It doesn't corrode either, so you don't have to worry about corrosion products containing americium. In a fire the alloy melts, but the temperature is usually too low to boil the alloy or either of its constituent elements, so there is little danger of inhalation. And, assuming that the fire was hot enough to boil the alloy, if you're so close to a boiling piece of this gold-americium foil from a smoke detector to inhale any of it then you're likely in the middle of a massive house fire and are already dead.

You'd have to make a conscious and determined effort to turn these 5mm discs of gold-americium foil into something that could actually harm you. Even eating it wouldn't kill you.

 

[anorlunda]

Perhaps smoke detectors should come with a warning label that says you shouldn't grind them up and smoke them?

My smoke detector has a sticker that says, "Do not ingest."

 

[hutchphd]

Of course we should not forget David Hahn, the "Nuclear Boy Scout"

On August 1, 2007, Hahn was charged with larceny in Clinton Township, Michigan for allegedly removing a number of smoke detectors from the halls of his apartment building

Sadly he passed at age 39 but it was alcohol and fentanyl not Americium.

 

[anorlunda]

In addition to the radiation, the ordinary chemistry strongly influences the hazards of different substances.

• Strontium 90 is attracted to bone structures.
• Plutonium sinters, creating tiny particles that can get lodged in the lungs.
• Tritium can become part of a water molecule. Our bodies are 70% water.
• Cobalt is brilliant blue. Children have been attracted to rubbing it on their skin.

The materials used in smoke detectors do not have unique biochemical hazards.

 

[meb68]

Im sure your laptop/desktop gives off more harmful things, than a smoke detector. Are you dying after typing? No. So relax a bit...

Bizarre reply

I'm not aware of any radioactive alpha-particle-emitters in or on my desktop computer that I could inhale and that would irradiate my bone tissue for years and decades.

 

[meb68]

In addition to the radiation, the ordinary chemistry strongly influences the hazards of different substances.

• Strontium 90 is attracted to bone structures.
• Plutonium sinters, creating tiny particles that can get lodged in the lungs.
• Tritium can become part of a water molecule. Our bodies are 70% water.
• Cobalt is brilliant blue. Children have been attracted to rubbing it on their skin.

The materials used in smoke detectors do not have unique biochemical hazards.

Yes, in the piece that I linked on Page 1, Lyman mentioned that "...impacts depend on the exact composition of the radioactive materials, their chemical forms, and the sizes of the particles that were inhaled..."

But he also said this about plutonium and americium -- "This incident is a reminder of the extremely hazardous nature of these materials, especially when they are inhaled, and illustrates why they require such stringent procedures when they are stored and processed."

Lyman probably knows more about radiation than anyone on here.

 

[meb68]

I'm not concerned, for two reasons. First, because the different components of the smoke detectors are manufactured in entirely different plants and are then shipped to where they will be assembled. There is simply no way for contamination to occur to such an extent as you are worried about because the components are never in a situation where that could happen.

In addition, the americium is itself mixed with gold, which is then plated with layers of gold and silver, to form a small piece of 'foil' that has two 5mm discs cut out that are inserted into the detector casing or circuit board. Alloying the americium with gold virtually assures that a person won't get contaminated, as gold is an extremely malleable metal that is very difficult to fracture by accident. It doesn't shatter into many tiny shards or turn into some sort of powder that can easily be inhaled. It doesn't corrode either, so you don't have to worry about corrosion products containing americium. In a fire the alloy melts, but the temperature is usually too low to boil the alloy or either of its constituent elements, so there is little danger of inhalation. And, assuming that the fire was hot enough to boil the alloy, if you're so close to a boiling piece of this gold-americium foil from a smoke detector to inhale any of it then you're likely in the middle of a massive house fire and are already dead.

You'd have to make a conscious and determined effort to turn these 5mm discs of gold-americium foil into something that could actually harm you. Even eating it wouldn't kill you.

Thanks for the detailed reply to the question, and I hear what you're saying.

But here's the issue when dealing with an "extremely hazardous" material like americium -- there is no room for error.

As Lyman showed, the Japanese worker who inhaled a microscopic ("about 150 micrograms") amount of plutonium will almost certainly develop a fatal cancer.

That said, you are confident that manufacturers of these "foils", or of complete ionization chambers can police themselves when it comes to detecting possible microscopic amounts of americium that could contaminate their products?

Do you know if these products are checked for contamination when they're received at the "assembly" plants?

Do NRC or independent inspectors ever get involved at any point in the process?

Heck, I can probably dig up a dozen incidents where radioactive materials were accidentally mishandled and/or released at national labs such as Los Alamos. And people working there likely have far more training and knowledge than Average Joes working at a smoke detector factory.

When microscopic amounts of these materials can be extremely dangerous and highly carcinogenic, I simply can't understand why we're even messing around with this stuff.

 

[russ_watters]

Heck, I can probably dig up a dozen incidents where radioactive materials were accidentally mishandled and/or released at national labs such as Los Alamos.

But, I assume, none for smoke detectors.

When microscopic amounts of these materials can be extremely dangerous and highly carcinogenic, I simply can't understand why we're even messing around with this stuff.

We've told you, but you won't listen. The things you are saying are quite simply meaningless. The first part of that sentence in particular. It sounds scary but means absolutely nothing.

The amount and means of exposure matters. This is true for anything that is potentially harmful. From sunlight to water.

 

[hutchphd]

But here's the issue when dealing with an "extremely hazardous" material like americium -- there is no room for error.

The radon in your basement will similarly kill you. If it decides to decay at an inopportune moment you will be similarly at risk. Without the numbers no decision can be rationally made. Inthe big scheme smoke detectors are a problem, but a very small one. Let us worry about the big ones.
This is called science.

 

[Vanadium 50]

Cyanide is dangerous.
Cyanide is a 3 syllable word beginning with C.
Therefore we need to avoid all three syllable words beginning with C.
Therefore prudent avoidance indicates that we shouldn't eat celery.

Simple logic.

 

[jim mcnamara]

Thread locked.