Measurements of Pool-Fire Temperature Using IR Technique. (419 K)

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

Abstract:
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)

Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899 USA

Table of Emissivities in Three Popular Spectral Regions

The Table of Emissivity on the INFRAPOINT Messtechnik GmbH website, posted in 2009 (No longer available online) had summary data for a wide variety of materials broken down into three distinct spectral regions for the wavelength regions where the majority of infrared radiation thermometers and Infrared Thermal Imaging cameras operate.

First and second are tables that deal with the narrow spectral bands about 0.9 µm and 1.6 µm, the regions where many Silicon (Si) photovoltaic detectors (peak wavelength response: (0.9 µm) and both Germanium (Ge) and Indium Gallium Arsenide (InGaAs) (nominal wavelength region (0.7 - 1.6 µm) are used.

The third table cover the 8 - 14 µm waveband where most "low" (near ambient) temperature IR thermometers and thermal imaging sensors operate.

It has been reproduced here below in the spirit of Internet openness from our archives. We hope there is no problem in doing so and if any heir or assigns of INFRAPOINT Messtechnik GmbH wishes to keep this information secret, obviously against the original intent of INFRAPOINT, please contact us according to our webpage contact information.

		Table of emissivity
	The emissivity ? (radiant emittance factor) is the relationship of the radiated intensity of a body to the intensity of a blackbody of the same temperature. It is the most important factor, in order to determine of an item exactly. If you want to measure the surface temperature with an infrared thermometer the emissivity must be known and correct adjusted on the instrument.
	Material	Emissivity			Material	Emissivity
	Metals	Wavelength 0.9 µm	Wavelength 1.6 µm		Non metals	Wavelength 8 - 14 µm
	Aluminium, bright	0.05 - 0.25	0.05 - 0.25		Asphalt	0.95
	Aluminium, anodized	0.2 - 0.4	0.1 - 0.4		Concrete	0.95
	Chrom, bright	0.28 - 0.32	0.25 - 0.3		Gypsum	0.85 - 0.95
	Iron, oxidised	0.4 - 0.8	0.5 - 0.9		Graphite	0.75 - 0.92
	Iron, not oxidised	0.35	0.1 - 0.3		Glass*, pane	0.80
	Gold, bright	0.02	0.02		Rubber	0.85 - 0.95
	Copper, bright	0.06 - 0.20	0.06 - 0.20		Wood, natural	0.8 - 0.95
	Copper, oxidised	0.5 - 0.8	0.7 - 0.85		Chalk	0.98
	Magnesium	0.03 - 0.8	0.05 - 0.3		Ceramics	0.85 - 0.95
	Brass, bright	0.8 - 0.95	0.01 - 0.05		Plastics	0.85 - 0.95
	Brass, oxidised	0.65 - 0.75	0.65 - 0.75		Masonry	0.85 - 0.95
	Nickel, oxidised	0.8 - 0.9	0.4 - 0.7		Human skin	0.98
	Platinum, black	-	0,95		Oil paints	0.85 - 0.95
	Silver	0.02	0.02		Paper	0.85 - 0.95
	Steel, melted	0.30	0.20 - 0.25		Porcelain	0.85 - 0.95
	Steel, oxidised	0.8 - 0.9	0.8 - 0.9		Quartz	0.8
	Steel, bright	0.40 - 0.45	0.30 - 0.4		Carbon black	0.95
	Titanium, bright	0.5 - 0.75	0.3 - 0.5		Chamotte	0.85 - 0.95
	Titanium, oxidised	-	0.6 - 0.8		Textile, Drapery	0.85 - 0.95
	Zinc, bright	0.6	0.4 - 0.6		Tone	0.95
	Zinc, oxidised	0.5	0.05		Water	0.95
	Tin	0.25	0.1 - 0.3		Cement	0.9

* The emissivity of glass (0.95 - 0.97 µm) is in the range of 4.5 - 7 µm particularly high. Glass has there an absorption band (spectral range, where materials absorb radiation). To measure glass surface temperatures, the best wavelength is at 5.14 µm, because the measurement at this range is not affected by absorption bands such as carbon or hydrogen.

Spectral emissivity of skin and pericardium

Spectral emissivity of skin and pericardium by J Steketee 1973 Phys. Med. Biol. 18 686-694 doi: 10.1088/0031-9155/18/5/307 Help

J Steketee, Department of Biological and Medical Physics, Erasmus University, Rotterdam, The Netherlands

Abstract.

A monochromator was modified to measure the emissivity, ?(?), of living tissue in the infrared region between 1 and 14 ?m. The infrared radiation from the tissue was compared with blackbody radiation and in this way ?(?) has been determined for white skin, black skin, burnt skin and pericardium.

A compensating skin thermometer was constructed to measure the temperature of the surface of the tissue. The temperature difference before and after contact between a gold ring and the surface was made as small as possible (0.05 K). A reference radiator with the same spectral radiance (experimentally determined) mas used in compensating for the environment.

It appeared that ?(?) for skin is independent of the wavelength and equal to 0.98+-0.01. These results contradict those of Elam, Goodwin and Lloyd Williams, but are in good agreement with those of Hardy and Watmough and Oliver.

In addition there was no difference between ?(?) for normal skin and burnt skin. Epicardium values were found to lie between 0.83 (fresh heart) and 0.90 (after 7 h and after 9 d).

Print publication: Issue 5 (September 1973)
PDF (504 KB)

Non-contact skin emissivity: measurement from reflectance

Reference Title:Non-contact skin emissivity: measurement from reflectance using step change in ambient radiation temperature Citation: T Togawa 1989 Clin. Phys. Physiol. Meas. 10 39-48 doi: 10.1088/0143-0815/10/1/004

Article by T Togawa of Inst. for Med. & Dental Eng., Tokyo Med. & Dental Univ., Japan

Abstract.

A method of estimating skin emissivity based on reflectance measurement upon transient stepwise change in the ambient radiation temperature was proposed. To effect this change, two shades at different temperatures were switched mechanically, and the change in radiation from the skin surface was recorded through an aperture for each shade by a high-resolution, fast-response radiometer having a sensitivity the 8-14 mu m range. Measurements were made on the forehead, forearm, palm and back of the hand in 10 male and 10 female subjects. No significant differences in emissivity were observed among sites and between sexes. The overall average of the skin emissivity obtained was 0.971+or-0.005 (SD). This result is inconsistent with most reported skin emissivity values. However, as the former studies had many inherent inadequacies, both theoretical and experimental, it is considered that most of these reported skin emissivities are unacceptable. The method proposed in the study has the following advantages: (1) relative calibration between instruments in unnecessary, (2) noncontact measurement can be achieved, and (3) each measurement can be made within one minute.

Available for purchase as a PDF (652 KB) downloadable document from the IOP website in the UK.