14.
Distance & Spot Size
As the distance (D) from the object increases, the spot size (S) of the area
measured by the unit becomes larger.
14-1. 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.
14-2. Reminders
Not recommended for use in measuring shiny or polished metal surfaces
(stainless steel, aluminum, etc.). See Emissivity
The unit cannot measure through transparent surfaces such as glass. It
will measure the surface temperature of the glass instead.
Steam, dust, smoke, etc., can prevent accurate measurement by
obstructing the unit’s optics.
14-3. Emissivity
Emissivity is a team used to describe the energy-emitting characteristics
of materials. Most (90% of typical applications) organic materials and
painted or oxidized surfaces have an emissivity of 0.95 (pre-set in the
unit). Inaccurate readings will result from measuring shiny or polished
metal surfaces. To compensate, cover the surface to be measured with
masking tape or flat black paint. Allow time for the tape to reach the
same temperatures as the material underneath it. Measure the
temperature of the tape or painted surface.
