NRPP Radon Mitigation Specialist (RMS) Exam — Questions and Answers

Question 1: Which type of continuing education activity typically qualifies for NRPP renewal credit?

Radon-specific technical training, conferences, or approved webinars (Correct answer)
General business accounting courses
HVAC installation training
General construction safety courses

Correct answer: Radon-specific technical training, conferences, or approved webinars

NRPP CE credits require radon-specific or directly relevant technical training, not general business or unrelated construction courses.

Question 2: What does a failing post-mitigation test indicate?

The test device was defective
The system may need additional suction points or sealing (Correct answer)
Radon mitigation is impossible for this building
The building is permanently unsafe

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 3: What career advancement paths exist for RMS certified professionals?

Advancement requires leaving the field entirely
No advancement is possible beyond initial certification
Leadership roles, specialized consulting, education and training, and executive management positions (Correct answer)
Only changing careers provides advancement

Correct answer: Leadership roles, specialized consulting, education and training, and executive management positions

Certified professionals can advance through specialization, leadership roles, consulting, academic/training positions, and executive management within their field.

Question 4: What should be done after a radon mitigation system is installed?

Ignore the results and wait for further testing.
Test radon levels again to ensure effectiveness (Correct answer)
Remove the mitigation system.
Seal all cracks again.

Correct answer: Test radon levels again to ensure effectiveness

After a radon mitigation system is installed, post-mitigation testing is crucial to verify its effectiveness. This follow-up testing confirms that the system is successfully reducing radon levels below the EPA action level. It ensures the investment in mitigation has achieved its intended health protection goal.

Question 5: A state requires radon contractors to carry general liability insurance with a minimum of $300,000 per occurrence. An RMS carries only $250,000. What is their compliance status?

Compliant, because federal guidelines override state rules
Non-compliant with state requirements (Correct answer)
Non-compliant only if a claim is filed
Compliant if they have NRPP certification

Correct answer: Non-compliant with state requirements

State licensing requirements are mandatory and take precedence; carrying less than the required minimum renders the contractor non-compliant.

Question 6: What is the primary purpose of a radon mitigation system?

To reduce the radon levels inside the building (Correct answer)
To increase energy efficiency.
To improve the building's aesthetic.
To regulate indoor temperature.

Correct answer: To reduce the radon levels inside the building

The sole and primary purpose of a radon mitigation system is to lower the concentration of radon gas within a building to levels considered safe by health organizations. Radon is a known carcinogen, and these systems are specifically designed to protect occupants from its harmful effects by preventing its entry or actively removing it.

Question 7: What is the importance of peer review in radon mitigation?

Peer review undermines professional confidence
Peer review is unnecessary for experienced professionals
Peer review ensures quality, catches errors, provides learning opportunities, and maintains professional standards (Correct answer)
Only management should review professional work

Correct answer: Peer review ensures quality, catches errors, provides learning opportunities, and maintains professional standards

Peer review is a cornerstone of professional quality assurance, providing independent verification, knowledge sharing, and continuous improvement opportunities.

Question 8: What is the recommended placement for a post-mitigation radon test device?

Lowest livable area, at least 20 inches above the floor (Correct answer)
Directly on the mitigation fan
On the roof
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 9: What is the stack effect and how does it relate to radon entry?

Warm air rising creates negative pressure at lower levels, drawing in soil gases (Correct answer)
Cold air sinking pushes radon out of the building
The stack effect only occurs in buildings with chimneys
Wind against the building forces radon through windows

Correct answer: Warm air rising creates negative pressure at lower levels, drawing in soil gases

The stack effect occurs when heated indoor air rises and exits through upper levels, creating negative pressure at lower levels that draws soil gases, including radon, into the building.

Question 10: What is a U-tube manometer used for in radon mitigation?

To test water pressure in plumbing
To measure exhaust air temperature
To measure the pressure differential created by the mitigation system (Correct answer)
To measure radon levels directly

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 11: A homeowner reports that the U-tube manometer installed on their radon system shows equal fluid levels on both sides. What does this indicate?

No pressure differential exists, suggesting the fan may not be operating (Correct answer)
The test was conducted correctly
The system pressure is too high
The system is operating at peak efficiency

Correct answer: No pressure differential exists, suggesting the fan may not be operating

Equal fluid levels in a U-tube manometer indicate no pressure difference, which means the fan is likely not creating sub-slab suction.

Question 12: A mitigation fan is operating but post-mitigation radon tests show levels above 4 pCi/L. Which diagnostic step should be performed first?

