New Info Worth Reposting
The bulk of this article is from a NIST Press Release with edits that was originally posted on our companion news website, TempSensorNEWS.com on 14 June 2012 as: NIST’s Drive to Replace Mercury Thermometers
Gaithersburg MD, USA — NIST researchers have developed a new website explaining the hazards associated with mercury thermometers and discussing potential alternatives for the temperature sensing needs of industry.
Reducing the amount of mercury in the environment by recycling mercury thermometers also helps to reduce the amount of electricity we need to produce, which in turn reduces the amount of coal burned.
More info online at: http://go.usa.gov/dt5.
The website also includes information about myths pertaining to mercury and temperature measurement and how to safely package and recycle mercury-containing products.
NIST stopped providing calibration services for mercury thermometers on March 1, 2011. This was motivated in part by NIST’s work with the Environmental Protection Agency to eliminate as many sources of mercury in the environment as possible.
According to Greg Strouse, leader of NIST’s temperature, pressure and vacuum programs, mercury thermometers are neither a superior nor a standard method for measuring temperature.
“We haven’t used mercury thermometers as a calibration standard since 1927 when the platinum resistance thermometer standard was adopted,” says Strouse.
“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.”
According to NIST researcher Dawn Cross, industrial scientists commonly object to replacing their mercury thermometers because they have grown accustomed to getting the same answer from their mercury thermometers over the years, even if it is less accurate than can be provided by modern digital thermometers.
“Some 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.”
Cross points out that other thermometers based on the principle of thermal expansion of a fluid, such as alcohol, are not hopelessly inaccurate. In fact, they are as accurate as mercury thermometers and are suitable for some applications that don’t require stringent temperature control.
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.
Visit the NIST website at 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.
Learn, too, about the NIST workshop this September “Selecting and Using Alternative Thermometers” by clicking on the name. It will be held Sept. 19-20, 2012 at NIST’s Headquarters in Gaithersburg, MD.
NIST’s description of the event says:
The NIST Selecting and Using Alternative Thermometers Mini-Workshop is offered every year and is a laboratory-based workshop designed to assist those in industry in the conversion from mercury thermometers to safer alternatives. The workshop covers different types of alternative thermometers, selecting the best alternative thermometer for your measurement application and uncertainty, calibrating alternative thermometers, and “in-the-field” validation methods.