ANSI/AARST MS-QA 2019 6 Radon Measurement Systems Quality Assurance Definitions That standard further specifies that: • the conditions in the STAR may vary outside these ranges for duration exposures longer than approximately 1 week, and • the MDC must be ≤ 1 pCi/L (37 Bq/m 3 ), for the minimummeasurement period recommended by the provider (at least 48 hours), and that for 1-hour CRMmeasurements, the MDC shall be ≤ 4 pCi/L (150 Bq/m 3 ), (1-hour measurements are not used in decisions on the need for mitigation), and • measurement systems must demonstrate sufficient proportionality so that the difference between the average RPE (also known as the IPE) of a set of five devices exposed at a non-zero low concentration and the average RPE of a set of five devices exposed at a high concentration (or integrated concentration) shall be in the range of 0 ± 15%. Performance Test: A Performance Test, or blind performance test, is a blind spike in which the radon reported by the device user or laboratory is compared by an independent party, such as a chamber or proficiency program, to the established chamber concentration in which the device was exposed. Performance Test criteria historically includes an IRE of no more than 25%. Independent verification is a demonstration of quality that is valuable to third parties such as certification bodies (State or private) and consumers. Qualified Professional (QP) : An individual who has demonstrated a minimum degree of appropriate technical knowledge and training specific to radon measurement in indoor environments as: (a) established in the certification requirements of the National Radon Proficiency Program (NRPP) or the National Radon Safety Board (NRSB) and, if applicable, (b) as required by statute, state licensure or certification programs. Quality Assurance Plan (QAP) : A formal document describing in comprehensive detail the quality system , including responsibility for data validity, QA policies, QC procedures and other technical activities that need to be implemented to ensure that the results of the work conducted will satisfy the stated performance criteria. The QAP must define objectives (e.g., QC limits at various stages of the operations) and the responsibilities and authorities of personnel, especially regarding data quality and corrective action , including an individual responsible for the implementation of the quality policies, who is usually known as a QA Manager or Officer. A QAP will include at least the following elements: (1) organization and responsibilities, including accountability for sufficient training of personnel and QC measurements and their documentation; (2) measurement, data review and reporting procedures; (3) systems for ensuring measurement device and data custody tracking; (4) analytical procedures; (5) assessments (audits) and corrective action ; and (6) QA reporting that is used to improve quality over time. All six elements are to be documented in a QAP and associated standard operating procedures. Quality System: Quality objectives, policies, organizational authority, responsibilities, accountability and implementation of an organization for ensuring the stated quality in its work processes and services. (ISO 9000:2000, 2.2.3) The quality system is documented in a QAP and is periodically reviewed and documented in accordance with changes and improvements in the measurement system (ANSI/ASQC 1994; U.S. EPA 2002). QC (Quality Control) : The technical activities that measure the attributes and performance of a process, item or service against defined standards to verify that they meet established specifications. QC Interval: The interval of time necessary to gather at least approximately 20 of each type of QC check is defined as the QC interval. For example, a laboratory analyzing 500 devices each month can use approximately 3-month QC intervals for spikes and may use shorter intervals for laboratory control samples and background QC intervals as those QC checks are made more frequently. QC intervals are more fully described in Section 7.7.