I’m always on the look out for evidence of equipment which isn’t of an acceptable standard and not long ago a member sent me a couple of endless webbing slings which aroused my interest. They bore the names of two different manufacturers, but looked very similar. Both were marked ‘ESLINGA UN SOLO USO’. They had been in use in a steel stockholder in the UK and one had clearly been loaded over a sharp edge and cut through.
The basic story is simple enough. They came from Spain on a pre-slung cargo of steel and, after arrival, had continued in use at the stockholder. The details are rather more disturbing and the consequences could have been very serious.
If you haven’t already guessed, ‘ESLINGA UN SOLO USO’ is Spanish for what we would call a one trip sling: a sling intended for a single journey of the load. Thirty years ago there was a British Standard for one trip webbing slings but it has long since been withdrawn. When the harmonised European standards for textile slings were being developed, the committee considered drafting a standard for one trip slings, but decided against doing so. The reasons for this will soon become apparent.
The legal context
European legislation does not prohibit one trip slings. However, the UK Machinery Directive 98/37/EC does require, as a general rule, a working coefficient (ie factor of safety) of 7, ‘provided the materials used are shown to be of very good quality and the method of manufacture is appropriate to the intended use. Should this not be the case, the coefficient is, as a general rule, set at a higher level in order to secure an equivalent level of safety.’ This requirement is embodied in CEN standard EN 1492-1: 2000. The legislation also requires the manufacturer to provide instructions for use which should deal with the intended use and also address foreseeable misuse. The slings in question here were CE marked, indicating compliance with the Directive. However, they only claimed a factor of 5:1, so quite how the CE marking could be justified is unclear. The weave of the webbing was very loose, an indication that the material is not of good quality, and no protection against sharp edges (such as an additional sleeve) was provided.
The only possible argument in favour of a one trip sling over a standard sling is the cost saving. The idea is that, with a very limited life, there is no need for any allowance for wear. Consequently, the factor of safety (or working coefficient as it is now known) can be lower. However it is worth considering exactly how a one trip sling is used, particularly for handling steel. At the initial point of despatch, the sling is attached, the load lifted and transferred onto transport. During this operation, one must hope that the sling isn’t positioned over a sharp edge. If it is, one must again hope that some packing is used to protect it. And when it is landed, there is a real risk of damage if the sling is trapped under the load. At the next stage of the journey, it will be lifted again; with luck any packing is still in place and the sling hasn’t been damaged by the cargo shifting in transport. And so it progresses through the various stages of the journey. A so-called ‘single trip’ can in fact comprise many different lifting operations.
Unlike a normal slinging operation, there is no incentive for the slinger to ensure that the sling is not trapped under the load as it doesn’t have to be recovered and there is no opportunity to check the sling for damage before attempting the next lift. The chances of it wearing out might be very low but the risk of it being damaged at some stage of the trip is high. If anything, it needs to be more robust and resistant to abuse than a normal sling.
In the case of the Spanish slings, these risks were compounded by fundamental failings in both their manufacture and use. As manufactured, irrespective of their intended use, they fell short of the both the legal requirements and the harmonised standard. We know that they were intended for single use, but not whether they were intended for slinging steel. If this was the case, they were not suitable as they lacked both the strength and sharp edge protection clearly needed. Furthermore, having arrived in the UK with the cargo, the employer who received them either didn’t know or didn’t care that they were one trip slings. The employer allowed them to be used further, with the result that one failed. All in all, a combination of events which could have had tragic consequences at several stages.
Ironically, good quality webbing slings are, size for size, inherently amongst the most economical of sling types to buy. Any attempt to shave the cost down even further by lowering quality is a false economy. The risk to life and limb notwithstanding, the potential loss arising from dropping a load of steel can be very high. The potential gain was at best a few pounds in cash.
