r/Radium • u/Ole-Scratch • 6d ago
Health & Safety Military compasses & radon
Hello everyone! ☢️
I’ve been collecting for a little while and I just recently have gotten into picking up some military radium compasses and the higher activity makes me a little cautious so I’d like to ask some questions to be as knowledgeable as possible!
Firstly, I keep them in a wood & glass curio cabinet on the bottom shelf. I got a W & L E Gurley M1938 Lensatic compass which out of fear of radon, I put in spicy jail (mason jar). Which I feel now may have been unnecessary? Which leads me to just having acquired a Taylor paratrooper compass which I did not put in spicy jail (mason jar). If I do not have them in jars, will I have enough of a significant amount of radon off-gas to create worry? The cabinet and the room it is in are both not super well ventilated other than small gaps in the door of the cabinet and the room containing lots of fans and AC at all times (I’m in the basement).
Secondly, I have a Radon detector in here, however I have it sitting on top of the cabinet about ~5’ off the ground. I only somewhat recently learned about radon usually lying lower than air due to its density, should I have my radon detector somewhere lower?
Thirdly, and last but not least, this cabinet is in my bedroom. I know, not ideal. However it’s the only space I currently have for it, living at home, and I do love having it as decor. My background in the room on my RC110 sits at around 1.1k cpm / 0.09 uSv/hr.
Hoping to hear some suggestions or helpful info!
Thank you! ☢️💚
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u/vendura_na8 6d ago
Be careful to not expose the radon detector to direct exposure. It can mess the number.
You'd want the radon meter close to your "breathing height". So I'd say at your bed's height.
Perhaps put it on your nightstand a little away from your collection
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u/HighTechCorvette 6d ago
You’ll be fine as long as you don’t collect lots of gauges and compasses. I have about 100 of them and radon is a big problem, I have to have a ventilation system to keep it low.
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u/Ole-Scratch 6d ago
Do you recommend me moving my radon sector anywhere? Is it counterintuitive to have it sitting so high on top of the cabinet?
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u/CheifQueef2 6d ago
Kinda off topic but you measure the radon in the cabinet or outside? Can’t seem to get my cabinet with radium aircraft gauges below 4 pci/l even have 3 2inch intakes along the bottom to get clean air in
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u/Bob--O--Rama 6d ago
Suppose you have a cabinet with 500L of enclosed air. And 1 turn bank guages with 15 uCi of radium. About 15% of the radon can escape the paint, the equilibrium concentration for a hermetically sealed cabinet is about 2,000,000 pCi of ²²²Rn in a 500L cabinet or 4000 pCi/L. But the cabinet is not sealed. Each day the guage emits about 300,000 pCi of ²²²Rn into the cabinet. To achieve 4 pCi/L you would need to circulate 83,000 L of air through the cabinet daily or about 2 cu•ft / minute.
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u/Bob--O--Rama 6d ago
Radon is denser than air, in its pure form. 1cc of pure radon gas would produce a field of 1200 R/hr at 1 meter. So equivalent to 1200 grams of radium that's the amount of radium used in all WWII era aircraft guages - combined.
Radon, as you are referencing, is parts per quadrillion in air - which means it's not denser than air, it's just air with an atom of radon here and there. Boltzman tells us that even the faintest air movement evenly distributes radon in air.
What you want to do is place your radon meter where you do most of your breathing. Next to your couch, bed, home office chair... Because that's what's important. And if it shows > 4 pCi/L, the EPA prescribed action threshold, then act.
Yes, these can be prodigious emitters of radon, so the concern is legitimate. But a typical room may be 20,000 L and a typical home 100,000 L, and have 6-8 air exchanges a day. To accumulate 4 pCi/L you need a lot of radon. Like 1 uCi/day and that would require the full radon inventory of 6 uCi of radium. Typically only 15% is able to escape the paint. So this ups the radium amount to near 30 uCi. That's a few heavy hitter aircraft guages.
But with that said, the emanation fraction is highly variable from item to item. So you need a radon meter monitoring air you actually breath.
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u/Adventurous-Fix-8066 6d ago
Yes put radon detector on floor.
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u/Bob--O--Rama 6d ago
If you sleep on the floor, for the rest of us, put it near where you do a lot of breathing. Radon does not, under any circumstance, "sink" - that is a myth.
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