For a single step on the aerial ladder, what are the minimum design load and minimum surface area?

• A. 400 pounds and 80 square inches
• B. 500 pounds and 100 square inches
• C. 600 pounds and 120 square inches
• D. 500 pounds and 120 square inches

Answer: (B)

Aerial ladder steps are designed to handle the weight of a climber plus gear with a safety margin, while giving enough footing area to prevent slipping under dynamic loading as you climb. The minimum design load must cover a person in turnout gear plus equipment, including the extra force that can occur when shifting weight or pausing on the step. The minimum surface area ensures there is enough footprint for stable footing and traction, distributing the load over a sufficient area.

Therefore, the smallest values that meet these safety requirements are a design load of 500 pounds and a surface area of 100 square inches. Higher values would still be acceptable but are not the minimum.