Wood platform planks on a scaffold are supported at each end. Where planks are overlapped rather than butted, the overlap must occur over a support and extend at least how far past the centerline of the support?

Giải thích

Correct: overlapped planks must overlap only over a support and extend at least 12 inches beyond the support's centerline (unless cleated or otherwise restrained). A 2- or 6-inch overlap risks the plank sliding off. 24 inches is more than required and, at the far end, a plank should not extend excessively past a support (generally no more than about 12-18 inches unless designed) to avoid a tipping/see-saw hazard.