OSHA Trench Sloping

Maximum slope ratio per soil class A/B/C and benching geometry.

Run the calculator

Example

You enter

Trench depth (ft) 8
Soil class B
Surcharge near trench false

You get

Setback per side 8.00 ft
Top width (2 ft floor) 18.00
Bench height 4.0 ft

Details, formula, and sources

Maximum allowable slope ratio (H:V) per OSHA 29 CFR 1926.652 and Appendix B: Type A 0.75:1, Type B 1:1, Type C 1.5:1. Benching geometry per Appendix B Figure B-1.1.

OSHA 29 CFR 1926 Subpart P and Appendix B by section.

Free at ecfr.gov.

Estimate. AHJ and licensed structural engineer govern.

Field names used by the API: depth_ft, soil_class, surcharge, max_horizontal_ft, top_width_ft, bench_height_ft

Soil-class table data/crosswalks/osha-trench.json29 CFR 1926 Appendix B