Install additional fans in series
Replace the fan immediately
Increase the fan exhaust height
Check for air bypasses such as open sumps, cracks, or uncapped drains (Correct answer)

Correct answer: Check for air bypasses such as open sumps, cracks, or uncapped drains

Air bypasses allow soil gas to enter the living space even when the system is running, and are the most common cause of persistent elevated radon post-installation.

Question 13: A smoke pencil or puffer is used during radon diagnostic testing primarily to:

Calibrate a continuous radon monitor
Measure radon concentration in soil gas
Identify air pathways and verify airflow direction around the foundation (Correct answer)
Test for carbon monoxide leaks in the gas line

Correct answer: Identify air pathways and verify airflow direction around the foundation

A smoke pencil visualizes airflow patterns to identify where soil gas may be entering and whether the system is drawing air effectively.

Question 14: What is the difference between passive and active radon mitigation systems?

Passive systems use larger fans
Active systems don't use electricity
They are identical systems
Passive relies on natural airflow; active uses a fan to create suction (Correct answer)

Correct answer: Passive relies on natural airflow; active uses a fan to create suction

Passive systems rely on thermal stack effect to draw radon through a vent pipe naturally, while active systems use a continuously running fan to create mechanical suction, achieving much greater radon reduction.

Question 15: When probing multiple diagnostic holes, what finding indicates that a second suction point is necessary?

Radon levels drop after installing the first suction point
The fan is drawing too much current
One or more sections show no negative pressure response (Correct answer)
All holes show equal negative pressure

Correct answer: One or more sections show no negative pressure response

Areas that show no pressure response are isolated from the suction point and require their own dedicated suction pit.

Question 16: What should be done after a radon mitigation system has been installed?

Seal all cracks again.
Remove the mitigation system.
Ignore the results and wait for further testing.
Test radon levels to ensure effectiveness (Correct answer)

Correct answer: Test radon levels to ensure effectiveness

Question 17: What is the importance of peer review in radon mitigation?

Peer review is unnecessary for experienced professionals
Peer review ensures quality, catches errors, provides learning opportunities, and maintains professional standards (Correct answer)
Only management should review professional work
Peer review undermines professional confidence

Correct answer: Peer review ensures quality, catches errors, provides learning opportunities, and maintains professional standards

Peer review is a cornerstone of professional quality assurance, providing independent verification, knowledge sharing, and continuous improvement opportunities.

Question 18: What is the significance of a negative pressure reading of -3 Pascals at a monitoring port compared to one of -12 Pascals in a sub-slab depressurization system?

Both readings indicate equal system effectiveness
-12 Pa indicates the system is over-pressurizing the slab
-3 Pa may indicate inadequate suction extension at that monitoring point (Correct answer)
Pressure readings are irrelevant to system quality

Correct answer: -3 Pa may indicate inadequate suction extension at that monitoring point

Lower negative pressure (e.g., -3 Pa) at a remote point may indicate the suction is not extending adequately to that area, suggesting a need for additional suction points.

Question 19: During a pressure field extension test, a manometer is inserted into a diagnostic hole. What result indicates good sub-slab communication?

No pressure change at the diagnostic hole
A positive pressure reading at the diagnostic hole
A negative pressure reading similar to that at the suction pit (Correct answer)
A reading of exactly zero pascals

Correct answer: A negative pressure reading similar to that at the suction pit

A negative pressure reading at the diagnostic hole similar to the suction pit pressure confirms the sub-slab is well-interconnected.

Question 20: Which radon measurement technique is considered the most reliable for long-term testing?

Short-term testing with active detectors.
Short-term testing with charcoal canisters.
Using a radon mitigation system.
Long-term testing with alpha track detectors (Correct answer)

Correct answer: Long-term testing with alpha track detectors

Long-term radon testing, typically lasting 90 days or more, provides the most accurate representation of a building's average radon levels over time. Alpha track detectors are passive devices well-suited for this purpose, as they are less susceptible to short-term fluctuations and provide a more reliable annual average concentration. This method helps account for seasonal variations and daily changes.

Question 21: Which ethical principle requires an RMS to disclose a conflict of interest to a client?

Referral exclusivity
Transparency and honesty (Correct answer)
Confidentiality
Competence

Correct answer: Transparency and honesty

Professional ethics demand that any financial or personal interest that could bias the RMS's recommendations be disclosed to the client.

Question 22: What does a U-tube manometer permanently installed on a mitigation system allow a homeowner to monitor?

