|
|
Infrared Temperature Measurement
Convenient and easy - but there are some traps
Click on pics to view larger images
|
|
|
At a glance...
- Infrared thermometers allow safe and easy temperature measurement
- The emissivity of the object being measured is critical to accuracy
- Many infrared thermometers have a fixed emissivity value
- Other important specs include angle of view and temp range
- Pick with care then you have a brilliant instrument
|
|
This article was first published in 2004
|
We’ve all seen them around and now they’re becoming very
cheap: infrared thermometers that can remotely measure the temperature of
surfaces look like God’s gift to automotive modifiers. After all, you can use
them to easily measure the temperature of brakes, intercoolers, oil coolers, the
sump, the airbox – you name it!
However, while there are some excellent applications for
infrared temp measurement, there are also some major traps. For example, if you
don’t know what you are doing, infrared temp measurement can have major errors.
Like the 60 degrees C that you measure is actually 90 degrees.... Or vice
versa.
What are the Benefits?
Infrared thermometers are remote sensing designs. That is,
you point the instrument at the surface to be measured and it reads off
temperature on a digital display, without any contact having to be made. This is
the major advantage over a traditional thermocouple – you don’t need to touch
the surface to make the measurement. This improves safety (you won’t get your
fingers burnt and the area being measured can be moving or difficult to safely
access), and as you don’t need to wait for a probe to come up to temperature,
the speed with which measurements can be made is high.
Emissivity
An infrared thermometer measures the amount of infrared
energy given off by the object to be measured. For a given temperature, the
amount of infrared energy depends on what is called the body’s emissivity. The
emissivity of a perfect radiator of infrared energy, called a blackbody, is 1.
However, many objects have emissivities that are less than
1, and if correction isn’t made for this change in emissivity, the
temperature measurement will be wrong. If the object either (a) reflects
infrared energy or (b) transmits infrared energy, the emissivity value won’t
equal 1. Shiny polished surfaces, such as aluminium, are so reflective of
infrared energy that accurate infrared temp measurements may not be possible.
Many infrared thermometers with fixed emissivity use a
default value of 0.95. Unoxidised aluminium has an emissivity of just 0.02 at 25
degrees C, while rubber’s emissivity is 0.94. So the measurement you just made
of your polished intercooler tank is likely to be way out in accuracy, but the tyre temp
measurement will be just fine!
To accurately measure the temperature of a variety of
surfaces, the infrared thermometer needs to be able to be programmed with the
emissivity of the surface that you are working with. If the thermometer doesn’t
have this capability, look for a better one or be aware that many readings
(especially of shiny and light coloured surfaces) are likely to be
wrong.
At the end of this article you’ll find an extensive list of
emissivities of different materials at different temperatures.
Measuring Angle
An infrared thermometer uses a lens to focus the infrared
energy onto a sensor. To accurately measure the temperature of an object, the
object should completely fill the field of view encompassed by this optical
system. If the object is much smaller than the field of view, the temperature of
the background will affect the measurement.
To ensure the correct field of view is being encompassed,
the instrument is placed a fixed distance from the surface to be measured. In
some designs, a pair of angled lights form a single dot on the surface when the
instrument is the correct measuring distance. Note that a single laser sight
doesn’t give you an indication of the angle of view or the correct
distance.
Other Measuring Problems
You should also be aware that other factors can also
influence the readings:
- Don’t make a measurement of a surface through dust, steam, gases or
rain
- Ensure that the instrument itself is within its correct working temp
range
- Make sure that the instrument’s lens is clean eg not fogged with
condensation
Interesting Car Uses for an Infrared Thermometer
- Brake temps to see if brakes are dragging and to determine their work
share
- Engine sump temps to see if installing an undertray increases oil
temps
- Temp drop across heat exchangers – engine oil cooler, trans oil
cooler, intercooler, radiator
- Power steering fluid temp
- Tyre temps to see
handling set-up
- Car sound amplifier temps
|
Different Instruments
When selecting an infrared thermometer, look at these
specifications:
- Range – many infrared thermometers are limited in their response to
high temperatures of the sort likely to be experienced with exhausts and brakes.
However, measuring these temps in car applications is fairly rare – but you
still want a max temp reading of at least 300 degrees C.
- Accuracy – this is most affected by the ability to input different
emissivities into the instrument. If the thermometer uses a fixed emissivity (eg
0.95) then any quoted accuracy is likely to be unobtainable when being used for
practical purposes.
