I thought OSHA was 4’ before you had to step the soil back or angle the trench based on soil type.
The drawing appears to be for type A soil. Type B soil would be 4 feet. Plus I think the illustration is strictly pointing out the location of a load in relation to the edge of the trench.
I think these numbers are correct it’s been a long time since I was a certified competent excavator. I haven’t been in a trench in a long time
All depends on soil type, moisture content, and compaction on depth, but any steps width should be at least 50% of the depth. So a step at 4 ft should be at least 2ft wide.
OSHA training for me was a long time ago as well, I just had 4’ stuck in my head and to not enter a trench that is deeper.
Yep I remember everything had to do with soil type and condition of the soil, and that things can change and be reclassified for safety as conditions change.
OSHA considers a trench at 4 foot or greater. There are also other considerations like width.
You may want to read this. 20 years ago I knew a plumbing apprentice that broke his back in a 3’ “trench” after it collapsed. After that all trench workers became competent workers.