RMS Post-Mitigation Testing 1 — Questions and Answers
Question 1: How soon after activating an active radon mitigation system should post-mitigation testing begin?
- At least 24 hours after activation, with minimum 48-hour test (Correct answer)
- Immediately upon activation
- One year after installation
- Testing is not required
Correct answer: At least 24 hours after activation, with minimum 48-hour test
Post-mitigation testing should begin at least 24 hours after system activation to allow conditions to stabilize, with a minimum test duration of 48 hours.
Question 2: What is a U-tube manometer used for in radon mitigation?
- To measure the pressure differential created by the mitigation system (Correct answer)
- To measure radon levels directly
- To test water pressure in plumbing
- To measure exhaust air temperature
Correct answer: To measure the pressure differential created by the mitigation system
A U-tube manometer, installed on the radon vent pipe, provides a visual indication that the mitigation fan is operating by displaying the pressure differential.
Question 3: What is the recommended placement for a post-mitigation radon test device?
- Lowest livable area, at least 20 inches above the floor (Correct answer)
- On the roof
- Directly on the mitigation fan
- In the attic
Correct answer: Lowest livable area, at least 20 inches above the floor
Post-mitigation tests should be placed in the lowest livable area, 20 inches or more above the floor, away from exterior walls and windows.
Question 4: What does a failing post-mitigation test indicate?
- The system may need additional suction points or sealing (Correct answer)
- The building is permanently unsafe
- Radon mitigation is impossible for this building
- The test device was defective
Correct answer: The system may need additional suction points or sealing
A post-mitigation test showing radon at or above 4 pCi/L indicates the system needs optimization: additional suction points, better sealing, or a more powerful fan.
Question 5: How often should post-mitigation radon levels be retested?
- Every 2 years, or after significant building changes (Correct answer)
- Never after initial test
- Every month
- Only when selling the property
Correct answer: Every 2 years, or after significant building changes
The EPA recommends retesting every 2 years, after significant renovations, HVAC changes, or if the mitigation system is modified.
Question 6: What type of radon test provides the most accurate long-term average?
- Alpha track detector deployed for 91 days to 1 year (Correct answer)
- A 48-hour charcoal canister test
- A grab sample collected in 5 minutes
- An electronic radon detector running for 4 hours
Correct answer: Alpha track detector deployed for 91 days to 1 year
Alpha track detectors deployed for 91 days to 1 year provide the most accurate long-term average radon concentration, accounting for seasonal and daily fluctuations.
RMS Post-Mitigation Testing 1
How soon after activating an active radon mitigation system should post-mitigation testing begin?