Part One of Two from the mind of FLIR
It health partners pharmacies starts:
Fill two soda cans with hot water and wrap one with scotch tape. Which one will radiate more heat?
You might be surprised at the answer
(It has all to do with Spectral Emissivity, although this video continues the illusion that it’s really simple “Emissivity” at work! The concept of Emissivity is simple and easy to grasp as the video shows. The understanding is a bit more difficult and begins when one realizes that it is really Spectral Emissivity.)
But looking beyond that technical fine point, the video illustrates two other things: Read More »
At Elevated Temperatures
Developed by ASTM Subcommittee: E21.04, on Space Simulation Test Methods, and in the Annual Book of ASTM Standards, Volume 15.0 Space Simulation; Aerospace and Aircraft; Composite Materials
Quoting from the standard’s Scope:
1.1 This test method describes a highly accurate technique for measuring the normal spectral emittance of electrically conducting materials or materials with electrically conducting substrates, in the temperature range from 600 to 1400 K, and at wavelengths from 1 to 35 ?m.
1.2 The test method requires expensive equipment and rather elaborate precautions, but produces data that are accurate to within a few percent. It is suitable for research laboratories where the highest precision and accuracy are desired, but is not recommended for routine production or acceptance testing. However, because of its high accuracy this test method can be used as a referee method to be applied to production and acceptance testing in cases of dispute…
Obtaining directly from ASTM International has two options:
1. Buy Standard (PDF): 6 pages $ 37.00 US (In PDF format, this active standard is the most current version published by ASTM. You will download the file after you check out of the ASTM Store.)
2. Buy Standard (Print): 6 pages $ 37.00 US (In printed format, this active standard is the most current version published by ASTM. After you place your order, ASTM will print this standard and deliver it to your ship-to address by common carrier.)
Ordering Options Outside of the United State. has many more: Click here: (http://www.astm.org/IMAGES03/InterNatDist.pdf)
Electro Optical Industries (EOI) uses one of two high emissivity coatings on the surface of its blackbodies.
The EOI mid-temperature coating is used on both cavity and flat plate blackbodies that have a maximum operating temperatures of up to 210 °C.
Read the rest by visiting their webpage at: www.electro-optical.com/eoi_page.asp?h=What%20Is%20Emissivity?
From the Electro-Optical Industries website:
“Effective emissivity is the ratio of the total amount of energy exiting a blackbody to that which is predicted by Planck’s law. This is the value most frequently referred to as “emissivity”.
Effective emissivity of a cavity type blackbody will normally be much higher than the surface emissivity due to the multiple energy bounces inside the body cavity.”
You can read the rest on this useful and informative webpage: www.electro-optical.com/html/bb_rad/emissivity/emisivty.asp
By Qian, C.; Saito, K.
Ref: Combustion Institute/Central and Western States (USA) and Combustion Institute/Mexican National Section and American Flame Research Committee. Combustion Fundamentals and Applications. Joint Technical Meeting. Proceedings. April 23-26, 1995, San Antonio, TX, Gore, J. P., Editor(s), 81-86 pp, 1995.
Sponsor: National Institute of Standards and Technology, Gaithersburg, MD
We made an attempt to measure the flame temperature of four different diameter hexane-pool-fires using IR technique. Emissivities for these four flames were estimated based on measurements of transmitted energy from a blackbody radiant source. The average flame temperature half way to the flame tip was 700-800 deg C, which was in good agreement with thermocouple-temperature measurements by others for a 3 m diameter hexane pool fire.
Click here to download a pdf version of the report:Measurements of Pool-Fire Temperature Using IR Technique. (419 K)