Many processes and procedures can benefit from alternatives to mercury thermometers. For example, petroleum companies and storage facilities need to know the temperature of material in tanks and at various stages of refinement. One traditional method of taking tank measurements employs an Hg thermometer (often called a "yellowback") of the sort shown at right.
Several initiatives are now underway to replace mercury instruments in the petroleum industry, and the Environmental Protection Agency has undertaken a pilot project with the American Petroleum Institute to test non-mercury thermometers in fuel-handling facilities and to examine the accuracy, durability, and temperature range of mercury-free thermometers in the field. (See Fig. 2.)
Left: Technician Dawn Cross of NIST's Temperature and Humidity Group (THG) demonstrates a platinum resistance thermometer approved for the petroleum industry. Right: A petroleum industry worker deploys the same kind of device in a storage tank.
Non-mercury sensors and electronic recording devices were employed in a landmark evaluation of vaccine refrigeration equipment and storage practices. Above, THG physicist Michal Chojnacky checks a small digital unit in a test refrigerator.
In addition, numerous activities in commerce, industry and government can benefit from digital systems' ability to record data from multiple sensors over time. Recently NIST's Temperature and Humidity Group used an array of thermometers to identify types of refrigeration equipment and storage practices that contribute to the annual waste of tens of millions of dollars in vaccines that must be discarded because they have not been stored within the proper temperature range. (See Fig. 3.)
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