100+ Free NRPP RMS Practice Questions
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Key Facts: NRPP RMS Exam
165
Questions (150 scored + 15 pretest)
NRPP exam specifications
3 hours
Time Limit
NRPP / Certiverse
25%
Exam weight on system design
NRPP RMS content outline
$175
Exam Fee (+$275 certification)
NRPP fee schedule
40 hours
Required prerequisite training (16-hr measurement + 24-hr mitigation)
NRPP certification requirements
2 years
Certification cycle
NRPP
4 pCi/L
EPA action level for mitigation
U.S. EPA
The NRPP RMS exam is the national certification test for radon mitigation system designers in the United States, administered by the National Radon Proficiency Program (AARST). It runs 165 multiple-choice questions (150 scored, 15 unscored) in 3 hours via Certiverse live online proctoring, with the ANSI/AARST SGM-SF-2023 and MAH-2023 standards accessible inside the exam. Content follows the official blueprint: mitigation system design is the largest domain at 25% (sub-slab and sub-membrane depressurization, drainage and sump systems, fan and pipe sizing, new construction), followed by troubleshooting and corrective actions at 17%, post-installation validation at 12%, mitigation quality assurance at 12%, radon science communication at 9%, ethics at 9%, pre-mitigation measurement evaluation at 8%, and worker health and safety at 8%. The pass point is criterion-referenced rather than a fixed percentage. Candidates must complete a 16-hour measurement course and a 24-hour mitigation course first; the exam costs $175 with a $275 initial certification fee on a two-year cycle. The current question pool reflects the 165-question format introduced October 1, 2024.
Sample NRPP RMS Practice Questions
Try these sample questions to test your NRPP RMS exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.
1A client asks where the radon in their home actually comes from. Radon-222 is produced directly by the radioactive decay of which radionuclide?
2What is the approximate half-life of radon-222, the property that allows it to migrate from soil into a building before decaying?
3When explaining the health risk of radon to a homeowner, which statement most accurately describes the primary mechanism of harm?
4A homeowner's confirmed indoor radon result is being compared against federal guidance. What is the U.S. EPA action level at or above which mitigation is recommended?
5A relocation company requires radon results reported in SI units. A measured concentration of 4.0 pCi/L is approximately equal to which value?
6Which mechanism is the dominant driver of radon entry into most houses with elevated indoor concentrations?
7Which two radon decay products deliver the majority of the alpha radiation dose to lung tissue?
8A client who smokes asks if radon is really a concern for them. What is the most accurate risk message?
9Assuming a typical indoor equilibrium ratio of 50 percent, one Working Level (WL) of radon decay products corresponds to approximately what radon gas concentration?
10Under ANSI/AARST MAH-2023, closed-building conditions for a short-term radon test lasting less than four days must begin how long before the test starts?
About the NRPP RMS Exam
The NRPP Radon Mitigation Specialist (RMS) exam certifies professionals who evaluate radon measurements and design, install, and verify radon reduction systems in homes. The exam contains 165 multiple-choice questions (150 scored plus 15 unscored pretest items) delivered in 3 hours through Certiverse with live remote proctoring. Candidates have in-platform access to the two governing standards, ANSI/AARST SGM-SF-2023 and MAH-2023, and must first complete a 16-hour measurement course and a 24-hour mitigation exam-prep course from an approved provider. Certification runs on a two-year cycle with continuing education, and many state radon licensing programs accept or require the credential.
