A warning to parts collectors.

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Staff Sergeant
Jul 2, 2006
Kiwi Land
Whilst doing some research I came across this rather disturbing post in a forum about aircraft instrument restoration. Excuse me if this has been posted before.



Whilst I was away I happened to test an old P8 compass with a professional grade radiation detector (long story) and the results were alarming!

Background radiation in the UK is around 0.1 micro Sieverts per hour. The compass gave a reading of 40 micro Sieverts per hour - that's 400 times greater than background!!
It would also classify the compass as radioactive waste.

The statutory maximum radiation exposure for a uranium miner is 20 times normal background, ie 20 milli Sieverts per year (radiation exposure is measured cumulatively). The compass would give you 350 milli Sieverts, or 0.35 Sievert - ie over 17 times the dose of a uranium miner


Obviously you will not be standing right next to an old compass forever - exposure decreases with distance. However, the real danger is from exposure to or ingestion of the dust or particles of the old luminous coatings. On compasses they tend to break off the wires and rattle around in the casing. Open one of them up and breathe this stuff in and you will be exposing yourself to high levels of radiation internally for the rest of your life.

Sorry to sound alarmist, but watch what you are doing out there!! I will also be testing all my new equipment in future!


Luminous dials of this nature apparently are very common, not just on compasses.
Have just seen your thread about radiation from compasses.

I have an interest in the RAF (me being ex and my father a Wop/ag on Lancasters)

I have just bought a p10 compass from ebay. I work for the ambulance service here in the UK and we have all been issued with radiation meters so I decided to stick mine on top of the compass!!

Current reading is 32 to 35 micro Sieverts an hour reducing to less than 1 micro Sievert 12" away.


In it's original box though, the reading was 11 to 12 micro Sieverts.

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