Since November is Radon Action Month, it seems appropriate to talk a bit about what’s currently happening in the industry. So, in no particular order, here are three quick things to know about radon in late 2024.
1. Don’t get caught short applying for BOMA BEST radon credits
If you’re considering doing radon testing in your building(s) as part of your BOMA BEST or other sustainability program activities for 2025, you need to get moving now.
Health Canada recommends, and BOMA BEST requires, that radon testing either take place over the course of an entire year, or, if for a shorter period, at least 91 days in the heating season. The heating season generally is accepted to mean between October and April.
As a practical matter, the vast majority of radon testing in commercial and large buildings opt for the 91-day testing period during the heating season.
The consequence of this is that if you don’t have radon detectors in place by January 30th of 2025, you’ll have missed the entire 2025 window in which you can qualify for the points. If the detectors are placed on January 30th, they should be picked up exactly 91 days later – April 30th. If placed October 1st, 2025, you won’t have time to get the results analyzed and reported until some time after December 31st, 2025.
For BOMA BEST, you’ll need to follow the Health Canada Guide for radon measurements in public buildings [1], use C-NRPP [2] accredited devices, and have a C-NRPP accredited radon measurement professional sign off on the final report.
You can find a current list of C-NRPP accredited professionals [3] online.
2. Re-testing every 5 years is not recommended by Health Canada
There is a persistent bit of misinformation floating around that Health Canada recommends re-testing your buildings for radon every five years. This is false.
Health Canada only recommends re-testing your buildings:
- After major renovations, or
- Following a radon mitigation project to reduce radon levels, and every 5 years thereafter (only to confirm that the radon levels are staying low).
Of course, you might choose to conduct ongoing or recurring testing for other reasons. For example, you may wish to have continuous reassurance for your organization or tenants that radon is not a problem in your buildings.
If you do choose to re-test, you may want to consider testing a smaller number of locations than the original radon survey, and/or use some strategically placed continuous radon monitoring instruments.
The main point, though, is this: don’t let anyone tell you Health Canada says you should re-test every 5 years if your original radon survey did not indicate a problem.
3. Are we exposing after hours workers to elevated radon levels?
Full disclosure: this is based on a talk I gave during this year’s 2024 CARST radon conference. [4]
The current Health Canada guidelines for radon testing in public buildings caution that radon levels can often vary as the result of different ventilation rates.[5] Typically, operational hours can have much lower radon levels due to increased ventilation, whereas non-operational hours can have proportionately higher levels due to decreased ventilation.
This means after-hours occupants (e.g. – security, cleaners) may be exposed to unacceptably high levels of radon even though long-term testing indicates average radon levels are within acceptable levels.
The consequence of this is that even if you haven’t found elevated radon levels at the conclusion of a radon survey, you need assess whether after hours occupants are at risk. The easiest way to do this is through a simple risk assessment.
At the conclusion of your initial radon survey, determine if:
- The building’s average radon level is below your target level
- The ventilation rate during testing varied due to the building’s operational factors
- There are occupants in the building for a substantial amount of time during non-operational (low ventilation) periods
If any of these conditions are not true, no further risk evaluation activities are indicated.
If they’re all true, however, you should consider doing further testing using continuous radon monitors (CRMs). CRMs measure radon levels at least hourly, as opposed to the single averaged measurements from the long-term radon detectors typically used for there surveys. Accordingly, we can use them to see the different radon levels during operational vs. non-operational hours. The details of how to conduct this CRM based survey would be too much to cover in this short post. However, we suggest you test for at least a week in at least 10% of the previously tested locations in every HVAC ventilation zone that was tested as part of the original survey.
One final note – before incurring the additional cost of CRM testing, you could conduct a more sophisticated quantitative risk assessment. Be aware that competently conducting such an assessment requires someone with a good deal of experience and expertise.
Cheers, and stay healthy,
Curt LaMontagne, Principal Consultant – C5 PLUS
[1] https://www.canada.ca/en/health-canada/services/environmental-workplace-health/reports-publications/radiation/guide-radon-measurements-public-buildings-schools-hospitals-care-facilities-detention-centres.html
[2] Canadian – National Radon Proficiency Program.
[3] https://c-nrpp.ca/find-a-professional/
[4] Canadian Association of Radon Scientists and Technologists (CARST), Annual Conference, April 26th, Should we be conducting CRM testing in public buildings even after long-term testing indicates radon levels are within acceptable limits? Curt LaMontagne
[5] Ibid., 5.1