32.8 Warning Lines and Barricades
32.10 Personal Protective Equipment
32.12 Shielding / Shoring Systems
32.14 Installation and Removal of Support System (shoring)
32.16 Stormwater, Sedimentation, and Erosion Control
32.2 Underground Utilities #
Prior to opening an excavation, efforts shall be made to ensure underground installations,
such as sewers, telephone lines, fuel lines, water lines, electric lines, etc., will not be damaged. Utility companies shall be contacted and advised at least a 72-hours in advance utility locations identified by MISS DIG or repeat MISS DIG if utility markings become disturbed.
| UNIFORM COLOR CODE FOR BURIED TAPE | |
| RED | Electric power lines, cables, conduit, and lighting cables |
| YELLOW | Gas, oil, steam, petroleum, or gaseous materials |
| ORANGE | Communication, alarm or signal lines, cable TV or conduit |
| BLUE | Water, irrigation, and slurry lines |
| GREEN | Storm sewers and drain lines |
| BROWN | Sanitary sewers |
When excavation operations approach the estimated location of underground installations, the exact location of the installations shall be determined by safe and acceptable means, usually by hand digging within 3 feet either side of the utility with a blunt insulated shovel or using a vacuum truck.
Diagram 1: Caution Zone for Hand Exposing
While the excavation is open, underground installations shall be protected, supported, or removed as necessary to safeguard employees.
When any contact with, or damage to, any pipe, cable, or its protective coating, or any other underground facility of a public utility occurs, the public utility shall be notified immediately. There may be unseen damage that requires specialized repair or inspection by a trained individual.
If an energized electrical cable is severed, an energized conductor is exposed, or dangerous fluids or gasses are escaping from a broken line, workers shall evacuate the immediate area while awaiting the arrival of the utility and/or emergency response personnel. Do not attempt to mitigate or pinch the severed line; wait for the utility owner to respond.
32.3 Daily Inspection #
Daily inspections of excavations, the adjacent areas, and protective systems shall be made by a competent person for evidence of a situation that could result in possible cave-ins, indications of failure of protective systems, hazardous atmospheres, or other hazardous conditions. An inspection shall be conducted by the competent person prior to the start of work involving workers entering an excavation. Inspections shall also be made after every rainstorm, snowstorm, thaw or other hazards increasing in occurrence.
Where the competent person finds evidence of a situation that could result in a possible cave-in, indications of failure of protective systems, hazardous atmospheres, or other hazardous conditions, exposed employees shall be removed from the hazardous area until the necessary precautions have been taken to ensure their safety.
32.4 Sloping and Benching #
For any excavation five (5) feet deep or more not using shoring or shielding protection systems shall be sloped or benched according to the table below or if the competent person determines it’s necessary.
If one side of an excavation is less than 5 feet deep and the other side is 5 feet or more deep, the deeper side shall be protected as provided in the table above. Special attention shall be given to a side that may be adversely affected by weather, moisture content, or other factors (e.g., vehicle traffic).
The competent employee needs to determine the soil classification prior to using sloping and benching methods. Note: soil classification may change with the depth of the excavation. If the soil classification is not easily determined, default to a lesser slope or the use of a trench box.
A professional engineer shall design the protective system for excavations greater than 20 feet deep.
32.5 Entry and Exit #
A stairway, ladder, ramp, or other safe means of egress shall be located in excavations that are 4 feet or more in depth, so as to require no more than 25 feet of lateral travel for employees with hand holds that extend not less than 3 feet above the landing.
Ramps:
- Equipment ramps will be designed by a person qualified in structural design (e.g., a professional engineer).
- Personnel ramps should be cleated or provided with a surface treatment to prevent slipping.
- The degree of angle of the ramp shall not be more than 45 degrees.
- The sides of the excavation above the ramp shall be maintained to the angle of repose or sheeted or shored along the means of egress.
- Ramps/walkways crossing over excavations deeper than six (6) feet require guardrail systems and will be of sufficient strength and shall have a designed capacity of not less than 3 times the imposed load.