- Emissivity – to be able to accurately measure the temperature of a
variety of surfaces, the thermometer must have the capability of being
programmed with different emissivities.
- Field of View – a narrow field of view (eg 8:1) allows pinpoint temp
reading.
- Sighting – how the instrument indicates the area being measured, eg
by laser or LED beams
- Data Hold – this is important because as soon as you move the
thermometer aim away from the sample area, the reading will change. In some
situations, reading the display at the same time as it is pointed at the correct area
can be difficult. A data hold function overcomes this problem.
Using It
So after all that, is it worth buying an infrared
thermometer? The answer is ‘yes’, so long as it is a good quality instrument.
If the emissivity cannot be
changed, the instrument can still be used for comparative measurements – ie to
determine whether a surface is getting hotter or colder over time.
Buying Used
With the reduction in price of infrared thermometers, even
high quality ones are these days going cheaply secondhand. This Steinel
ThermoCheck was bought on eBay for about AUD$90. It has adjustable emissivity
from 0.5 – 1, a range of -30 to 300 degrees C and measures a 5mm diameter field
from a distance of 40mm. It uses two focused flashing LEDs to show the correct
measurement distance – these form a dot when the distance is
correct.
|
Emissivity of Materials
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Adobe |
68 |
20 |
0.90 |
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Alloys: |
|
Alloy 24ST, polished |
75 |
24 |
0.90 |
|
Alloy 75ST |
75 |
24 |
0.11 |
|
20-Ni, 25-Cr, 55-Fe, oxidized |
392
932 |
200
500 |
0.90
0.97 |
|
60-Ni, 12-Cr, 28-Fe, oxidized |
518
1040 |
270
560 |
0.89
0.82 |
|
80-Ni, 20-Cr, oxidized |
212
1112
2372 |
100
600
1300 |
0.87
0.87
0.89 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Aluminum: |
|
Unoxidized |
77
212
932 |
25
100
500 |
0.02
0.03
0.06 |
|
Oxidized |
390
1110 |
199
599 |
0.11
0.19 |
|
Oxidized @1110°F |
390
1110 |
199
599 |
0.11
0.19 |
|
Heavily oxidized |
200
940 |
93
504 |
0.20
0.31 |
|
Highly polished |
212 |
100 |
0.09 |
|
Roughly polished |
212 |
100 |
0.18 |
|
Commercial sheet |
212 |
100 |
0.09 |
|
Highly polished plate |
440
1070 |
227
577 |
0.04
0.06 |
|
Bright rolled plate |
338
932 |
170
500 |
0.04
0.05 |
|
Alloy A3003, oxidized |
600
900 |
315
482 |
0.40
0.40 |
|
Alloy 1100-0 |
200 to 800 |
93 to 427 |
0.05 |
|
Alloy 24ST |
75 |
24 |
0.09 |
|
Alloy 24ST, polished |
75 |
24 |
0.09 |
|
Alloy 75ST |
75 |
24 |
0.11 |
|
Alloy 75ST, polished |
75 |
24 |
0.08 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Asphalt: |
|
Pavement |
100 |
38 |
0.93 |
|
Tar paper |
68 |
20 |
0.93 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Basalt |
68 |
20 |
0.72 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Bismuth: |
|
Bright |
176 |
80 |
0.34 |
|
Unoxidized |
77
212 |
25
100 |
0.05
0.06 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Brass: |
|
Matte |
68 |
20 |
0.07 |
|
Burnished to brown color |
68 |
20 |
0.40 |
|
Cu-Zn, brass oxidized |
392
752
1112 |
200
400
600 |
0.61
0.60
0.61 |
|
Unoxidized |
77 |
25 |
0.04 |
|
Unoxidized |
212 |
100 |
0.04 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Brick: |
|
Red, rough |
70 |
21 |
0.93 |
|
Gault cream |
2500 to 5000 |
1371 to 2760 |
0.26 to 0.30 |
|
Fire clay |
2500 |
1371 |
0.75 |
|
Light buff |
1000 |
538 |
0.80 |
|
Lime clay |
