Locating A Hot Spot - PeakTech 4975 Mode D'emploi

8.3. Locating a hot Spot

To find a hot spot aim the thermometer outside the area of interest,
then scan across with an up and down motion until you locate hot
spot.
Reminders
1. The unit cannot measure through transparent surfaces such as
glass. It will measure the surface temperature of the glass instead.
2. Steam, dust, smoke, etc. can prevent accurate measurement by
obstructing the unit´s optics.
8.4 Emissivity
Most (90 % of typical applications) organic materials and painted or
oxidised surfaces have an emissivity of 0,95. Inaccurate readings will
result from measuring shiny or polished metal surfaces. To
compensate, cove the surface to be measured with masking tape or
flat black paint. Allow time for the tape to reach the same temperature
as the material underneath it. Measure the temperature of the tape or
painted surface.
Material
Aluminium
Brass
Condition
polished
Raw surface
oxidized
Aluminium oxide,
Aluminium
powder
matt
oxidized at 600°C 200°C ... 600°C
Polished
Wrought with
sandpaper
Temperature-
Range
50°C ... 100°C
20°C ... 50°C
50°C ... 500°C
normal
Temperature
20°C ... 350°C
200°C
20°C
35
Emissivity-
factor (ɛ)
0.04 ... 0.06
0.06 ... 0.07
0.2 ... 0.3
0.16
0.22
0.59 ... 0.61
0.03
0.2