Safety第 104 / 110 题
A trench 90 ft long and 6 ft deep requires egress so no worker travels more than 25 ft laterally to a ladder. A ladder placed mid-run protects 25 ft in each direction, or 50 ft total. What is the minimum number of ladders required?
a.1 ladder
b.3 ladders
c.4 ladders
d.2 ladders
解析
Each ladder covers 50 ft of trench (25 ft of lateral travel on each side), so 90 ft / 50 ft = 1.8, which rounds up to 2 ladders. The 25 ft maximum travel ensures rapid exit if a wall fails or the atmosphere changes. Egress is required in any trench 4 ft or deeper and must extend above the top edge.
法律依据: 29 CFR 1926.651免费刷完整 110 道题库 — 无需注册。
同考点相关题目
- A 2,000 lb cast-iron section is lifted by a two-leg sling with each leg at 60 degrees from horizontal. Each leg carries (load / 2) / sin(60 degrees), with sin(60) about 0.866. What is the tension in each sling leg?
- During sewer confined-space work, the attendant outside must maintain what capability?
- A trench 10 ft deep in Type B soil is sloped at 1 to 1 (horizontal to vertical) on both sides. If the trench bottom is 3 ft wide, how wide is the excavation at the top?
- Before servicing a sewage ejector pump, the plumber must control hazardous energy. What procedure prevents the pump from starting during service?
- On a California jobsite, a trench 5 ft or deeper in which workers will enter also requires a specific state permit beyond federal rules. What is that requirement?
- Cutting and grinding cast iron or concrete for a plumbing penetration generates respirable crystalline silica. What is the primary control the plumber should use?