Slings requirements and definitions

The slings standard covers slings made from alloy steel chain, wire rope, metal mesh, natural or synthetic fiber rope (conventional three‑strand), and synthetic web (nylon, polyester, polypropylene). Employers should apply the requirements in 1910.184(a) to those sling types when used for hoisting material.

• Cite: Scope in 1910.184(a).

"Angle of loading" means the inclination of a leg or branch of a sling measured from the horizontal or vertical plane; angles within 5° of vertical may be treated as vertical. Employers must use the angle of loading to determine sling forces and capacity as shown in the standard figures. See the definition in 1910.184(b).

• Use the diagrams in the standard figures to determine how sling leg angles change load on each leg.

A sling must be removed from service whenever it is damaged or defective and cannot be used safely. Employers must follow the removal-from-service requirement in 1910.184(c)(1) and ensure that damaged slings are not used until repaired or reconditioned by an authorized entity.

• Examples of defects include broken wires, worn links, badly worn webbing, or deformed fittings; see specific inspection criteria in 1910.184(d).

No — slings shall not be shortened with knots, bolts, or other makeshift devices. This prohibition is stated in 1910.184(c)(2).

• Use only manufacturer‑approved shortening methods or properly designed and rated hardware; makeshift alterations can reduce sling capacity and create hazards.

No — sling legs shall not be kinked. Kinks weaken the sling and are specifically prohibited by 1910.184(c)(3).

• Remove any kinked sling from service and have it inspected or repaired by a competent party before reuse.

You must not load a sling in excess of its rated capacity as given by the sling manufacturer and as required by 1910.184(c)(4) and 1910.184(c)(13).

• Check the sling’s permanently affixed identification marking for rated capacity before each lift.
• Consider hitch type, sling angle, and load balance when calculating actual load on each sling leg (see angle/figures in 1910.184(b)).

When using a sling in a basket hitch, you must balance the load to prevent slippage. The basket hitch requirement is in 1910.184(c)(5).

• Make sure the load is positioned and secured so it cannot shift or slide out of the sling during lifting; use appropriate chocks, dunnage, or hardware if needed.

Slings shall be securely attached to their loads and shall be padded or otherwise protected from sharp edges of the load as required by 1910.184(c)(6) and 1910.184(c)(7).

• Use edge protectors, dunnage, sleeves, or other protective devices where the sling contacts sharp or abrasive surfaces to prevent cutting, chafing, or abrasion that could reduce sling strength.

Employees must be kept clear of suspended loads and the area around loads about to be lifted; all employees shall be kept clear as required by 1910.184(c)(8) and 1910.184(c)(9).

• Establish and enforce exclusion zones and use taglines or signal persons to avoid placing workers under or near suspended loads.

No — hands or fingers shall not be placed between the sling and its load while the sling is being tightened around the load, per 1910.184(c)(10).

• Use hooks, spreader bars, or tools to adjust and tighten slings so personnel do not have to place their hands in pinch points.

No — shock loading is prohibited and you must not pull a sling from under a load when the load is resting on the sling, as specified in 1910.184(c)(11) and 1910.184(c)(12).

• Plan lifts to avoid sudden starts/stops and never use the sling as a pry bar or to drag a load from under another object.

Yes — employers must not use slings without affixed and legible identification markings, as required by 1910.184(c)(14).

• Identification should show rated capacity, size, grade, and reach (for alloy chain slings see 1910.184(e)(1)).

A competent person designated by the employer must inspect each sling and its attachments daily before use, with additional inspections during use as warranted, per 1910.184(d).

• Daily visual checks look for cuts, broken wires, worn components, deformations, and missing identification.
• Remove defective slings immediately from service.

Alloy steel chain slings must have permanently affixed durable identification stating size, grade, rated capacity, and reach as required by 1910.184(e)(1).

• Keep identification legible; if it becomes unreadable, take the sling out of service until re‑identified by the manufacturer or qualified entity.

