Guardrails and window fall protection

Where guards are requiredR312.1.1#

A guard is required on any walking surface, stair landing, deck, porch, or raised floor located more than 30 inches above the floor or grade below, measured within 36 inches horizontally from the edge.

Guard heightR312.1.2#

Guards on walking surfaces must be at least 36 inches high, measured vertically from the adjacent walking surface.

Guards on the open side of stairs must be at least 34 inches, measured vertically from the sloped plane connecting the tread nosings. The difference between stair guard and landing guard heights is a common plan-check catch.

Opening limitsR312.1.3#

Required guards must not have openings that allow the passage of a 4-inch-diameter sphere from the walking surface up to 34 inches.

On the triangular opening formed by the stair riser, tread, and bottom rail, openings must not allow the passage of a 6-inch sphere.

From 34 inches up to 36 inches on a guard, openings must not allow the passage of a 4-3/8-inch sphere.

Window fall protectionR312.2#

Operable windows with a sill height less than 24 inches above the finished floor and with the exterior of the window more than 72 inches above the grade below must either limit the opening to 4 inches or have a fall prevention device that meets ASTM F2090.

Fixed windows and windows that meet the egress escape opening requirements are still subject to the fall protection rule when the sill height condition applies.

Common inspection flags#

Frequent failure points:

• Stair guard set at 36 inches instead of 34. Not a failure, but landing-to-stair height transitions get caught when the geometry is wrong
• Baluster spacing greater than 4 inches at any point in the guard
• Open triangles at the bottom of a stair guard wider than 6 inches
• Upper-story windows with low sills missing fall protection