Title: Protective Systems: Sloping, Shoring & Shielding
Type: Lesson
OSHA requires that any trench 5 feet deep or greater must have a protective system in place — unless the trench is entirely made of stable rock (rare). The system used depends on soil type, trench depth, and site conditions.
The trench walls are angled away from the excavation to prevent collapse
Angles vary by soil type:
Type A: ¾:1 slope (53°)
Type B: 1:1 slope (45°)
Type C: 1½:1 slope (34°)
Benching is a stepped version of sloping, but only allowed in Type A or B soil
Requires plenty of space
Uses hydraulic, mechanical, or timber supports to brace trench walls
Prevents soil movement or collapse in deep or unstable trenches
Must be installed from the top down and removed from the bottom up
Common in urban areas where space is limited
A steel or aluminum structure placed in the trench to protect workers
Does not stop cave-ins, but protects workers inside if one occurs
Must be used according to manufacturer specs and properly extended above trench walls
Ideal for repetitive utility work
Trench is 5 feet or deeper
Shallower trenches if conditions are hazardous (e.g., loose soil, water nearby)
Trench is not entirely stable rock
The competent person must determine what system is required and ensure it’s installed properly.
Each site is different. The protective system must match the soil conditions, trench depth, and work duration. No worker should enter a trench over 5 feet deep without protection.
Click “Mark Complete” to continue to Lesson 5: Access, Egress & Hazard Controls, where we’ll cover how to safely enter, exit, and work around trenches.