RMS System Design & Installation 3 — Questions and Answers
Question 1: According to EPA guidelines, radon vent pipe discharge must terminate at least how far from any window or opening into the conditioned space?
- 6 inches
- 1 foot
- 10 feet horizontally or 2 feet above (Correct answer)
- 20 feet
Correct answer: 10 feet horizontally or 2 feet above
EPA requires discharge points to be at least 10 feet from any opening, or 2 feet above openings within 10 feet, to prevent re-entry of radon.
Question 2: What is the primary reason a radon fan should NOT be installed in a conditioned living space?
- It increases electricity costs
- Motor failure could release radon into the home (Correct answer)
- Fans are too noisy for occupied areas
- Fans require outdoor temperatures to operate correctly
Correct answer: Motor failure could release radon into the home
If the fan fails or pipe connections loosen while the fan is in conditioned space, radon can be drawn into living areas, creating a serious health hazard.
Question 3: What is the standard pipe size for most residential sub-slab depressurization systems?
- 1.5-inch PVC
- 2-inch PVC
- 3-inch PVC (Correct answer)
- 4-inch PVC
Correct answer: 3-inch PVC
3-inch PVC Schedule 40 is the standard pipe size for most residential SSD systems, providing adequate airflow with minimal resistance.
Question 4: A system performance indicator (SPI) or warning device should be installed in which location?
- At the fan housing
- In a visible location in the living area (Correct answer)
- At the exterior pipe termination
- Adjacent to the electrical panel
Correct answer: In a visible location in the living area
EPA and AARST standards require the SPI to be installed in a visible location within the living area so occupants can easily monitor system operation.
Question 5: When is block wall depressurization (BWD) an appropriate radon mitigation technique?
- In homes with poured concrete walls and high water tables
- In homes with hollow masonry block foundation walls where radon enters through the block (Correct answer)
- In all basement applications as a supplement to SSD
- Only in commercial buildings with CMU construction
Correct answer: In homes with hollow masonry block foundation walls where radon enters through the block
BWD is specifically used when radon migrates through the hollow cores of concrete masonry unit (CMU) block foundation walls, creating suction inside the block cavities.
Question 6: What does an extension field communication test help determine in system design?
- The radon decay rate within the sub-slab material
- Whether one or multiple suction points will be needed (Correct answer)
- The appropriate fan model for the home size
- The radon entry rate through floor cracks
Correct answer: Whether one or multiple suction points will be needed
By testing how far pressure differential extends from a single drill point, the contractor determines whether one suction pit will be sufficient or multiple points are needed.
Question 7: In cold climates, where is condensation most likely to form in a radon vent pipe?
- At the fan inlet connection
- In sections routed through unconditioned exterior walls (Correct answer)
- At the sub-slab drill point fitting
- Inside the manometer tube
Correct answer: In sections routed through unconditioned exterior walls
Pipe sections running through cold unconditioned spaces are prone to condensation as warm moist air from the sub-slab cools, potentially causing water to back up into the system.
RMS System Design & Installation 3
According to EPA guidelines, radon vent pipe discharge must terminate at least how far from any window or opening into the conditioned space?