Excavation and trenching - Oregon

Oregon operates an OSHA-approved State Plan covering most private sector workers and all state and local government workers. Oregon OSHA has adopted by reference many federal OSHA standards that relate to state and local government and private sector workplace operations. Oregon OSHA has unique excavation standards.

“Excavation” is defined in the Oregon regulations (OAR 437-004-3100) as a man-made cut, hole, pit, trench, or depression in the earth. The regulations note that before digging, a person must call 800-322-2344 and comply with Oregon's “Call Before You Dig” law.

Key excavation rules set forth in Oregon regulations include the following:

• Five feet or more. Employees must not enter any excavation five feet or deeper unless protective systems are in place to protect from cave-in or sloughing.
• Less than 5 feet. Employees must not enter any excavation less than five feet deep when the sides are losing their shape, are loose or show other signs of being unstable unless protective systems are in place to protect from cave-in or sloughing.
• Strength. Systems installed in the excavation must be strong enough and engineered to provide protection from hazards of the particular excavation.
• Design. Systems must be designed by a registered professional engineer and designed using the manufacturer or other tabulated data.
• Follow instructions. When using manufactured systems, follow the instructions and do not exceed the limitations of the system.
• System size. Systems must extend from the bottom of the excavation to at least the top edge.
• Sloping. Sloping is an acceptable system to protect workers. Sloping must be at a ratio of at least 1 and 1/2 to 1. That means a horizontal setback of 1 and 1/2 feet for every 1 foot of trench depth.
• Access/Exit. There must be a safe way, such as a ladder or steps, to get into and out of excavations four or more feet deep. In trenches, these exits must be at least every 25 linear feet.
• Water. Workers will not enter excavations where there is accumulating water, either from ground seepage or surface run-off, unless there are adequate protections from hazards caused by the water.
• Inspect daily. A person familiar with these rules and the work must inspect all excavations daily, before workers enter or reenter.
• Spoils and equipment. Keep soil and material removed from the excavation (spoils) at least two feet away from the edge of the excavation or restrained. Equipment that could roll or fall into the excavation must also be at least two feet back or restrained.

Oregon Utility Notification Center

In addition to the above rules relating to "underground installations" adopted in OAR 437-004-3100, the following Oregon Revised Statutes and Oregon Administrative Rules administered by the Oregon Public Utility Commission (PUC) will apply:

• ORS 757.542, 757.547, 757.552, 757.557, and 757.562;
• OAR 952-001-0001 to 952-001-0100; and
• OAR 860-024-0007.

Key definitions

"Excavation" means any operation in which earth, rock or other material on or below the ground is moved or otherwise displaced by any means, except sidewalk, road and ditch maintenance less than 12 inches in depth that does not lower the original grade or original ditch flow line. "Excavation" does not include the tilling of soil for agricultural purposes conducted on private property that is not within the boundaries of a recorded right-of-way or easement for underground facilities.

"Operator" means any person, municipal corporation, political subdivision of the state with control over underground facilities. Operator includes any person, as defined in ORS 756.010, having the right to bury underground facilities in any public right-of-way, or in any utility easement.

"Oregon Utility Notification Center" (Center) means the state agency that administers a statewide system through which a person can notify operators of underground facilities of proposed excavations and can request that the underground facilities be marked.

"Underground facilities" means items partially or entirely below the surface of the ground for use in connection with the storage or conveyance of electrical energy, water, sewage, petroleum products, gas, gaseous vapors or hazardous liquids, or the transmission of electronic, telephonic, telegraphic or cable communications. Such items include, but are not limited to, pipes, sewers, conduits, cables, valves, lines, wires, manholes, attachments and those parts of poles or anchors that are underground.

Excavator duties

General requirements. Once underground facilities have been marked, the excavator must:

• Maintain marks during the excavation period to ensure that the original marks remain effective for the life of the project or the ticket life, whichever is the shorter period;
• Stop excavating in the vicinity of the underground facility and notify the Oregon Utility Notification Center to have the route remarked as specified in these rules, if prior to or during the excavation process, the marking or route of any underground facility is removed or no longer visible; and
• Employ hand tools or other non-invasive methods either to determine the exact location of the underground facility or down to 24 inches beyond the depth of intended excavation within 24 inches of the outside dimensions of a marked underground facility.

Lateral and subjacent support. The excavator must provide such lateral and subjacent support for underground facilities as may be reasonably necessary for the protection of such facilities.

Horizontal directional drilling. When excavating using horizontal directional drilling, the excavator must visually monitor the drill head and back reamer pass through the tolerance zone.

Causing or observing facility damage. If the excavator causes or observes damage to underground facilities, the excavator must notify the operator of the underground facilities immediately. If the damage causes an emergency, or if the damage from excavation activity is to a pipeline and causes the release of any natural gas, other gas, or hazardous liquid from the pipeline, the excavator must promptly report the release to appropriate emergency response authorities by calling the 911 emergency telephone number, and take reasonable steps to ensure the public safety. The excavator must not bury damaged underground facilities without the consent of the operator of the damaged underground facilities.

Discovery of underground facilities. If an excavator discovers underground facilities in an area where the operator of the underground facilities had previously stated there were no underground facilities, prior to continuing excavation the excavator must notify the Oregon Utility Notification Center. After providing notification, the excavator must use extreme care in the affected area.

Critical facilities. If an excavator is informed that a critical facility, as determined by the operator, is in the area of their excavation and that an operator-provided monitor is required on site during the excavation, the excavator must not begin excavation without that monitor being present or without the facility operator's consent. The scheduling and fulfillment of this monitoring must in no way interfere with or delay the work.