What type of construction is required for vertical openings for escalators?

The requirement for non-combustible construction for vertical openings related to escalators is primarily driven by fire safety regulations. Escalators, being a means of egress in commercial buildings, must ensure that they provide a safe passage during emergencies. Non-combustible materials are essential in these scenarios because they do not ignite easily or contribute to the spread of fire, thereby reducing the risk of fire-related hazards.

Using non-combustible materials, such as steel or concrete, helps maintain the structural integrity of the opening and the escalator assembly, even when exposed to high heat. This is critical for ensuring that occupants can safely evacuate the building if necessary.

Other construction types, such as wood frame, do not meet the necessary fire safety standards for vertical openings used by escalators due to wood's combustibility. Steel frame and reinforced concrete could be acceptable under certain circumstances, but they do not inherently prevent fire risks to the same extent as non-combustible materials established by code requirements for escalators. Thus, the emphasis on non-combustible construction reflects the importance of maintaining safety, functionality, and durability in the design of escalator systems within commercial buildings.