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

Question 1: A real estate transaction requires a post-mitigation test. Which professional should conduct the test according to most state protocols?

The homeowner using a DIY kit from a hardware store
An independent, state-certified radon measurement professional (Correct answer)
The mitigation contractor who installed the system
A licensed home inspector without radon certification

Correct answer: An independent, state-certified radon measurement professional

Most states and EPA guidelines recommend that post-mitigation testing for real estate transactions be performed by a measurement professional independent of the contractor who installed the system.

Question 2: Under OSHA regulations, what personal protective equipment is required for workers core drilling through a concrete slab with potential silica exposure?

Hearing protection only
Safety glasses only
N95 respirator at minimum; P100 or supplied-air respirator depending on silica levels (Correct answer)
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.

Question 3: Which AARST standard defines quality and qualifications for radon measurement professionals, used to benchmark RMS knowledge?

ANSI/AARST SGM-SF
ANSI/AARST R-MMP (Correct answer)
ANSI/AARST MALB
ANSI/AARST MAMF

Correct answer: ANSI/AARST R-MMP

ANSI/AARST R-MMP (Radon Measurement and Mitigation Professional) sets qualification standards for the field.

Question 4: What is the purpose of a short-circuit test in sub-slab depressurization diagnostics?

To measure how fast radon decays in soil
To test the electrical wiring of the mitigation fan
To identify locations where outdoor air is entering the sub-slab and reducing system efficiency (Correct answer)
To test the battery backup of the system alarm

Correct answer: To identify locations where outdoor air is entering the sub-slab and reducing system efficiency

A short-circuit test identifies locations where atmospheric air enters the sub-slab zone, reducing the system's ability to maintain sufficient negative pressure.

Question 5: A homeowner asks a radon contractor if their neighbor's high radon levels legally obligate them to test. What is the correct response?

No, radon levels vary significantly between adjacent properties and no law mandates testing based on neighbors' results (Correct answer)
Yes, state law always requires testing within 50 feet of a confirmed high-radon property
No, but the contractor must report the neighbor's result to the EPA
Yes, federal law requires testing when a neighbor's levels exceed 4 pCi/L

Correct answer: No, radon levels vary significantly between adjacent properties and no law mandates testing based on neighbors' results

Radon concentrations can vary dramatically between adjacent homes due to soil conditions and building characteristics; no federal or common state law mandates testing based on a neighbor's results.

Question 6: How can a radon mitigation specialist reduce radon levels in a building?

By increasing the number of radon detectors.
By sealing cracks, improving ventilation, or installing mitigation systems (Correct answer)
By opening windows year-round.
By covering the walls with plastic.

Correct answer: By sealing cracks, improving ventilation, or installing mitigation systems

Radon mitigation involves several strategies to reduce indoor radon levels. Sealing cracks and openings in the foundation prevents radon entry, while improving general ventilation helps dilute existing radon. Installing active mitigation systems, such as sub-slab depressurization, directly removes radon from beneath the building before it can enter the living space.

Question 7: During post-mitigation testing, a continuous radon monitor (CRM) is used. What advantage does a CRM offer over a passive device?

CRMs can be mailed to a laboratory for more accurate analysis
CRMs are less expensive and easier to deploy
CRMs do not require closed-house conditions
CRMs provide hourly data allowing detection of system anomalies during the test period (Correct answer)

Correct answer: CRMs provide hourly data allowing detection of system anomalies during the test period

Continuous monitors record radon levels at regular intervals, making it possible to identify periods of elevated levels that may indicate system problems or protocol violations.

Question 8: What does a U-tube manometer permanently installed on a mitigation system allow a homeowner to monitor?

The indoor radon concentration level
Whether the fan is maintaining negative pressure in the suction pipe (Correct answer)
Fan motor operating temperature
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 9: Which pipe diameter is most commonly specified for radon mitigation suction pipes in residential installations?

6-inch PVC
2-inch PVC
4-inch PVC (Correct answer)
3-inch PVC

Correct answer: 4-inch PVC

4-inch PVC pipe is the most commonly used diameter for residential radon mitigation suction pipes per EPA guidelines.

Question 10: A charcoal canister radon test must be analyzed within how many days of retrieval to ensure valid results?

30 days
7 days (Correct answer)
3 days
14 days

Correct answer: 7 days

Charcoal canisters must be analyzed within 7 days of retrieval because adsorbed radon continues to decay and the charcoal's collection capacity diminishes over time.

Question 11: A contractor is bidding a commercial SSD project in a multi-tenant office building. Who must be notified before core drilling begins?

