Injury Illness Prevention Plan - Flipbook - Page 191
Health and Safety Program Manual
Teamwrkx
Construction, Inc.
Issue Date: 10/16/23
Revision Date: 10/16/23
Trenching and Excavation
Reference: A-15
Maximum allowable slopes for excavations less than 20' based on soil type and angle to the horizontal are as
follows:
Soil Type
Type B
Type C
Height/depth ratio
1:1
1 1/2:1
Slope angle
45 degrees
34 degrees
A 10-foot-deep trench in Type B soil would have to be sloped to a 45-degree angle or sloped 10 feet back in
both directions. Total distance across a 10-foot-deep trench would be 20 feet, plus the width of the bottom of
the trench itself. In Type C soil, the trench would be sloped at a 34-degree angle, or 15 feet back in both
directions for at least 30 feet across, plus the width of the bottom of the trench itself. All simple slope
excavations 20 feet or less in depth shall have a maximum allowable slope of 1 1/2:1.
Benching
9