Design of Sloping and Benching Systems

The slopes and configurations of sloping and benching systems must be selected and constructed by the employer and must be in accordance with one of the following four options.

Option 1: Allowable Configurations and Slopes

Excavations must be sloped at an angle not steeper than one and one-half horizontal to one vertical (34 degrees measured from the horizontal), unless the employer uses one of the other options listed below. Such slopes must be excavated to form configurations that are in accordance with the slopes shown for Type C soil in Appendix B to subpart P.

Option 2: Determination of Slopes and Configurations Using Appendices A and B

Determine the maximum allowable slopes and allowable configurations for sloping and benching systems in accordance with the conditions and requirements set forth in Appendices A and B to subpart P.

Option 3: Designs Using Other Tabulated Data

Designs of sloping or benching systems must be selected from and be in accordance with tabulated data, such as tables and charts.

The tabulated data must be in written form and must include all of the following:

• Identification of the parameters that affect the selection of a sloping or benching system drawn from such data
• Identification of the limits of use of the data, to include the magnitude and configuration of slopes determined to be safe
• Explanatory information as may be necessary to aid the user in making a correct selection of a protective system from the data

At least one copy of the tabulated data identifying the registered professional engineer who approved the data must be maintained at the jobsite during construction of the protective system. After that time, the data may be stored off the jobsite, but a copy of the data must be made available to OSHA on request.

Option 4: Design by a Registered Professional Engineer

A registered professional engineer must approve sloping and benching systems that do not use option 1, 2, or 3. Designs must be in written form and must include at least the following:

• The magnitude of the slopes determined to be safe for the particular project
• The configurations determined to be safe for the particular project
• The identity of the registered professional engineer approving the design

At least one copy of the design must be maintained at the jobsite while the slope is being constructed. After that time, the design need not be at the jobsite, but a copy must be made available to OSHA on request.

To learn more about Trenching and Excavation visit our Trenching and Excavation Safety Online Training web page.