NRPP RMFT flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Radon-222 half-life

Radon-222 has a half-life of about 3.82 days, decaying by alpha emission into polonium-218. This short half-life means short-term tests must account for ingrowth and decay during the exposure period.

EPA action level

The U.S. EPA action level for radon in indoor air is 4 picocuries per liter (pCi/L), roughly 148 becquerels per cubic meter. Mitigation is recommended at or above this concentration.

Closed-house conditions

Exterior doors and windows are kept closed and devices that draw in outside air are off, starting at least 12 hours before the test begins and continuing through the entire measurement period.

Short-term test duration

A short-term radon test typically runs from 2 to 90 days, with 2 to 7 days common for charcoal devices. It indicates potential for elevated radon but not an annual average.

Long-term test duration

A long-term test exceeds 90 days, commonly using alpha-track detectors, and better represents the annual average radon concentration experienced by occupants across seasons.

Charcoal device holding time

Activated charcoal detectors must be returned to the laboratory within the manufacturer's specified holding time after exposure ends, because continued radon decay and moisture affect the collected sample.

Electret ion chamber

A passive device in which radon decay products reduce the voltage on a charged electret. The voltage drop, read before and after exposure, is converted to radon concentration using a calibration factor.

Alpha-track detector

A passive long-term device using plastic film that records alpha particle tracks from radon decay. Track density after chemical etching is proportional to integrated radon exposure.

Lowest livable level

The lowest floor of a building that is regularly occupied, such as a basement, slab-on-grade living space, or ground-floor room. Devices are normally placed there because radon is densest near entry points.

Device placement height

Place the measurement device about 20 inches (50 cm) above the floor, in the breathing zone, and at least 12 inches (30 cm) from exterior walls to avoid stagnant or atypical air.

Avoid these rooms

Do not place devices in kitchens, bathrooms, laundry rooms, closets, crawl spaces, or hallways, because moisture, ventilation, and limited occupancy make results unrepresentative of normal exposure.

Distance from vents

Keep devices at least 3 feet (about 1 meter) from windows, exterior doors, and air vents, since localized airflow can dilute or concentrate radon near the device.

Duplicate measurement

Two devices placed side by side at the same location for the same period. Comparing their results verifies precision and detects handling or laboratory errors.

Chain of custody

A documented record tracking each device from deployment through retrieval and laboratory analysis, including serial numbers, dates, times, and signatures of everyone who handled it.

Placement floor sketch

A simple drawing of the building showing room names, device locations, and distances from walls and vents. It makes the test reproducible and supports the reported result.

Annual calibration

Continuous radon monitors and electret readers require calibration at least annually, traceable to a primary standard, with the calibration date and due date recorded in the device log.

Cross-check measurement

An active monitor is compared against a reference device or known radon chamber. The measured-to-reference ratio is recorded and judged against the program's acceptance window.

Blank sample

An unexposed device from the same production lot, handled like a deployed device but not exposed. Its result estimates background and handling contamination in the analysis.

Spike sample

A device exposed to a known radon concentration in a chamber. Comparing the reported value to the known value checks the accuracy of the device and laboratory analysis.

Calibration due date

The date by which a device must be recalibrated. A device whose calibration has expired cannot be deployed for client measurements until recalibration is completed and documented.

Pump flow verification

For active or pump-driven samplers, confirm the flow rate before each use against the manufacturer's specification. Incorrect flow changes the sampled volume and biases the calculated concentration.

pCi/L to Bq/m3

To convert picocuries per liter to becquerels per cubic meter, multiply by 37. For example, 4 pCi/L equals about 148 Bq/m3, the EPA action level.

Result interpretation

Below 2 pCi/L is low; 2 to 4 pCi/L warrants considering mitigation; at or above 4 pCi/L mitigation is recommended. Report the number, units, and test conditions together.

Invalid test report

When closed-house conditions were broken, the device was tampered with, or holding time was exceeded, report the test as invalid, state the reason, and recommend a retest.

Report required elements

A report includes client and property identification, method and device type, serial numbers, placement locations, start and stop times, duration, result with units, and any deviations.

Client confidentiality

Radon results belong to the client. Do not release them to buyers, sellers, agents, or others without the client's written authorization, consistent with applicable privacy requirements.

Stack effect

Warm indoor air rising and escaping at upper levels creates a slight negative pressure at the foundation, drawing soil gas containing radon into the building through cracks and openings.

Sub-slab depressurization

A mitigation method using a pipe through the slab and a continuously running fan to draw soil gas from beneath the foundation and vent it above the roof, reducing radon entry.

Radon entry routes

Common paths include slab cracks, slab-to-wall joints, sump pits, floor drains, and hollow-block foundations. Sealing these openings supports, but does not replace, a depressurization system.

Post-mitigation verification

An independent radon test performed after a mitigation system has operated for at least 24 hours, using the same placement and closed-house rules, to confirm the system reduced radon levels.

Conflict of interest

A measurement technician who also sells mitigation services on the same property faces a conflict of interest. Disclose it and keep measurement independent of mitigation decisions.

Continuing education

Certification bodies and state programs require periodic continuing education and current calibration records to maintain credential status. Keep documentation available for audit.