What is the working load limit for a hoisting chain with a minimum breaking strength of 25 tons, after being proof tested to 33,000 pounds?

The working load limit (WLL) for hoisting chains is typically derived from their minimum breaking strength (MBS) and is subject to safety factors that account for dynamic loads and other variables that may affect the chain's performance during use.

In this case, the minimum breaking strength of the hoisting chain is given as 25 tons, which is equivalent to 50,000 pounds (since 1 ton equals 2,000 pounds). The proof test conducted at 33,000 pounds indicates that this is the load the chain could withstand without permanent deformation.

To calculate the working load limit, a common safety factor is applied. For chains, a safety factor of 4:1 is often used. This means that to determine the WLL, you would divide the minimum breaking strength by this factor.

Using the safety factor:

• Minimum breaking strength: 50,000 pounds
• Safety factor: 4

Calculating the working load limit: 50,000 pounds ÷ 4 = 12,500 pounds.

However, the problem provides a proof test load of 33,000 pounds, which is significant. A more conservative approach may consider the proof test load when determining the WLL, but regardless, the final working load