ProTen Services feature in Public Sector & Local Government Building magazine

Revealing Radon

Martin Freeman explains the ins and outs of radon gas and why, left in the hands of non-specialists, the problem can easily be made worse.

Click here to view this article in PDF format as it appeared in PSLGBuilding

Radon, the naturally occurring radioactive gas, is fast becoming a primary concern for Local Authorities. From Building Control to Environmental Services to Housing Officers, Local Authorities have a responsibility to ensure that the health of those living and working in the local community is not being jeopardised by exposure to high levels of radon.

The gas is formed during the decay of uranium in the ground, and when it permeates the ground into open air, it is quickly diluted to harmless concentrations. If, however, it rises into a building, high concentrations can accumulate, posing a serious threat to the occupants. Each year in the UK, approximately 2500 people die from lung cancer, developed as a direct result of exposure to radon. The gas accounts for the second greatest number of lung cancer cases in the UK, second only to smoking.

Given the serious consequences that could result should an individual be exposed to high levels of radon, legislation is in place to help eliminate such exposure.

Under the Management of Health & Safety at Work Regulations 1999, employers must assess all risks posed to their staff. If a workplace is either in a Government designated radon Affected Area, or has a basement or other area beneath ground level where employees spend a significant amount of time, an assessment of radon exposure must be made.

The only way to assess the level of radon in a building is to use a specialist detector. This should ideally be left in place for a three month period, before being sent to a laboratory for analysis. The Health & Safety Executive, who are responsible for enforcement of radon testing, are currently touring the country in a bid to crack down on employers who have failed to properly assess this risk, and non-compliance can lead to prosecution.

Similar requirements are placed upon landlords, who hold a duty of care towards their tenants, whether domestic or commercial.

If high levels of radon are found in a workplace or rented building (above the Government's Action Level of 400 bq/m³), the employer or landlord is required under the Ionising Radiation Regulations 1999 (IRR99) to either reduce the hazard, or treat the building as a radioactive space. The latter effectively means restricting general access, so in the vast majority of cases, the only practicable choice is to reduce radon levels, which can be done at a relatively low cost, and with minimum disruption.

Sucked from soil

In the absence of a proper understanding of the science of radon, however, well-intentioned but uninformed measures can make the problem worse, rather than better. Radon is drawn into buildings through a process called advection; the pressure inside a building is normally lower than outside, so gases from the soil are literally sucked in. Increasing ventilation, particularly through the use of extraction fans can lower the pressure inside the building further, thus escalating the rate at which radon is drawn in and increasing its concentration.

ProTen Services Ltd, the nation's leading experts with over 20 years experience in radon testing and remediation, recently dealt with a domestic property, where the owners had employed a general contractor to reduce the radon in their home. ProTen Services conducted a radon test, revealing levels of over 2100 bq/m³. The non-specialist had previously installed a ventilation system, which ProTen suspected to be exacerbating the problem. When the system was switched off, the radon level halved. ProTen then designed a specialist positive pressure system to dispel the gas currently trapped inside the property and increase the pressure of the building, preventing any further gas infiltration. A subsequent radon test revealed the level of radon in the property had been reduced to 63 bq/m³. This highlights not only the need to use a specialist contractor, but also the need for testing after measures have been taken, as without this, it is impossible to know if the actions have been effective, or indeed detrimental. The system also gave improved air quality and incorporated a heat exchanger.

Radon mitigation is a specialist and potentially life-saving area of construction, where training and sophisticated accuracy are imperative to its success. It would be unwise to place this responsibility in the hands of a general contractor.