Test de radon de 2h est-ce valide?

Is it true? A 2 hours radon test is valid?

Some home inspectors offer a radon test performed during the home inspection. A test that last about 2 hours. The home inspector uses a digital detector which displays a result after 10 minutes. It's reassuring, isn't it? At the end of the inspection this inspector can tell me whether or not I am close to the limit of 200 bq/m3. Like a case where the result is 95 bq/m3 after 2 hours. The inspector tells me that I am far from 200 bq/m3 and everything is ok. But that this test is not precise he said. Is it valid as a test? I can sleep in peace my family is safe? NO!

The ACSTR (Canadian Association of Radon Scientists and Technologists) issued a guideline for the professionals of the PNCR-C (National Radon Proficiency Program-Canada) in 2018 which can be consulted at the following address: https://carst.ca/resources/Documents/CARST%20Guideline%20for%20Conducting%20a%20Radon%20Screening%20Assessment%20as%20Part%20of%20a%20Real%20Estate%20Transaction%20of%20a%20Residential%20Dwelling%20in%20Canada%20-%20Final%202018.pdf

A preliminary test should be carried out over a minimum of 2 days and a maximum of 7 days. The ideal period is 4 days. According to scientific data even a continuous measuring device needs a minimum period of 4 hours of measurement before the data can subsequently be used.

The devices recommended for a rapid test are either a continuous measurement detector, an alpha trace detector or an ionization chamber and electret detector. Digital devices are not currently part of the recommended devices.

Why does Health Canada not recognize digital detectors as valid? It is impossible to validate the accuracy of the calibration of these devices or to modify the parameters. A test carried out by Health Canada in 2020 with this type of device shows significant variables from one device model to another. As an example, a device of a model "X" from the manufacturer "Y" provides a value 20% above the radon level maintained in the test chamber. While an identical device displays 20% less. How reliable will your "X" device be? Impossible to know if it displays a real rate, above or below the radon rate present. Let's say the device displays 170 bq/m3. If the latter displays a high reading, the value must be reduced by 20% and a rate of 136 bq/m3 should be used. If, on the contrary, it displays a low reading, 20% should be added, which would give a result of 204 bq/m3. A significant margin of error that can create a false sense of security even when using this type of device over the long term. The use of an approved device is recommended at all times according to recognized protocols, whether for a rapid or a long term test.

Radon fluctuates over time. In order to protect the public ACSTR has issued a directive lowering the minimum rates compared to the target rate for long term testing. It is only 75 bq/m3 during the heating period and 50 bq/m3 in the summer period. Beyond these thresholds for a short duration test a long duration test is recommended.

Don't be fooled by a false sense of security. Do business with a recognized PNCR-C professional or an inspector who has undergone appropriate training and uses a device according to recognized measurement protocols.

Back to blog