ASTM E2488-22

SIGNIFICANCE AND USE 5.1 The design of a controlled temperature bath will determine what thermometers can be calibrated and to what extent an isothermal condition is achieved. The lack of thermal stability and uniformity of the bath are sources of error that contribute to the overall calibration uncertainty. 5.2 This guide describes a procedure for determining the effective working space for a controlled temperature fluid bath. 5.3 This guide describes a procedure for determining the thermal stability within a controlled temperature fluid bath. Overall thermal stability is composed of the bath performance as specified by the manufacturer of the bath equipment and as a component of calibration uncertainty. 5.4 This guide describes a procedure for determining the temperature uniformity of the working space of the controlled temperature fluid bath. SCOPE 1.1 This guide is intended for use with controlled temperature comparison baths that contain test fluids and operate within the temperature range of –100 °C to 550 °C. 1.2 This guide describes the essential features of controlled temperature fluid baths used for the purpose of thermometer calibration by the comparison method. 1.3 This guide does not address the details on the design and construction of controlled-temperature fluid baths. 1.4 This guide describes a method to define the working space of a bath and evaluate the temperature variations within this space. Ideally, the working space will be as close as possible to isothermal. 1.5 This guide does not address fixed point baths, ice point baths, or vapor baths. 1.6 This guide does not address fluidized powder baths. 1.7 This guide does not address baths that are programmed to change temperature. 1.8 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.