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What to do without NIST-Calibrated Mercury Thermometers?

April 2011

First, mercury thermometers were phased out by hospitals; then they were banned by several European Union countries. Now the National Institute of Standards and Technology (NIST) has announced that, as of March 1, 2011, it will no longer provide calibration services for mercury thermometers. This is the first time since its inception in 1901 that this service has not been available from NIST, and it marks a major milestone in a larger effort to phase out the use of mercury thermometers altogether.

Of course before mercury thermometers can be fully phased out, the American Society for Testing and Materials (ASTM) standards will have to catch up with the regulations of many states that have outlawed the sale and transport of mercury thermometers. But that process is moving forward too. Already nearly half of the ASTM standards have been modified to allow the use of mercury-free liquid-in-glass or digital thermometers.

So where do you turn when you need a reference thermometer for industrial and commercial applications? One of the best alternatives is a digital thermometer. But beware, not all digital thermometers are equally effective. Although most digital portable reference thermometers are more durable than their mercury-filled predecessors, many come up short in accuracy and dependability.

The new Fluke 1551A/1552A “Stik” Thermometers are an exception. Designed for precision temperature calibration, these thermometers feature a thin-film RTD sensor that provides repeatable accuracy of ± 0.05°C (± 0.09°F) over its full range from -10°C to 50°C (14°F to 122°F). A stainless steel probe sheath protects the sensor, making it much more rugged than the glass stem of mercury thermometers and thus much better suited for challenging industrial environments. Plus, “Stik” Thermometers are intrinsically safe (ATEX- and IECEx-compliant) so you can use them in environments where potentially explosive gases are present. With their superior probe design and electronically-assisted measurement, Fluke “Stik” Thermometers deliver stellar accuracy, stability, and durability.

Each “Stik” Thermometer includes a NVLAP-accredited, NIST-traceable report of calibration as standard. (NVLAP accredits third-party testing and calibration laboratories based on the requirements of ISO/IEC 17025.) Additionally, a three-point calibration function makes it easy to perform accurate in-house calibrations if desired.

For more information on alternatives to mercury-filled thermometers go to

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Fluke 1551A Ex/1552A Ex Intrinsically Safe “Stik” thermometers »
Is it time to replace that mercury thermometer »