Posted By Ken Taylor Presumably you are referring to ionisation type detectors. I, also, shall await a reply on this with interest. Some years ago, when we were providing these to the public cheaply, we were advised that, as the Americium 241 was at less than 1 micro Curie (that will show how long ago it was to the 'radiation community') we could keep up to 100 in any one secure place within our local authority premises.

Posted By Ken Taylor John, Do you know whether the exemption from registration of workplaces where employees work with less than 500 allows this number to be stored together in one place and considered safe?

Posted By John Donaldson Ken and Alasdair, I must start by saying that only the enforcers, HSE, EA and SEPA, can give a definitive answer. If you are storing more than 500 you would be subject to the IRR 99 and all that entails. So far as storage is concerned the EA and SEPA would have a view on this but that would be looking at the environmental impact if something was to go wrong. Also I suspect the Fire Brigade would wish to know if you were storing large numbers of smoke detectors and may well impose conditions as well. You must also consider transport if you are moving large number of detectors by road or rail. Radiation protection is never simple.

Posted By John Donaldson Remember the Certificate of Approval only exempts you from reporting to HSE that you are working with Ionising Radiations. Para 3 of the Explanatory Notes reminds you that you still have to comply with the all the other requirements of IRR99 Radioactive Substances Act 93 enforced by EA and SEPA also still apply.