Accepted engineering practices. Those requirements that are compatible with standards of practice required as a registered professional engineer

Aluminum hydraulic shoring. A pre-engineered shoring system comprised of aluminum hydraulic cylinders (cross-braces) used in conjunction with vertical rails (uprights) or horizontal rails (whales). Such system is designed specifically to support the sidewalls of an excavation to prevent cave-ins.

Benching. A method of protecting employees from cave-ins by excavating the sides of an excavation to form one or a series of horizontal levels or steps, usually with vertical or near vertical surfaces between levels.

Excavation. Any man-made cut, cavity, trench, or depression in an earth surface formed by earth removal. This definition includes core drilling, jack hammering, and asphalt- or concrete-cutting and indoor drilling/digging operations that may contact soil. In general, excavations are operations where contact with soil is expected, such as trenching and removing soil to install foundation footings or exposing underground pipes for repair or replacement.

Excavation competent person. The Occupational Safety and Health Administration (OSHA) defines a competent person as

One who is capable of identifying existing and predictable hazards in the surroundings, or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them.
from OSHA, Competent Person

Beyond meeting the OSHA definition, a SLAC excavation competent person must have successfully completed the required training courses (see Training). A subcontractor excavation competent person who routinely performs trenching and excavation activities (for example back-hoe operators, engineering subcontractors, demolition subcontractors, excavation subcontractors), must meet the qualifications of the SLAC excavation competent person, with the exception of university technical representative (UTR) training (see Training).

Failure. The breakage, displacement, or permanent deformation of a structural member or connection so as to reduce its structural integrity and its supportive capabilities

Hazardous atmosphere. An atmosphere that by reason of being explosive, flammable, poisonous, corrosive, oxidizing, irritating, oxygen deficient, toxic, or otherwise harmful, may cause death, illness or injury

Protective system. A method of protecting employees from cave-ins, from material that could fall or roll from an excavation face or into an excavation, or from the collapse of adjacent structures. Protective systems include support systems, sloping and benching systems, shield systems, and other systems that provide the necessary protection.

Penetration. An opening made by drilling, cutting, or otherwise piercing a wall, ceiling, or floor (see ES&H Manual, Chapter 44, "Penetration Safety")

Project manager. A SLAC employee assigned to oversee a project. The project manager has overall responsibility for a project, accountability for project results, and the authority to execute the project.

SLAC construction inspector. A member of the ES&H Chemical and General Safety Department who is responsible for inspecting all construction projects and approving excavation plans. The construction inspector will be a SLAC excavation competent person.

SLAC excavation program manager. A member of the ES&H Chemical and General Safety Department who is responsible for administering the excavation permit program. The program manager will be a SLAC excavation competent person.

Tabulated data. Tables and charts approved by a registered professional engineer and used to design and construct a protective system.

Trench. A narrow excavation made below the surface of the ground. In general, the depth is greater than the width, but the width of a trench (measured at the bottom) is not greater than 15 feet. If forms or other structures are installed or constructed in an excavation so as to reduce the dimension measured from the forms or structure to the side of the excavation to 15 feet or less (measured at the bottom of the trench), the excavation is considered to be a trench.

University technical representative. A university technical representative (UTR) is appointed for each project undertaken by one or more subcontractors that involves modifications to the grounds or structures on site. The role of the UTR is field supervision of the job to ensure compliance with the technical aspects of the specifications, including all environmental, safety, and health related regulations. UTR responsibilities are described in the SLAC University Technical Representative Guide [pdf].