The tolerance between the largest and smallest riser height or tread depth in any flight of stairs shall not exceed how many inches?

• A. 1/2
• B. 3/8
• C. 1/4
• D. 1/8

Answer: (B)

The correct answer indicates that the tolerance between the largest and smallest riser height or tread depth in any flight of stairs must not exceed 3/8 inches. This requirement is established to ensure safety and accessibility in stair design. Uneven riser heights or tread depths can create tripping hazards, particularly for individuals who may have mobility issues or are less steady on their feet.

By maintaining a tolerance of only 3/8 inches, the building code promotes a more consistent and predictable walking surface, which is crucial in preventing accidents. This standard helps to create a uniform experience for users, making stairs safer and more navigable.

Other options suggest different tolerances, which could allow for greater discrepancies in riser heights or tread depths. Allowing a larger tolerance could lead to increased risks of tripping and falling, as small variations become more pronounced, especially in situations with poor visibility or when individuals are carrying objects. Thus, the selection of 3/8 inches aligns best with safety principles in stair design as outlined in the building code.