Framing & StructuralQuestion 453 of 700
On an open stair with a guard, the triangular opening formed by the tread, riser, and bottom rail is limited so that what size sphere cannot pass through?
a.A 4-inch-diameter sphere
b.A 5-inch-diameter sphere
c.A 6-inch-diameter sphere
d.An 8-inch-diameter sphere
Explanation
For the special triangular opening at the tread, riser, and bottom guard rail, the code allows a slightly larger limit: a 6-inch sphere must not pass. The general 4-inch sphere applies to other guard openings, while 5- and 8-inch limits are not recognized values for this location.
Law Reference: 2025 CA Residential Code §R312.1.3Practice all 700 questions free — no signup required.
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