The test method described in this standard will ensure that the thermometers listed in Specification E 1 will indicate temperatures within the maximum scale errors listed, be compatible with the apparatus, and serve the purpose for which they were designed.Fig. 1

Thermometers that do not pass the visual and dimensional inspection tests may give erroneously high or low temperature readings, or may not fit into existing equipment used in ASTM methods. If the pigment in the scale etchings washes out or fades, the thermometer will be difficult to read. Improper annealing of the bulb, as determined by the bulb stability test, will result in thermometer readings rapidly changing with time and use. For accurate temperature measurements the scale readings of the thermometer should be verified as described in this test method.

FIG. 1 Oven for Permanency of Pigment Test

1.1 This test method covers visual and dimensional inspection, test for permanency of pigment, test for bulb stability, and test for scale accuracy to be used in the verification of liquid-in-glass thermometers as specified in Specification E 1. However, these procedures may be applied to other liquid-in-glass thermometers.

Note 1—The use of NIST SP250-23 is recommended.

1.2 This standard does not purport to address all of the safety problems, 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.