Performance Characteristics of Webbing

Nylon
The most widely used general purpose synthetic web sling, is
unaffected by grease and oil. It has good chemical resistance
to aldehydes, ethers, and strong alkalis; but is not suitable
for use with acids and bleaching agents or at temperatures in
excess of 194 degrees F (90º C). Stretch at rated capacity is approximately 8-10%.

Polyester
Used mainly where acid conditions are present or a minimum stretch is desired, polyester is unaffected by common acids and hot bleaching agents. It is not suitable for use with concentrated sulfuric acids, alkalis or at temperatures in excess of 194 degrees F (90º C). Stretch at rated capacity is approximately 3% (untreated).

Calculating Load Factors

When you lift a load with a leg or legs of a sling at an angle, you can calculate the load per leg and the slings rated capacity by using the following formula example:
1) Total Load is 1,000 lbs., divided by 2 legs = 500 lbs. (load per leg)
2) Suppose sling angle is 60º
3) Multiply 500 lbs. x 1.154 (load factor from table) = 577 lbs. (actual load per leg)
You will need a sling rated at 1,154 lbs. in basket capacity to safely lift this 1,000 lb. load.

Inspection Frequency
Three important factors need to be
reviewed to determine your sling
inspection frequency:
• Sling Usage: The more frequently
sling is used, the more often it
requires inspection.
• Use Environment: The harsher
the working environment the sling
is used in, the more often it
requires inspection.
• Sling Service Life: Base your
conclusions on your previous
experience in using slings.
The individual handling your slings
should visually inspect all slings before each lift. Additional inspections
should be made at least once a year
by a qualified individual, and permanent records should be kept.
OSHA mandates that “Each day before being used, the sling and all
fastenings and attachment shall be
inspected for damage or defects by
a competent person designated by
the employer. Additional inspections
shall be performed during sling use,
where service conditions warrant.”

Replacement Guidelines

If you see damage such as the following listed below, remove slings (including roundslings) immediately from service. Return them to service only when approved by a qualified individual. Following are the removal criteria established by ANSI B30.9:

1. Acid or caustic burns.
2. Melting or charring of any part of the sling.
3. Holes, tears, cuts or snags.
4. Broken or worn stitching in load-bearing splices.
5. Excessive abrasive wear.
6. Knots in any part of the sling.
7. Excessive pitting or corrosion, or cracked, distorted or broken fittings.
8. Signs of Ultraviolet (UV) light degradation.
9. Other visible damage that causes doubt as to the strength of the sling.

In addition, Safeway Sling USA recommends four other important reasons to remove slings from service:
1. If you see our Red Core warning yarns.
2. Distortion of the sling.
3. The sling has an identification tag that is in any way unreadable.
4. Anytime a sling is loaded beyond its rated capacity, for any reason.

While these standards are quite specific regarding reasons for removal, others require your good judgement and common sense. Critical areas to watch are wear to the body of the sling, the selvage edge of the webbing, and the condition of the eyes.