Safety Focus of the Week: Trench Excavation
OSHA 1926 Part P addresses excavations. The minimum sloping requirements are given for soil classification Types A, B, and C. The soil type is selected by the “competent person”.
We generally select a Type C soil which is the least stable soil condition and therefore applicable for any excavation. The steepest allowable slope for a Type C soil is 1.5H:1V.
Occasionally, we encounter a soil that meets a Type B, or possibly an A. However, there are several conditions besides the soil strength that need to be considered and would require us to downgrade the soil to a Type C, including: ground water, fill versus natural soil, adjacent construction activities, etc. For more information check out OSHA’s Standard:
At ECI, it is necessary to get approval from Matt or Stu when considering a Type B or C. When that approval is granted, it becomes the responsibility of the Competent Person to assess the soil type daily, or more frequently if soil and work conditions change. These assessments and accompanying strength data must be documented to show compliance. Selection of a Type B or A soil requires serious thought and commitment to remain diligent in the effort to reassess the conditions.