REDUCING RADON IN YOUR HOME
PART II
In Part I of our feature article, we discussed how radon is
cancer causing radioactive gas that may be a problem in your
home. We also explained why testing your home for radon is
the only way to know if you and your family are at risk. In
Part II we will discuss what to do if you have tested and
found elevated radon levels in your home. In general, the
EPA recommends fixing your home if your radon level is confirmed
to be 4 picocuries per liter (pCi/L) or higher. Radon levels
less than 4 pCi/L still pose a risk, and in many cases may
be reduced.
In dealing with a radon problem, the EPA recommends that you
use a qualified contractor to fix your home. Contractors that
are certified through the EPA's Radon Contractor Proficiency
Program (RCP) have taken courses and passed an exam. Contractors
that meet these qualifications are listed in a national RCP
report and are required to carry a current RCP photo ID card
and meet minimum EPA quality standards. When you choose a
radon contractor it is wise to get more than one estimate,
to ask for references, and to contact some of these references
to ask if they are satisfied with the contractors work. Also
be aware that if you have a radon professional test your home
for radon, there is a potential conflict of interest if you
use the same professional or company for radon reduction work.
The cost of making repairs to reduce radon depends on the
characteristics of your house and other factors. Most homes
can be fixed for about the same cost as having a new hot water
heater installed or having the house painted. The average
cost for a contractor to lower radon levels in a home is about
$1,200, although this can range from $500 to about $2500.
RADON REDUCTION TECHNIQUES
There are several methods that a contractor can use to lower
radon levels in your home. Some techniques prevent radon from
entering your home while others reduce radon levels after
it has entered. The EPA generally recommends methods which
prevent the entry of radon.
Your contractor will perform a visual inspection of your house
and design a system that considers the specific features of
your home. If this inspection fails to provide enough information,
the contractor will need to perform diagnostic tests. For
example, a "smoke gun" can be used to find the source
and direction of air movement. These sources of air flow show
possible radon routes. Another type of diagnostic test is
a "soil communication test". This test uses a vacuum
cleaner and a smoke gun to determine how easily air can move
from one point to another under the foundation.
The type of foundation that your house has will affect the
kind of radon reduction system that will work best. In New
Mexico, the most common foundation designs are slab-on-grade
and crawlspaces. Some houses have more than one design feature.
For instance, it is possible to have a slab-on-grade under
part of the house and a crawlspace under the rest. In these
situations a combination of radon reduction systems may be
needed.
In houses that have slab-on-grade foundations, radon is usually
reduced by subslab suction. Active subslab suction (also called
subslab depressurization) is the most common and usually the
most reliable radon reduction method. Suction pipes are inserted
through the floor slab into the crushed rock or soil underneath.
They also may be inserted below the concrete slab from outside
the house. The number and location of suction pipes that are
needed depends on how easily air can move in the crushed rock
or soil under the slab, and on the strength of the radon source.
Acting like a vacuum cleaner, a fan connected to the pipes
draws the radon gas from below the house and releases it into
the outdoor air. Passive subslab suction is the same as active
subslab suction, except it relies on air currents instead
of a fan to draw radon from below the house. This is generally
not as effective in reducing high radon levels as active subslab
suction.
In house with crawlspaces, radon levels can sometimes be lowered
by ventilating the crawlspaces passively (by opening or installing
vents) or actively (with the use of a fan). Crawlspace ventilation
lowers indoor radon levels both by reducing the homeÕs suction
on the soil and by diluting the radon beneath the house. If
this approach is used, care must taken to insulate water pipes
in crawl spaces against cold weather. Another effective method
to reduce radon levels in crawlspaces involves covering the
earth floor with a heavy plastic sheet. A vent pipe and fan
are used to draw the radon from under the sheet and vent it
to the out doors. This type of soil suction is called submembrane
depressurization.
Other radon reduction techniques that can be used in any type
of house include sealing cracks in the foundation and natural
ventilation . These methods are considered to be either temporary
measures, or partial solutions to be used in combination with
other methods.
RADON IN WATER
Compared to radon entering the home through soil, radon entering
the home through water in most cases will be a small source
of risk. Radon gas can enter the home through well water.
It can be released into the air you breathe when water is
used for showering and other household uses. Research suggests
that swallowing water containing radon may pose some risk,
too. Radon problems in water can be readily fixed by using
one of two methods: aeration treatment or granular activated
carbon (GAC) treatment. In either treatment it is important
to treat the water where it enters your home (point of entry
device) so that all the water will be treated.
AFTER YOU INSTALL A RADON SYSTEM
After a radon reduction system has been installed, it is
important to do a follow up radon test to determine the systemÕs
effectiveness. Having an independent tester perform the test,
or conducting the test yourself, will eliminate any potential
conflict of interest with the contractor. In addition, systems
installed by a RCP contractor must include a warning device
to alert you if the system stops working properly. Make sure
the contractor tests the warning device as well as explains
and demonstrates how the system operates. Ask the contractor
for written operating and maintenance instructions and copies
of any warranties. Your radon reduction system will need some
occasional maintenance including checking the fan regularly
and repairing or replacing it as necessary. Maintaining your
system takes little effort and keeps the radon levels in your
home low.
We extend our appreciation to the U.S. Environmental Protection
Agency and U.S. Department of Health for the information in
this article.
