Excavation and trenching - Indiana

Indiana operates an OSHA-approved State Plan covering most private sector workers and all state and local government workers. The Indiana Occupational Safety and Health Administration (IOSHA) is part of the Indiana Department of Labor. Federal OSHA covers the issues not covered by the Indiana Plan. IOSHA adopts all OSHA standards and regulations except it has some unique excavation standards.

Underground plants

Indiana has established the Underground Plant Protection Service, an association of operators of underground utilities, that excavators can give notice to prior to excavation in order to have the utilities marked to prevent damage or worker injury. The rules are found in Burns Ind. Code Ann. §§ 8-1-26-1 – 8-1-26-26.

Action to avoid damage. In addition to the required notice, a person responsible for an excavation or demolition operation must:

• Plan the excavation or demolition to avoid damage to or minimize interference with underground facilities in and near the construction area.
• Maintain a clearance between an underground facility, as marked by the operator, and the cutting edge or point of mechanized equipment equal to the tolerance zone of the physical plant.
• Notify the association if there is evidence of an unmarked facility in the area of the excavation or demolition, or if the markings indicating the location of an underground facility have become illegible.

If the clearance is less than two feet, or if an underground facility is located or contained in or under pavement or another manmade hard surface, exposure of the underground facility may be accomplished only using hand excavation, air cutting, vacuum excavation, or hydro vacuum excavation.

Mechanized equipment may not be used within the tolerance zone of the physical plant unless the person responsible for the excavation or demolition:

• Visually identifies the precise location of the underground facilities or visually confirms that no facility is present within the depth of the excavation.
• Takes reasonable precautions to avoid any substantial weakening of the underground facilities’ structural or lateral support.
• Takes reasonable precautions to avoid penetration or destruction of the underground facilities, including their protective coatings.
• Requires an individual other than the equipment operator to visually monitor the excavation activity.

Mechanized equipment may be used for the initial penetration and removal of pavement or other manmade hard surfaces if an underground facility is located or contained in or under pavement or another manmade hard surface, or if there is pavement or another manmade hard surface extending up to the tolerance zone of the physical plant, if:

• The person responsible for the excavation or demolition plans the excavation to avoid damage to or minimize interference with the underground facilities.
• The person responsible for the excavation or demolition takes into account the known limits of control of the mechanized equipment’s cutting edge or point.
• The mechanized equipment is used only to the depth necessary to remove the pavement or other manmade hard surface.

Action after damage occurs. A person responsible for an excavation or a demolition operation that results in damage to an underground facility must:

• Immediately upon discovery of the damage, notify the operator of the facility and the association of the location and nature of the damage; and
• Allow the operator of the facility reasonable time to accomplish necessary repairs before completing the excavation or demolition in the immediate area of the facility.

A person responsible for an excavation or a demolition operation that results in damage to an underground facility permitting the escape of flammable, toxic, or corrosive gas or liquid must:

• Immediately upon discovery of the damage, notify the operator and the association and local police and fire departments having jurisdiction; and
• Take other actions necessary to protect persons and property and to minimize the hazards until the arrival of the operator’s personnel or police and fire personnel.

Underground tanks

Excavations for underground tanks must not undermine the foundations of existing structures. Underground tanks must be set on firm foundations and surrounded with at least six inches of noncorrosive inert material, such as clean sand or gravel well tamped in place or in accordance with the manufacturer's installation instructions. In addition:

• Tanks must be covered with a minimum of two feet of earth or by not less than one foot of earth, on top of which must be placed a slab of reinforced concrete not less than four inches thick.
• When underground tanks are, or are likely to be, subjected to traffic, they must be protected against damage from vehicles passing over them by at least three feet of earth cover, or 18 inches of well-tamped earth plus six inches of reinforced concrete, or eight inches of asphaltic concrete.
• When asphaltic or reinforced concrete paving is used as part of the protection, it must extend at least one foot horizontally beyond the outline of the tank in all directions.
• The clearance from the tank to the nearest wall of a basement, pit, or property line must not be less than one foot.