Radon Terminology Defined 2


There are a lot of uncommon words, abbreviations and scientific references involved in radon mitigation & testing. Here are some definitions and explanations to help as you continue your research:

  • “Action Level” – The EPA has defined 4.0 pCi/L as the ‘action level’, or point at which radon reduction or mitigation is recommended.  According to the EPA, levels higher than 4.0 pCi/L are most likely to pose a health risk.
  • Active Radon Tests – Active radon-testing devices need power to operate. They include continuous radon monitors and continuous working-level monitors.
  • ASAPDB Above-slab air pressure differential barrier technology (or ASAPDB) creates an air-tight seal through interior pressure and then a small blower is used to gather up and then release radon to outdoor areas.  The cost, workmanship, and attention to detail required for this technique to be successful are reasons it is not very popular.
  • ASD Active Slab Depressurization, aka Sub-Slab Depressurization, is a method by which the air from beneath a building is actively draw through pipes and exhausting above a building where it is diluted by outside air.  The differential in pressure beneath the building and inside the building prevents radon from entering the building envelope.
  • Charcoal Canisters Charcoal canisters are perhaps the most widely used and available type of radon testing devices.  These small canisters are inexpensive, costing between $20-40, and are widely available and hardware stores and online.  Tests are quick, taking only a few days, and results can be had in only a few hours.  The drawback to charcoal canisters are that they do not accurately represent a period in time longer than 12-18 hours, whereas a CRM will give readings over a longer 48-72 hour period.  Changes in outdoor weather, wind & humidity can bias the results.
  • CRM – Continuous Radon Monitors are used by Akron Radon Reduction Systems.  A CRM is an active device that measures radon concentration levels in regular intervals over a 2-3 day period.  These readings are then charted on a graph to illustrate fluctuations or test tampering. Some CRM’s have built-in alarms that indicate if a machine was moved or tampered with during a test. Generally, CRM’s are the most widely accepted radon testing devices in real-estate transactions. As long as they are calibrated annually(required by OH law), the printouts can provide a wealth of information that passive devices cannot.
  • Curie – A measurement of radioactivity, named after the famed radioactvity researcher Marie Curie.
  • DP – “Delta” P – Is a measurement of pressure differentials.  Test holes are drilled into slabs and measurements taken before a SSD system is installed to determine optimal suction point locations.
  • Exterior Installation – This is our standard installation, with the fan and exhaust pipes on the exterior of the building.
  • Interior Installation – The fan and exhaust pipes will be installed in an attic space, with the pipe terminating through the roof. An additional charge will apply.
  • Passive Radon Tests – Passive radon-testing devices do not require power to function.  These include charcoal canisters, alpha-track detectors, charcoal liquid scintillation devices, and electret ion chamber detectors.
  • pCi/L – Picocuries per Liter. A pCi is a measure of the rate of radioactive decay of radon. One pCi is one trillionth of a Curie, 0.037 disintegrations per second, or 2.22 disintegrations per minute. Therefore, at 4 pCi/L (picocuries per liter, the EPA’s recommended action level), there will be approximately 12,672 radioactive disintegrations in one liter of air during a 24-hour period.
  • Radon – Radon is an invisible, odorless, tasteless gas that is naturally present in NE Ohio soils.  Radon is a noble gas with symbol Rn and atomic number 86.  Radon gas is an intermediate step in the natural decay of uranium and thorium into lead.
  • Radon Elimination – “Elimination” of radon is not a realistic expectation in NE Ohio. See the definition of Radon Mitigation below, as well as our article “Radon Elimination –  Is it Possible?”
  • Radon MitigationAny process used to reduce radon gas concentrations in the breathing zones of occupied buildings, or radon from water supplies.
  • Radon Mitigation Specialist – The Ohio Department of Health licenses Radon Mitigation Specialists and Radon Mitigation Contractors.  Don’t be afraid to ask for credentials!
  • Radon Testing – Testing is the first step in radon mitigation.  A variety of testing methods can be used and vary widely in accuracy.  These are generally broken into two categories – passive or active.
  • SSD-  Sub-Slab Depressurization, aka Active Slab Depressurization, is a method by which the air from beneath a building is actively draw through pipes and exhausting above a building where it is diluted by outside air.  The differential in pressure beneath the building and inside the building prevents radon from entering the building envelope.

Leave a comment

Your email address will not be published. Required fields are marked *

2 thoughts on “Radon Terminology Defined