Revised on
01/26/17 02:48pm
SafetyNet #
136

Excavation/Trenching/Shoring

Contact information

During 1992-2001, the Census of Fatal Occupational Injuries maintained by the Bureau of Labor Statistics identified 542 fatalities associated with excavation and trenching operations.  Excavation and trenching hazards include suffocation, crushing and being struck by rescue equipment.

Excavation, trenching, and shoring operations rules, regulations, requirements, and guidelines are set forth in Title 8, California Code of Regulations, Section 1539 to 1543.  Generally, shoring is required for any excavation or trench greater than 5 feet in depth.

A qualified "competent person" is required to supervise and inspect any excavation, trenching, and shoring operation.  A “Competent Person” must make daily inspections of the excavation/trench and protective systems prior to work commencing and as the work progresses.  “Competent Person” is defined by Cal/OSHA as one who must demonstrate:

  • Knowledge of the regulations pertaining to excavations, trenches and earthwork as found in Title 8, California Code of Regulations, Section1539-1543
  • Knowledge of soil analysis pertaining to excavations, trenches and earthwork as found in Title 8, California Code of Regulations, Section 1539-1543
  • Knowledge of the use of protective systems
  • Authority to take prompt corrective action on the job as conditions warrant
  • Ability to recognize and test for hazardous atmospheres

Each employee in an excavation shall be protected from cave-ins by an adequate protective system except when:

  • Excavations are made entirely in stable rock; or
  • Excavations are less than 5 feet in depth and examination of the ground by a competent person provides no indication of a potential cave-in

Excavations and trenches over 5 feet in depth are required to be shored, properly sloped or benched.  If there is the possibility of soil movement, even shallower excavation and trenches are required to be shored.  A stairway, ladder, ramp, or other safe means of egress must be located in excavations/trenches that are 4 feet or more in depth so as to require no more than 25 feet of lateral travel for employees.

Department Responsibilities

Departments are responsible for the following:

  • Implementing a written departmental excavation, trenching, and shoring operations program
  • Ensuring employees receive initial and annual refresher training for:
    • Potential hazards associated with excavation, trenching, and shoring operations
    • Standard Operating Procedures developed within each department
    • Safety procedures and the use of personal protective equipment
  • Providing training for the competent person
  • Ensuring that excavation, trenching, and shoring procedures and requirements are followed
  • Providing and ensuring appropriate excavation, trenching, and shoring equipment is used

Contracting Recommendations

The following recommendations are for departments contracting excavation and trenching activities:

  • Trenching/shoring must be in compliance with Title 8, California Code of Regulations, Section1539-1543
  • Require contractor to demonstrate knowledge of Title 8 regulations
  • Require contractor to identify and provide qualification documentation for the “Competent Person” to be used on the project
  • Verify current training records for personnel identified to used on the project

Excavation/Trenching Trigger Numbers

2 FEET: Required distance for spoils piles from edge of excavation/trench

3 FEET: Length ladder must extend above excavation/trench

4 FEET: Depth at which a ladder or ramp is required for access and egress

5 FEET: Depth at which mandatory shoring, benching, and/or a protection system is required

6 FEET: Depth at which fall protection is required for bridges/walkways across excavations/trenches

20 FEET: Shoring designed by a registered engineer is required

25 FEET: Maximum travel distance to an exit ladder

“IF IN DOUBT, GET OUT”

 

References

1.            Title 8, California Code of Regulations, Section 1539-1543

2.            UC Davis Policy & Procedure Manual, Section 290-86 – Hazardous Operations