ISO 527-4 is an international testing standard for determining the tensile properties of fiber-reinforced plastic composites.  ISO 527-4 covers test conditions for isotropic and orthotropic non-unidirectional composites and refers to ISO 527-1.

The methods are used to investigate the tensile behavior of the test specimens and for determining the tensile strength, tensile modulus, Poisson's ratios and other aspects of the tensile stress-strain relationship under the defined conditions.

The test method is suitable for use with the following materials:
Fiber-reinforced thermosetting and thermoplastic composites incorporating non-unidirectional reinforcements such as mats, woven fabrics, woven rovings, chopped strands, combinations of such reinforcements, hybrids, roving, short or milled fibers or prepregs.