By how many inches must a ladder or steps in window wells not encroach into the required dimensions of the window well?

A ladder or steps in window wells must not encroach into the required dimensions of the window well by a specific measurement to ensure safety and functionality. The correct answer is 6 inches because this clearance is established to allow for the safe operation of the window well as an emergency escape route. The guideline is to ensure that occupants can exit safely in case of an emergency without obstruction from ladders or steps, which could impede egress.

Having a 6-inch clearance provides sufficient space for individuals to maneuver in the window well, reducing the risk of entrapment or injury. This dimension helps ensure that the window well meets the necessary life-safety codes and is functional for its intended purpose.

The other choices do not provide enough clearance to guarantee safe egress, which is critical in the design and use of window wells in commercial buildings.