HEALTH & SAFETY
radon affected area, radon testing is a legal requirement. If a workplace falls close to a radon affected area, or if a precautionary approach is taken, radon testing should be considered as part of a building’s safety policy. Most buildings or parts of buildings fall below action levels; however, testing may show that something needs to be done about radon – remember that the radon atlas is indicative, so there may be areas affected that were not identified through mapping.
is the installation of active radon sumps, this involves the removal of a small volume of fill from beneath a building, with pipework sealed into this void and actively exhausted to the outside air with an in-line electric fan. The fan creates an area of negative pressure beneath the footprint which radon will preferentially migrate to. Exhausts are typically above the building eaves (where practical) and away from windows or doors.
CONTRACTOR CHOICE The installation of radon protection
1,100 PEOPLE DIE
PREMATURELY EVERY YEAR
FROM RADON EXPOSURE.
RADON MITIGATION Where radon levels are elevated
within a building, effective retrofit solutions are available to reduce these levels and to reduce risk to building users. A popular solution
www.tomorrowsfm.com
systems may appear basic, but in practice it is not always easy to reduce radon levels to below exposure limits, due to the multitude of factors which affect radon ingress. Choice of contractor is essential in increasing the chance of mitigation systems working in the first instance. Specialist radon contractors will be experienced in installing the most appropriate systems for the building type, size and measured radon levels. Many specialist contractors will use pressure or smoke testing to demonstrate effective seals within the system. Radon monitoring equipment is also sometimes used to immediately indicate effectiveness of systems and to identify whether they need to be fine tuned. Expect to pay more for a specialist radon contractor, but use one to give you peace of mind that building occupants are being suitably protected, as well as reducing the risk of needing multiple mitigation attempts. A list of Radon Council approved contractors and consultants can be found on the Radon Council website.
MAINTAINING ACTIVE
SYSTEMS Active radon sumps have moving parts; therefore need to be maintained to ensure effective long term operation. The expected life of an active sump system should be at least 5 years, but this is dependent on the fan speed required for the building. An inspection and maintenance plan can be written into the general maintenance procedures
for the building, radon sump fans make an audible whirring sound, so an audible inspection is suitable. Ducting should be physically tested for integrity to ensure it remains firmly fixed and sealed. Visible lights on circuit breakers can be used for a quick check to show that the fan is still connected to the mains supply.
Some specialist radon contractors will offer telemetry systems and battery backups in the event of a power outage. Telemetry units will alert (by email or SMS) designated individuals of faults with the mitigation system, such that these can be quickly repaired.
Whichever system is used (manual inspections or telemetry) a procedure for maintenance and repair should be produced for the building. Depending on the extent of the repair required this could be undertaken by the building maintenance contractor or a specialist radon contractor. Major system repairs should be followed by re-testing of the internal radon levels, as a change to the system may affect the dynamics of radon ingress.
VERIFICATION Radon mitigation measures, both
in new and existing buildings, do not always work first time, buildings should be tested for radon after measures are installed to demonstrate that they work. This commonly involves the use of passive track etch detectors; should levels still be unacceptably high, mitigation systems may be modified or extended to improve their effectiveness.
LONG TERM
VERIFICATION Within managed buildings or in any building with particularly high radon levels in the first instance, long term validation testing may be prudent. This can be undertaken on an annual, or 14 month (to identify seasonal trends) basis.
Retesting of an affected building should also take place following any change to: the building structure, e.g. extensions; the heating or ventilation systems; the building use.
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