Extech Instruments IR267 - Emissivity and Alarms; Emissivity Explained; Material Emissivity Values; Temperature Alarm Functions

IR267‐en‐GB_v1.18/16
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Emissivity
TheEmissivitysettingisshowninsmalldigitsatthelowerleftcornerofthedisplay.Toadjust
theEmissivitypleaserefertotheSettingsmodesection.
Emissivityrepresentsthereflectivityofamaterial.Mostorganicmaterialsandpaintedor
oxidizedsurfaceshaveanemissivityofapproximately0.95.Ifpossible,masking
tapeorflatblack
paintshouldbeappliedtocoverthemeasuredsurface.
Waitaperiodoftimetoallowthetapeorpainttoreachthermalequilibriumwiththesurfaceof
thecoveredobject.Measurethetemperature ofthesurfacecoveredwithtapeorpaintonly
afterequilibriumhas
beenachieved.
AnotherwaytofindtheemissivityofasurfaceistousetheType‐Kthermocoupletotakea 
contacttemperaturereading.Notethisreadingandthentakeanon‐contacttemperature
readingandadjusttheemissivityuntilthenon‐contactmeasurementmatchesthecontact
measurement.
EmissivityFactorsfor
CommonMaterials
Materialundertest Emissivity Materialundertest Emissivity
Asphalt 0.90to0.98 Cloth(black) 0.98
Concrete 0.94 Skin(human) 0.98
Cement 0.96 Leather 0.75to0.80
Sand 0.90 Charcoal(powder) 0.96
Soil 0.92to0.96 Lacquer 0.80to0.95
Water 0.92to0.96 Lacquer(matt) 0.97
Ice 0.96to0.98 Rubber(black) 0.94
Snow 0.83 Plastic 0.85to0.95
Glass 0.90to0.95 Timber 0.90
Ceramic 0.90to0.94 Paper 0.70to0.94
Marble 0.94 ChromiumOxides 0.81
Plaster 0.80to0.90 CopperOxides 0.78
Mortar 0.89to0.91 IronOxides 0.78to0.82
Brick 0.93to0.96 Textiles 0.90
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HighandLowTemperatureAlarms
TheIR267hasalowalarmandahighalarmutility.Setthelowandhighalarmlimitsinthe
Settingsmode.SeetheSettingsmodesectionfordetails.Thelowand/orthehighalarmscan
alsobedisabledintheSettingsmode.WhentheloworhighalarmlimitsarereachedtheL(low
alarm)orH(highalarm)iconwillblinkandthealarmbuzzerwills ound(thebuzzercanbe
disabledintheSettingsmode.

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