2500 |
1371 |
0.43 |
|
Fire brick |
1832 |
1000 |
0.75 to 0.80 |
|
Magnesite, refractory |
1832 |
1000 |
0.38 |
|
Gray brick |
2012 |
1100 |
0.75 |
|
Silica, glazed |
2000 |
1093 |
0.88 |
|
Silica, unglazed |
2000 |
1093 |
0.80 |
|
Sandime |
2500 to 5000 |
1371 to 2760 |
0.59 to 0.63 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Cadmium |
77 |
25 |
0.02 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Carbon: |
|
Lamp black |
77 |
25 |
0.95 |
|
Unoxidized |
77 |
25 |
0.81 |
|
Unoxidized |
212
932 |
100
500 |
0.81
0.79 |
|
Candle soot |
250 |
121 |
0.95 |
|
Filament |
500 |
260 |
0.95 |
|
Graphitized |
212
572
932 |
100
300
500 |
0.76
0.75
0.71 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Carborundum |
1850 |
1010 |
0.92 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Cast iron: |
|
Oxidized |
390
1110 |
199
599 |
0.64
0.78 |
|
Unoxidized |
212 |
100 |
0.21 |
|
Strong oxidation |
104
482 |
40
250 |
0.95
0.95 |
|
Liquid |
2795 |
1535 |
0.29 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Ceramic: |
|
Alumina on Inconel |
800 to 2000 |
427 to 1093 |
0.69 to 0.45 |
|
Earthenware, glazed |
70 |
21 |
0.90 |
|
Earthenware, matte |
70 |
21 |
0.93 |
|
Greens, No. 5210-2C |
200 to 750 |
93 to 399 |
0.89 to 0.82 |
|
Coating, No. C20A |
200 to 750 |
93 to 399 |
0.73 to 0.67 |
|
Porcelain |
72 |
22 |
0.92 |
|
White, Al2O3 |
200 |
93 |
0.90 |
|
Zirconia on Inconel |
800 to 2000 |
427 to 1093 |
0.62 to 0.45 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Chromium: |
|
Chromium |
100
1000 |
38
538 |
0.08
0.26 |
|
Chromium, polished |
302 |
150 |
0.06 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Clay: |
68 |
20 |
0.39 |
|
Fired |
158 |
70 |
0.91 |
|
Shale |
68 |
20 |
0.69 |
|
Tiles, light red |
2500 to 5000 |
1371 to 2760 |
0.32 to 0.34 |
|
Tiles, red |
2500 to 5000 |
1371 to 2760 |
0.40 to 0.51 |
|
Tiles, dark purple |
2500 to 5000 |
1371 to 2760 |
0.78 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Columbium: |
|
Unoxidized |
1500
2000 |
816
1093 |
0.19
0.24 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Concrete: |
|
Rough |
32 to 200 |
0 to 93 |
0.94 |
|
Tiles, natural |
2500 to 5000 |
1371 to 2760 |
0.63 to 0.62 |
|
Tiles, brown |
2500 to 5000 |
1371 to 2760 |
0.87 to 0.83 |
|
Tiles, black |
2500 to 5000 |
1371 to 2760 |
0.94 to 0.91 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Copper: |
|
Black, oxidized |
100 |
38 |
0.78 |
|
Etched |
100 |
38 |
0.09 |
|
Matte |
100 |
38 |
0.22 |
|
Roughly polished |
100 |
38 |
0.07 |
|
Polished |
100 |
38 |
0.03 |
|
Highly polished |
100 |
38 |
0.02 |
|
Rolled |
100 |
38 |
0.64 |
|
Rough |
100 |
38 |
0.74 |
|
Molten |
1000
1970
2230 |
538
108
1221 |
0.15
0.16
0.13 |
|
Nickel plated |
100 to 500 |
38 to 260 |
0.37 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Cotton cloth |
68 |
20 |
0.77 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Dolomite lime |
68 |
20 |
0.41 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Dow metal |
0 to 600 |
-18 to 315 |
0.15 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Emery corundum |
176 |
80 |
0.86 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Glass: |
|
Convex D |
212
600
932 |
100
315
500 |
0.80
0.80
0.76 |
|
Nonex |
212
600
932 |
100
315
500 |
0.82
0.82
0.78 |
|
Smooth |
32 to 200 |
0 to 93 |
0.92 to 0.94 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Gold: |
|
Enamel |
212 |
100 |
0.37 |
|
Plate (0.001) on 0.0005 silver |
200 to 750 |
