How to Test
Large Buildings for Radon
Protocols: Placement protocols vary from state to state.
Most states instruct people testing large buildings to:
Place radon detectors in every
frequently occupied room where the floor has contact with the
soil, including edges and corners.
radon detectors in the breathing zone, 2-6 feet above the
floor, and away from drafts, exterior walls, windows, sumps,
drains or doors.
one radon detector for every 2000 square feet in large rooms.
Assurance and Control: Some states require testers and
mitigators to follow some or all of the quality assurance
tests where two radon detectors are placed in the same
location. This tests to see if the analysis process is
producing consistent results. Usually, duplicates are
placed in one of every ten locations (10%) with no limit on
the total number of duplicates.
detectors are radon detectors that are not opened until just
before they are returned. Blank radon detectors test to
see if the analysis process can distinguish between tracks
caused by radon and background. Frequently, the number
of blanks must equal at least 5% of the total number of detectors,
possibly with a cap on total number of blanks performed.
Spiked detectors are exposed in a
certified radon chamber. This tests to see if the
analysis process is producing accurate results. State
regulations indicate the number of spikes to be tested
annually, usually about 3% of the total number of detectors,
possibly with a cap on total number of spikes performed.
blank, and spike QC tests should be labeled so that the
analysis lab does not know which detectors are QC tests.
This may not always be possible.
and Licensing: Many states have regulations for radon testing and
mitigation. Any state radon regulations do not apply to home
testing by an owner or
occupant. State regulations also do not apply to
exclusive-use federal property. Regulations vary among:
that require testers and mitigators to be licensed by the
that require a separate certification for testing schools or
radon office to learn about the requirements that apply to
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