Proof Test of Alloy Chain Sling
Chain Sling: an assembly consisting of alloy steel chain joined to upper and lower end components for attaching loads to be lifted by a crane or lifting machine.
Proof Testing Defined
Proof testing is a quality control test where a load is applied to a sling. For chain slings this is usually twice the working load limit or rated load. This is done to assure that each and every part of that sling is more than capable of performing at the working load limit before it is put into service.
Proof Test Requirements
Safety standards for chain slings, such as the Occupational Health and Safety Organization (OSHA) 1910.184 and the American Society for Mechanical Engineers (ASME) B30.9 on “Slings” require that all parts of a chain sling must have been proof tested prior to the sling being put into service. Performance specifications, such as the American Society for Testing and Materials (ASTM) A 952/A 952M “Standard Specification for Grade 80 and Grade 100 Chain Slings” also have this requirement.
Proof Testing of chain slings is an industry standard and an important part of providing a quality product.
It is allowed by these standards to assemble a sling out of parts that have all been previously proof tested and not proof test the final assembled sling. However, it is an added measure of safety and quality assurance and a good practice to proof test all chain slings in their final assembled condition. You should check with supervisor or employer as to your company’s policy.
Along similar lines, all repairs to a chain sling need to be proof tested prior to being returned to service. The safety standards mentioned earlier only require the repaired areas to be proof tested, but like a new sling, it is again a good practice to proof test the entire repaired sling.