Injury Illness Prevention Plan - Flipbook - Page 192
Health and Safety Program Manual
Teamwrkx
Construction, Inc.
Issue Date: 10/16/23
Revision Date: 10/16/23
Trenching and Excavation
Reference: A-15
There are two basic types of benching, single and multiple, which can be used in conjunction with sloping.
All benched excavations 20 feet or less in depth shall have a maximum allowable slope of 1:1.
In Type B soil, the vertical height of the benches must not exceed 4 feet. Benches must be below the maximum
allowable slope for that soil type. In other words, a 10-foot-deep trench in Type B soil must be benched back 10
feet in each direction, with a maximum of a 45-degree angle.
Benching is not allowed in Type C soil.
Shoring
Shoring or shielding is used when the location or depth of the cut makes sloping back to the maximum allowable
slope impractical. There are two basic types of shoring, timber, and aluminum hydraulic.
Hydraulic shoring provides a critical safety advantage over timber shoring because workers do not have to enter
the trench to install them. They are also light enough to be installed by one worker; they are gauge-regulated
to ensure even distribution of pressure along the trench line; and they can be adapted easily to various trench
depths and widths. However, if timber shoring is used, it must meet the requirements of 29 CFR 1926.650, .651,
and .652.
All shoring shall be installed from the top down and removed from the bottom up. Hydraulic shoring shall be
checked at least once per shift for leaking hoses and/or cylinders, broken connections, cracked nipples, bent
bases, and any other damaged or defective parts.
The top cylinder of hydraulic shoring shall be no more than 18 inches below the top of the excavation.
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