Mercury Thermometers & Alternatives in the USA

Thermometer Image
Thermometer Image: Courtesy FreeDigitalPhotos.net & mistermong

USA — The USA’s National Institute for Standards and Technology (NIST) began an active mercury-reduction campaign in 2007, and stopped calibrating Mercury (Chemical symbol: Hg) thermometers entirely on March 1, 2011.

A full range of thermometric calibration services continues for non-mercury devices according to the special NIST webpage at: www.nist.gov/pml/mercury.cfm

Mercury is a potent neurotoxin, and every thermometer that contains it is a potential environmental threat. In the 21st century, however, that is a risk that no one needs to take, and a worldwide effort is underway to deploy substitute devices (alternatives) in consumer, professional, and industrial applications.

New analog thermometers with safe filling materials are in production at several companies and recent ASTM standards have been developed to cover them. See ASTM Standards E1 (www.astm.org/Standards/E1.htm) and E2251 (www.astm.org/Standards/E2251.htm).

For more information on each, click each standard’s title (above).

Digital thermometry technologies are plentiful, trials versatile, and generally superior to modern variations on the mercury-in-glass design. Many of these digital devices have wider effective temperature ranges, and nearly all of them equilibrate about 10 times faster than Mercury-filled devices.

There are three classes of sensors that produce signals which can be converted into a digital temperature read-out: thermistorsplatinum resistance thermometers and thermocouples. For more information on each, click on the name on on their name.

Each sensor type used is digital thermometers uses a slightly different aspect of a well-characterized relationship between temperature and electrical resistance or induced voltage in certain materials.

The term “thermometer,” when used in the context of digital equipment, refers to electronic systems that capture signals from the sensors, convert them into temperatures using conversion methods compatible with ASTM and/or ITS-90 standards, and then display the result in some format.

The accuracy of digital thermometers thus depends on the sensor type used, the sensor’s quality, its calibration, and conformance to specified standards. Plus,  the conversion system’s electronics, it’s calibration and conversion technique used and the unit’s sensitivity to ambient temperature and other conditions result additional sources needing traceable calibration.

In many modern devices, these details can be transparent to the user and summary details are described in the unit’s ‘System” calibration certification.

If not, then it is the responsibility of the user to assure that all major components of the measuring system have certified, traceable calibration and then perform the required calculations to determine the system’s measurement capability and combined measurement uncertainty.

This is not always an easy task, but is quite straightforward, as described in the NIST Publication: NIST/SEMATECH Engineering Statistics Handbook (http://www.nist.gov/itl/sed/gsg/handbook_project.cfm)

Reference webpage: Selection of Alternatives to Liquid-in-Glass Thermometers

Promoting alternatives to mercury thermometers

Thermistors

Thermocouple

Ref: ASTM E230 / E230M – Standard Specification and Temperature-Electromotive Force (emf) Tables for Standardized Thermocouples

Platinum Resistance Thermometers (PRTs)

Standard Specification for Industrial Platinum Resistance Thermometers:
ASTM E1137 / E1137M – 08

Verification Methods for Alternative Thermometers

Background References & Links
(Laws and Regulations),

EPA’s Mercury home page — (www.epa.gov/hg/index.html)

State Regs: 2005 Mercury Compendium www.ecos.org/section/committees/cross_media/quick_silver/2005_mercury_compendium1/

The Environmental Council of the States
50 F Street NW Suite 350,
Washington, DC 20001

Tel: +1  202-266-4920
Fax: +1 202-266-4937
Email: ecos (at) ecos (dot) org
Website: www.ecos.org

The Pros & Cons of RTDs & Thermocouples – By Jim Pinto

Jim Pinto One useful resource on RTD and Thermocouple sensors was found at Jim Pinto’s Writings section of his website, borrowed from the original article that he wrote for Instruments & Control Magazine in June 2000, at: www.jimpinto.com/writings/tempsensors.html.

In the article Jim takes particular care to describe the likely errors that can occur with less-than-perfect cold junction correction in some electronic thermocouple instruments (i.e. signal conditioners, displays, controllers and transmitters)

He prefaces his remarks by saying:

Resistance temperature detectors and thermocouples can be used for some of the same measurements, but each has strengths and weaknesses that must be carefully matched to the application at hand.

The original version of this article was published in the leading USA magazine – Instruments & Control Systems, June 2000

(Click here for a copy from the I&CS website: http://ics.pennnet.com/home/articles.cfm?ARTICLE_ID=76441&VERSION_NUM=1&Section=Articles).

Jim Pinto is an extraordinary person who has been very active in the ISA – the International Society for Automation, where he is Fellow of the Society. He founded Action Instruments and since about 1998 has shared his thoughts and experiences with the world through various media including, since about 2000, his website, www.JimPinto.com  and his YouTube Channel, online at: www.youtube.com/user/jimpinto?feature=watch.

