100+ Free NRSB RRS Practice Questions
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Key Facts: NRSB RRS Exam
125 questions
Exam Length (2.5 hours)
NRSB Digital Exam Information
70%
Passing Score
NRSB Digital Exam Information
$120
Exam Fee (non-refundable)
NRSB
24 + 16 hours
Required Mitigation + Measurement Training
NRSB Certification Requirements
4.0 pCi/L
EPA Radon Action Level
EPA A Citizen's Guide to Radon
10 feet
Minimum Discharge Height Above Grade
ASTM E2121 / ANSI-AARST SGM-SF
8 CE hours/year
Continuing Education to Maintain Certification
NRSB
The NRSB RRS is the National Radon Safety Board's mitigation credential for contractors who design and install residential radon reduction systems - the NRSB counterpart to the NRPP RMS. The exam runs 125 single-best-answer questions in 2.5 hours with a virtual live proctor, costs $120, and requires 70% to pass; failed attempts trigger a 14-day wait before re-registration, and a passing score stays valid for one year toward certification. Content spans mitigation system design and selection (active sub-slab, sub-membrane, drain-tile, sump-hole, and block-wall depressurization), pressure field extension diagnostics with micromanometers and chemical smoke, fan selection along performance curves, installation requirements from ASTM E2121-13 and ANSI/AARST SGM-SF-2023 (10-foot discharge rules, fan location limits, labeling, u-tube performance indicators, combustion backdraft checks), pre- and post-mitigation measurement protocols, worker safety (silica, ionizing radiation, electrical, asbestos), and troubleshooting plus OM&M. Prerequisites are 24 hours of approved mitigation training including 8 hands-on hours plus 16 hours of measurement training; certification renews with 8 CE hours annually.
Sample NRSB RRS Practice Questions
Try these sample questions to test your NRSB RRS exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.
1Radon-222, the isotope of primary concern in residential radon mitigation, is produced directly by the radioactive decay of which element?
2What is the approximate half-life of radon-222?
3The lung-cancer risk from radon exposure is primarily caused by which mechanism?
4What is the EPA action level at which radon mitigation of a home is recommended?
5Using the standard conversion factor, an indoor radon concentration of 4.0 pCi/L is equivalent to approximately how many becquerels per cubic meter (Bq/m3)?
6According to EPA estimates, approximately how many lung cancer deaths per year in the United States are attributable to radon?
7Assuming the conventional 50% equilibrium ratio, an indoor radon gas concentration of 200 pCi/L corresponds to a decay-product concentration of approximately how many working levels (WL)?
8How does cigarette smoking interact with radon exposure with respect to lung cancer risk?
9What is the primary mechanism by which radon enters most homes?
10Using the commonly cited transfer rule of thumb, well water containing 10,000 pCi/L of radon will contribute approximately how much radon to the indoor air?
About the NRSB RRS Exam
The NRSB Radon Reduction/Mitigation Specialist (RRS) exam certifies professionals to design and install radon remediation systems in residential buildings. Administered remotely with a virtual live proctor, the 125-question, 2.5-hour multiple-choice exam requires a 70% score and draws on ASTM E2121-13, the ANSI/AARST soil gas mitigation standards, and EPA technical guidance. Candidates must first complete 24 hours of NRSB-approved mitigation training (including 8 hands-on hours) and 16 hours of measurement training. Certified RRS professionals maintain the credential with 8 hours of continuing education per year and adherence to the NRSB Code of Ethics.
