The CFR requires that when materials are dropped more than how many feet outside the exterior walls of a building, an enclosed chute be used?

The correct requirement outlined in the Code of Federal Regulations (CFR) states that when materials are dropped from a height greater than 20 feet outside the exterior walls of a building, an enclosed chute must be utilized to ensure safety on construction sites. This regulation is designed to minimize the risk of injury to workers and bystanders from falling materials, which can cause significant harm if they are dropped from heights.

Using an enclosed chute provides a controlled pathway for materials being moved downward, effectively containing the debris and preventing accidents related to falling objects. This measure is crucial in maintaining a safe work environment, particularly in construction zones where multiple workers and activities may be in close proximity. The specification of 20 feet reflects an understanding of the potential danger associated with such heights and the necessity for appropriate safety measures.