Bosch GIS 1000 C Professional Originalbetriebsanleitung Seite 24

OBJ_BUCH-2270-005.book Page 24 Wednesday, September 21, 2016 5:29 PM
24 | English
Preparing for Measurement
Setting the Emissivity Degree for Surface-temperature
Measurements
To determine the surface temperature, the natural infrared
heat radiation emitted by the object is measured contact-
free. For correct measurements, the emissivity degree set on
the measuring tool (see "Emissivity Degree", page 30) must
be checked and if required, adapted to the object being meas-
ured prior to each measurement.
To change the set emissivity degree, open the "Main Menu"
(see "Navigating the "Main Menu"", page 28).
– A selection of saved emissivity degrees is available for
some of the most common materials. Select the appropri-
ate material in the "Material" menu item. The correspond-
ing emissivity degree  is shown in the line beneath.
– If you know the exact emissivity degree of your measuring
object, you can also set it as a numerical value in the "Emis-
sivity Degree" menu item.
Inform yourself of the emissivity degree of your material. In
addition to the materials stored in the measuring tool, you will
find more in the table below.
Material Emissivity degree
Aluminium, oxidised 0.25
Brass, oxidised 0.61
Iron, slightly rusted 0.65
Iron, galvanised 0.25
Roofing felt 0.90
Glass 0.88
 Correct surface-temperature indications are only pos-
sible when the set emissivity degree and the emissivity
degree of the object correspond. Correct notes on ther-
mal bridges and the risk of mould thus also depend on the
set emissivity degree.
If multiple objects made of a different material or having a dif-
ferent structure are measured during a measurement, the sur-
face temperature indication is only binding for the objects
matching the set emissivity degree.
1 609 92A 211 | (21.9.16)
Measuring Surface for Surface-temperature
Measurements
The laser points generated by the measuring tool indicate the
left-hand and right-hand boundaries of the circular measuring
surface. The infrared radiation of this measuring surface is de-
termined when performing contactless surface temperature
measurement.
To achieve an optimum measuring result, align the measuring
tool as perpendicular as possible to the centre of the measur-
ing surface.
 Do not point the laser beam at persons or animals and
do not look into the laser beam yourself, not even from
a large distance.
Increasing the distance between measuring tool and measur-
ing object will increase the distance of the laser points and
therefore the size of the measuring surface accordingly.
 Do not hold the measuring tool directly against hot sur-
faces. The measuring tool can be damaged through heat.
If the laser points are difficult to see, you can switch on the
Measuring Frame b on the display (see "Measuring Frame",
page 29). The measuring frame can be used as an indicator
for the measuring surface and helps to improve orientation.
Depending on the measuring distance, the measuring frame
may deviate from the measuring surface. The area located be-
tween the laser points is decisive for the measurement.
Notes on the Measuring Conditions
Highly reflective or shiny surfaces (e.g. shiny tiles or polished
metals) may impair the surface temperature measurement. If
necessary, mask the measuring surface with a dark, matt ad-
hesive tape that conducts heat well. Allow the tape to acclima-
tise briefly on the surface.
Ensure that a favourable measuring angle is used on reflective
surfaces, in order to ensure that reflected heat radiation from
other objects does not distort the result. For example, the re-
flection of your body heat may interfere with the measure-
ment when measuring head-on from a perpendicular position.
Measuring through transparent materials (e.g. glass or trans-
parent plastics) is principally not possible.
The accuracy and reliability of the measuring results increase
with better and more stable measuring conditions.
The humidity and ambient temperature sensor 5 can be dam-
aged by chemical contaminants, such as through the evapora-
tion of paints or enamels. Infrared temperature measurement
is impaired by smoke, vapour or dusty air.
For this reason, ventilate indoor areas prior to measurement,
especially when the air is contaminated or steamy.
After ventilating, allow the room to acclimatize for a while until
the usual temperature has been reached again.
Ambient temperature and relative humidity are measured di-
rectly on the measuring tool using the humidity and ambient
temperature sensor 5. To achieve substantial results, do not
hold the measuring tool directly over or next to sources of in-
terference such as radiators or open liquids. Do not under any
circumstances cover off the sensor 5.
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