Lifting slings are used in areas like commercial crane services and the material handling industry to move things like heavy rigging equipment and machinery. Sling types can be endless, single, two, three or four leg. Regardless of type they should be inspected yearly for normal service use, and monthly to quarterly for severe service use.

This can vary depending on if you’re using wire rope slings, industrial chain slings, or one of the other materials they can be made from. When it comes to polyester lifting slings though you have to be especially careful. Here are five physical factors that can negatively impact these kind of lifting slings.

1. Repeated Rubbing: The primary cause of durability issues in lifting slings is usually a result of load edge movement against sling. Especially at high temperatures, polyester can be damaged from the constant cutting of load’s sharp edge.
2. Improper Loading: It should go without saying, but not correctly loading a piece whether through shock loading, unbalanced loading, over loading, or inadequate consideration of angle will drastically shorten the lifespan of standard lifting slings.
3. Foreign Substances: There are plenty of things that can find their way onto a sling. Oil, metal chips, spatter from welding, spilled chemicals, or any other foreign substance should be cleaned off immediately.
4. Ultraviolet Light: In addition to the temperature of the environment, the sheer exposure to UV rays can do a great deal of damage too. You’ll know if your lifting sling has been adversely affected in this way if it starts to look bleached and becomes stiff. Keep in mind the sun isn’t the only culprit, arc welding emits these rays as well.
5. Angle of Sling: Sling angle is the angle measured between a horizontal line and the sling leg or body. As this angle decreases, the load on each leg increases. This can play a huge role in the overall integrity of a sling and its rated lift capacity.

These are just a few of the things to watch out for when maintaining your polyester lifting straps/slings. Follow the recommendations of the sling manufacturer when you use metallic-core wire rope slings of any grade at temperatures above 400 degrees F or below minus 40 degrees F.