Injury Illness Prevention Plan - Flipbook - Page 195
Health and Safety Program Manual
Teamwrkx
Construction, Inc.
Issue Date: 10/16/23
Revision Date: 10/16/23
Trenching and Excavation
Reference: A-15
Shielding
Trench boxes are different from shoring because, instead of shoring up or otherwise supporting the trench face,
they are intended primarily to protect workers from cave-ins and similar incidents.
The excavated area between the outside of the trench box and the face of the trench should be as small as
possible. The space between the trench box and the excavation side must be backfilled to prevent lateral
movement of the box. Shields may not be subjected to loads exceeding those which the system was designed
to withstand.
Trench boxes are generally used in open areas, but they also may be used in combination with sloping and
benching.
The box must extend at least 18 inches above the surrounding area if there is sloping toward the excavation.
This can be accomplished by providing a benched area adjacent to the box.
Any modifications to the shields must be approved by the manufacturer.
Shields may ride two feet above the bottom of an excavation, provided they are calculated to support the full
depth of the excavation and there is no caving under or behind the shield.
Workers must enter and leave the shield in a protected manner, such as by a ladder or ramp.
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