Section 5.2 of ICEA S-81-570 specifies that insulation tensile strength, elongation at rupture, and retention after air oven aging shall be tested per ANSI/NEMA WC-53 and meet Table 3-2 requirements.
For 75°C rated: initial 2000 psi min tensile, 300% min elongation; after aging 48h at 100°C, 75% retention. For 90°C rated: initial 1800 psi, 250% elongation; after aging 168h at 121°C, 75% retention.