Codes & SafetyQuestion 117 of 120
A trench must be excavated 22 ft deep in Type B soil to reach an existing sewer main. Which statement about the protective system and the excavated material is correct?
a.The standard sloping tables may be used at any depth, and the spoil may be piled at the trench edge to serve as a barrier
b.Sloping is prohibited over 20 ft so only a trench box may be used, and the spoil must be kept 1 ft back
c.The competent person may design the protective system on site at this depth, and the spoil must be kept 5 ft back
d.A protective system for an excavation deeper than 20 ft must be designed by a registered professional engineer, and excavated material must be set back at least 2 ft from the edge
Explanation
The tabulated sloping, benching and shoring options in the standard stop at 20 ft; anything deeper requires a protective system designed by a registered professional engineer. Spoil, tools and other surcharge loads must be kept at least 2 ft from the edge, or retained by a device that prevents material from falling in. Piling spoil at the edge adds load to the very wall that is most likely to fail, so it is never a barrier. A competent person inspects the excavation daily, before each shift and after rainstorms, but cannot substitute his own judgment for the engineered design a 22 ft trench requires.
Practice all 120 questions free — no signup required.
Related questions on this topic
- A crew is setting sewer pipe in a trench 5 ft 6 in deep with vertical walls cut in previously disturbed soil. No sloping, shoring or shielding has been installed. What does OSHA require before a worker enters?
- A trench 7 ft deep with a 3 ft wide bottom is excavated in Type C soil and will be protected by sloping the walls at 1-1/2 to 1. How wide must the excavation be at the top?
- 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?
- Before anyone enters a 12 ft deep sewer manhole classified as a permit-required confined space, the atmosphere is tested and the meter reads 19.2 percent oxygen. What is the correct interpretation, and in what order must the atmosphere be tested?
- A plumber is brazing copper joints in a finished mechanical room with combustible wood framing a few feet away. Which practice meets the fire prevention requirements for the work?
- While replacing a section of galvanized water piping in a building from the 1950s, a plumber finds an adjacent steam line wrapped in crumbling fibrous insulation and sees that the old water joints were made with 50/50 tin-lead solder. What is the correct response?
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against Journeyman Plumber Licensing Exam (UPC/IPC-based) · How we review