Guide for Radon Measurements in Public Buildings

Annex

Government of Canada Radon Procedure for Public Dwellings (Buildings and Schools)

Where to Test

1. Test all rooms with floors or walls that are in direct contact with the ground or a crawl space. If none of these levels have occupied rooms, test all occupied rooms on the first occupied level.
2. Test every 3rd room on the floor level above the floor meeting criterion #1.
3. Test every 3rd room on the top floor of the building.
4. Test every 3rd room of every 5th floor (e.g. Floor 5, 10, 15, 20, 25,...).

One detector is required for rooms of area less than 200 m². Larger rooms will require detectors for every 200 m². Rooms are defined at an area with walls from floor to ceiling (or false ceiling). Thus cubicles would not be treated as individual rooms. The entire square footage occupied by cubicles would be needed and the area (200 m²) would be treated as one room.

• Only rooms that are, or might be, occupied by someone for more than 4 hours a day will be tested.
• Bathrooms, kitchens, closets, storerooms and warehouse space will not be tested.
• A 3-month test will be done.

Where to Locate the Detector

The preferred device location is by an interior wall at a height of 0.8 m to 2 m (3 to 6.5 feet) from the floor in the typical breathing zone, however, at least 50 cm (20 inches) from the ceiling and 20 centimetres (8 inches) from other objects so as to allow normal airflow around the detector. Detector should be placed approximately 40 cm (16 inches) from an interior wall or approximately 50 cm (20 inches) from an exterior wall. In some schools for instance, to avoid tampering by taller students, the detector may have to be placed at a greater height as described earlier. Similarly, a greater deployment height may also be required in high traffic areas of public buildings. In these cases, depending on the detector used, this may be accomplished by suspending the detector from the ceiling.

Do not place the detector in kitchens, laundry rooms, bathrooms, closets, cupboards, sumps, crawl spaces or nooks within the foundation.

Do not place the detector by heating, ventilating and air conditioning vents, doors, fans, windows, fireplaces, electrically powered equipment, on computers, television sets, stereos or speakers, or in direct sunlight.

Add one duplicate detector for quality control purposes for every 10 detectors deployed for measurements. Place the duplicate detector side-by-side (about 10 cm apart or 4 inches) with the measurement detector. If the results of the two measurements (measurement detector and its duplicate) are different by a factor of 2, investigate the problem with the device supplier, analytical laboratory or the person who made the original device placements to correct the problem. Measurements for the room or area in question should be repeated.

Reading the detector

After the monitoring period of 3 to 12 months the detector is returned to the supplier for processing and evaluation of radon concentrations.