93 to 399 |
0.11 to 0.14 |
|
Plate (0.001) on 0.005 nickel |
200 to 750 |
93 to 399 |
0.07 to 0.09 |
|
Polished |
100 to 500
1000 to 2000 |
38 to 260
538 to 1093 |
0.02
0.03 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Granite |
70 |
21 |
0.45 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Gravel |
100 |
38 |
0.28 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Gypsum |
68 |
20 |
0.80 to 0.90 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Haynes Alloy C., oxidized |
600 to 2000 |
316 to 1093 |
0.90 to 0.96 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Haynes Alloy 25, oxidized |
600 to 2000 |
316 to 1093 |
0.86 to 0.89 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Haynes Alloy X., oxidized |
600 to 2000 |
316 to 1093 |
0.85 to 0.88 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Ice: |
|
Smooth |
32 |
0 |
0.97 |
|
Rough |
32 |
0 |
0.98 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Inconel: |
|
Sheet |
1000
1200
1400 |
538
649
760 |
0.28
0.42
0.58 |
|
Inconel X, polished |
75 |
24 |
0.19 |
|
Inconel B, polished |
75 |
24 |
0.21 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Iron: |
|
Oxidized |
212
930
2190 |
100
499
1199 |
0.74
0.89
0.89 |
|
Unoxidized |
212 |
100 |
0.05 |
|
Red rust |
77 |
25 |
0.70 |
|
Rusted |
77 |
25 |
0.65 |
|
Liquid |
2760 to 3220 |
1516 to 1771 |
0.42 to 0.45 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Lacquer: |
|
Black |
200 |
93 |
0.96 |
|
Blue, on aluminum foil |
100 |
38 |
0.78 |
|
Clear, on aluminum foil, 2 coats |
200 |
93 |
0.08 (0.09) |
|
Clear, on bright copper |
200 |
93 |
0.66 |
|
Clear, on tarnished copper |
200 |
93 |
0.64 |
|
Red, on aluminum foil, 2 coats |
100 |
38 |
0.61 (0.74) |
|
White, on aluminum foil, 2 coats |
100 |
38 |
0.69 (0.88) |
|
White |
200 |
93 |
0.95 |
|
Yellow, on aluminum foil, 2 coats |
100 |
38 |
0.57 (0.79) |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Lead: |
|
Polished |
100 to 500 |
38 to 260 |
0.06 to 0.08 |
|
Rough |
100 |
38 |
0.43 |
|
Oxidized |
100 |
38 |
0.43 |
|
Oxidized @ °F |
100 |
38 |
0.63 |
|
Oxidized, gray |
100 |
38 |
0.28 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Lime mortar |
100 to 500 |
38 to 260 |
0.90 to 0.92 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Limestone |
100 |
38 |
0.95 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Magnesium |
100 to 500 |
38 to 260 |
0.07 to 0.13 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Magnesium oxide |
1800 to 3140 |
982 to 1727 |
0.16 to 0.20 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Marble: |
|
White |
100 |
38 |
0.95 |
|
Smooth |
100 |
38 |
0.56 |
|
Polished gray |
100 |
38 |
0.75 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Mercury |
32
77
100
212 |
0
25
38
100 |
0.09
0.10
0.10
0.12 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Mica |
100 |
38 |
0.75 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Oil on nickel: |
|
0.001 film |
72 |
22 |
0.27 |
|
0.002 film |
72 |
22 |
0.46 |
|
0.005 film |
72 |
22 |
0.72 |
|
Thick film |
72 |
22 |
0.82 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Oil, linseed: |
|
On aluminum foil, uncoated |
250 |
121 |
0.09 |
|
On aluminum foil, 1 coat |
250 |
121 |
0.56 |
|
On aluminum foil, 2 coats |
250 |
121 |
0.51 |
|
On polished iron, 0.001 film |
100 |
38 |
0.22 |
|
On polished iron, 0.002 film |
100 |
38 |
0.45 |
|
On polished iron, 0.004 film |
100 |
38 |
0.65 |
|
On polished iron, thick film |