His personal profile is available on TED.com at: www.ted.com/profiles/3154 (credit for Jim Pinto’s Picture belongs to that page) and on Linkedin at: www.linkedin.com/in/jimpinto1. where many images and video recordings of Jim may be viewed.

NPL’s Beginner’s Guides to Temperature & Humidity & More…

NPL_Screen_Shot

The Guide to temperature is an introductory guide which aims to help first-time users who have no experience of how to measure temperature beyond what they may have picked up in school, college or everyday life.

You can visit the Comment Page on this provisional Guide by Richard Rushby online at the comment webpage for the Temperature guide at: http://www.npl.co.uk/publications/guides/comment/comment-temperature-guide. Read more NPL’s Beginner’s Guides to Temperature & Humidity & More…

Industrial Sensor Publications By G. R. Peacock

Papers & Presentations

“The Role of Standards & Calibration in IR Thermography”,  Proceeding of IR/INFO 2012, Infraspection Institute, January 2012

“What Is Infrared Thermography?”TempSensorNEWS, July 9, 2011

“Keeping up with Web & Smart Phone Trends”,  MeasurementBlog, October 10, 2010

“Spectral Emissivity in Infrared Applications”, Proceeding of IR/INFO 2008, Infraspection Institute, January 2010

“Commissioning a New Sensor”, Sensors, December 17, 2008

“Installing Your New Sensor” , Sensors, November  18, 2008

“The Internet for Thermographers “   Proceeding of IR/INFO 2008, Infraspection Institute, January 2008 Read more Industrial Sensor Publications By G. R. Peacock

Pyrometry or Radiation Thermometry (Continued) – Lecture 18

The Tenth Lecture in the 11 Lecture Sub-Series on Temperature Measurement.

Also online at youtu.be/a9tawff4LuI and NPTEL at: nptel.iitm.ac.in/video.php?subjectId=112106138.

Lecturers for these videos are Prof. Shunmugam M. S., Department of Mechanical Engineering , IIT Madras.(email: shun@iitm.ac.in) and.Prof. S.P. Venkateshan, Department of Mechanical Engineering , IIT Madras (email: spv@iitm.ac.in).

Numbers after the lecture title indicate the length of the lecture in (hh:mm:ss) format. You can appreciate from the list and times shown, this is about a 50 hour course, equivalent to a substantial opportunity to learn the topics in significant depth.

Lectures in this course: 50

– Syllabus: PDF.

Resistance Thermometry (Continued) (Thermistors) & Pyrometry – Lecture 17

The Ninth Lecture in the 11 Lecture Sub-Series on Temperature Measurement.

Also online at youtu.be/7JsnhzojHo0 and NPTEL at: nptel.iitm.ac.in/video.php?subjectId=112106138.


Lecturers for these videos are Prof. Shunmugam M. S., Department of Mechanical Engineering , IIT Madras.(email: shun@iitm.ac.in) and.Prof. S.P. Venkateshan, Department of Mechanical Engineering , IIT Madras (email: spv@iitm.ac.in).

Numbers after the lecture title indicate the length of the lecture in (hh:mm:ss) format. You can appreciate from the list and times shown, this is about a 50 hour course, equivalent to a substantial opportunity to learn the topics in significant depth.

Lectures in this course: 50

– Syllabus: PDF.

Measurement of Temperature Under Various Conditions – Lecture 13

The Fifth Lecture in the 11 Lecture Sub-series on Temperature Measurement.

Also online at youtu.be/PWXhWm3oQ68 and NPTEL at: nptel.iitm.ac.in/video.php?subjectId=112106138.

Lecturers for these videos are Prof. Shunmugam M. S., Department of Mechanical Engineering , IIT Madras.(email: shun@iitm.ac.in) and.Prof. S.P. Venkateshan, Department of Mechanical Engineering , IIT Madras (email: spv@iitm.ac.in).

Numbers after the lecture title indicate the length of the lecture in (hh:mm:ss) format. You can appreciate from the list and times shown, this is about a 50 hour course, equivalent to a substantial opportunity to learn the topics in significant depth.

Lectures in this course: 50

– Syllabus: PDF.

