Abstract
The reliability of measurements made by any instrument depend on susceptibility to interference from environmental conditions and to degradation of performance with age or through damage. A consensus standard was developed to delineate acceptable performance of radiation survey instruments over a wide range of conditions. To assure that the standard was reasonable, tests were performed on a large variety of portable radiation survey instruments and air monitors over the ranges dictated in the standard. Results showed that instruments can be designed to perform reliable measurements; however, not every instrument can be expected to meet requirements for reliable measurements over the full range of conditions. The performance observed with radiation survey instruments is briefly described, and the implications of such testing for the reliability of measurements with other types of health-protection instruments are noted.