Hi All - after some support with regards to Radon Sampling at sites.

We've been working on controls with regards to Radon exposure at a site which sits in an area with a potential exposure rate of 30% as stated by Public Health England. We have as such completed measurement tests which indicate exposure rates above 400bqm3 and have placed controls within (limiting time spent in basement).

I would like some advise please on our requirements to take radon measurement checks on sites which may fall in the lower brackets of potential exposure rates 0-1%, 1-3%, 3-5%, 5-10%. Is the expectation of the Ionising Regs for these sites to be measured with the support of a Radiation Protection Officer as I believe?

Many thanks,

JC

Have a look at the HSE page for "radon in the workplace". Most of the answers you ask are there in detail. In summary:

Where the workplace measurements show radon levels below 400 Bq/m3, as is the case for the majority of employers, then the only further action required is to decide when the risk assessment will be reviewed.

A Radiation Protection Adviser with radon experience should normally be consulted about how best to manage radon exposures but, if the employer plans to immediately remove the radon so that the IRR99 do not apply, it is better to consult a specialist radon removal (remediation) contractor in the first instance. The specialist will be able to advise on the most cost effective engineered means of reducing radon levels. It is usually appropriate to continue monitoring in these areas at least until the reduction measures have been put in place.

Behind the legal airborne concentration trigger level are some generalised assumptions about the relative equilibrium between radon gas and the associated radon radioactive decay products, and occupancy time which I believe is based on 2000 hours per year, leading an inhalation dose (which is really from the radioactive decay products of radon) of around 6 mSv per year. Some slight changes in relation to radon exposures are planned with the introduction of IRR18, based on the last set of ICRP Recommendations.

generally the areas affected by Radon gas are in the south west due to the granite rock etc, however if you think you need to monitor for radon you will need to place out some radon detectors. To get a reliable readings the monitors will need to be rdetecting for a period of three months, if you are above 400 further mitigation may be required depending on usage of room etc, if below then no need to worry. If you do mitigate you will need to remonitor (PHE recommend 2 yearly) if you don't then further test between 5 and 10 years would be satisfactory.