Resilience of polyurethane foam is determined by dropping a metallic sphere on a slab of foam kept on a horizontal surface from a height of 500 mm and finding the height to which it rebounds after striking the surface of foam.
The Ball Resilience Tester for polyurethane foam consists of a flat horizontal platform, a vertical acrylic tube in which the sphere is dropped, and a hand operated arrangement to release the sphere from a pre-determined height.
The platform on which the test specimen is kept also forms the base of the equipment. It has four leveling screws to make it horizontal.
The acrylic tube is held over the base with the help of a holding block, which can be moved vertically to adjust the height of the tube to enable test specimens of different thicknesses to be tested. This adjustment is carried out with the help of a screw so that the height of the tube can be precisely set. The tube is held firmly after adjustment so that it does not rock during the test.
ASTM D 3574 â€“ 1986 : Standard Methods of Testing Flexible Cellular Materials â€“ Slabs, Bonded, and Molded Urethane Foam
ISO 8307 â€“ 1990 : Flexible Cellular Polymeric Materials â€“Determination of Resilience