Attachments (hooks, rings, links, coupling links, etc.) must have a rated capacity at least equal to the chain or the sling’s use must be limited to the weakest component; makeshift links or fasteners made from bolts or rods are prohibited, per 1910.184(e)(2)(i) and 1910.184(e)(2)(ii).

• Use only properly rated, manufacturer‑approved attachments—never jury‑rig bolts or rods as replacements.

Alloy steel chain slings must receive a thorough periodic inspection at intervals determined by use frequency, service severity, nature of lifts, and experience, and in no case less often than once every 12 months; the inspection must be done by a competent person designated by the employer, per 1910.184(e)(3)(i)–(iii).

• The employer must keep a record of the most recent month each chain sling was thoroughly inspected as required in 1910.184(e)(3)(ii).

A thorough inspection must include checking for wear, defective welds, deformation, and increase in length; slings with such defects must be immediately removed from service as stated in 1910.184(e)(3)(iii).

• Examples include worn links beyond allowable limits, cracked or broken welds, bent or stretched links, and elongation of chain beyond manufacturer tolerances.

Yes — each new, repaired, or reconditioned alloy steel chain sling (including welded components) must be proof tested by the sling manufacturer or an equivalent entity in accordance with ASTM A391‑65 (referenced in 1910.184(e)(4)), and the employer must retain and make available the proof test certificate as required by 1910.184(e)(4).

• Keep proof test certificates with your safety records so they are available for inspection.

You must permanently remove an alloy steel chain sling from service if it has been heated above 1000 °F, and if exposed to service temperatures above 600 °F you must reduce the sling’s maximum working‑load limits in accordance with the chain or sling manufacturer's recommendations, per 1910.184(e)(6).

• Document the manufacturer’s temperature‑degradation guidance and any load‑rating reductions applied.

If an attachment (hook, ring, link, etc.) has a lower rated capacity than the chain, the sling shall not be used in excess of the rated capacity of the weakest component as required by 1910.184(e)(2)(i).

• Either replace the weak attachment with a properly rated component or reduce the permissible working load to match the weakest link.

Employers must make and maintain a record of the most recent month in which each alloy steel chain sling was thoroughly inspected and make that record available for examination, per 1910.184(e)(3)(ii); daily inspection findings should be done by a competent person under 1910.184(d).

• Records need not be lengthy, but should identify the sling and the month of the last thorough inspection.

A competent person designated by the employer must perform the daily and the thorough periodic inspections; the thorough periodic inspection for alloy chain slings must be done by such a competent person as specified in 1910.184(d) and 1910.184(e)(3)(iii).

• Competent person means someone the employer designates who has the knowledge and authority to identify hazards and take corrective action.

When sling legs are more than 5° off vertical you must consider the actual angle of loading to determine the load on each leg, using the figures in the standard; angles within 5° of vertical may be treated as vertical, per 1910.184(b) and the illustrated figures in the standard.

• Use the applicable load‑angle multiplier tables/figures in the standard to compute leg loads and ensure the sling rating is not exceeded.

No — makeshift links or fasteners formed from bolts, rods, or similar items shall not be used on slings as stated in 1910.184(e)(2)(ii), and slings shall not be shortened with knots or makeshift devices per 1910.184(c)(2).

• Such improvised hardware is not rated and can fail catastrophically; always use manufacturer‑rated components.

The sling manufacturer or an equivalent entity must perform proof testing of each new, repaired, or reconditioned alloy steel chain sling, and the employer must retain the proof test certificate and make it available for examination as required by 1910.184(e)(4).

• Keep certificates with equipment records or safety files so they can be produced during inspections.

The standard requires that contact surfaces (bending or bearing surfaces) have a minimum diameter of curvature relative to rope diameter to avoid excessive bending stress; refer to the illustrated guidance in the figures included with 1910.184(b) and the figures (e.g., N‑184‑5).

