Performance-Specifications-for-Instrumentation-Systems

MS-PC 2015: Performance Specifications for Instrumentation Systems Designed to Measure Radon Gas in Air Page 5 of 20 4 Definitions & Abbreviations Continued NIST – National Institute of Standards and Technology. Precision – a measure of mutual agreement among individual measurements of the same property, under prescribed and similar conditions. Precision may be expressed as variance, relative percent difference, coefficient of variation, or a similar statistic that expresses the spread of the measurements from one another. Progeny – one or more radionuclides that occur in the decay chain from a specified parent radionuclide. Provider – manufacturer, laboratory or other entity that submits devices for exposure in a STAR f or the purpose of demonstrating compliance with the performance requirements of this standard. Quality Control – the overall system of technical activities whose purpose is to measure and control the quality of a product or service so that it meets the needs of users. Radon – the specific isotope radon-222 ( 222 Rn). Representative – devices that are from the same lot, batch, model number or other identifying characteristics and are identical in operation and configuration to such devices made available to consumers. Sample Standard Deviation – the estimate of the standard deviation of a distribution, given by s, calculated by the square root of the sum of the squares of the deviations about the mean divided by one less than the sample size. Shall – signifies a mandatory requirement. Note: An appropriate qualifying statement may be included in this standard to indicate if conditional exceptions are allowed. As an example, if a specification is stated as being a “should” or a “may” and is later followed by a subsequent “shall” in the same subsection, the “shall” applies only if the “should” or “may” is implemented. Short-Lived Radon Progeny – the following specific radionuclides in the 222 Rn decay chain: 218 Po, 214 Pb, 214 Bi and 214 Po. Short-Lived Thoron Progeny – the following specific radionuclides in the 220 Rn decay chain: 216 Po, 212 Pb, 212 Bi, 212 Po and 208 Tl. Should – signifies a recommended specification or method. It is understood that if something this standard states should be done is not done, the manufacturer or user shall have included in a technical basis document the justification for not doing so. Significant change –A measurement system change requiring retesting for conformance to this standard includes: 1. A change in the detection mechanism and/or geometry that results in a change in the operating characteristics of the instrument in the field or the laboratory analysis of the device; 2. Changes in recommended measurement durations; 3. Expansion of the manufacturers’ recommended range of temperature, pressure, relative humidity or radon concentration within which it should be used. Note: Manufacturers periodically change device user interfaces, software, internal electrical components and instrument housings; such changes do not generally change the method’s response characteristics and are not considered a significant change.

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