For roof-mounted equipment in HVHZ, what is the minimum leg height required for equipment with a width of 42 inches?

• A. 12 inches
• B. 18 inches
• C. 24 inches
• D. 30 inches

Answer: (C)

In HVHZ, rooftop equipment must sit on legs that elevate the unit a safe distance above the roof to help with flashing, drainage, and securing the unit against wind uplift. The required leg height is determined by the equipment’s width: wider equipment needs more clearance to allow proper flashing and to prevent base moisture issues while still providing a solid mounting foundation.

For a piece of equipment that is 42 inches wide, the standard calls for a minimum leg height of 24 inches. This height ensures there’s enough clearance for correct flashing installation and for robust anchorage, while meeting the wind resistance requirements appropriate for a larger, wider unit. The smaller height options would not provide adequate clearance for a unit of this width, while a 30-inch height isn’t the required minimum for this width category.