Hazet 1991-1, Operating Instructions Manual

Page: 17 / 28

GB
USA
17
Do not let the beam enter your eye, another person’s eye or the eye of an animal!
This may cause severe eye injuries.
Reminders
• Not recommended for use in measuring shiny
or polished metal surfaces ( stainless steel,
aluminium, 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 ac-
curate measurement by obstructing the unit’s
optics.
Emissivity
•
Emissivity is a term 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 compen-
sate, 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.
(
See EMS adjustment on pages 15 and 16)
Emissivity Values
Substance Thermal emissivity
Asphalt 0.90 to 0.98
Cloth (black) 0.98
Concrete 0.94
Human skin 0.98
Cement 0.96
Leather 0.75 to 0.80
Sand 0.90
Charcoal (powder) 0.96
Earth 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
3
Design and Function