ASTM International has released a new recommended standard for contact digital thermometers. ASTM E2877, Guide for Digital Contact Thermometers, provides a number of recommendations for the manufacture and selection of the devices. It was developed by an ASTM International subcommittee on the devices.
Christopher W. Meyer, a member of ASTM International’s E20 committee on temperature measurement, of which the digital contact thermometers subcommittee is a part, acknowledged that a number of industries, including the petroleum industry, are looking to phase out mercury-in-glass thermometers with digital ones but there hasn’t been an international standard. “Also, there has been no set of defined accuracy classes that could help specify the type of thermometer needed for a given application,” Meyer added.
Meyer noted that ASTM E2877 provides instructional basics of digital thermometers and a standard that can be used in operation protocols. “It will allow industries that have previously specified mercury thermometers in their protocols to use digital thermometers,” he said.
Included in ASTM E2877 is a set of accuracy classes pertaining to the temperature interval from -200 to 500 deg C. In order to qualify for a specific accuracy class, a thermometer must measure correctly to within a specified value over this interval or the subinterval in which the thermometer is capable of making measurements.
The new standard describes three types of sensors used in digital thermometers: platinum resistance sensors, thermistors and thermocouples. It also discusses the relative characteristics of each type of contact digital thermometers.
ASTM International, moreover, is inviting any interested parties to join in the standards developing activities of E20.09. Its next E20 committee meeting is scheduled for May 20-21 in Indianapolis.