NRPP RMI 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 3.82 days and decays by alpha emission into polonium-218, beginning the short-lived progeny chain that produces the alpha dose in the lung.

Working level definition

One working level equals any combination of short-lived radon progeny that releases 1.3 x 10^5 MeV of potential alpha energy per liter of air, equivalent to 100 pCi/L of radon at full equilibrium.

EPA action level

The U.S. EPA action level for indoor radon is 4 pCi/L in homes and in schools and large buildings; follow-up testing is required at or above this level.

Closed-building conditions

Windows and doors closed except for normal entry and exit, no whole-house or window fans running, and normal HVAC operation, maintained for at least 12 hours before a short-term test begins.

Minimum short-term test duration

A short-term radon test must last at least 48 hours, with closed-building conditions maintained for 12 hours before the test starts and throughout the exposure period.

Device placement height

Place radon devices at least 20 inches (50 cm) above the floor, 12 inches (30 cm) from exterior walls, and 4 inches (10 cm) from other objects to sample representative breathing-zone air.

Duplicate measurement purpose

Duplicate devices deployed side by side assess measurement precision; the relative percent difference between paired results should typically fall within 25% for charcoal and 20% for alpha-track detectors.

Blank device purpose

An undeployed device analyzed alongside field samples detects detector background and contamination; blank results should remain below the device's lower limit of detection.

Spike test definition

A spike is a device exposed to a known radon concentration in a chamber; results should fall within plus or minus 25% of the known value to confirm measurement accuracy.

Equilibrium ratio

The equilibrium ratio is the measured progeny concentration divided by the radon concentration that would exist at full equilibrium; typical indoor values range from 0.3 to 0.7.

Lower limit of detection

The LLD is the lowest radon concentration a device can reliably measure; results below it are reported as less than that value rather than as zero.

Charcoal adsorption device

A passive short-term detector exposed for 2 to 7 days, then analyzed by gamma spectroscopy or liquid scintillation; its response is sensitive to temperature and humidity.

Alpha-track detector

A passive long-term detector using plastic film that records alpha tracks, which are counted after chemical etching; exposure typically runs 1 to 12 months and humidity has little effect.

Electret ion chamber

A passive detector whose charged electret loses voltage in proportion to radon exposure; voltage is read before and after deployment to calculate the average concentration.

Continuous radon monitor

An active instrument that records hourly radon concentrations, detects tampering and unusual conditions, and requires annual calibration plus a daily function check.

Post-mitigation test timing

A post-mitigation test is conducted at least 24 hours after system start-up and within 30 days of installation, using a minimum 48-hour exposure under closed-building conditions.

Sub-slab depressurization

The most common mitigation method: a fan draws soil gas from beneath the slab and vents it above the roof, creating a negative pressure field under the foundation.

Stack effect

Warm indoor air rising and escaping through upper floors creates negative pressure in lower levels, drawing soil gas through foundation openings; the effect peaks in winter.

Radon entry routes

Soil gas enters through foundation cracks, sump pits, floor drains, and gaps around pipes, driven by the stack effect, wind, and mechanical exhaust depressurization.

Two-test averaging rule

When two short-term tests are performed, their average determines the mitigation decision; if results differ by more than a factor of two, a third or long-term test is advised.

Real-estate follow-up rule

If the first short-term real-estate test is 4 pCi/L or higher, a second short-term test is conducted immediately and the average of the two guides the mitigation decision.

Radon health risk ranking

Radon is the second leading cause of lung cancer after smoking and the leading cause among non-smokers; the EPA estimates about 21,000 U.S. lung cancer deaths yearly are radon-related.

Smoking synergy

Tobacco smoke and radon exposure act synergistically, so smokers exposed to elevated radon face a far higher lung cancer risk than non-smokers at the same concentration.

Chain of custody record

Documentation of device serial numbers, deployment and retrieval dates and times, location, and handler names, kept so samples reach the lab within the device hold time.

CRM calibration interval

Continuous radon monitors are calibrated at least annually against a known radon source or a calibrated reference monitor, with the calibration factor documented.

State regulatory authority

Several states impose their own radon certification, testing, and reporting rules that may be stricter than EPA protocols; the professional follows the rules of the state where testing occurs.

Conflict of interest disclosure

A measurement professional must disclose business relationships with mitigation contractors and must not condition test results on the sale of mitigation services.

Record retention period

Test records, QA results, and calibration records are retained for at least three years, or longer if the certification program or state regulation requires it.

Working level formula

Working level equals radon concentration in pCi/L multiplied by the equilibrium ratio and divided by 100, linking measured radon gas to progeny alpha energy.

Unit conversion pCi to Bq

One picocurie per liter equals 37 becquerels per cubic meter; converting between the two units is required when reporting to clients using SI units.

Interference invalidation

If occupants open windows or run exhaust fans during a test, the result may not represent closed-building conditions; the interference is documented and retesting is considered.

Proficiency testing requirement

Certified measurement professionals participate in their program's proficiency testing and must maintain a passing score to keep device-specific certification active.