ISO 844 is used to investigate the compressive behavior of cellular plastics for determining the compressive strength, compressive strength at pre-defined deformations, compressive modulus, and other aspects of the compressive stress/strain relationship under the conditions defined.

In principle, the test specimen is centrally positioned between the two parallel anvils then compressed along its major axis at a constant rate of displacement until the specimen has deformed as a percentage of the specimen's original height. For this test type, we use the preload feature of  Software to determine the anvil height. The load sustained by the specimen is measured during this procedure. To record the test it is important to have a high speed intelligent test data logging rate. This is the transfer rate to the PC of 100Hz or more to capture and record all data.