Protective Systems

Trenching & Excavation — from the Anvil & Co. course library. What you will learn: • Choose sloping, benching, shoring or shielding. • Understand soil types A, B, C and stable rock. Key points: • Required at 5 feet or deeper unless in stable rock; under 5 feet if a competent person sees cave-in potential. • Maximum allowable slopes (Appendix B): Type A 3/4:1 (53°), Type B 1:1 (45°), Type C 1-1/2:1 (34°). • Trench boxes and shoring follow the manufacturer's tabulated data — keep it on site. • 20 feet or deeper: design by a registered professional engineer. Scenario: You're digging an 8-foot sewer trench in previously disturbed soil (Type C). The box is too short. What are your options?