# Standard Interpretations
1 - 1926.650 - Permissibility of using average excavation depth to determine protective system requirements for the excavation.
2 - 1926.650 - Registered professional engineer approval requirements for manufactured trench protection systems deeper than 20 feet.
3 - 1926.650 - Clarification of utility "owner" as used in the Safety and Health Standards for Excavations, Underground Installations.
4 - 1926.650 - Trench shield must extend 18" above excavation walls when below grade.
5 - 1926.650 - Hazards associated with drilled foundation activities.
6 - 1926.650 - Stacking trench boxes in trenches.
7 - 1926.650 - Classification and subsequent designs may be used if they have been approved by a registered professional engineer.
8 - 1926.650 - Manufacturer's Tabulated Data in the design and application of trench safety systems.
9 - 1926.650 - Testing of type C soil is not necessary if employees are adequately protected.
10 - 1926.650 - Clarification of Competent and Qualified Person, as it Relates to Subpart P.
11 - 1926.650(b) - Registered professional engineer approval requirements for combination trench shield and sloping system trenches with a depth greater than 20 feet.
12 - 1926.650(b) - Can a person who qualifies as a "competent" person under one section of support P also qualify as a competent designer of structural ramps under 1926.651(c)(1)(i)?.
13 - 1926.650(f) - Warning garments for flagmen at construction sites