Fan motor operating temperature
The indoor radon concentration level
Whether the fan is maintaining negative pressure in the suction pipe (Correct answer)
The outdoor radon concentration

Correct answer: Whether the fan is maintaining negative pressure in the suction pipe

The U-tube manometer provides a visual indicator that the system is functioning by showing fluid displacement corresponding to negative pressure in the pipe.

Question 23: What is the primary goal of health and safety regulations in radon mitigation?

To ensure safe and effective radon mitigation (Correct answer)
To reduce the time spent on mitigation.
To increase the cost of mitigation systems.
To eliminate the need for radon testing.

Correct answer: To ensure safe and effective radon mitigation

Health and safety regulations in radon mitigation are designed to protect both the occupants of the building and the mitigation specialists performing the work. These regulations ensure that mitigation systems are installed correctly, effectively reduce radon levels, and do not introduce new hazards. The overarching goal is to achieve safe indoor air quality while ensuring worker safety.

Question 24: In a large commercial building with multiple sub-slabs, what is the primary reason for installing multiple suction points?

To simplify system maintenance
To ensure adequate pressure field extension across all zones (Correct answer)
To reduce electrical costs
To comply with fire code requirements

Correct answer: To ensure adequate pressure field extension across all zones

Multiple suction points are required when a single point cannot extend the negative pressure field across the entire sub-slab area.

Question 25: How should RMS professionals handle conflicts of interest?

Only financial conflicts matter
Keep conflicts hidden to avoid complications
Conflicts of interest are normal and need not be addressed
Disclose potential conflicts, recuse when appropriate, and always prioritize the client's best interests (Correct answer)

Correct answer: Disclose potential conflicts, recuse when appropriate, and always prioritize the client's best interests

Conflicts of interest must be identified, disclosed, and managed transparently to maintain professional integrity and client trust.

Question 26: What is the primary purpose of performing diagnostic testing before installing a radon mitigation system?

To verify the building's electrical capacity
To determine optimal sub-slab communication and suction point locations (Correct answer)
To measure indoor air quality for other pollutants
To calculate the home's total square footage

Correct answer: To determine optimal sub-slab communication and suction point locations

Diagnostic testing identifies where suction points should be placed by assessing sub-slab communication and soil permeability.

Question 27: Which lung cancer risk classification has the International Agency for Research on Cancer (IARC) assigned to radon?

Group 2A – probable carcinogen
Group 3 – not classifiable as to carcinogenicity
Group 1 – known human carcinogen (Correct answer)
Group 2B – possible carcinogen

Correct answer: Group 1 – known human carcinogen

IARC classifies radon as a Group 1 known human carcinogen based on sufficient epidemiological evidence linking indoor radon exposure to lung cancer.

Question 28: What role does soil permeability play in radon mitigation system design?

Lower permeability always produces better results
Higher permeability allows better sub-slab communication and more effective depressurization (Correct answer)
Permeability only matters for crawlspace systems
Soil permeability has no effect on mitigation design

Correct answer: Higher permeability allows better sub-slab communication and more effective depressurization

Soil permeability affects how well suction from a mitigation point extends beneath the slab. Highly permeable soils allow better communication, while tight soils may require multiple suction points.

Question 29: According to EPA guidance, how soon after completing a radon mitigation system installation should a post-mitigation test be conducted?

90 days after installation
One full year after installation
At least 24 hours but no more than 30 days after installation (Correct answer)
Immediately after fan startup

Correct answer: At least 24 hours but no more than 30 days after installation

EPA guidance recommends conducting a post-mitigation test at least 24 hours after installation, ideally within 30 days, to confirm the system is working effectively.

Question 30: Under OSHA regulations, what personal protective equipment is required for workers core drilling through a concrete slab with potential silica exposure?

N95 respirator at minimum; P100 or supplied-air respirator depending on silica levels (Correct answer)
Safety glasses only
Hearing protection only
Chemical-resistant gloves and apron

Correct answer: N95 respirator at minimum; P100 or supplied-air respirator depending on silica levels

OSHA's silica standard (29 CFR 1926.1153) requires respiratory protection when cutting or drilling concrete, with P100 or supplied-air respirators for higher exposure tasks.

NRPP Radon Mitigation Specialist (RMS) Exam

The NRPP Radon Mitigation Specialist exam certifies professionals in the design, installation, and verification of radon mitigation systems for residential and commercial buildings, based on ANSI-AARST standards SGM-SF and MAH.

Questions

35 min

Time Limit

70%

To Pass

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These practice questions were written with AI tools. They are not real exam questions. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy

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