Extech Instruments IRT25 User Manual

EXTECHINSTRUMENTS
6IRT25‐en‐GB_V1.02/17
LocatingHotorColdSpots
Todetectahotorcoldspot,aimthethermometerataregionbeyondthetargetandthenscan
theentireregioninaslow,up/downmotion.

DistancetoSpotRatio(FieldofView)
Themeter’s fieldof view is12:1(distance to spotratio). For example,ifthemeter is 24inches
fromthetarget(spot),thediameterofthetargetmustbeatleast2inches.Otherdistancesare
shownbelowinthefieldofviewdiagram.
Notethatmeasurementsshouldnormallybe
madecloserthan2feetfromthetarget.Themeter
canmeasurefromfurther distances but the measurementmaybeaffectedbyexternalsources
oflight.Inaddition,thespotsizemaybesolargethatitencompassessurfaceareasnotintended
tobemeasured.

Itisnecessary to ensurethatthe size ofthe target islarger thanthespot size. Thesmaller the
target,thecloserthedistanceshouldbe.Seetheaccompanyingdiagram.

Emissivity
Emissivityrepresents the energy 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.

Extech Instruments IRT25 Specifications

General

Brand	Extech Instruments
Model	IRT25
Category	Thermometer
Language	English