Codes & Safety第 116 / 120 题
A trench 5 ft deep and 90 ft long is open, with workers spread along its full length installing pipe. What is the minimum number of ladders required and how must they be placed?
a.Two, placed so that no worker has more than 25 ft of lateral travel to reach a means of egress
b.None, because a ladder is required only in trenches 6 ft deep or greater
c.One, placed at the midpoint of the trench
d.Four, one for every 25 ft of trench length
解析
Trenches 4 ft deep or more need a stairway, ladder, ramp or other safe means of exit located so that a worker travels no more than 25 ft laterally to reach it, so each ladder serves 25 ft in each direction, or 50 ft of trench. Ninety feet therefore needs two ladders, positioned so their 50 ft zones overlap and cover the whole length. The depth trigger is 4 ft, not 6 ft, so doing nothing is a violation. A single ladder at the midpoint leaves workers at the ends 45 ft from egress, and four ladders exceeds what the rule requires.
法律依据: 29 CFR 1926.651(c)(2)免费刷完整 120 道题库 — 无需注册。
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