Performance-Specifications-for-Instrumentation-Systems

MS-PC 2015: Performance Specifications for Instrumentation Systems Designed to Measure Radon Gas in Air Page 11 of 20 6.3.2 Liquid Scintillation Spectroscopy This type of equilibrating device uses liquid scintillation spectroscopy to detect alpha particles emitted by 222 Rn, 218 Po and 214 Po, and possibly also beta particles emitted by 214 Pb and 214 Bi, to quantify the adsorbed radon. The device is typically in the form of a small vial or cartridge containing activated charcoal. 7 PERFORMANCE & TESTING CRITERIA The following criteria are applicable to all types of radon devices or systems within the scope of this standard. As described in Section 3, results of testing in a STAR c onducted for other purposes could partially or fully suffice to demonstrate compliance with this standard. Due to the diversity of technologies addressed within this standard and the natural limitations of each technology, the provider shall stipulate limits upon test procedures (e.g., ranges of exposure durations and integrated concentrations) that are consistent with literature published for consumers who will use the device(s). If exposures of shorter or longer durations may cause interferences or other degradations of measurement reliability, it is incumbent upon the device provider to address in its documentation how shorter or longer durations affect the accuracy of results. The ranges of environmental conditions specified in this standard are typical of indoor environments. In order for a device or measurement system to meet this standard’s specifications, it must meet the requirements in this section, including the requirements for the high and low ranges of temperature and humidity. To meet this standard, devices, or the laboratories analyzing the devices, shall not report measurement results for durations less than the time period for which they have met the requirements of this standard. 7.1 Accuracy & Precision (Total Error) 7.1.1 Criteria Each device shall demonstrate an Individual Percent Error (IPE) within 0 ± 25% when tested in a STAR (defined in Section 4) for the shortest duration recommended by the provider at a radon concentration in the range of 222 – 555 Bq/m 3 (6 – 15 pCi/L), a temperature in the range of 18 – 24°C (65 – 75°F), and a relative humidity in the range of 10 – 55%, with radon concentration, temperature and relative humidity held as constant as practicable (defined in Section 4). The precision of the devices shall be assessed using the COV of the set of five devices, which shall be less than or equal to 15%. 7.1.2 Test for Accuracy & Precision (Total Error) A set of at least five representative devices is placed in a STAR f or the minimum period of time recommended for use by the provider and under the conditions stated in Subsection 7.1.1, with the radon concentration, temperature and relative humidity held as constant as practicable in the ranges stated in that subsection during the exposure period. If appropriate, the devices may be exposed to an integrated radon concentration in Bq-h/m 3 (or pCi-d/L) equal to the minimum time specified by the provider times a radon concentration in the range specified in Subsection 7.1.1. The conditions in the STAR may vary outside of the ranges specified in Subsection 7.1.1 for exposures of durations longer than approximately 1 week (see the definition of “as constant as practicable” in Section 4).