ISO 1421:2016 specifies two methods for the determination of the tensile strength of fabrics coated with rubber or plastics. - Method 1 ? the strip test method, which is a method for the determination of tensile strength and elongation at break. - Method 2 ? the grab test method, which is a method for the determination of tensile strength only. The methods apply to test pieces in equilibrium with specific standard atmospheres for testing and to wet test pieces. Both methods require the use of a constant rate of extension (CRE) tensile-testing machine.