Shielding Systems are not designed to prevent trench wall collapse, but serve instead to “shield” the workers within the shielding system itself. Some of the advantages would include:

Excavations over 4 feet deep or in unstable soil must be shored according to WISHA. OSHA standard is 5’ deep.

Excavation of material may extend 2 feet below the bottom of a shield only if the shield is designed for the full depth of the trench and there is no evidence of soil loss from below the bottom of the shield.

ISHA/OSHA allows the use of 1 1/8” plywood or 3/4” Finform sheeting in conjunction with hydraulic shoring.

Vertical shoring can be used in C60 soil type when the manufacturers tabulated date allows for it.

Pre-engineered shoring systems can be used in trenches over 20’ deep when the manufacturers tabulated data allows for it.

Tables and charts approved by a registered professional engineer. These tables and charts provide information on the shoring capabilities.

One who is capable of identifying predictable hazards and who has the authority to take corrective measures to eliminate them.

Method of classifying soils based on environmental

conditions. This must be completed by the competent person.

Type A: Cohesive soils with an unconfined compressive strength of 1.5 TSF or greater. Examples would be dry stable material such as clay, silty clay loam, and cemented soils.

Type B: Cohesive soil with an unconfined compressive strength of 0.5 TSF, but less than 1.5 TSF. Examples would be dry to moist soils, clays, and gravels.

Type C: Cohesive soil with an unconfined compressive strength of 0.5 TSF or less. Examples would be some granular or submerged soils.