• For wire rope slings, the contact surface diameter must be at least 8 times the rope diameter in some configurations; consult the figures and manufacturer recommendations for specific minimums.

They must not be used until they are repaired, and if welding or heat testing was done the sling must be repaired, reconditioned, and proof tested by the sling manufacturer or an equivalent entity before being returned to service. See 1910.184(e)(7)(i).

• If welding or heat testing is performed, the standard requires a proof test by the manufacturer (or equivalent) before initial use. See also 1910.184(f)(4)(ii) regarding certificates for proof tests.

No — mechanical coupling links or low carbon steel repair links must not be used to repair broken lengths of chain. See 1910.184(e)(7)(ii).

• Use only approved repair methods and qualified repairers such as the sling manufacturer or an equivalent entity.

You must remove the chain from service if the chain size at any point of the link is less than the minimum values listed in Table N-184-1. See 1910.184(e)(8).

• Inspect links for wear and measure the link thickness; compare to the minimum allowable sizes in Table N-184-1 in the standard.
• If any link is below the table value, take the entire sling out of service.

Alloy steel chain slings must be removed from service if they have cracked or deformed master links, coupling links, or other components. See 1910.184(e)(9)(i).

• Any visible crack or permanent deformation of attachments requires immediate removal from service until repaired by an authorized entity.

Slings must be removed from service if hooks are cracked, opened more than 15 percent of the normal throat opening measured at the narrowest point, or twisted more than 10 degrees from the plane of the unbent hook. See 1910.184(e)(9)(ii).

• Measure the throat opening at its narrowest point to determine percentage of opening.
• Measure twist angle relative to the original plane; >10° requires removal.

Wire-rope slings must have permanently affixed, legible identification markings that show the recommended safe working load for the hitch(es) used, the angle it’s based on, and the number of legs if more than one. See 1910.184(f)(1).

• Do not use slings without this permanent identification from the manufacturer.

Minimum clear lengths depend on the construction: cable laid and 6×19 and 6×37 slings need 10 times the rope diameter between splices/sleeves/end fittings; braided slings need 40 times the rope diameter between loops or end fittings; grommets and endless slings must have a circumferential length of 96 times their body diameter. See 1910.184(f)(2)(i), 1910.184(f)(2)(ii), and 1910.184(f)(2)(iii).

• Measure rope diameter accurately and verify clear length between fittings or splices.

Fiber-core wire rope slings of all grades must be permanently removed from service if exposed to temperatures in excess of 200 °F. See 1910.184(f)(3).

• For nonfiber-core slings used above 400 °F or below −60 °F, follow the sling manufacturer's recommendations.

Welding of end attachments (except covers to thimbles) must be done before assembly of the sling, and all welded end attachments cannot be used unless proof tested by the manufacturer or equivalent at twice their rated capacity prior to initial use; the employer must keep the proof-test certificate available. See 1910.184(f)(4)(i) and 1910.184(f)(4)(ii).

• Keep proof-test certificates with your safety records and make them available for inspection.

Wire rope slings must be immediately removed from service for any of these: ten randomly distributed broken wires in one rope lay or five broken wires in one strand in one rope lay; one-third loss of outside wire diameter due to wear; kinking, crushing, birdcaging or structural distortion; evidence of heat damage; cracked, deformed or worn end attachments; hooks opened >15% or twisted >10°; or corrosion of rope or end attachments. See 1910.184(f)(5).

• Inspect slings before use and remove any that meet these criteria.

Each metal mesh sling must have a durable marking stating the rated capacity for vertical, basket, and choker hitches; handles must have a rated capacity at least equal to the metal fabric and show no deformation after proof testing; and handles must be attached so the sling's rated capacity isn't reduced, the load is evenly distributed, and sharp edges won't damage the fabric. See 1910.184(g)(1), 1910.184(g)(2), and 1910.184(g)(3).

