NRPP RMP common mistakes
NRPP RMP · Understand the traps and how to avoid them.
Treating the 4 pCi/L action level as a legal limit and telling a client a home 'passes' or 'fails' at that number.
Candidates conflate the EPA action level (a recommendation) with a regulatory maximum contaminant level, since radon has no MCL.
What to do instead
State that 4 pCi/L is an EPA action level, not a legal standard; describe results as above or below the action level and recommend mitigation as a risk-reduction decision.
Placing a test device in a closet, bathroom, kitchen, hallway near a door, or on an exterior wall, or within a few inches of the floor.
Candidates pick a spot for convenience or to keep the device out of the way, forgetting closed-room and proximity restrictions.
What to do instead
Follow the closed-building and placement rules: livable room, interior wall, roughly breathing-zone height, away from exterior walls, doors, windows, drains, and heat sources, with the required closed-building period and normal HVAC operation.
Ending the closed-building condition early or opening windows during a test, then reporting the result as valid.
Occupants open windows for comfort or the technician vents the home, and the candidate does not recognize the test is invalidated.
What to do instead
Enforce and document the closed-building period before and during the test, note any deviation, and void or restart the test if the condition was broken.
Failing to place a required duplicate or blank, or placing them incorrectly, and reporting results without the QA data.
Candidates treat QC samples as optional paperwork and misplace spares (e.g., duplicate not co-located, blank not in the same environment or not left sealed).
What to do instead
Build a written QC plan with the required number and type of duplicates, blanks, and spikes per the protocol; co-locate duplicates and handle blanks per the device protocol; review QC before releasing results.
Confusing short-term and long-term devices, or misstating the exposure period each device measures.
Candidates memorize device names without linking them to their exposure duration and intended use.
What to do instead
Map each device to its exposure window and purpose (e.g., short-term screening versus long-term confirmation), and state the correct test duration and interpretation for each.
Attributing elevated radon entirely to the basement or slab and ignoring the actual driving forces and entry routes.
Candidates focus on one pathway and forget pressure-driven soil gas entry, stack effect, and other routes.
What to do instead
Explain the pressure-driven entry mechanism (soil gas drawn in by lower indoor pressure), stack and wind effects, and multiple entry paths (cracks, sumps, utility penetrations, block walls), and match mitigation to the actual entry route.
Reporting a single short-term result as a definitive annual exposure or guaranteeing the level will stay the same.
Candidates overstate precision and ignore seasonal and daily variation in radon concentrations.
What to do instead
Present results with appropriate uncertainty, explain variability and the value of confirmatory or long-term testing, and avoid guarantees; recommend follow-up testing or mitigation based on the action level.
Skipping or mishandling chain-of-custody and device deployment/retrieval documentation.
Candidates rush fieldwork and treat paperwork as secondary to the measurement.
What to do instead
Complete deployment and retrieval records at the time of service, record dates, locations, and device IDs, maintain chain of custody, and reconcile records before analysis.
Giving mitigation advice or interpreting results beyond the measurement scope without the proper role or disclosure.
Candidates want to be helpful and blur the line between measurement, mitigation, and conflict-of-interest rules.
What to do instead
Stay within the measurement role, disclose any conflicts of interest, refer mitigation decisions to qualified mitigators, and follow the applicable standards and ethics requirements.
Misapplying unit conversions or misreading device calibration/reference data when computing a result.
Candidates make arithmetic or unit errors (e.g., pCi/L versus Bq/m3, working-level conversions) under time pressure.
What to do instead
Use a consistent unit system, show the conversion steps, verify against device calibration and reference values, and double-check calculations before reporting.