Excavation Protective System and Egress Triggers (OSHA Subpart P)

Whether an excavation requires a protective system at all -- and the two triggers sit at DIFFERENT depths, in the order people get backwards. Egress (1926.651(c)(2)) bites at 4 FT or more, within 25 ft of LATERAL travel. Cave-in protection (1926.652(a)(1)) bites at 5 FT, unless the dig is entirely in stable rock. So a 4.5 ft trench needs a ladder and may need no shoring at all. The other trap: that under-5-ft exception has TWO conditions, not one -- under 5 ft AND examined by a competent person with no indication of a cave-in. Depth alone exempts nothing. Also counts egress points over a run, since 25 ft each way means one ladder covers 50 ft. OSHA is public domain, so the text is quoted.

a means of egress is required where depth >= 4 ft, within 25 ft of lateral travel, so with each point serving 25 ft in each direction the count is max(1, ceil(trench length / 50)); cave-in protection is required unless the excavation is entirely in stable rock OR depth < 5 ft AND a competent person has examined the ground with no indication of a potential cave-in.

OSHA 29 CFR 1926.651(c)(2) and 1926.652(a)(1), Subpart P - Excavations. US federal regulations in the public domain, quoted directly.

29 CFR is published in full at no cost by OSHA and the eCFR.

Estimate. AHJ and licensed professional govern.

Field names used by the API: depth_ft, trench_length_ft, egress_points, stable_rock, competent_person_exam, max_lateral_travel_ft, egress_points_needed, worst_travel_ft

• Egress trigger trench excavations 4 ft or more in depth29 CFR 1926.651(c)(2)
• Lateral travel no more than 25 ft, measured along the trench29 CFR 1926.651(c)(2)
• Point spacing each point serves 25 ft each way, so one covers 50 ft of runarithmetic on the travel limit
• Cave-in trigger required unless entirely in stable rock, or under 5 ft AND examined29 CFR 1926.652(a)(1)
• Two conditions the shallow exception needs both depth and examination - depth alone exempts nothing29 CFR 1926.652(a)(1)
• Not determined which protective system, soil class, PE approval, inspections, water, utilitiesstated scope limit