Testing Physical Characteristics of Foams

Unless otherwise specified, 12 mm(1/2 in.) thick plywood or 14 mm (5/8 in.) waferboard sheets are used for the standard sample preparation. It may be convenient to spray on a [1.2 m X 1.2 m(4 ft X 4 ft)] sheet and cut this sheet into smaller specimens just before performing the actual tests. During the foam application, ambient temperatures should be close to room conditions, namely 24 ± 4°C (74 z 6°F), and the relative humidity should be in the range of 30% to 80% RH. Spray about 25 mm (1 in.) foam layer on the central 1 m (3 1 /2 ft) part ofthe sheet and rotate the sheet.’2 Then, apply either an approximately 60 mm(2 1/2 in.) thick layer for tests ofHD-type or an approximately 80 mm (3 1/4 in.) thick layer for tests on MD-type or LD-type foams. The thickness of a