Standard
STD 420-0003
Volvo Group
Version
1
Page
2
1 Scope
This standard specifies a test method which is intended to determine the fogging characteristics of materials that
are used in the interior of motor vehicles.
The method may also be applicable to fluid, pasty, powdered or solid raw materials which are the basis for such
materials or from which the materials are manufactured. The method may also be applicable to other materials and
finished products.
The procedure is applicable to the measurement of fog condensate on glass surfaces within the limits of the test
conditions. This test will not measure or cannot measure reflectometer values accurately in those cases where:
-
the surface tension of the condensate is low, resulting in early coalescing into a thin transparent film;
-
the condensate is present in such a large quantity that the droplets coalesce and form a heavy/clear film
(this heavy film gives false reading). In these cases, the gravimetric method is preferred.
2 Principle
A test piece is heated in a glass beaker. Any volatile constituents are condensed on either a cooled glass plate or a
disc of cooled aluminium foil.
Method F: The fogging value F is the ratio, expressed in per cent, of gloss before and after the fogging test. The
gloss is measured with a glossmeter with a 60
°
measuring angle.
Method G: The fogging value G is the mass of the condensation on the aluminium foil, i.e. it is the difference,
expressed in mg, between the masses of the aluminium foil before and after testing.
3 Materials
3.1 Thermal-transfer fluid,
for the thermostatically controlled bath. The fluid shall be temperature-stable and
preferably water-soluble for easier cleaning. A suitable fluid is a modified polyhydric aliphatic alcohol.
A fluid of this type is marketed by BASF under the brand Heizenbadfluessigkeit.
3.2 Glass-cleaning detergent,
of non-alkaline type (alkaline washing-up detergent corrodes the glass and thus
affects the result).
3.3 Diisodecyl phthalate (DIDP),
available from the stated source.
Reference liquid DIDP shall be obtained from:
The Swedish National Testing and Research Institute (SP)
Materials Technology
P.O. Box 857
SE-501 15 BORÅS
SWEDEN
Fax: +46 33 16 53 16
E-mail:
It is permissible to buy DIDP from other suppliers than the Swedish National Testing and Research Institute (SP)
but the supplier must then quality assure his testing procedure by buying DIDP from the Swedish National Testing
and Research Institute (SP) and perform acceptence tests in accordance with sections 6.1.3 and 6.2.3. In order to
comply with the requirements, the test results must be within the specified tolerances of ISO 6452.
3.4 Test fluid
for checking the cleanliness of the glass plate shall consist of a methanol-water mixture containing
27,1 % of methanol (PA quality) and 72,9 % of distilled water by volume and having a surface tension of 46 mN/m
calculated according to Fowkes Theory. About 1 g of a soluble red dye (e.g. fuchsin) can be added to 1 litre of the
test fluid for easier detection.
