What is the maximum rise for alternating tread devices between floor levels or landings?

The maximum rise for alternating tread devices between floor levels or landings is established to ensure safety and accessibility. The correct answer, which indicates a limit of 20 feet, is designed to balance functionality and safety in building design.

Alternating tread devices serve as a space-saving alternative to traditional staircases, making them suitable for areas where space is limited. However, due to their unique design, which can be steeper than standard stairs, regulations impose a height limit on how far they can extend between two levels.

A limit of 20 feet allows for reasonable ascent without excessive strain on individuals using these devices. Beyond this height, the risk of falls and the physical demands on users increase significantly, making it vital to have additional safety measures in place or to consider a traditional stair configuration.

This standard ensures that while alternating tread devices can be utilized effectively, they still adhere to safety guidelines that protect individuals in commercial buildings.