BS EN ISO 844Rigid cellular plastics - Determination of compression properties
ISO 844 specifies a method of determining a) the compressive strength and corresponding relative deformation, or b) the compressive stress at 10 % relative deformation, and c) when desired, the compressive modulus of rigid cellular plastics.
There are two procedures:
Procedure A employs crosshead motion for determination of compressive properties. Procedure A is intended to be used when compressive stress at 10 % relative deformation has to be determined.
Procedure B employs strain measuring devices mounted on the specimen (contact extensometer) or similar device which measures directly sample deformation. Procedure B is intended to be used when compressive modulus has to be determined.
Before conducting ISO 844, it is important to read the entire specification. Standards can be obtained from appropriate standard authorities.