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Case Study – Positive pressure system cuts radon levels by 89%
High radon levels in a two bedroom house in Cornwall have been reduced to safe levels by installing a positive pressure system costing less than £600.00.
As part of a purchase survey a two bedroom semi-detached property in Wadebridge, Cornwall, was tested for radon gas during May to August 2009. Test pods were placed in the ground floor living room and the main bedroom above it. In the living room the collected figure was 624 becquerels per cubic metre (bq m3) and in the bedroom the recording amounted to 251 bq m3.
High radon levels in a two bedroom house in Wadebridge, Cornwall have been reduced to safe levels by installing an Airtech Dryair positive pressure system
These measurements exceed the ‘Action Level’ of 200 bq m3 set by the Health Protection Agency (HPA), a government department that protects UK public health.
Radon gas is produced during the radioactive decay of radium which comes from uranium. It occurs naturally through the presence of uranium in most rocks, soils, bricks and concrete. It is not possible to see, hear, smell or taste radon gas. While the gas itself does not present too serious a radiological hazard when breathed in and immediately exhaled, radon decay products behave like solids and can attach themselves to dust and moisture in the atmosphere. These solids can take up residence in lungs and airways and emit alpha particles which cause cell damage.
Outdoors, radon disperses harmlessly into the air, but once it finds its way indoors, through gaps and cracks in floors and walls, it may build up to potentially harmful levels. Warm air inside a house draws the gas in through flooring and any gaps or cracks in the building structure. High concentrations of radon can also accumulate in confined spaces such as basements.
Health data from nine European countries confirms that domestic exposure to radon increases the risk of lung cancer. In the UK between 1000 and 2000 deaths each year are estimated to be caused by exposure to radon. Results based on a European wide epidemiological study showed that the risk from radon is approximately 25 times higher for cigarette smokers than for non-smokers.
Following a survey of the property engineers from Airtech Environmental Systems radon division recommended fitting a positive pressure system to reduce radon levels. This device draws radon free air from the loft space and gently introduces it throughout the dwelling to prevent the build-up of radon gas.
Airtech's Low energy Dryair positive pressure systems draw radon free air from the loft and gently introduce it throughout a dwelling to prevent the build-up of radon gas. The devices are simple to install an inexpensive to run.
Low energy Dryair positive pressure systems produced by Airtech are simple to install an inexpensive to run. Two versions are available; one for loft installation in houses and one for flats. Both come with fan speed control and preheat options which offer temperature control of the air introduced. Their design includes a digital motor, large capacity filters fitted with a pressure sensor and innovative ‘Feedback’ control that ensures the system continues to operate at 100% efficiency until the filter becomes 70% clogged. All the systems are quiet, BRE 390 compliant and offer lower energy costs for tenants in keeping with the Government Directive regarding energy efficient appliances in social housing.
Following normal practice the loft unit was fitted in the roof void and ducted via an air diffuser, normally mounted in the ceiling above a stairwell. Fan speed and air heater controls were sited on the landing wall at a convenient height. No major construction works were required and the job was complete within two hours.
Radon-free air from the Dryair loft unit is ducted via an air diffuser, normally mounted in the ceiling above a stairwell
Re-test results
The installation was carried out in December 2009 and radon level tests were repeated during May to August 2010. Sensors were placed in the same location as before and the estimated annual average levels recorded were 70 bq m3 in the living room and 40 bq m3 in the bedroom – below the ‘Action Level’ and lower than a new minimum ‘Target Level’ of 100 bq m3 proposed by the HPA in July this year.
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