3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 The term sorption has been adopted for this test
method, since mineral fiber insulation may absorb water within
its bulk when viewed macroscopically, while it adsorbs water
onto individual fibers on a microscopic scale.
(1) sorption—refers to the taking up and holding of matter
by other matter by various processes such as absorption and
adsorption.
(2) absorption—refers to the taking up of matter in-bulk by
other matter; for example, the penetration of substances into
the bulk of another solid or liquid.
(3) adsorption—refers to surface retention or adhesion of
an extremely thin layer of molecules to the surfaces of solids or
liquids with which they are in contact.
4. Summary of Test Method
4.1 The insulation is dried to a constant weight and exposed
to a high-humidity atmosphere for 96 h. The amount of water
sorbed from the vapor phase is the difference in specimen
weights, and is expressed in either weight or volume percent.
5. Significance and Use
5.1 The sorption of water can result in an increase in weight
and a resultant potential degradation of the properties of the
insulation.
6. Apparatus
6.1 Air-circulating oven, capable of maintaining a temperature
between 102° and 121°C [215° and 250°F].
6.2 Desiccator, with calcium chloride as a desiccant.
6.3 Scale, accurate to 60.1 % of specimen weight.
6.4 Environmental test chamber, capable of maintaining a
temperature of 49 6 2°C [120 6 3°F] and a relative humidity
of 95 6 3 %.