The National Institute of Standards and Technology has launched a website to further educate industrial end-users about mercury in old temperature sensors and provide alternatives to their use.
is a potent neurotoxin, and NIST created the website to help industry
scientists and engineers decide the best temperature measurement alternative
for their purposes. The website includes information about myths pertaining to
mercury and temperature measurement, and how to safely package and recycle
stopped providing calibration services for mercury thermometers in 2011,
motivated in part by NIST’s work with the Environmental Protection Agency to
eliminate as many sources of mercury in the environment as possible.
thermometers are neither a superior nor a standard method for measuring temperature,
according to Greg Strouse, leader of NIST’s temperature, pressure and vacuum
haven’t used mercury thermometers as a calibration standard since 1927 when the
platinum resistance thermometer standard was adopted,” Strouse says. “Our goal
with this new website is to show that there is a temperature-sensing technology
that will satisfy their needs as well as, or better than, a mercury
thermometer, all without the added liability of containing a neurotoxin that is
hugely expensive to clean up if released into the environment.”
scientists commonly object to replacing their mercury thermometers because they
have grown accustomed to getting the same answer from their devices over the
years, even if it is less accurate than can be provided by modern digital
thermometers, says Dawn Cross, a NIST researcher.
people who are used to using mercury thermometers think that they define
temperature, and this simply isn’t true,” Cross says. “Graduations on a piece
of glass filled with a fluid can never give as accurate a reading as a digital
thermometer, based on how the conductivity of metals change as a function of
temperature, something we know and can characterize very, very well.”
thermometers based on the principle of thermal expansion of a fluid, such as
alcohol, are not hopelessly inaccurate, according to Cross. In fact, they are
as accurate as mercury thermometers and are suitable for some applications that
don’t require stringent temperature control, she says. For example, alcohol
thermometers might be suitable for measuring the temperature of gasoline and
other fuels, but they would be unsuitable for monitoring the temperature of
vaccines, the viability of which relies on strict control of their temperature.
to www.nist.gov/pml/mercury.cfm for more information
about how NIST can help your industry find an accurate, nontoxic and
environmentally benign alternative to mercury thermometers.