Determining The Final Weight; Sampling - Wohler DTEST Notice D'utilisation

Dust surface density / level of cleanliness in air ducts and air-guiding surfaces
4.5 Determining the final
weight
4.6

Sampling

34
After sufficient drying time has elapsed, place
•
the test cloths in the respective, assigned test
canister.
Now determine the final weight using the
•
scales.
• To increase measurement accuracy when the
dust accumulation level measured is below
3.0 g/m², you should greatly increase the sur-
face area to be wiped with a test cloth.
Recommendation!
>3.0 g/m² : Three-fold test to VDI 6022
<3.0 g/m² : Three-fold test, but with the same
test cloth
< 1.0 g/m² : Mind. 2 x three-fold test, but with
the
same test cloth
Using the same test cloth to wipe several surface
areas is the same as averaging the results, and is
in practice equivalent to a three-fold determination
to VDI 6022 1.3.
Affix the magnetic disk at the predetermined
•
sampling points one after the other and wipe
the additional surfaces using the same test
cloth (if necessary, dampen the test cloth
again with solvent).
Optionally the surface to be wiped can be
•
defined or marked in another way. It is im-
portant that it is exactly 100 cm
• If it is necessary to increase accuracy follow-
ing intermediate weighing, it is possible to use
the same test cloth to wipe a further 100 cm²
of surface area of the constructional element
being examined
2
.