This guide is intended to be used by laboratories interested in the calibration of industrial platinum resistance thermometers that are intended to satisfy the requirements of Specification E 1137/E 1137M. It is intended to provide a consistent method for calibration and uncertainty evaluation while still allowing the user some flexibility in choice of apparatus and instrumentation. It is understood that the limits of uncertainty obtained depend in a large part upon the apparatus and instrumentation used. Therefore, since this guide is not prescriptive in approach, it provides detailed instruction in uncertainty evaluation to accommodate the variety of apparatus and instrumentation that may be employed.

This guide is intended primarily to satisfy applications requiring compliance to Specification E 1137/E 1137M. However, the techniques described may be appropriate in applications where higher accuracy calibrations are needed.

1.1 This guide describes the techniques and apparatus required for the accuracy verification of industrial platinum resistance thermometers constructed in accordance with Specification E 1137/E 1137M and the evaluation of calibration uncertainties. The procedures described apply over the range of –200 °C to 650 °C.

1.2 This guide is not intended to describe the procedures necessary for the calibration of platinum resistance thermometers intended to be used as calibration standards or Standard Platinum Resistance Thermometers. Consequently, calibration of these types of instruments is outside the scope of this guide.

1.3 Industrial platinum resistance thermometers are available in many styles and configurations. This guide does not purport to determine the suitability of any particular design, style, or configuration for calibration over a desired temperature range.

1.4 The evaluation of uncertainties is based upon current international practices as described in ISO/TAG 4/WG 3 “Guide to the Evaluation of Uncertainty in Measurement” and ANSI/NCSL Z540-2-1997 “U.S. Guide to the Expression of Uncertainty in Measurement”.

1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.