NRPP RMS flashcards

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

Radon action level

The U.S. EPA-recommended concentration at which mitigation should be considered is 4 pCi/L; the WHO reference level is 100 Bq/m3, roughly 2.7 pCi/L.

pCi/L to Bq/m3

One picocurie per liter equals 37 becquerels per cubic meter. To convert pCi/L to Bq/m3, multiply by 37; to convert Bq/m3 to pCi/L, divide by 37.

Working level definition

A working level is any combination of short-lived radon decay products that releases 1.3 million MeV of alpha energy per liter of air; 1 WL equals 100 pCi/L of radon at equilibrium.

Equilibrium ratio

The equilibrium ratio is the measured working level divided by the potential working level for the radon present. It reflects how much of the decay product has built up relative to full equilibrium.

Closed-building conditions

Doors and windows are kept closed and fans and dryers that exhaust air are off for 12 hours before testing and throughout the exposure period, to represent normal occupied conditions.

Charcoal canister limitation

Charcoal adsorbers are short-term passive devices, typically exposed 2-7 days. They are sensitive to humidity and temperature, and their results are less reliable for long-term average estimation.

Alpha track detector

A passive long-term device using a plastic film that records alpha particle tracks from radon decay. It is exposed 90 days to a year and read by chemical etching and counting.

Electret ion chamber

A passive device that measures radon through voltage decay on a charged electret. Exposure is typically 2-7 days short-term or up to a year long-term, read with a voltmeter.

Continuous radon monitor

An active electronic device that samples air and records hourly radon concentrations. It supports short-term tests of at least 48 hours and produces time-series data that reveal tampering or unusual conditions.

Duplicate measurement

Two devices exposed side by side at the same time and place. Results should agree within 25 percent of their mean or 0.3 pCi/L, whichever is larger, to demonstrate precision.

Blank spike control

A blank is an unexposed device processed with a batch to detect contamination; a spike is a device exposed to a known radon concentration to verify accuracy and bias.

Device placement rule

Place test devices in the lowest livable level, 20 inches above the floor, at least 12 inches from exterior walls, and at least 4 inches from other objects.

Short-term test follow-up

If a short-term test result is 4 pCi/L or higher, a second test is recommended: either a short-term test under closed-building conditions or a long-term test over 90 days.

Long-term test value

A test longer than 90 days better represents the annual average because it spans seasonal variation in radon entry, which is typically higher in winter when the stack effect is strong.

CRM calibration interval

Continuous radon monitors require annual calibration and a 30-day control check with a known radon source, recorded on a control chart to detect drift.

Tampering indicators

Unexpectedly low or flat hourly readings, abrupt drops, or unusual timing in continuous monitor data suggest open windows or interference; such tests may be invalidated and repeated.

Active soil depressurization

ASD uses a fan to draw soil gas from beneath the slab through a sealed pipe and exhaust it above the roof, lowering the pressure field and reducing radon entry.

Sub-slab suction point

A pit excavated through the slab into the aggregate beneath, connected to the vent pipe. It must be sealed at the slab to prevent indoor air from being drawn into the system.

Vent stack discharge rule

The exhaust must terminate above the roofline, at least 10 feet above grade and 10 feet from windows, doors, or air intakes, and be labeled as a radon vent.

Pressure field extension

The reach of the suction-induced pressure change through the sub-slab material, measured as pressure differential at diagnostic holes. A common design target is at least 50 Pa.

Depressurization field test

A diagnostic measurement of pressure difference at test holes relative to indoor air, used to confirm that the suction field reaches the far side of a slab before finalizing design.

U-tube manometer

A visual indicator of fan operation and suction, filled with colored fluid. The installation baseline reading is recorded so future changes in the system can be detected.

Post-mitigation retest

A test run within 30 days of system start-up, no sooner than 24 hours after activation, under closed-building conditions. A result below 4 pCi/L indicates success; 2 pCi/L or less is the goal.

Sump pit sealing

A sump can serve as a suction point if fitted with a gasketed, sealed lid and the pit is connected to the ASD pipe. An unsealed sump is a major radon entry route.

Sealing alone not approved

Caulking cracks and sealing openings is supplemental only. It is not an approved stand-alone mitigation method because it cannot reliably reduce radon below the action level.

Combustion appliance backdrafting

ASD can depressurize a building and pull exhaust from furnaces or water heaters. Before and after installation, test for spillage and backdrafting and address any hazard found.

Fan sizing factors

Fan selection depends on sub-slab permeability, number of suction points, pipe diameter, and stack length. The goal is adequate suction across the field, not maximum airflow.

System failure indicator

A device such as a u-tube or electronic monitor that shows the fan is running and suction is present. It must be visible, labeled, and checked by occupants periodically.

Multifamily mitigation standard

ANSI/AARST MAH governs radon mitigation in multifamily buildings, addressing unit-by-unit testing, shared systems, and pressure interactions between adjacent units.

Large building standard

ANSI/AARST MA-MFLB addresses mitigation in schools and large commercial buildings, where HVAC pressure differentials and multiple zones require diagnostic balancing before ASD design.

Radon in water

Waterborne radon is addressed separately from air testing. Aeration or granular activated carbon treatment is used when water concentrations are elevated; testing follows a different sampling protocol.

Radon entry driving forces

Radon enters buildings driven by the stack effect, appliance and exhaust depressurization, and diffusion. The pressure difference between soil and indoor air is the dominant mechanism.