100 |
38 |
0.83 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Paints: |
|
Blue, CO2O3 |
75 |
24 |
0.94 |
|
Black, CuO |
75 |
24 |
0.96 |
|
Green, Cu2O3 |
75 |
24 |
0.92 |
|
Red, Fe2O3 |
75 |
24 |
0.91 |
|
White, Al2O3 |
75 |
24 |
0.94 |
|
White, Y2O3 |
75 |
24 |
0.90 |
|
White, ZnO |
75 |
24 |
0.95 |
|
White, MgCO3 |
75 |
24 |
0.91 |
|
White, ZrO2 |
75 |
24 |
0.95 |
|
White, ThCO2 |
75 |
24 |
0.90 |
|
White, MgO |
75 |
24 |
0.91 |
|
White, PbCO3 |
75 |
24 |
0.93 |
|
Yellow, PbO |
75 |
24 |
0.90 |
|
Yellow, PbCrO4 |
75 |
24 |
0.93 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Paints, aluminum: |
100 |
38 |
0.27 to 0.67 |
|
10% Al |
100 |
38 |
0.52 |
|
26% Al |
100 |
38 |
0.30 |
|
DOW XP-310 |
200 |
93 |
0.22 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Paints, bronze: |
Low |
0.34 to 0.80 |
|
Gum varnish, 2 coats |
70 |
21 |
0.53 |
|
Gum varnish, 3 coats |
70 |
21 |
0.50 |
|
Cellulose binder, 2 coats |
70 |
21 |
0.34 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Paints, oil: |
|
All colors |
200 |
93 |
0.92 to 0.96 |
|
Black |
200 |
93 |
0.92 |
|
Black gloss |
70 |
21 |
0.90 |
|
Camouflage green |
125 |
52 |
0.85 |
|
Flat black |
80 |
27 |
0.88 |
|
Flat white |
80 |
27 |
0.91 |
|
Gray green |
70 |
21 |
0.95 |
|
Green |
200 |
93 |
0.95 |
|
Lamp black |
209 |
98 |
0.96 |
|
Red |
200 |
93 |
0.95 |
|
White |
200 |
93 |
0.94 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Palladium plate(0.00005)
on 0.0005
silver |
200 to 750 |
93 to 399 |
0.16 to 0.17 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Paper: |
|
Kraft (average non-glass) |
— |
— |
0.90 |
|
Offset (glass) |
— |
— |
0.50 to 0.60 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Plastics (average) |
Low |
0.95 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Platinum: |
|
Platinum, black |
100
500
2000 |
38
260
1093 |
0.93
0.96
0.97 |
|
Platinum, oxidized @ 1100°F |
500
1000 |
260
538 |
0.07
0.11 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Quartz: |
|
Rough, fused: |
70 |
21 |
0.93 |
|
Glass, 1.98 mm |
540
1540 |
282
838 |
0.90
0.41 |
|
Glass, 6.88 mm |
540
1540 |
282
838 |
0.93
0.47 |
|
Opaque |
570
1540 |
299
838 |
0.92
0.68 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Red lead |
212 |
100 |
0.93 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Rhodium flash:
0.0002 on 0.0005
Ni |
200 to 700 |
93 to 271 |
0.10 to 0.18 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Rubber: |
|
Hard |
74 |
23 |
0.94 |
|
Soft, gray |
76 |
24 |
0.86 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Sand |
68 |
20 |
0.76 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Sawdust |
68 |
20 |
0.75 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Silica: |
|
Glazed |
1832 |
1000 |
0.85 |
|
Unglazed |
2012 |
1100 |
0.75 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Silver: |
|
Plate 0.0005 on nickel |
200 to 700 |
93 to 271 |
0.06 to 0.07 |
|
Polished |
100
500
1000
2000 |
38
260
538
1093 |
0.01
0.02
0.03
0.03 |
|
Slate |
100 |
38 |
0.67 to 0.80 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Snow: |
|
Fine particles |
20 |
7 |
0.82 |
|
Granular |
18 |
8 |
0.89 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Soil: |
|
Surface |
100 |
38 |
0.38 |
|
Black loam |
68 |
20 |
0.66 |
|
Plowed field |
68 |
20 |
0.38 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Steel: |
|
Cold rolled |
200 |
93 |
0.75 to 0.85 |
|
Ground sheet |
1720 to 2010 |
938 to 1099 |
