ISO 844:2026

This document specifies methods for determining the compressive strength, the corresponding compressive strain, the compressive stress at 10% nominal compressive strain, and the compressive modulus of rigid cellular plastics.

Two procedures are specified. Procedure A and Procedure B.

Procedure A utilizes the compression plate displacement for the nominal property determination. It is used to determine:

• compressive strength and the corresponding nominal compressive strain;
• compressive stress at 10% nominal compressive strain;
• nominal compressive modulus.

Procedure B uses an extensometer and determines the conventional properties. It is used to determine:

• compressive strength and the corresponding compressive strain;
• compressive modulus.