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Radon Risk Evaluation
before New Home Construction
It is possible to screen
a building site before construction in order to evaluate the risk for
an increased radon level in the home after completion of construction.
This Radon Risk Evaluation
is our specialty. We wrote a paper on this research and presented an
invited talk to the radon community about it at the national radon
conference organized by the American Association of Radon Scientists
and Technologists (AARST) on September 28, 2005 in San Diego.
For home owners or
builders who want to have this radon risk evaluation on their site
performed, call Dr. Leo Moorman at (970) 416-0196 before construction
begins. Depending on the building site a number of tests need to be set
up.
The picture below shows an
example of a test with a background calibration test next to it. This
kind of test should only be interpreted by experts. At RHMM we have the
expertise to perform a reliable test and give a solid interpretation of
the result based on our extensive testing experience.
Radon Risk Evaluation with background calibration test.
A
simplified scenario in case the home has only concrete slab flooring.
 Use a layer that is at least 4" thick of pea
gravel that is approximately 3/8" in diameter and install a draintile
flexible corrugated pipe to PVC or ABS pipe TEE 4" sch.40 penetrating
the slab. Use a rubber endcap to close off the stub before pouring the
concrete slab.
Pour the concrete slab.
Caulk all expansion and floor joints flush with
caulk as well as floor to wall joints and around all penetrations
through the slab. (Use a liberal amount of caulk, i.e. fill the grooves
completely. For wide cracks use backer rod.).
In Larimer County (Colorado) perform a test:
depending on the subdivision a test must be done in order to obtain an
occupancy permit. The requirement also specifies whether the home needs
to be tested with an active test or that a passive test is sufficient.
Finish home and use radon barrier over all
rough-in's that have sand exposed.
Live in home for a couple of weeks and perform a
radon test. (Except Larimer County where the test may have to be done
before finishing the home as stated above).
If a test indicates a radon concentration larger
than 4.0 pCi/L but not much larger than 4.0 pCi/L a passive mitigation
system may be sufficient and therefore cost effective. This means that
a 4" diameter schedule 40 pipe system may be installed completely
through the (warm area of the ) house. Such a system is known as a
passive radon mitigation system as opposed to an active system. A radon
concentration test done after this installation shows whether the
passive system is sufficient. A well designed passive system can be
transformed into an active system easily if the test shows that this is
necessary.
If the initial test indicates a radon
concentration much higher than 4.0 pCi/L it may be cost effective and
faster to install an active radon mitigation system at once. An active
system has an appropriately sized in-line turbo ventilator placed in
the attic. (With a turn-off switch mounted in the attic and a
monitoring manometer in the basement).
OBVIOUSLY THERE ARE
DIFFERENT SCENARIOS FOR VARIOUS SITUATIONS (e.g. CRAWLSPACE). TO ENSURE
THE MOST COST EFFECTIVE INSTALLATION WORK WITH A NEHA-CERTIFIED RADON
SPECIALIST.
For instance in areas with
high radon risk situations (In Ft. Collins CO, 75% of the homes tested
above the EPA action level for mitigation) the builder may decide that
on the long run it will be more cost effective to install a passive
system in every home he builds. This means that the pipe plumbing
through the home may be done immediately after the mechanical, plumbing
and electrical installation and before the installation of drywall on
the walls. In addition the builder may allow for an option to the
prospective buyer to install a full active radon system if they desire.
AT RHMM WE ARE CONSULTING
BUILDERS ALL THE TIME, PERFORM NEW HOME RADON TESTING AND WE ARE
SPECIALIZED IN TRANSFORMING A PASSIVE INTO AN ACTIVE SYSTEM ON SHORT
NOTICE, QUICKLY AND IN A COST EFFECTIVE MANNER FOR THE BUILDER.
Contact us for
information about new construction radon issues.
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