0.55 to 0.61 |
|
Polished sheet |
100
500
1000 |
38
260
538 |
0.07
0.10
0.14 |
|
Mild steel, polished |
75 |
24 |
0.10 |
|
Mild steel, smooth |
75 |
24 |
0.12 |
|
Mile steel, liquid |
2910 to 3270 |
1599 to 1799 |
0.28 |
|
Unoxidized |
77
212 |
25
100 |
0.80
0.08 |
|
Oxidized |
77 |
25 |
0.80 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Steel alloys: |
|
Type 301, polished |
75
450
1740 |
24
232
949 |
0.27
0.57
0.55 |
|
Type 303, oxidized |
600 to 2000 |
316 to 1093 |
0.74 to 0.87 |
|
Type 310, rolled |
1500 to 2100 |
816 to 1149 |
0.56 to 0.81 |
|
Type 316, polished |
75
450
1740 |
24
232
949 |
0.28
0.57
0.66 |
|
Type 321 |
200 to 800 |
93 to 427 |
0.27 to 0.32 |
|
Type 321, polished |
300 to 1500 |
149 to 816 |
0.18 to 0.49 |
|
Type 321, with black oxide |
200 to 800 |
93 to 427 |
0.66 to 0.76 |
|
Type 347, oxidized |
600 to 2000 |
316 to 1093 |
0.87 to 0.91 |
|
Type 350 |
200 to 800 |
93 to 427 |
0.18 to 0.27 |
|
Type 350, polished |
300 to 1800 |
149 to 982 |
0.11 to 0.35 |
|
Type 446, polished |
300 to 1500 |
419 to 816 |
0.15 to 0.37 |
|
Type 17-7PH |
200 to 600 |
93 to 315 |
0.44 to 0.51 |
|
Type 17-7PH, polished |
300 to 1500 |
149 to 816 |
0.09 to 0.16 |
|
Type C1020, oxidized |
600 to 2000 |
316 to 1093 |
0.87 to 0.91 |
|
Type PH-15-7MO |
300 to 1200 |
149 to 649 |
0.07 to 0.19 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Stellite, polished |
68 |
20 |
0.18 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Stonework |
100 |
38 |
0.93 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Tantalum: |
|
Unoxidized |
1340
2000
3600
5306 |
727
1093
1982
2930 |
0.14
0.19
0.26
0.30 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Tin: |
|
Unoxidized |
77
212 |
25
100 |
0.04
0.05 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Tinned iron: |
|
Bright |
76
212 |
24
100 |
0.05
0.08 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Titanium: |
|
Alloy C110M, polished |
300 to 1200 |
149 to 649 |
0.08 to 0.19 |
|
Alloy C110M, oxidized @ 1000°F |
200 to 800 |
93 to 427 |
0.51 to 0.61 |
|
Alloy TI-95A, oxidized @ 1000°F |
200 to 800 |
93 to 427 |
0.35 to 0.48 |
|
Anodized onto stainless steel |
200 to 600 |
93 to 316 |
0.96 to 0.82 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Tungsten: |
|
Unoxidized |
77
212
932
1832
2732
3632 |
25
100
500
1000
1500
2000 |
0.02
0.03
0.07
0.15
0.23
0.28 |
|
Filament (aged) |
100
1000
5000 |
38
538
2760 |
0.03
0.11
0.35 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Uranium oxide |
1880 |
1027 |
0.79 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Water |
100 |
38 |
0.93 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Wood: |
Low |
0.80 to 0.90 |
|
Beech, planed |
158 |
70 |
0.94 |
|
Oak, planed |
100 |
38 |
0.91 |
|
Spruce, sanded |
100 |
38 |
0.89 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Wrought iron: |
|
Dull |
77
660 |
25
349 |
0.94
0.94 |
|
Smooth |
100 |
38 |
0.35 |
|
Polished |
100 |
38 |
0.28 |
|
|
|
MATERIAL |
TEMPERATURE |
EMISSIVITY |
|
°F |
°C |
|
Zinc: |
|
Bright galvanized |
100 |
38 |
0.23 |
|
Commercial 99.1% |
500 |
260 |
0.05 |
|
Galvanized |
100 |
38 |
0.28 |
|
Oxidized |
500 to 1000 |
260 to 538 |
0.11 |
|
Polished |
100
500
1000
2000 |
38
260
538
1093 |
0.02
0.03
0.04
0.06 |
- Table courtesy of Cole-Parmer
Did you enjoy this article?
Please consider supporting AutoSpeed with a small contribution. More Info...
|
More of our most popular articles.
|
|
|
|
Email a friend
Print article
|