Radon in the Workplace

Reviewed April 2008

Measurement service for workplace buildings

If you are an employee and are concerned about radon in your workplace, you should speak initially to your employer; a leaflet about radiation at work is available.

Employers are required by the Management of Health and Safety Regulations at Work 1999, to assess risks from radon in workplaces in Affected Areas, and this usually requires a measurement. The Ionising Radiations Regulations 1999 require action to protect employees if the average radon gas concentration exceeds 400 Bq m-3 (becquerels per cubic metre of air).

The HPA runs a routine radon monitoring service for employers. Monitors cost £21.15 (including VAT) each, which includes processing, a written report of the results and brief advice. Between two and ten monitors are usually sufficient for all but the largest premises. Measurements should normally be conducted over three months and monitors are sent to the employer by post with instructions for placement. Monitors are then posted back for processing and reporting.

Monitor placement

There are no types of indoor ground floor workplace in which the radon can assumed always to be low because of ventilation or working conditions. It is not, however, generally necessary to measure above the ground floor. The number of monitors required for each building depends on the workplace type and use, see below. There is no need to place monitors in cupboards or stores that cannot be entered.

Detectors for workplaces cannot yet be ordered on-line but can be ordered using the order form Radon measurement in workplaces: Order form (PDF, 72 KB)

, accompanied by either your own official company order or cheque. You can also order by credit card on 01235 822622.

Monitors are usually despatched within seven working days and must be placed at the measurement location within three days of receipt.

The number of monitors required for each building depends on the workplace type and use, see below, and should be placed in the lowest routinely occupied floor and any basement areas.

Workplace type*	Number of monitors	Examples
Office, individual or small	One per 100 m2, generally corresponds to between a half and third of all ground floor rooms	Banks, shops, professional practice
Open plan office, and retail or workshop up to about 1000 m2, also public access areas	One per 250 m2	Administrative and call centres, light industry, hotels, schools
As above, up to 5000 m2	One per 500 m2	Large retail etc
Very large areas of several thousand m2	One for each distinct area with obviously different environmental conditions, not less than 1 per 1000 m2.	Manufacturing or process plant, warehouses
Basements	One in each separate room, section or area irrespective of size. Even if rarely used, changes in procedures might increase exposure.	Retail, bank and professional storage areas
Wholly underground	As a guide at least one in each main working area, and other normally occupied areas, but seek specialist advice	Water industry, mines and caves

* Effect of ventilation - In principle, radon may be prevented from accumulating in premises with particularly high influx of fresh air, but a measurement is still required unless a risk assessment can show that the radon level at a particular location is necessarily low at all times when it is occupied. Furthermore there will often be adjoining or linked places, such as an office, store, computer area or access duct, with quite different conditions where a measurement would be required.

Last reviewed: 22 April 2008