Performance-Specifications-for-Instrumentation-Systems

MS-PC 2015: Performance Specifications for Instrumentation Systems Designed to Measure Radon Gas in Air Page 3 of 20 4 Definitions & Abbreviations Continued Calibration Factor – that factor or function that represents the relationship between the method’s response and the concentration to which it is responding. The calibration relationship is the ratio of “rise,” or the response (dependent variable represented on the vertical axis), to the “run” of the concentration being analyzed (independent variable represented on the horizontal axis), and therefore in all cases the calibration factor is based on method response divided by the concentration to which it is responding. Coefficient of Variation (COV) – the sample standard deviation ( s ) of a set of measurements expressed as a percentage of the arithmetic mean of the measurements; COV = 100 (s / mean ). Continuous Radon Monitor (CRM) – an electronic device that (1) is capable of providing reviewable, numeric measurements of radon concentration averaged over time intervals of 1 hour or less, (2) has a minimum detectable concentration (MDC) of no greater than 148 Bq/m 3 (4 pCi/L) for a 1-hour measurement, and (3) has a calibration factor of at least 2 counts per hour per 37 Bq/m 3 (0.054 counts per hour [cph] per Bq/m 3 or 2 cph per pCi/L). Conventionally True Value – the best estimate of the value of a quantity determined by a primary or secondary standard, or by a reference instrument that has been calibrated against a primary or secondary standard. For the purpose of this standard, the average radon concentration value reported by the facility that exposes a device i n a STAR is considered to be the conventionally true value. Conversion Convention – conversions are rounded to no more than three significant figures. For example, 4.0 pCi/L is converted to 148 Bq/m 3 and not rounded to 150 Bq/m 3 . However, if a conversion results in more than three significant figures, only three significant figures are used. For example, 1500 pCi-d/L is converted to 1.33 x 10 6 Bq-h/m 3 . Electronic Integrating Device (EID) – an electronic radon measuring device that (1) does not meet the specifications of the definition of a CRM in this standard, and (2) displays or otherwise provides results only for time periods at least as long as those for which it has demonstrated compliance with the performance requirements of this standard. EPA – the U.S. Environmental Protection Agency. Equilibrating Device – a detector that functions by adsorbing and/or desorbing radon from or to the ambient air until an equilibrium is established between the quantity of adsorbed radon and the radon concentration in the ambient air. Individual Percent Error (IPE) – the degree from which a single measured value ( X ) deviates from the conventionally true value ( T) . The IPE is calculated using the following equation: IPE = [100 ( X – T ) / T ] X = Measured value (Bq/m 3 , pCi/L, Bq-h/m 3 , or pCi-d/L) T = Conventionally true value (in the same unit as X ) Integrating Device – a device that records or registers information that is directly related to the integral of radon concentration over time within the operating range of the device.