Synthetic Web Sling Inspection Guide (Nylon & Polyester)
How often to inspect nylon and polyester flat web slings, what damage to look for, and when a web sling must come out of service, based on OSHA 1910.184 and ASME B30.9. A sling that is worn or damaged can fail without warning, so a quick, consistent inspection before every use is the best protection for your crew and your load.
Safety first: Inspect every sling, with all its fastenings and attachments, each day before use, and remove damaged or defective slings from service immediately. This guide is a summary; always follow the sling manufacturer’s instructions and the current OSHA 1910.184 and ASME B30.9 requirements.
On this page: When to inspect · Who inspects · How to inspect · Removal criteria · Tags · Rejected slings · Records · FAQ
When to Inspect
ASME B30.9 sets three levels of inspection for nylon and polyester web slings.
Initial
Before first use, inspect every new, altered, modified or repaired sling to confirm it is correct, undamaged and properly tagged. No written record is required.
Frequent (daily)
Each shift, before the sling is used, do a visual check for damage. Slings in severe or special service should be checked before each use. No written record is required by ASME.
Periodic
A complete inspection of the entire sling, including splices and fittings, at least once a year. ASME guideline intervals: normal service yearly; severe service monthly to quarterly; special service as recommended by a qualified person. Document the most recent periodic inspection.
Slings in storage or sitting idle do not need periodic inspections, but if more than a year has passed since the last one, give the sling a full periodic inspection before putting it back in service.
Who Should Inspect
OSHA requires daily inspections by a competent person designated by the employer: someone trained to recognize sling damage and authorized to take a sling out of service. ASME B30.9 says inspections are performed by a designated person, and any deficiency is evaluated by a qualified person, who decides whether it is a hazard and approves any sling before it goes back into service.
How to Inspect, Step by Step
- Check the tag first: it must be present and legible and show the rated capacities and the webbing material. Confirm the rating suits the load and hitch.
- Lay the sling out flat in good light.
- Look at and feel both faces and both edges along the full length. Some damage is easier to feel than to see.
- Check the eyes and the load-bearing stitching closely; this is where slings take the most stress.
- Look for cuts, holes, snags, burns, melted or charred spots, knots, abrasion, and stiff or discolored areas. On slings with red warning yarns, look for any red showing.
- Inspect any fittings for pitting, corrosion, cracks, bends, twists, gouges or breaks.
- If you find any removal condition, tag the sling “Do Not Use” and take it out of service.
Removal Criteria
Check both faces and both edges of the webbing, the eyes, the load-bearing stitching and any fittings. OSHA does not allow nylon or polyester web slings to be used above 180°F, nylon around acids or phenolics, or polyester around caustics.
Remove the sling from service if you find:
- Missing or illegible sling identification
- Acid or caustic burns
- Melting or charring of any part of the sling
- Holes, tears, cuts or snags
- Broken or worn stitching in load-bearing splices
- Excessive abrasive wear
- Knots in any part of the sling
- Discoloration and brittle or stiff areas, which may mean chemical or ultraviolet (sunlight) damage
- Fittings that are pitted, corroded, cracked, bent, twisted, gouged or broken
- Any other condition that causes doubt about continued use
Red core warning yarns: many web slings are made with red warning yarns inside the webbing. If yours has them, any red showing through the surface means the sling is worn through and must be removed. This is a manufacturer feature, not an ASME requirement, so check the manufacturer’s instructions for your slings.
Before you replace a sling, check the rating you need: see our nylon sling capacity chart or shop nylon slings.
Missing or Illegible Tags
Every sling must carry permanently affixed, legible identification. OSHA prohibits using a sling without it, and ASME B30.9 lists a missing or illegible tag as the first removal criterion. Without the tag, nobody can confirm the rated load. OSHA requires web slings to be marked or coded with the rated capacity for each type of hitch and the type of web material.
What to Do With a Rejected Sling
- Remove it from service immediately and tag it “Do Not Use.”
- Store it apart from slings in service so it cannot be picked up by mistake.
- A qualified person decides whether the sling can be repaired. It may not return to service until a qualified person approves it.
- Repaired web slings must be proof tested to twice the rated capacity before reuse, and temporary repairs are not allowed (OSHA).
- If the sling will not be repaired, destroy it so it cannot be used again.
When in doubt, take it out.If you are not sure a sling is safe, do not use it. Remove it from service and set it aside for a qualified person.
Record Keeping & Printable Checklist
- OSHA: keep the proof test certificate (to twice the rated capacity) for every repaired web sling.
- ASME B30.9: keep documentation that the most recent periodic inspection was performed. Written records are not required for initial or frequent (daily) inspections, and individual inspection records for each sling are not required.
- Good practice: give every sling an ID, and log daily checks so removed slings are tracked. Our one-page printable checklist lists every removal criterion with a code and has a daily log.
Frequently Asked Questions
How often should nylon and polyester web slings be inspected?
Each day (each shift) before use, by a competent person designated by the employer, plus a documented periodic inspection at least once a year, or monthly to quarterly in severe service (ASME B30.9).
What temperature can a web sling be used at?
OSHA does not allow nylon or polyester web slings to be used at temperatures above 180°F. Melting, charring or other heat damage means the sling must be removed.
Should I use nylon or polyester around chemicals?
OSHA does not allow nylon web slings where acids or phenolics are present, or polyester web slings where caustics are present. Acid or caustic burns on any web sling mean it comes out of service.
What do red yarns showing on a web sling mean?
On slings made with red core warning yarns, visible red means the webbing is worn through and the sling must be removed. Check the manufacturer’s instructions, since not every web sling has warning yarns.
Other inspection guides: Chain slings · Wire rope slings · Round slings
Questions about a sling or need a replacement? Call (706) 750-9099.
Sources: OSHA 29 CFR 1910.184, Slings; ASME B30.9-2021, Slings. This guide summarizes those requirements and does not replace them.