When is it necessary to refer to shop drawings during lifting operations?

Referring to shop drawings during lifting operations is crucial for determining the allowed angles for lifting lines. Shop drawings provide specific details regarding the construction and design of the components being lifted, including information about weight distribution, lift points, and any necessary rigging requirements. These details are essential for ensuring that the load is lifted safely and efficiently while minimizing the risk of accidents or equipment failure.

By consulting the shop drawings, lifting crews can verify the manufacturer's specifications and ensure that the lifting equipment is set up correctly to avoid potential hazards associated with lifting operations. This consideration is vital for maintaining safety standards and ensuring that the operation complies with the relevant safety regulations and guidelines.

In contrast, the other options relate to different aspects of project management and inspection that do not directly impact the immediate lifting operation, such as checking a completed product, scheduling production, or managing personnel, which do not require detailed technical information from shop drawings.