This paper addresses the safe use of lifting slings and tie down straps in the field. From time to time, web straps used as lift slings or tie down devices fail in service. The appearance of the failed portion of the web provides insight into the cause of the strap failure and provides physical evidence of the pre-failure condition of the strap. The safety analysis consists of a technical literature review, research of applicable safety standards and guidelines, results of testing of slings and straps to failure in a variety of initial conditions, and evaluation of the appearance of the straps after testing. The paper presents an evaluation of the effect on breaking strength of the web or sling of various intentionally-applied cuts to the material, and an appraisal of the post-test appearance as it relates to the pre-test condition. Furthermore, comparisons using macroscopic and microscopic techniques are made of the failed surfaces of the tested slings and straps to products that are known to have failed during field applications. The results presented in this paper make a significant contribution to the technical literature concerning the safety and failure prevention of industrial sling and strap products.
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