Heavy Equipment Industry News Updates

The term ‘textile sling’ encompasses slings made from fibre rope and webbing and those of endless roundsling construction. Natural fibre rope is by far the oldest lifting medium and, although its popularity has declined, there is still a current standard for manila, sisal and hemp fibre rope slings. Natural fibres have largely been superseded by manmade fibres such as polyamide, polyester and polypropylene. The harmonised European standard for both natural and man-made fibre rope slings is EN 1492-4.
Size for size the strength varies according to the type of fibre. Hemp and sisal are of similar strength and are the weakest. In ascending order, the others are manila, polypropylene, polyester and polyamide (usually known as nylon). Nylon is approximately two and a half times as strong as grade 1 manila of the same diameter. Polypropylene rope has the advantage that it will float in water.
Natural fibres are susceptible to rot and mildew in damp conditions and are not suitable for most chemical environments. Manmade fibres are immune from rotting but have varying resistance to chemicals. Manmade fibre ropes have varying resistance to chemicals as follows:

• Polyamide (nylon) is virtually immune to alkalis but it is attacked by moderate strength acids. It loses up to 15% of its strength when wet.
• Polyester is resistant to moderate acids but is damaged by alkalis.
• Polypropylene is affected little by acids and alkalis but damaged by solvents.

All fibre ropes are prone to deterioration at high temperatures. Manmade fibres rarely show a sharp melting point. They will either soften over a range of temperatures or they will char or decompose before melting. Generally textile slings should not be used above 80°C or below 0°C without consulting the supplier.
Fibre rope slings are soft compared to chain and wire rope and are therefore less likely to damage the surface of a load. However they can easily be cut if loaded over a sharp edge or corner without adequate packing and the length of a fibre rope sling cannot be adjusted.
Fibre rope slings are amongst the cheapest types of sling although other types of textile sling are very competitive and becoming more so. Some users regard them as disposable and replace them every six months rather than have them thoroughly examined.