MS-QA_06-2019 rev5

ANSI/AARST MS-QA 2019 18 Radon Measurement Systems Quality Assurance Field Operations—EIC, Alpha Track and Charcoal Adsorption 5.4.3 Field Operation Duplicates—Warning and Control Limits Each measurement system can develop more restrictive limits than those presented here based on its QC results, which are to be derived in all cases using the method described in Section 3.5 (or another statistically defensible control limit generation algorithm) and documented. Until a measurement system derives such limits from its own QC results, the limits warning and control limits shall be equal to or more stringent than the minimums presented in Table 5.4 as described in Section 3.5 . Table 5.4: Criteria for Duplicates Using ATD, CAD and EIC Methods Average of the two devices Warning Limit RPD Control Limit RPD ≥ 4.0 pCi/L ( ≥ 150 Bq/m 3 ) 28.0% 36.0% < 4.0 and ≥ 2.0 pCi/L (< 148 and ≥ 75 Bq/m 3 ) 50.0% 67.0% < 2.0 pCi/L (< 75 Bq/m 3 ) n/a Absolute value of the difference between the devices ≤ 1.0 pCi/L (37 Bq/m 3 ) or both are reported as less than the MDC If any duplicate pair result exceeds these criteria, which may happen even in a small percentage of perfectly operating, in-control operations (especially at low radon concentrations), then an investigation in consultation with the analyst or analysis laboratory is required as described in Section 3.5 . 5.5 EIC Field Operations—Additional Requirements for Electret Ion Chambers Analysis of EIC detectors requires additional information to ensure that the voltage loss is due only to the radon in the air being tested. Information to be logged and relayed to the EIC analyst includes: a) Log and Report Test Location Elevation. The elevation at the measurement location is to be accurately logged and relayed to the EIC analyst; and b) Log and Report Potential Gamma Interference and Exact Test Location. If there is anecdotal or other information about radioactivity in building components—natural stone (such as rock collections, granite counter tops, stone hearths or slate pool tables) or exposed bedrock in or near the building—this information is to be logged and relayed to the analyst or analysis laboratory for consideration and retention in records for that test location.