Radon Measurement Protocols

To ensure the most accurate measurement possible when detecting radon gas,
it’s imperative to follow these guidelines as stipulated by the Environmental Protection Agency (EPA):

Short-Term Radon Measurements

A “short-term” radon measurement takes place over a two to seven-day period and determines whether or not a certain dwelling contains high radon concentrations. The process uses an E-PERM detector; if the average of two co-located E-PERM detectors is 4.0 picocuries per litre (pCi/L) or higher, the living conditions are deemed potentially hazardous and the EPA recommends that further action be taken.

Short-term radon measurement protocol

The EPA recommends that anyone conducting short-term radon measurements follows these rules:

  1. Maintain “closed house conditions.” If the measurement period is less than four days, “closed house conditions” should be initiated 12 hours before testing. To create closed-house conditions:
    • All windows must be closed; doors can only be opened long enough to enter and exit
    • Exhaust fans, window air-conditioners or whole-house fans must be turned off
    • Unless they’re the primary test source, fireplaces must not be used and dampers must be closed
    • Permanent radon mitigation systems (E-PERMs) should be turned on and functioning 24 hours before measurement
    • Don’t conduct measurements during severe weather
  2. Place your E-PERM in the lowest “lived-in” area. Your device should be opened and placed in the lowest lived-in area, a.k.a. the physically lowest area that residents currently use or that could be readily adapted for living. Traditionally, this area would be the basement, whether or not it’s a finished one.
  3. Keep the E-PERM in the proper location. The E-PERM must be at least 30 inches above the floor, at least 24 inches away from the ceiling and away from exterior walls, doors and windows. Bathrooms, kitchens, laundry rooms, cellars, garages, crawl spaces, and sumps are also not suitable locations for E-PERM measurements.
  4. Don’t disturb the E-PERM. It shouldn’t be touched or disturbed until the test is over. Afterwards, it should be closed and returned for analysis as soon as possible. You can also use a “twin box,” used with a single-use plastic seal or lock tie threaded through a small hole in the stem of the plunger, to discourage (or detect) any tampering with the device.

Long-Term Radon Measurements

A “long-term” radon measurement takes place over a period of 91 or more days and determines whether or not a certain dwelling contains high radon concentrations. The process uses an E-PERM detector; if the average of two co-located E-PERM detectors is 4.0 picocuries per litre (pCi/L) or higher, the living conditions are deemed potentially hazardous and the EPA recommends that further action be taken.

Long-term radon measurement protocol

The EPA recommends that anyone conducting long-term radon measurements follows these rules:

  1. Place your E-PERM in the lowest “lived-in” area. Your device should be opened and placed in the lowest lived-in area, a.k.a. the physically lowest area that residents currently use or that could be readily adapted for living. Traditionally, this area would be the basement, whether or not it’s a finished one. The EPA recommends that at least half the long-term exposure period be during a season in which the living area is heated.
  2. Keep the E-PERM in the proper location. The E-PERMA must be at least 30 inches above the floor, at least 24 inches away from the ceiling and away from exterior walls, doors and windows. Bathrooms, kitchens, laundry rooms, cellars, garages, crawl spaces, and sumps are also not suitable locations for E-PERM measurements.
  3. Don’t disturb the E-PERM. It shouldn’t be touched or disturbed until the test is over. Afterwards, it should be closed and returned for analysis as soon as possible. You can also use a “twin box,” used with a single-use plastic seal or lock tie threaded through a small hole in the stem of the plunger, to discourage (or detect) any tampering with the device.