5.5 Compression set 5.5.1 Test picec Peace cuts and brings it down from 3 molded test peace experimentally and makes it. Refer to Fig.2 for how to cut it out. The size of test piece is 25±1mm in thickness and 50±1mm in width and length. Test piece has not skin layer, and the thickness direction shall be the foaming direction. The mumber of test pieces shall be five.