What is the minimum design factor required for a boom hoist rope?

The minimum design factor required for a boom hoist rope is 3.5. This design factor ensures that the rope can handle the dynamic loads and stresses it may encounter during operation, including the weight of the load being lifted, as well as additional factors such as wind, momentum, and sudden halts.

A design factor of 3.5 means that the rope is tested and constructed to withstand at least three and a half times its expected maximum load. This extra safety margin accounts for variances in loading conditions and contributes to overall operational safety. Such a factor is necessary to prevent failure under unforeseen circumstances or extreme conditions.

In contrast, the other options represent design factors that are below the safety standards required for boom hoist ropes in crane operations. These lower factors would not provide the necessary strength and safety assurance when lifting heavy loads or during dynamic movements. Thus, relying on a design factor less than 3.5 could lead to increased risk of rope failure and potential accidents on the job site.