A trench shield's tabulated data covers depths up to 12 ft, but the planned pipe run reaches 15 ft in the same soil. What should the superintendent require?
Correct Answer
D) Use a protective system within its tabulated data or obtain a registered professional engineer's design
Protective systems must be used within their tabulated data or be designed by a registered professional engineer for the actual conditions. Other choices rely on an unapproved use or unsafe equipment support.
Why This Is the Correct Answer
Protective systems must be used within their tabulated data or be designed by a registered professional engineer for the actual conditions. Other choices rely on an unapproved use or unsafe equipment support.
Why the Other Options Are Wrong
Option A: Use the box because the difference is only 3 ft
Choice A (Use the box because the difference is only 3 ft) is rejected because Use the box because the difference is only 3 ft uses the wrong excavation protective-system trigger or exception.
Option B: Stack spoil against the box to stiffen it
In site construction, Stack spoil against the box to stiffen it is the wrong selection for Trench shield limitations: the choice would not get the project to Use a protective system within its tabulated data or obtain a registered professional engineer's design, which is the Trench shield limitations result verified by the source.
Option C: Enter only while the excavator holds the shield and leave trench shield limitations unchecked
The trap in C is Enter only while the excavator holds the shield. That selection is wrong because it leaves the work at an informal or incomplete stage, while Trench shield limitations requires Use a protective system within its tabulated data or obtain a registered professional engineer's.; Protective systems must match tabulated data or a registered professional engineer design.
Memory Technique
Use the phrase "problem, control, result" for trench shield limitations; the result side is Use a protective system within its tabulated data or obtain a registered professional engineer's design.
Reference Hint
Open 29 CFR Part 1926, Subpart P - Excavations; use 29 CFR 1926.652(c) to confirm that Protective systems must be used within their tabulated data or be designed by a registered professional engineer for the actual conditions.
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