Chapter 5 - Quality Assurance & Quality Control
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Radon measurement operators should maintain permanent records containing sufficient information on each measurement conducted.  The permanent record should be maintained for a minimum of five years to allow for future data comparisons and interpretations as wells as reporting to clients and State regulators.  The permanent record of each measurement should include the following:

  1. A copy of the final report, including measurement results, and a statement describing any recommendations concerning retesting or mitigation provided to the client, the occupant, the building owner or his/her representatives.
  2. The address of the building measured including zip code. A diagram of the measurement space noting the exact locations of all measurement devices deployed and any information that would allow for future data comparisons and interpretations.
  3. Exact start and stop times of the measurement period as required for analysis.
  4. Type of instrument used and serial number or identification number.
  5. A description of the condition of any permanent vents, such as crawlspace vents or combustion air supply to combustion appliances.
  6. The name and license/certification number of the service or analysis organizations used to analyze devices.
  7. The name and license/certification number of the individual who conducted the test.
  8. A description of any variations from or uncertainties about standard measurement procedures, closed-building conditions or other factors that may affect the measurement result.
  9. A description of non-interference controls used and copies of the signed non-interference agreements.
  10. A record of QC measures for each test such as the results of simultaneous or diagnostic measurements.

Chain of Custody

Chain-of-custody procedures to track detectors and placement/analysis dates should be established and documented in the SOP. These may be as simple as designating storage space for unexposed detectors ready to be used, detectors ready to be shipped/analyzed, and detector custody sign in/out logs.

For detector types that need to be analyzed immediately following exposure, a daily check that all detectors received have been shipped/analyzed may be appropriate.  Detailed spreadsheets are useful tools for maintaining records of QA practices and QC measurements, including calibration results, background measurements results, and any changes in operators, materials, or procedures. Entries should include the name of the person entering the data and the date. Any relevant documents such as placement diagrams and non-interference agreements should be included with the log records. These logs are a key element for management and regulatory auditor.

Details for each active or passive device used in a program should be itemized in a separate QA logbook including the following information:

  1. Equipment calibration records (for analytical service providers), including:
    • The date of the calibration and the date the calibration expires
    • The facility where the calibration was performed
    • The procedures used (an SOP or calibration report can be referenced)
    • Calibration results
    • Changes in calibration factors implemented
  2. Laboratory background measurements (for analytical service providers), including:
    • The date of the background measurement
    • The location and type of measurement (e.g., aged air or nitrogen)
    • The procedures used (an SOP can be referenced).
    • Analysis results
    • Changes in LLD or background values
  3. Field background measurements (for both analytical and residential service providers), including:
    • The date and location of the field background measurement
    • The procedures used (appropriate documentation can be referenced)
    • Analysis results
    • Changes implemented because of the results
  4. Results of all QC measurements (for both analytical and residential service providers), including:
    • Results of comparison measurements (for users of active instruments).
    • Results of duplicate measurements.
    • Results of spiked measurements.
  5. Routine instrument performance checks (for analytical and some residential service providers using active devices) including:
    • Battery checks/replacement.
    • Check source/cell measurements.
    • Pump flow-rate measurements.
    • Self-diagnostic checks.

Control charts containing the results of any of these QC measurements should be kept in the QAP notebook or available for quick reference.