This standard specifies how to determine the compressive residual strain, moist heat compressive residual strain, and cyclic compressive residual strain of flexible foam materials. However, the method for determining compressive residual strain and repeated compressive residual strain applies only to flexible polyurethane foam and flexible latex foam.
2004JIS K 6400-4:2004 Flexible cellular polymeric materials -- Determination of physical properties -- Part 4: Compression set and fatigue characteristics