32.6 Falling Materials #
No employee will be permitted underneath loads handled by lifting or digging equipment. No employee shall be in the excavation while digging is taking place. Note: Employees will be required to stand away from vehicles being loaded or unloaded to avoid being struck by any spillage or falling materials. Operators may remain in the cabs of vehicles being loaded or unloaded when the vehicles are equipped to provide adequate protection for the operator during loading and unloading operations.
Employees will be protected from excavated materials or equipment that could pose a hazard by falling, sliding or rolling into the excavation. Protection will be provided by placing and keeping such materials or equipment at least two (2) feet from the edge of excavations, or by the use of retaining devices that are sufficient to prevent materials or equipment from falling or rolling into excavations, or by a combination of both, if necessary.
Adequate protection will be provided to employees from loose rock or soil that could pose a hazard by falling or rolling from an excavation face. Such protection will consist of:
- Scaling to remove loose material;
- Installation of protective barricades at intervals as necessary on the face to stop and contain falling materials; or
- Other means that provide equivalent protection.
A walkway or sidewalk that is adjacent to an excavation shall be separated from the excavation and protected by a guardrail.
32.7 Excavators #
Only trained and permitted operators shall operate excavation equipment.
Overhead power lines in the area of the excavator must be de-energized or protected if within minimum safe distance according to the table below.
Table 2: Minimum safe distance from power lines
| Line Voltage | Minimum Safe Distance |
| Up to 50,000 volts | 10 feet |
| 50,000 to 115,000 volts | 12 feet |
| 115,000 to 230,000 volts | 16 feet |
| 230,000 to 500,000 volts | 25 feet |
Before excavating, engage the parking brake, shift to neutral, lower the stabilizers, and level the machine.
Secure the work area by setting up safety barriers to the side and rear of the swing radius. Ensure that there are adequate clearances around the swing pivot area.
Never allow anyone to enter into the swing pivot area.
Never swing or position the attachment or load over anyone or over the cab of a truck.
Do not dig under the machine or stabilizers. Avoid undercutting and working close to the edge of excavations. Never undercut a high bank.
Keep spoils a sufficient distance from the edges of excavations (minimum of 2 feet) to prevent cave-ins.
When operating on a slope, swing to the uphill side to dump the load. Place the undercarriage up or down a slope, not across a slope, for the best stability.
Do not cross railroads unless there is a crossing designed for heavy equipment.
32.8 Warning Lines and Barricades #
When mobile equipment (vehicles, etc.) is used/operated near open excavations, a warning system (i.e., barricading, hand or mechanical signals) shall be used.
All open excavations must be barricaded to sufficiently warn of the hazards associated with the work.
32.9 Confined Space #
Excavations over four (4) feet deep might be considered confined spaces, depending on access, hazards present, and based on the tasks being performed. Generally, if the excavation is sufficiently sloped/shored/shielded with appropriate access, it will not be classified as a confined space. A formal confined space evaluation should be conducted for every excavation with a potential for a hazardous atmosphere.
If an excavation is considered a permit-required confined space, use the confined space entry procedures as outlined in the Confined Space Entry Program in the CSP.
32.10 Personal Protective Equipment #
All employees shall be protected with personal protective equipment (PPE) for the hazards present, as necessary.
Use of PPE will conform to the requirements of the PPE Program in the CSP. All workers entering an excavation should at least wear a hard hat, safety glasses, safety boots, and high visibility vest.
32.11 Water Accumulation #
Employees shall not work in excavations in which there is accumulated water or in excavations in which water is accumulating unless adequate precautions have been taken to protect employees against the hazards posed by water accumulation. Controls could include special support or shield systems to protect from cave-ins or water removal to control the level of accumulating water. If water removal controls become ineffective, all employees shall exit the excavation.
If water is controlled or prevented from accumulating by the use of water removal equipment, a competent person must ensure proper operation and shall monitor the water removal equipment and operations.
If excavation work interrupts the natural drainage of surface water (such as streams), diversion ditches, dikes, or other suitable means shall be used to prevent surface water from entering the excavation and to provide adequate drainage of the area adjacent to the excavation. Excavations subject to runoff from heavy rains require regular inspection by a competent person.
32.12 Shielding / Shoring Systems #
Shielding/shoring systems will not be subjected to loading exceeding their maximum design limits.
