When is it generally unsafe to lift a load in windy conditions?

Lifting loads in windy conditions can pose significant safety risks for both the load being lifted and the personnel involved. The generally accepted threshold for safe lifting in windy conditions is typically around 20 mph. At this speed, wind can create instability for the load, especially if it is large or has a large surface area, which may cause it to sway or become uncontrollable.

When wind speeds reach or exceed this threshold, it can compromise the crane's ability to maintain control over the load. Documentation from various safety standards, including those from organizations like OSHA and ANSI, often specifies this as a safe limit.

Additionally, the impact of wind can vary based on crane type, load characteristics, and the surrounding environment, reinforcing the importance of adhering to the 20 mph guideline. Operators must consistently evaluate wind conditions before commencing lifts to ensure safety.

Each of the other options presents higher wind speeds which are more likely to escalate the risks involved in lifting operations. For effective operational safety, understanding and adhering to the recommended limits is crucial.