How is the minimum headroom for a stairway defined?

The minimum headroom for a stairway is defined as the clear vertical space above the stair treads and is measured from the sloped plane adjoining the tread nosing. This standard ensures that individuals using the stairs will have adequate vertical space to prevent head injuries while ascending or descending. The measurement begins at the nosing of the treads, which is the part of the step that protrudes the farthest, and extends upward to the nearest obstruction, such as a ceiling or a beam.

This definition is important because it establishes a safe environment for stair usage, thereby promoting accessibility and safety in building design. Adhering to this standard helps prevent accidents that can occur when users misjudge headroom, particularly in residential and commercial constructions where stairways are commonly used.