A lifting strap or an endless sling is usually made from a synthetic material. In general, the specified working load is 14.3% of the breaking force. This means that the maximum guaranteed load which can be absorbed by the lifting strap or endless sling is factor 7.
Lifting straps or endless slings are available in a variety of different designs made from synthetic materials. The colour of the label indicates what the material is for the load-bearing fibres. For example, a green label stands for Polyamide (PA), a blue one for Polyester (PES), and brown for Polypropylene (PP).
The most common material used for lifting straps and endless slings is polyester (blue).
Often, a lifting strap or an endless sling is stitched along its length by a black wire. This wire stands for 1 ton. For a 3-ton strap or sling, there are three black wires along its length.
How to use straps/slings
The user is required to inspect the lifting straps and endless slings on a regular basis. If in any doubt, call in an expert from the EKH. The use of lifting straps and endless slings can be influenced by a number of factors:
- Straps made of synthetic material have a temperature range of between -40 to +100 C.
- Wet slings and straps that have become frozen should never be used.
- Corrosive acids and lyes affect the strength of polyester straps and slings.
- Longer periods of exposure to sunlight can have a negative effect on the strength of synthetic straps and slings.
- Sand and cement can increase the amount of wear and tear. Often the fibres cannot easily be cleaned.
Accidents normally result from a combination of factors. By assessing each factor individually and taking appropriate measures, the chance of an accident with lifting gear can be reduced. Negative influences:
The weight of the load to be lifted is not known
Lifting straps or endless slings are
- soiled by sand, cement, grease
- in contact with paint, chemical substances
- improperly stored (not suspended)
- aged due to excessive exposure to UV light
- without a label
- at the end of their operational life
Advice: never take any risks. Especially if the lifting gear is no longer in a proper condition, this should not be used.
Lifting straps and endless slings which have one or more defects must be rejected immediately and dispensed with:
- The working load, quality of material and manufacturer’s name is no longer designated
- External damage, such as incisions and damage to the edges, broken stitching, chemical corrosion due to e.g. paint, the negative action of welding spatters and heat
Testing of lifting straps and endless slings
Lifting slings and endless slings are only inspected if, after inspection, there is no indication of the residual strength or the lifespan of the synthetic lifting strap or endless sling.