Sling Safety:  Don’t be the Weak Link

By Renee Witherspoon, MS, CSP, CIH, CHMM, South Plains Chapter President

Deformation in a chain link found during inspection.

Being able to move materials safety and efficiently is key to a successful  job.  Everyone responsible for handling or moving materials from one location to the other should be familiar with the hazards especially if they have to rely on a sling.  Whether it is a chain sling, web sling or a rope sling, a sling is a tool, like other tools must be inspected and maintained in good working condition for it to work safely.Having good equipment is important, but knowing how to rig a load safely can save a life.   Good riggers are sometimes not appreciated as they should be.  They have many technical skills, such as being able to calculate weight distributions, understand load tables and hitch types, read engineering drawings, understanding of structural dimensions of a load and how it might affect the surrounding area, and a very important skill – being able to think fast on their feet so that they can avoid a possible accident.

If you have a job that requires a sling to move materials, a well-trained rigger is the key for a safe and efficient job. Although riggers have specific training and experience, everyone can learn to recognize the hazards of slings and attachments.

OSHA Standards for Slings

Since employees of states, cities and counties are exempt from OSHA coverage, it is a good policy that all public-sector employers follow the OSHA standards as a minimum.  For slings and rigging the OSHA requirement can be found in Title 29 of the Code of Federal Regulations (CFR) 1910.184.  Since OSHA has not updated this regulation significantly since it was introduced in 1975, sling manufacturers have relied on the American Society of Mechanical Engineers (ASME) standard B30.9-2010 for current standards and specifications.

Whenever any sling is used, OSHA standards require the following safe operating practices:

  • Damaged or defective slings shall not be used.
  • Slings should not be used without affixed and legible identification markings.
  • Slings shall not be loaded in excess of their rated capacities.
  • A sling must not be loaded in excess of its recommended safe working load as required by the sling manufacturer on the identification markings permanently affixed to the sling.
  • Slings shall be securely attached to their loads.
  • Slings used in a basket hitch shall have the loads balanced to prevent slippage.
  • A sling shall not be pulled from under a load when the load is resting on the sling.
  • Slings shall not be shortened with knots or bolts or other makeshift devices.
  • Slings shall be padded or protected from the sharp edges of their loads.
  • Sling legs shall not be kinked.
  • Hands or fingers shall not be placed between the sling and its load while the sling is being tightened around the load.
  • Suspended loads shall be kept clear of all obstructions.
  • All employees should be kept clear of loads about to be lifted and of suspended loads.
  • Shock loading is prohibited.

OSHA requires that slings be inspected “each day before being used” and that inspection must include all fastenings and attachments including shackles, hooks, rings and links.  OSHA also requires additional inspection during sling use.  If damaged or defective slings are found, they must be immediately removed from service.  All of these inspections according to OSHA must be completed by the employers “competent person”.

The OSHA “Competent Person”

How do you know if you are a “competent person” by the OSHA standard?  According to the definition, a competent person is someone who is capable of identifying a hazard either an existing hazard or predicting a potential hazard, in a working area that may endanger employees.  Importantly, the OSHA competent person must be able to take prompt corrective action if necessary.

Types of Slings

There are six basic types of slings:

  1. alloy steel chain
  2. wire rope
  3. metal mesh
  4. natural or synthetic fiber rope
  5. synthetic web
  6. synthetic round

Each has its advantages and disadvantages.  Choosing the best sling for the job takes not only training but experience by a well-trained rigger.   Here is a brief summary of some of the key inspection items for each type of sling.

Alloy Steel Chain Inspections

All alloy steel chain slings should have an identification tag with its size, grade, rated capacity and reach.  Common with all sling inspections;  if there’s no tag or legible marking – don’t use the sling.  Inspections should include a thorough examination for wear, defective welds, deformation and an increase in length.  As part of the maintenance of a chain sling, a written inspection should be completed at least once every 12 months.

Wire Rope Sling Inspections

As with the alloy steel chain inspections, wire-rope slings should have permanently affixed and legible identification markings that show the recommended safe working load for the type of hitch(es) used. Inspections for wire rope should include examination for broken wires, wear, kinking, crushing, corrosion, bird caging or any other damage or distortion of the wire rope structure or end attachments.  Hooks that have been opened more than 15 percent or twisted more than 10 degrees should be taken out of service.

Metal Mesh Sling Inspections

Metal mesh slings are used in metalworking and other industries where the loads are hot, abrasive or could possibly cut a synthetic sling, so we may not see this type of sling in common use.   If your organization uses them, the inspection is similar to the other types of slings.  Each metal mesh sling has a permanently affixed marking that has the rated capacity for hitch loadings.  Inspections should include examination for broken welds or brazed joints along the sling edge, lack of flexibility due to distortion of the mesh material and distortion of either handle.

Natural and Synthetic Fiber Rope Slings

Fiber rope slings as with the other types of slings have permanently affixed and legible identification marking stating the rated capacity, as with the wire rope slings, with the types of hitch(es) used and the angle upon which is it based.  The identification marking will also have the type of fiber material and number of legs if more than one.  Inspections should include examination for abnormal wear, broken or cut fibers, powdered fiber between strands, discoloration, rotting or distortion of the hardware in the sling.

Synthetic Web Slings

Web slings are marked or coded to show the rated capacities for each type of hitch and type of web material.  Inspections should include examination of the webbing to make sure it is of uniform thickness and width with selvage edges in good condition and not split, melted or charred, broken or worn stiches, snags, punctures, tears or cuts.  Fittings should also be free of distortion or sharp edges that may cut the webbing.

Since work with hazardous chemicals is typical in water and wastewater operations, care needs to be taken as nylon slings can be damaged where acids are present and polyester or polypropylene slings can be damaged where caustics are present.  If web slings have aluminum fittings these can also be damaged by chemical vapors or liquids present in the area.

Synthetic Round Slings

Interestingly OSHA does not specifically cover round slings in its regulations.  Since there is not a specific OSHA regulation, general rules for sling inspection would apply.  Round slings are typically made of polyester tubing and color coded for size reference.   Each sling is marked to show the rated capacity, type of hitches, material and number of legs if more than one.  Inspections should be similar to that of fiber ropes and web slings looking for any abnormal wear, broken or cut fibers, powdered fiber between strands, discoloration, rotting or other distortion.

Conclusion

There is a sling for each operation, each has its advantages and disadvantages but it takes a trained person to not only do the inspections, but to actually move the material safely without damaging materials or having an injury.

A well trained rigger can prevent costly accidents and avert a possible tragedy.  Learning how to rig safely is a skill, and should not be performed by untrained operators.  So if you move materials or equipment learn what it takes to become a “competent person” in rigging, so that you are not a weak link in safety.

References: 

OSHA Regulation 29 CFR 1910.184

Guidance on Safety Sling Use, US Department of Labor OSHA

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