Subpart P: Excavations
Excavation requirements
Subpart P, 1926.650–1926.652, requires a competent person to inspect excavations daily and after rain or other changes. Utilities must be located before digging. Protective systems-sloping, benching, shoring, or shielding-are required for excavations 5 feet or deeper unless the competent person determines there is no hazard, and for shallower excavations with hazards. Trenches 4 feet or deeper need a means of egress within 25 feet of lateral travel.
Soil and spoil
Soil must be classified as Type A, B, or C. Type C soil is the least stable and requires a 1.5H:1V slope if sloping is used; Type B is 1H:1V; Type A is 0.75H:1V. Spoil piles and equipment must be kept at least 2 feet from the edge. Water accumulation must be controlled, and hazardous atmospheres must be tested where oxygen deficiency or toxic gas may exist.
Worked example
A 6-foot trench is dug in Type C soil. The competent person cannot classify it as stable; a protective system is required. If the crew slopes, the slope must be at least 1.5 horizontal to 1 vertical. If there is no room to slope, a trench shield or shoring system must be used, and the crew needs a ladder within 25 feet.
Traps
The protective-system trigger is 5 feet, not 4 feet. The 2-foot spoil-pile rule is measured from the edge, not the bottom. A ladder is required at 4 feet, not 5 feet. A competent person cannot waive the requirement for a protective system without a documented determination.