As you’ll all know, the termination efficiency factor for a hand-spliced cable-laid sling (the splice used to make an eye in a large diameter sling) has been taken as 0.75 since at least the days of the HSE’s PM20 (1987 revision), subsequently superseded by IMCA’s M179 in 2005. Other codes have copied this value including ND’s 0027/ND, HMC’s SC-291, Saipem’s ENG-212, and BS EN ISO 19901-6. Seaway Heavy Lifting (SHL), however, think this value is optimistic – the following just received the following response to a query on why they quoted a termination factor of 0.55 in a design brief:
Based on in-house executed tests on hand-spliced cable-laid slings, SHL has concluded that the efficiency factor for hand-spliced cable laid slings of 0.75 appears optimistic. Therefore SHL conservatively uses an efficiency factor for hand-spliced cable load slings of 0.55.
SHL are outnumbered by the rest of the industry’s codes, and rigging systems have successfully been designed using the larger value for over 25 years. However, as they say that their opinion is based on test results, we should all be aware of it.