• Do not use mesh slings missing durable rated-capacity markings.

New and repaired metal mesh slings (including handles) must be proof tested by the manufacturer or equivalent at a minimum of 1½ times their rated capacity before use, and non-impregnated metal mesh slings may be used between −20 °F and +550 °F without reducing working load; elastomer-impregnated slings have narrower temperature limits. See 1910.184(g)(5) and 1910.184(g)(7).

• Follow manufacturer recommendations for any operation outside these ranges.

After repair, you must either permanently mark or tag the sling or keep a written record showing the date, nature of repairs, and who did them; those repair records must be made available for examination. See 1910.184(g)(8)(ii).

• If the manufacturer repaired the sling, document that and retain proof for inspections.

Fiber-rope slings must have permanent, legible identification showing rated capacities, hitch angles, fiber type, and number of legs; they may be used between −20 °F and +180 °F (except wet frozen slings); splices must meet specific tuck and tail-length requirements; and only slings made from new rope are permitted—repaired or reconditioned fiber rope slings are prohibited. See 1910.184(h)(1), 1910.184(h)(2), 1910.184(h)(3), and 1910.184(h)(6).

• Follow the detailed splice tuck counts and tail-lengths in 1910.184(h)(3)(i)–(vii).
• Do not use knotted or reconditioned fiber rope slings.

For fiber rope splices, strand end tails must not be trimmed flush; for ropes under 1 inch diameter the tail must project at least six rope diameters beyond the last full tuck, and for ropes 1 inch or larger the tail must project at least six inches; eye splices must provide an included angle not greater than 60 degrees at the splice when placed over a load or support. See 1910.184(h)(3)(iii) and 1910.184(h)(3)(vii).

• If the tail interferes with use, the standard allows tapering and splicing back with at least two extra tucks (which increases the required tail length).

Natural and synthetic fiber rope slings must be immediately removed from service for abnormal wear; powdered fiber between strands; broken or cut fibers; variations in strand size or roundness; discoloration or rotting; or distortion of hardware. See 1910.184(h)(5).

• Inspect slings regularly and remove any that meet these criteria.

Synthetic web slings must be marked or coded to show rated capacities for each hitch and web material, and fittings must have a minimum breaking strength equal to that of the sling and be free of sharp edges that could damage the webbing. See 1910.184(i)(1) and 1910.184(i)(3).

• Do not use slings with fittings that could cut, chafe, or otherwise damage the webbing.

End fittings and eyes must be attached only by stitching (not other methods), with a thread pattern and number of stitches sufficient to develop the sling's full breaking strength; and nylon slings must not be used where acids or phenolics are present while polyester/ polypropylene slings must not be used where caustics are present. See 1910.184(i)(4) and 1910.184(i)(6).

• Inspect stitching and fittings; do not expose web slings to incompatible chemicals.

Synthetic web slings repaired must be repaired only by a sling manufacturer or equivalent, proof tested by that entity to twice the rated capacity before returning to service (and the employer must keep the proof-test certificate), temporary repairs are prohibited, and slings must be removed immediately for acid/caustic burns, melting/charring, snags/tears, broken or worn stitches, or distorted fittings. See 1910.184(i)(8)(i), 1910.184(i)(8)(ii), 1910.184(i)(8)(iii), and 1910.184(i)(9).

• Keep repair and proof-test documentation available for inspection.
• Do not rely on temporary field fixes for web slings.

Metal mesh slings must be removed from service for a broken weld or brazed joint; reduction in wire diameter of 25% due to abrasion or 15% due to corrosion; lack of flexibility from distortion; handle distortions beyond specified limits (depth increased >10%, eye width decreased >10%); a 15% reduction in original cross-sectional area around the handle eye; or distortion of handles out of plane. See 1910.184(g)(9).

• Measure wire diameter and handle dimensions against original specifications to determine removal thresholds.