Polyester slings had their origins in the Scandinavian countries and began making their way to the Western Hemisphere in the mid-seventies. There is a unique advantage endless polyester roundslings have over eye and eye configuration slings. The endless configuration is more versatile because the connection and load contact points can be rotated, enhancing sling service life. Another key advantage for polyester round lifting slings is that many slings can be made simultaneously.
Due to the manufacturing efficiencies, polyester slings will generally be less expensive than nylon rigging straps. Because the body of polyester roundslings is comprised of multiple windings of polyester yarn, the sling body is soft and supple. The supple body prevents the polyester roundsling from locking to the load or binding at the point of choke when polyester round slings are used in a choker hitch. Slings are color coded, but never rely upon color to determine roundsling strength.
Slings Safety Practices
Sling capacity must be indentified from its identification tag. The outer sheath which encapsulates the load carrying yarns on polyester round slings is a double wall thickness material. Polyester round slings are provided with a contrasting color inner sheath to alert the user that the outer cover has been breached.
Remember, when you see inner load carrying yarns, you cannot use the sling. An outer bulked nylon cover can also be provided which is four times more abrasion resistant than normal polyester covers. If you see undamaged yarn it is not allowed to repair it. Slings must be protected from ultraviolet during storage.
How to store slings
When your nylon lifting slings, polyester round slings are not in use, store them in a dark, dry, cool location that is free from mechanical and environmental damage. Slings produced from 1 000 kg. to 40 000 kg. rated vertical capacities. Polyester round lifting slings can be made from 0.5 m to over 45 m in length. The sling length for polyester roundslings is always measured from one end or bearing point of the sling to the other.