ASTM E639-78(2002)

1.1 This test method covers the measurement of the total-radiance temperature (see section 2.1.20) of surfaces using a radiation pyrometer that is not in contact with the surface. The measured total-radiance temperature is then converted to the "true" surface temperature using an assumed or measured value of the surface emittance.

1.2 This test method includes those pyrometers which respond to a wide band of radiant energy (heat), that is, total radiation pyrometers, as well as those which respond to a relatively narrow band of radiant energy, that is, monochromatic or pseudomonochromatic radiation pyrometers. The latter are often referred to as "optical" pyrometers. The visual optical pyrometer, sometimes referred to as a "disappearing-filament" or "brightness" pyrometer, is not covered by this test method.

1.3 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.