The peel test is identified as a destructive test for heat shrink sleeves because it assesses the bond strength and integrity of the sleeve when it is subjected to a force that attempts to separate it from the substrate. By applying a controlled amount of force to peel the sleeve away, inspectors can determine whether the adhesive and the shrinkable material have adequately adhered to the surface they are protecting. This test ultimately provides insight into the performance of the sleeve under actual service conditions.
The peel test is considered destructive because it compromises the integrity of the heat shrink sleeve itself—once the test is performed, the sleeve can no longer serve its intended function. This is in contrast to non-destructive tests, which evaluate quality without damaging the product. For example, holiday detection at a low voltage, visual inspection, and physical inspection do not involve breaking the sleeve or reducing its protective capabilities, making them non-destructive methods. Thus, while those methods evaluate other aspects of sleeve performance, they do not provide a measure of adhesive strength like the peel test does.