What is the primary purpose of having both a warning device and a prevention system for two-block conditions?

The primary purpose of having both a warning device and a prevention system for two-block conditions is to ensure maximum safety. Two-blocking occurs when the hook or other lifting attachment makes contact with the crane's boom, which can lead to significant damage or catastrophic failure. Installing a warning device alerts the operator to an impending two-block condition, allowing for timely corrective actions. Meanwhile, a prevention system serves to stop the crane's motion before a two-block condition occurs, thereby eliminating the risk altogether.

This layered approach to safety, incorporating both warning devices and prevention systems, is vital in minimizing the potential for accidents and injuries on the job site. While other options may pertain to operational efficiency or regulatory compliance, the foremost objective in crane operation should always be the protection of workers and equipment from harm.