Building owner, tenants in affected areas, and local building authority if a permit is required (Correct answer)
EPA regional office
Only the building owner
State radon program coordinator only

Correct answer: Building owner, tenants in affected areas, and local building authority if a permit is required

Core drilling in occupied commercial buildings requires notifying the owner, affected tenants to minimize disruption, and the local authority having jurisdiction if a permit is required.

Question 12: A homeowner requests that the RMS skip the post-mitigation radon test to save money. What should the RMS do?

Explain that post-mitigation testing is required by standards and strongly recommend it (Correct answer)
Agree but note the waiver in writing and sign the project file
Offer to perform a visual inspection instead of a test
Skip the test at the client's request since they own the property

Correct answer: Explain that post-mitigation testing is required by standards and strongly recommend it

Post-mitigation testing is required by AARST-ANSI standards to verify system performance; the RMS must advise the client accordingly even if they decline.

Question 13: When installing a radon mitigation fan in an attic, which factor is most critical for maintaining system effectiveness?

Fan motor speed controller
Weatherproof housing rated for temperature extremes (Correct answer)
Decorative housing to match roof aesthetics
Fan color to reflect sunlight

Correct answer: Weatherproof housing rated for temperature extremes

Attic-mounted fans must have weatherproof housings rated for the temperature extremes experienced in unconditioned attic spaces.

Question 14: 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 if they have NRPP certification
Non-compliant with state requirements (Correct answer)
Non-compliant only if a claim is filed
Compliant, because federal guidelines override state rules

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 15: In a two-story house with a basement, which area typically has the highest negative pressure relative to outdoor conditions due to the stack effect alone?

Basement floor level (Correct answer)
Second floor bedrooms
Attic
Main floor living areas

Correct answer: Basement floor level

The stack effect creates maximum negative pressure at the lowest point of the building (basement floor level) and maximum positive pressure at the highest point, drawing outdoor and soil air in at the base.

Question 16: During diagnostic testing of a slab-on-grade home, a technician notices that a floor drain is open to the sub-slab area. What is the appropriate response?

Install the mitigation fan directly in the drain opening
Fill the drain with concrete permanently without further assessment
Ignore it because drains are sealed by water traps
Identify it as a potential radon bypass pathway and address it in the mitigation plan (Correct answer)

Correct answer: Identify it as a potential radon bypass pathway and address it in the mitigation plan

Open floor drains can be direct pathways for soil gas radon to enter the living space and must be addressed as part of a complete mitigation design.

Question 17: Which factor most influences the choice between an interior and exterior routing for the radon mitigation pipe?

Pipe diameter requirements
The brand of mitigation fan selected
Climate, aesthetics, and whether the pipe must pass through conditioned space (Correct answer)
The homeowner's color preference for the pipe

Correct answer: Climate, aesthetics, and whether the pipe must pass through conditioned space

Pipe routing decisions depend on climate (freezing risk for exterior pipes), aesthetic preferences, and the requirement to seal interior pipe joints gas-tight.

Question 18: A long-term radon test (90 days) and a short-term test (48 hours) are conducted simultaneously post-mitigation. The short-term result is 1.8 pCi/L and the long-term result is 4.3 pCi/L. Which result should be used for compliance determination?

The long-term test because it better represents actual exposure over time (Correct answer)
The short-term test because it is more precise
The average of both results
Whichever result the homeowner prefers

Correct answer: The long-term test because it better represents actual exposure over time

Long-term tests provide a more representative measure of chronic radon exposure and are preferred for compliance determination when both are available.

Question 19: A diagnostic test shows very high sub-slab air resistance (low communication). Which mitigation technique is MOST appropriate?

Single suction point SSD with a high-capacity fan
Natural ventilation with no mechanical system
Block wall depressurization only
Multiple suction points or sub-membrane depressurization (Correct answer)

Correct answer: Multiple suction points or sub-membrane depressurization

Poor sub-slab communication requires multiple suction points or alternative methods like sub-membrane depressurization to achieve adequate depressurization.

Question 20: What is the primary purpose of performing diagnostic testing before installing a radon mitigation system?

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

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 21: Under ANSI/AARST SGM-SF-2017, which building component must never be used as the sole pathway for a sub-slab depressurization system?

Poured concrete slab
Block wall interior cavities when they communicate with living space (Correct answer)
Dirt crawl space floor
Gravel sub-base beneath the slab

Correct answer: Block wall interior cavities when they communicate with living space

Block wall cavities that open into living areas cannot serve as the sole depressurization pathway because pulling air through them may draw radon into living spaces rather than exhausting it.

Question 22: A post-mitigation test is conducted in a home with a basement and an attached garage. Where should the test device NOT be placed?