1 – Introduction to the Study of Mechanical Measurement (57:28)
2 – Errors in Measurement (55:15)
3 – Errors in Measurement(Contd..) (58:31)
4 – Propagation of Errors (57:02)
5 – Regression Analysis (56:47)
6 – Regression Analysis (Contd) (55:57)
7 – Design of Experiments (57:29)
8 – Design of Experiments(Contd) (56:52)
9 – Temperature Measurement (56:50)
10 – Overview of Thermometry (57:48)
11 – Thermoelectric Thermometry (57:35)
12 – Thermoelectric Thermometry(Contd) (56:33)
13 – Measurement of Temperature Under Various Conditions (56:35)
14 – Errors in Temperature Measurement (59:07)
15 – Measurement of Transient Temperature and Resistance Thermometry (59:21)
16 – Resistance Thermometry(Contd) (59:47)
17 – Resistance Thermometry(Contd)and pyrometry (59:07)
18 – pyrometry (Contd) (58:50)
19 – pyrometry(Contd) (58:47)
20 – Pressure Measurement(Contd) (59:03)
21 – Pressure Measurement(Contd) (01:00:41)
22 – Pressure Measurement(Contd) (59:41)
23 – Pressure Measurement(Contd) (01:00:08)
24 – Transient Response of Pressure Transducers (59:20)
25 – Transient Response of Pressure Transducers (59:45)
26 – Measurement of High Vacuum (59:33)
27 – Measurement of Fluid Velocity (59:05)
28 – Hot Wire Anemometry and Laser Doppler Velocimetry (59:09)
29 – Laser Doppler Velocimetry and Ultrasonic Methods (57:24)
30 – Measurement of Heat Flux (59:30)
31 – Measurement of Heat Flux(Contd) (59:59)
32 – Transient Method of Heat Flux Measurement (59:37)
33 – Measurement of Volume and Mass Flow Rate of Fluid (59:41)
34 – Flow Measuring Devices (58:17)
35 – Measurement of Stagnation and Bulk Mean Temperature (56:28)
36 – Measurement of Thermo-Physical Properties (01:00:29)
37 – Measurement of Thermal Conductivity (57:51)
38 – Measurement of Heat Capacity and Heating Value (01:00:11)
39 – Measurement of Viscosity (59:17)
40 – Measurement of Viscosity(Contd) (59:03)
41 – Integrating Sphere and Measurement of Emissivity (56:25)
42 – Measurements of Gas Composition (58:03)
43 – Measurements of Gas Composition(Contd) (59:29)
44 – Measurements of Gas Composition and Smoke (58:34)
45 – Measurement of Force (59:00)
46 – Force Measurement (01:00:39)
47 – Vibration and Acceleration Measurement (58:04)
48 – Laser Doppler Accelerometer,Speed,Torque (58:35)
49 – General Issues in Mechanical Measurement (59:52)
50 – Case Studies (01:01:42)

Thermoelectric Thermometry (Continued) – Lecture 12

The Fourth Lecture in the 11 Lecture Sub-series on Temperature Measurement.

Also online at youtu.be/_STPaaaDB8Y and NPTEL at: nptel.iitm.ac.in/video.php?subjectId=112106138.

Lecturers for these videos are Prof. Shunmugam M. S., Department of Mechanical Engineering , IIT Madras.(email: shun@iitm.ac.in) and.Prof. S.P. Venkateshan, Department of Mechanical Engineering , IIT Madras (email: spv@iitm.ac.in).

Numbers after the lecture title indicate the length of the lecture in (hh:mm:ss) format. You can appreciate from the list and times shown, this is about a 50 hour course, equivalent to a substantial opportunity to learn the topics in significant depth.

Lectures in this course: 50

– Syllabus: PDF.

Thermoelectric Thermometry – Lecture 11

The Third Lecture in the 11 Lecture Sub-series on Temperature Measurement.

Also online at youtu.be/_q7P9UCae1o and NPTEL at: nptel.iitm.ac.in/video.php?subjectId=112106138.

Lecturers for these videos are Prof. Shunmugam M. S., Department of Mechanical Engineering , IIT Madras.(email: shun@iitm.ac.in) and.Prof. S.P. Venkateshan, Department of Mechanical Engineering , IIT Madras (email: spv@iitm.ac.in).

Numbers after the lecture title indicate the length of the lecture in (hh:mm:ss) format. You can appreciate from the list and times shown, this is about a 50 hour course, equivalent to a substantial opportunity to learn the topics in significant depth.

Lectures in this course: 50

– Syllabus: PDF.

Overview of Thermometry – Lecture 10

The Second Lecture in  the 11 Lecture Sub-series on Temperature Measurement.

It may also be viewed directly on YouTube.com at: youtu.be/c31i3JOTkuc and the NPTEL website at: nptel.iitm.ac.in/video.php?subjectId=112106138.

Lecturers for these videos are Prof. Shunmugam M. S., Department of Mechanical Engineering , IIT Madras.(email: shun@iitm.ac.in) and.Prof. S.P. Venkateshan, Department of Mechanical Engineering , IIT Madras (email: spv@iitm.ac.in).

Numbers after the lecture title indicate the length of the lecture in (hh:mm:ss) format. You can appreciate from the list and times shown, this is about a 50 hour course,  a substantial opportunity to learn the topics in significant depth.

Lectures in this course: 50

– Syllabus: PDF.