Questions
165 scored questions
Time Limit
3 hours
Passing Score
Criterion-referenced pass point established by psychometric study; 150 scored items worth 1 point each
Exam Fee
$175 exam fee plus $275 initial certification fee (National Radon Proficiency Program (NRPP), a program of AARST - Indoor Environments Association; delivered via Certiverse live online proctoring)
NRPP RMS Exam Content Outline
Radon Science & Client Communication
Radium-226 decay to radon-222 in the uranium-238 chain, the 3.8-day half-life, alpha-emitting progeny (polonium-218/214) and lung cancer mechanism, EPA 4 pCi/L action level and 2-4 pCi/L consideration range, 37 Bq/m3 per pCi/L conversion, smoking synergy, stack-effect-driven soil-gas entry, and Working Level concepts
Pre-Mitigation Measurement Evaluation
ANSI/AARST MAH-2023 protocols: 12-hour pre-test closed-building conditions for short tests, 46-hour minimum valid sampling for the nominal 48-hour test, device placement (20 inches above floor, 3 feet from exterior doors/windows), lowest occupiable level, real estate paired-test averaging, and seasonal variability
Mitigation System Design
Active sub-slab depressurization, sub-membrane systems with sealed overlapped seams, drain-tile and sealed-sump suction, block-wall depressurization, suction pits and pressure field extension diagnostics, high-suction vs high-flow fan selection, pipe sizing and condensate slope, SGM-SF-2023 fan placement (attic/garage/outdoors, never interior or below occupiable space), discharge at/above eave and 10 feet from openings, labels, u-tube manometers, NFPA 70 wiring, and RRNC passive-stack activation
Post-Installation Validation
Post-mitigation testing no sooner than 24 hours after continuous operation and within 30 days, closed-building short-term protocol with the system running, remote test-hole micromanometer and smoke verification, fan-curve performance checks, combustion appliance backdraft assessment, baseline manometer documentation, and the client OM&M package
Troubleshooting & Corrective Actions
Diagnosing manometer readings (zero = fan failure, elevated vacuum = blockage from ice/water/debris), condensate gurgling and freeze-ups, exhaust re-entrainment near windows, bearing-worn fan replacement, dead pressure-field zones across footings requiring added suction points, renovation-created entry routes, return-duct leakage interactions, and ASD-induced backdrafting fixes
Worker Health & Safety
OSHA ionizing radiation limits for radon (29 CFR 1910.1096, about 100 pCi/L over a 40-hour week), respirable crystalline silica controls for slab drilling (29 CFR 1926.1153, wet methods/HEPA extraction), crawlspace hazard assessment and PPE, time-distance-ventilation exposure control, ladder 4:1 setup, and electrical de-energization and verification
Quality Assurance & Professional Ethics
SGM-SF-2023 conformance checklists, instrument calibration schedules, photo and job-file documentation, corrective-action records, state licensure verification, NRPP two-year credential maintenance, RMS vs RMI scope, conflict-of-interest disclosure for self-testing, accurate credential claims (no EPA certification exists), confidentiality, honest guarantees, and falsification penalties
How to Pass the NRPP RMS Exam
What You Need to Know
- Passing score: Criterion-referenced pass point established by psychometric study; 150 scored items worth 1 point each
- Exam length: 165 questions
- Time limit: 3 hours
- Exam fee: $175 exam fee plus $275 initial certification fee
Keys to Passing
- Complete 500+ practice questions
- Score 80%+ consistently before scheduling
- Focus on highest-weighted sections
- Use our AI tutor for tough concepts
NRPP RMS Study Tips from Top Performers
Frequently Asked Questions
How many questions are on the NRPP Radon Mitigation Specialist exam?
Since October 1, 2024 the RMS exam has 165 multiple-choice questions: 150 scored items worth 1 point each plus 15 unscored pretest items. Candidates get 3 hours to complete the exam through Certiverse with live remote proctoring.
What standards is the RMS exam based on?
The exam is built on ANSI/AARST SGM-SF-2023 (Soil Gas Mitigation Standards for Existing Homes) and ANSI/AARST MAH-2023 (radon measurement protocol for homes). Both standards are accessible within the exam platform during the test, so knowing how to navigate them quickly is a major advantage.
What are the prerequisites for taking the RMS exam?
NRPP requires completion of a 16-hour Radon Measurement Professional initial training course plus a 24-hour Radon Mitigation Specialist exam-prep course, both from NRPP-approved training providers, before certification.
How much does the NRPP RMS exam and certification cost?
The exam fee is $175, and the exam must be scheduled and completed within 30 days of purchase. Initial certification costs an additional $275, and the credential renews on a two-year cycle with continuing education.
What score do I need to pass the RMS exam?
NRPP uses a criterion-referenced passing point set through psychometric study rather than a fixed percentage. You see a pass/fail notification at completion, with official results emailed within about 48-72 business hours.
What happens if I fail the RMS exam?
A 30-day waiting period applies between attempts, each retake requires purchasing a new exam, and candidates may not exceed 4 attempts within 12 months.
What content areas carry the most weight on the exam?
Designing mitigation systems is the heaviest domain at about 25%, covering sub-slab and sub-membrane depressurization, drainage systems, fan and piping sizing, and new construction. Troubleshooting and corrective actions follow at about 17%, then post-installation validation and mitigation QA at about 12% each.