1.1 This International Document applies to total radiation pyrometers that measure radiance temperature by making use of the relationship between the radiance of the source, integrated over the major part of the spectrum of thermal radiation, and its temperature. 1.2 This Document is designed to: · ensure that all total radiation pyrometers give correct readings (within limits of permissible errors) when measuring the temperature of a black body; · specify means and conditions for the calibration of total radiation pyrometers with a given degree of accuracy and reliability. 1.3 This Document specifies for total radiation pyrometers: · measurement units, · general technical characteristics, · characteristics of the auxiliary equipment used for calibration, · basic methods to be used to ensure uniformity of calibration, · basic requirements for calibration. 1.4 The use of other calibration and verification methods for total radiation pyrometers is permitted, provided that such methods ensure the same accuracy as that specified in this Document. 1.5 This Document applies to total radiation pyrometers graduated in units of temperature, and to sensors of these pyrometers (*). It also applies to pyrometers which give a value of an electrical signal as output, and which are supplied with data or other means for converting that value into an indication of temperature.