Click HERE to view their stories


P.O. Box 6325
Richmond, VA  23230

Learn more 
about Radon at

  University of Minnesota Environmental & Occupational Health
The EPA Radon Website
EPA Radon homepage

Please report any problems 
or broken links to

Quality Control of Radon Monitors

Quality Assurance / Quality Control of Radon Monitors is of paramount importance to running an Accurate Reliable radon testing procedure. If your radon service provider cannot provide proof of following these procedures, run. The information that comes out of a radon monitor is useless unless there is an active QA/QC in place. EPA indicates in the excerpts from their QA/QC guidance that each active device must be calibrated annually.

United States
Environmental Protection
Air and Radiation
National Air and Radiation
Environmental Laboratory
540 South Morris Avenue
Montgomery, AL 36115-2601
EPA 402-R-95-012

8.4.3 Routine Instrument Performance Checks for Residential Service Providers Operating
Active Monitors

Residential service providers using active monitors provided by an analytical organization should have some means to assess the continued satisfactory operation of the active monitor they are using. The analytical service organization should provide written instructions and training for performing tests of the equipment and set up a system for obtaining and analyzing results from the residential service provider. Particularly important are pump flow-rate checks prior to and after each continuous WL measurement. Also useful are built-in self-diagnostic tests of the detector and electronics. Routine instrument performance checks can be monitored using means control charts (see Section A.3.1 of Appendix A).

If a check source is unavailable or incompatible with the type of active monitor being used, and a system and detector diagnostic check is impossible, the organization should perform a comparison measurement with approximately ten percent of the measurements. This comparison measurement will serve as a check of the continued satisfactory operation of the instrument.

Because the two results were not obtained with identical equipment, however, a statistical analysis for the purpose of assessing precision would not be appropriate.

RPP QA Guidance
EPA 402-R-95-012
Date: 10/22/97

These guidelines are recommendations for the radon measurement industry as a whole. They are specifically intended to guide RPP participants in meeting their QAP requirements. EPA recognizes that this guidance will therefore serve as de facto required practices for anyone operating a radon measurement business in the U.S. Because of this, and because these guidelines are meant to serve the public and the measurement industry, EPA is interested in receiving constructive comments about this guidance.

Quality control requirements from The National Environmental Health Association

Taken from the NRSB.ORG Application page

For initial certification, users of continuous radon monitors must submit a proficiency test for each model (device code) of continuous radon monitor used and a certification of calibration for each continuous radon monitor used to perform measurements. A certificate of calibration must be issued by an accredited radon chamber that is manufacturer-authorized to perform calibration for the instrument model.  For a list of approved NRSB Chambers

For renewal certification, a current certificate of calibration must be submitted for every continuous radon monitor used to perform measurements.


Continuous Radon Monitors (CRM)CRM devices require annual calibration in known radon environments. The manufacturer of the instrument performs most calibrations, but this is not always the case. Some calibration facilities have the permission of the manufacturers to change the device’s internal settings to correct for bias discovered during the calibration process. (Note that an inherent element of the process is a thorough determination of the background count rate using clean, aged air or nitrogen). At the conclusion of the calibration a certificate should be issued and a sticker should be attached to the monitor to display the calibration date, facility, and expiration.

Some CRMs sample through scintillation cells. (Some Scintrex/EDA and Pylon Electronics equipment does this.) When these devices are calibrated, each scintillation cell requires independent calibration as well.

Continuous Working Level Monitors (CW) – CW devices require annual exposure to known amounts of radon decay products in a radon chamber. The manufacturers calibrate most CW devices. Similar to the CRMs, certificates and stickers should be issued upon successful calibration.

This document was prepared as a Guide for use by the National Radon Proficiency Program (NRPP) National Radon Proficiency Program (NRPP). The content was gathered from the U.S. EPA’s Indoor Radon and Radon Decay Product Measurement Device Protocols (EPA 402-R-92-004), July 1992, and interpretations provided by Mr. Samuel W. Poppell, Jr., former Program Manager for the U.S. EPA Radon Proficiency Program (RPP). Prepared by Shawn Price, Air Chek, Inc., former Quality Assurance Coordinator for the EPA RPP.

Specific appeal to this document should be made in writing to the NRPP, PO Box 2109, Fletcher, NC 28732, fax (828) 890-4161 or email


About Us
| Services | FAQs | Area Radon Levels
Request Info | Links | Risk Chart

© 1987-2021 Radon-Ease, Inc. | Privacy Statement
This site was last updated Thu, Nov 15, 2012