In the basement laundry area used daily
In the attached garage (Correct answer)
In the basement family room near the TV
In the basement bedroom used nightly

Correct answer: In the attached garage

Garages are not considered livable space and often have separate ventilation; placing a device there would not reflect occupant exposure and would likely yield an invalid low result.

Question 23: What is the first step in designing a radon mitigation system for a building?

Seal all cracks without testing.
Install ventilation without testing.
Install a generic system regardless of testing.
Test radon levels to assess the appropriate system (Correct answer)

Correct answer: Test radon levels to assess the appropriate system

Before designing any radon mitigation system, it is critical to conduct accurate radon testing to determine the existing indoor levels. This initial assessment provides crucial data to understand the severity of the problem and helps in selecting the most effective and appropriate mitigation strategy for that specific building. Without testing, the system might be ineffective or over-engineered.

Question 24: What is the relationship between radon concentration and lung cancer risk according to the linear no-threshold (LNT) model?

Risk increases only above 4 pCi/L
Risk plateaus above 10 pCi/L
There is no risk below 2 pCi/L
Risk increases proportionally with any exposure level (Correct answer)

Correct answer: Risk increases proportionally with any exposure level

The LNT model assumes any amount of radiation exposure carries some proportional risk, with no safe threshold.

Question 25: When installing a sub-slab depressurization (SSD) system in a house with multiple isolated sub-slab areas, what is the recommended approach?

Seal all but one section and install a single suction point
Install one suction point in the largest section only
Increase fan capacity to compensate for isolated sections
Install separate suction points for each isolated section (Correct answer)

Correct answer: Install separate suction points for each isolated section

Each isolated sub-slab area requires its own suction point because air cannot flow between disconnected sections.

Question 26: When troubleshooting a system that has lost vacuum while the fan continues running, which component should be inspected first?

The radon test kit expiration date
The electrical panel breaker
The exterior concrete slab surface
The suction pipe for cracks, disconnections, or blockages (Correct answer)

Correct answer: The suction pipe for cracks, disconnections, or blockages

Physical disconnections, cracks, or obstructions in the suction pipe are the most common mechanical cause of vacuum loss in an otherwise running system.

Question 27: A diagnostic test reveals very low sub-slab airflow despite a high-powered fan. What is the most likely cause?

The radon level is naturally below the action level
The fan is oversized for the application
The sub-slab gravel bed is too thick
The sub-slab fill has very low permeability such as clay or fine sand (Correct answer)

Correct answer: The sub-slab fill has very low permeability such as clay or fine sand

Low-permeability sub-slab materials like clay restrict air movement, resulting in poor pressure field extension regardless of fan power.

Question 28: What does the term 'system failure warning device' refer to in a commercial radon mitigation system?

A shut-off valve that closes if radon exceeds 4 pCi/L
A visual or audible indicator that alerts occupants when the fan fails or loses pressure (Correct answer)
A CO detector wired to the fire panel
An HVAC interlock that stops the air handler if radon rises

Correct answer: A visual or audible indicator that alerts occupants when the fan fails or loses pressure

A system failure warning device (such as a manometer or alarm) alerts building managers when the mitigation fan loses suction or fails.

Question 29: For a home with a basement and an attached garage with a slab, how should the radon system address both areas?

Treat the garage with SSD only and the basement with sealing only
Connect both areas to a single common suction system if sub-slab communication is confirmed (Correct answer)
The garage does not require mitigation since it is not living space
Install separate independent systems for each area

Correct answer: Connect both areas to a single common suction system if sub-slab communication is confirmed

If sub-slab communication between the basement and garage is confirmed, a single system may address both; otherwise separate suction points connected to one fan may be required.

Question 30: Why do radon concentrations in a home typically fluctuate significantly from hour to hour and day to day?

Radon half-life varies with temperature
Soil moisture is the only variable affecting radon, and it changes slowly
Wind speed, indoor HVAC operation, and occupant behavior continuously change the driving pressures and ventilation rates (Correct answer)
The rate of radium decay in soil changes throughout the day

Correct answer: Wind speed, indoor HVAC operation, and occupant behavior continuously change the driving pressures and ventilation rates

Dynamic factors including wind pressure on the building envelope, HVAC cycling, opening of doors and windows, and stack effect changes all continuously alter the pressure differentials and air exchange rates that control radon entry and dilution.

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

Checking for saved progress...

Exam Rules

You can skip questions and return to them later
Flag questions for review before submitting
No feedback shown until you submit the entire exam
Unanswered questions count as wrong — answer everything
10 pretest questions are mixed in and don't affect your score
Timer auto-submits when time runs out
Your progress is auto-saved every 30 seconds