Measuring Radon Gas

MEASURING radon gas

The 2 most common types of radon detectors used for testing houses are short term and long term detectors. The short term detectors can be used for a period of 2-7 days, the long term detectors can be used for a period of 3-12 months. Since the radon concentration inside a house varies over time, measurements gathered over a longer period of time will give a more accurate indication of the radon level in a house. Health Canada recommends that houses be tested for a minimum of 3 months, ideally between September and April when windows and doors are typically kept closed

Short-Term Detector
Radon Safe Northwest Ltd. uses a Corentium Pro continuous radon monitor for short-term readings. They provide an accurate hourly reading and are certified by C-NRPP. Our price for this report is $290 plus HST

Long-Term Detector
Radon Safe Northwest Ltd. can provide the AccuStar AT-100 Alpha Track test kit which can be used for radon testing from 91 days to one year. The kit includes the test device, instructions and laboratory analysis.Results can be checked on-line. Contact for Pricing. No returns are accepted for this item.

Measurment in homes

Health Canada recommends that every homeowner test their home for radon through the placement of at least one long-term detector for a minimum of 3 months. Ideally, this testing period should be when indoor radon levels are highest. In Canada, this is typically during the heating season from October to April, when homeowners keep windows closed for extended periods of time, and the thermal stack effect (rising air currents due to buoyancy of air) that tends to draw in more radon gas from the soil is generally strongest.

In homes, radon levels can generally be assessed by measuring in a single location, chosen in accordance with the criteria in Section 5.2.

Radon measurements in newly constructed homes should be conducted during the first heating season after occupancy.

Homeowners should always consider re-testing whenever major renovations are performed that might substantially change the ventilation or airflow in the home or the use of the rooms in the lowest-occupied level. If substantial changes are made, a 3-month test should be performed during the first heating season after completion of the renovations.

Radon Preventive Measures

Radon levels in a home can vary significantly over time depending upon occupant use patterns and there is currently no way to determine or predict what the radon concentrations within a completed dwelling will be prior to construction. Long-term testing is required after construction and post–occupancy to determine radon concentrations, and mitigation efforts may be required should radon concentrations be found to be above the Canadian guideline of 200 Bq/m3. Steps can be taken during construction to facilitate the efforts and reduce the cost of mitigation.

There are three main types of radon preventive measures that can be installed in new construction:

  • Level 1 is a rough-in for a radon mitigation system,
  • Level 2 is a full passive radon stack,
  • Level 3 is a full active soil depressurization (ASD) system.

These 3 levels are described in more detail in “Annex 5- Radon Preventive Measures in New Construction”.

It is important for homeowners to realize that the presence of these construction features does not ensure that the radon levels in the home are below the guideline. The only way to know is to conduct a long-term radon measurement and, in some cases, additional mitigation may be required.

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