Questions
125 scored questions
Time Limit
2.5 hours
Passing Score
70% or higher
Exam Fee
$120 (non-refundable) (National Radon Safety Board (NRSB))
NRSB RRS Exam Content Outline
Radon Science & Health Effects
Uranium-238/radium-226 decay chain and the 3.8-day half-life of Rn-222, alpha-emitting progeny (Po-218/Po-214) and lung cancer risk including the ~21,000 annual US deaths estimate and smoking synergy, EPA 4.0 pCi/L action level, pCi/L-Bq/m3 conversions, working levels and the ~0.4-0.5 equilibrium ratio, stack-effect driven soil gas entry, and the 10,000:1 water-to-air transfer rule
Measurement & Testing Protocols
Pre-mitigation baseline testing, post-mitigation verification no sooner than 24 hours of continuous operation and within 30 days, 48-hour minimum short-term tests with 12-hour prior closed-building conditions, device selection (charcoal, alpha-track, CRM) and breathing-zone placement rules, QA duplicates and field blanks, independent verification testers, and EPA's 2-year retest interval
Diagnostics & System Design
Building investigation and foundation typing, pressure field extension (communication) testing with shop-vac suction, 0.001-in-w.c. micromanometers and chemical smoke, 5-15 gallon suction pits, selecting among active sub-slab, sub-membrane, drain-tile, sump-hole, and block-wall depressurization, HRV dilution options, groundwater interactions, and combination-foundation strategies
System Installation Standards
ASTM E2121-13 and ANSI/AARST SGM-SF-2023 requirements: discharge at least 10 ft above grade, above the eave, and 10 ft from openings unless 2 ft above them; fan placement outside and never below conditioned space; system description and per-floor pipe labels; u-tube performance indicators; sealing of sumps, drains, and major entry routes; 6-mil sealed SMD membranes; NEC-compliant wiring; firestopping; and post-activation combustion appliance backdraft checks
Fans, Piping & Materials
Fan performance curves, high-suction/low-flow versus high-flow fan selection from diagnostic data, continuous-duty listed fans mounted vertically with flexible couplings, Schedule 40 PVC piping, diameter selection for friction and noise, 1/8-inch-per-foot condensate slope with no sags, freeze protection, and recording manometer baselines
Worker Safety
Managing occupational radon exposure with ventilation and time limits, P100/HEPA protection against particle-attached progeny, OSHA respirable crystalline silica (29 CFR 1926.1153) wet/HEPA controls, the ionizing radiation standard (29 CFR 1910.1096), GFCI use in damp spaces, crawlspace hazard assessment, asbestos awareness in pre-1980s homes, and ladder/PPE rules
Troubleshooting, OM&M & Client Communication
Interpreting zero, elevated, and depressed u-tube readings, winter discharge icing and frozen condensate, sealed-fan replacement at flexible couplings, responding to failed post-mitigation tests, OM&M documentation with baselines and retest schedules, supplemental system alarms, written performance guarantees below 4.0 pCi/L, and plain-language risk communication under the NRSB Code of Ethics
How to Pass the NRSB RRS Exam
What You Need to Know
- Passing score: 70% or higher
- Exam length: 125 questions
- Time limit: 2.5 hours
- Exam fee: $120 (non-refundable)
Keys to Passing
- Complete 500+ practice questions
- Score 80%+ consistently before scheduling
- Focus on highest-weighted sections
- Use our AI tutor for tough concepts
NRSB RRS Study Tips from Top Performers
Frequently Asked Questions
How many questions are on the NRSB RRS exam and how long is it?
The RRS exam has 125 single-best-answer multiple-choice questions with a 2.5-hour time limit. It is taken remotely on a desktop or laptop (not a phone or tablet) with a virtual live proctor, and digital tools include a notepad, formula sheet, and calculator plus one piece of scrap paper.
What score do I need to pass the RRS exam?
You must score 70% or higher. Candidates who fail must wait 14 days before re-registering (and paying the fee again), and a passing exam result is valid for one year toward NRSB certification.
What training is required before taking the NRSB RRS exam?
Certification requires 24 hours of NRSB-approved radon mitigation training, including at least 8 hours of hands-on experience, plus 16 hours of NRSB-approved measurement training. After certification, 8 hours of NRSB-approved continuing education are required each certification year.
How much does the NRSB RRS exam and certification cost?
The exam fee is $120 and is non-refundable. NRSB certification fees are $125 for one year or $200 for two years, and you may not cancel or reschedule the exam within 24 hours of your appointment.
What standards and documents is the RRS exam based on?
Questions are drawn from ASTM E2121-13 (Standard Practice for Installing Radon Mitigation Systems in Existing Low-Rise Residential Buildings), the ANSI/AARST soil gas mitigation standards such as SGM-SF, EPA's A Citizen's Guide to Radon and Consumer's Guide to Radon Reduction, and other EPA technical guidance on radon reduction techniques.
What mitigation techniques does the exam cover?
The exam covers active sub-slab depressurization (the primary technique), sub-membrane depressurization for dirt crawlspaces, drain-tile and sump-hole depressurization, block-wall depressurization, sealing as an adjunct, and ventilation/HRV approaches, plus the diagnostics - pressure field extension and smoke testing - used to choose among them.
How does the NRSB RRS differ from the NRPP radon mitigation credential?
NRSB and AARST-NRPP are the two national radon certification bodies. The NRSB RRS and the NRPP RMS both certify residential mitigation professionals; which one you need depends on your state's radon licensing program, and some states accept either credential.