OSHA Excavation Slopes

Type C: 1.5 H : 1 V (3 4^{\circ}) B: 1 H : 1 V A: 0.75 H : 1 V

OSHA soil types A (stable rock/firm clay), B, C (granular/soft). Maximum allowable slopes for excavations < 20 ft. Type C is 1½ H : 1 V. A competent person inspects. Bench, shield, or slope. 5-ft exception with no cave-in hazard.

$H$: Vertical cut height
$S$: Horizontal run per 1 V

Step-by-step solved example

Type C trench 8 ft deep. Minimum horizontal setback of the slope per face?

OSHA slope on Type C soil is 1.5H:1V (34°).

1. Slope
1.5 H : 1 V → run = 1.5×8 = 12 ft each side.

Answer: 12 ft each side

10 practice questions

0/10 correct

1.Type C maximum slope is

2.Type A is the

3.A competent person must

4.Shields (trench boxes) allow

5.The 5-ft deep exception still needs

6.Water in a trench generally

7.Egress (ladder) is required every

8.Spoil piles should be at least

9.Benching in Type C

10.1.5H:1V is an angle of about