1.1 This International Standard specifies methods for testing flexible and semi-rigid cellular plastics made from polyethylene. Cellular plastics containing copolymers of ethylene or blends of polymers with polyethylene may also be tested by the procedures of this International Standard provided these materials have characteristics similar to polyethylene as described in ISO 1872-1, or copolymers of ethylene as described in ISO 4613-1. 1.2 Mandatory tests suitable for characterization of cellular polyethylene, regardless of end use, are described in Clause 7. Optional tests for the determination of properties that are relevant to certain uses are described in Clause 8.