| RADON |
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Health hazards from radon occur with long-term exposure.
Radon is a naturally occuring soil gas. It is believed to be the
greatest cause of lung cancer in non-smokers, and is estimated to
cause 20,000 deaths per year. A certain amount of radon is found
in all homes. It is found naturally in the atmosphere at approximately
.5 Pci/L which is a measurement used to denote the percentage of
Radon found in one liter of air.
The EPA recommends that all
homes be tested for radon. A study published by the EPA late in
1988 shows 30% of all homes studied contained radon amounts that
exceeded the agency's action level of 4 Pci/L. We advise clients
that if they like the home, they should still purchase it even if
it has elevated levels, as the radon can easily and inexpensively
be reduced to a safe quantity. The cost of abatement in an existing
home typically runs between $800-$1,500. At the present time we
are attempting to educate residential home builders to incorporate
passive radon resistant construction techniques during new construction
for an additional $200-$300.
EPA guidelines for radon
testing with real estate transactions require that a home be tested
in the lowest finished or potential living space under closed house
conditions for either a passive or active short term test for a
minimum of 48 hours. There are many disadvantages of doing a short-term
test as there are many conditions which can influence the radon
level in a home during that short duration. Atmospheric conditions,
seasonal influences, mechanical air movement (air conditioning,
bath fans, dryer vents, etc.) and home owner interference can all
impact the test results. Because real estate transactions are time
sensitive, short-term testing is normally recommended.
A better, more realistic representation of the true average radon
levels in a home would be achieved by conducting a long term test
over a span of 3-12 months. Long term testing methods include Alpha
Track and Electret Chamber devices. Short term test devices include
passive (charcoal canisters) or active continuous monitors for a
period not less than 48 hours. Both active and passive devices are
considered equal for accuracy, though active devices have the advantage
of detecting tampering with the testing device or closed home conditions.
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Should results above the EPA recommended action level of 4 Pci/L
be found on an initial short term test, a second short term test
is recommended to verify results. If the levels are still elevated,
then mitigation by an state approved EPA contractor is recommended.
It is also highly recommended that you use an EPA listed and approved
radon measurement contractor to perform the testing.
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The Active
Soil Depressurization (ASD) system is the most common and
effective method used today for reducing airborne radon levels.
This system depressurizes the soil beneath the concrete slab, effectively
drawing in radon, as well as other soil gasses.
This is accomplished by penetrating the slab and installing suction
points in one or more locations. 3"PVC pipe is then run from
the suction point(s) to the exterior in a suitable manner.
An in-line exhaust fan is installed on the piping to draw in the
radon and exhaust it safely above the roof of the building. |
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| Typically radon levels can be reduced significantly
with this method of mitigation. In one basement office where this
system was recently installed radon levels went from 8.9 - 9.8 prior
to installation to 0.4 - 1.0 after the installation, sampling from
several areas of the basement. |
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