The competent person selects a simple sloped system for Type B soil in an excavation under 20 ft deep. Which maximum slope ratio matches OSHA Appendix B?
Correct Answer
A) 1 horizontal to 1 vertical
OSHA Subpart P Appendix B Table B-1 lists the maximum allowable simple slope for Type B soil as 1 horizontal to 1 vertical. Other choices are Type A, Type C, or a flatter project-specific slope.
Why This Is the Correct Answer
OSHA Subpart P Appendix B Table B-1 lists the maximum allowable simple slope for Type B soil as 1 horizontal to 1 vertical. Other choices are Type A, Type C, or a flatter project-specific slope.
Why the Other Options Are Wrong
Option B: 3/4 horizontal to 1 vertical
The trap in B is 3/4 horizontal to 1 vertical. That selection is wrong because 3/4 horizontal to 1 vertical is a different drainage slope than the pipe size in the item; the accepted slope is 1 horizontal to 1 vertical; Type B simple slope is 1H:1V for excavations less than 20 ft deep.
Option C: 1-1/2 horizontal to 1 vertical
Choice C gives 1-1/2 horizontal to 1 vertical. Its specific error: 1-1/2 horizontal to 1 vertical is a different drainage slope than the pipe size in the item; the accepted slope is 1 horizontal to 1 vertical. The accepted answer is 1 horizontal to 1 vertical.
Option D: 2 horizontal to 1 vertical
Choice D (2 horizontal to 1 vertical) is rejected because 2 horizontal to 1 vertical is a different drainage slope than the pipe size in the item; the accepted slope is 1 horizontal to 1 vertical. The cited answer is 1 horizontal to 1 vertical.
Memory Technique
Treat type B soil slope like a labeled shelf; only the matching condition belongs with 1 horizontal to 1 vertical.
Reference Hint
Open 29 CFR Part 1926, Subpart P - Excavations; use 29 CFR 1926 Subpart P Appendix B, Table B-1 to confirm that OSHA Subpart P Appendix B Table B-1 lists the maximum allowable simple slope for Type B soil as 1 horizontal to 1 vertical.
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