What is the minimum dimension between projections when a door to a stairway opens on a landing and is flush?

The minimum dimension between projections when a door to a stairway opens on a landing and is flush is established to ensure safety and accessibility. In this case, the choice of 22 inches and 7 inches is based on established building codes that dictate how much clearance is necessary to prevent obstructions that could impede egress or make it difficult for individuals to use the stairway safely.

The 22 inches dimension typically refers to the horizontal space needed to allow a door to open fully without hitting any obstructions, such as walls or other projections. This dimension is crucial for ensuring that the door swings freely in both the open and closed position, allowing for safe passage.

The 7 inches vertical space likely refers to the clearance required above the door or landing to ensure that individuals do not risk hitting their heads when passing through. This height consideration is especially important in maintaining a safe and accessible environment, particularly in emergency situations where quick access is necessary.

The other available options do not meet the minimum safety requirements set forth by building codes, which are designed to protect occupants and ensure that exits remain usable under various conditions. Hence, the required dimensions of 22 inches and 7 inches provide an acceptable standard that supports safe egress in the event of an emergency.