Shielding/shoring will be installed according to the manufacturer’s specifications so as to resist cave-in.
Access and egress shall be positioned within the protected area of the trench.
Employees will not be allowed inside of portable shields when shields are being installed, removed, or moved vertically.
Shields must extend 18 inches above excavations. The bottom of the shield must be no more than 2 feet from the bottom of the excavation.
Always follow manufacturers’ recommendations. Deviations from manufacturers’ recommendations must be requested in writing to the manufacturer.
32.13 Adjacent Structures #
Where the stability of nearby buildings, walls, roads, sidewalks, utilities, or other structures are endangered by an excavation operation, support systems such as shoring, bracing, or underpinning will be provided to ensure the stability of these structures.
Before the excavation begins, the design of the protection used shall be set forth by a qualified person who is knowledgeable in the subject area.
Excavations below the level of the base or footing of any foundation or retaining wall that could be reasonably expected to pose a hazard to employees will not be permitted except when:
- A support system, such as underpinning, is provided to ensure the safety of employees and the stability of the structure
- The excavation is in stable rock
- A qualified person (e.g., professional engineer) has made the determination that such excavation will not pose a hazard to employees
- Sidewalks, pavement, or related structures will not be undermined unless a support system or another method of protection is provided to protect employees from the possible collapse of such structures
32.14 Installation and Removal of Support System (shoring) #
Members of support systems shall be securely connected together to prevent sliding, falling, kickouts, or other predictable failure.
Support systems shall be installed and removed in a manner that protects employees from cave-ins, structural collapses, or from being struck by members of the support system.
Design load limits of individual members of support systems shall not be exceeded.
Before temporary removal of individual members begins, additional precautions shall be taken to ensure the safety of employees, such as installing other structural members to carry the loads imposed on the support system.
Removal shall begin at, and progress from, the bottom of the excavation. Members shall be released slowly so as to note any indication of possible failure of the remaining members of the structure or possible cave-in of the sides of the excavation.
Backfilling shall progress together with the removal of support systems from excavations.
32.15 Traffic Control #
Any excavation work being conducted in or near a road or other powered vehicle or pedestrian route will implement appropriate barricades, warnings, and visibility equipment. Apparel, traffic signs or flagger personnel shall be implemented to safeguard workers, the work site, and the traffic in accordance with applicable state and local requirements.
Personnel acting as flaggers will be adequately trained and equipped for their flagger duties, and in accordance with state and local requirements. Refer to the PPE Program in the CSP for required PPE.
32.16 Stormwater, Sedimentation, and Erosion Control #
All exterior excavations will conform to the University’s regulatory requirements as specified in the Soil Erosion and Sedimentation Control Program (SESC) Procedures and Storm Water Management Program Plan (SWMPP). Notifications to EHS regarding projects involving earthwork is an important initial step as some projects may require additional plans, permits and/or best management practices depending upon earthwork size and location.
Notifications can be made through the EHS website or call (734) 647-1143.
General Storm Water and SESC information can be found here.
32.17 Training #
All employees whose duties require them to work in excavation or trench shall be trained, as listed below, and in the following areas:
Excavation and trenching training shall cover the following topics:
• The nature of the hazardous conditions or hazardous atmospheres associated with trenching and excavation
• Situations that could result in possible cave-ins, and indications of possible failures of protective systems
• Inspection procedures in the excavation and trenching standards
Confined Space Training:
All employees required to enter into confined or enclosed spaces shall be instructed as to the nature of the hazards involved and the necessary precautions to be taken, and in the use of protective and emergency equipment required. Refer to the Confined Space Program in the CSP.
Fall Protection Training shall cover the following topics:
• The nature of the fall hazards in the work area
• The correct procedures for erecting, using, maintaining, disassembling and inspecting fall protection systems
• The use and operation of guardrail systems, personal fall arrest systems, and any other fall protection used
• The physical limitations of mechanical fall protection equipment
• The role of the employee in the fall protection plans
Ladder Training:
Each employee required to use a ladder will receive training as part of the Safety Orientation Training Program, or will receive on the job training from their supervisor on how to recognize hazards related to ladder use, and procedures to minimize those hazards. Training will include the following topics:
- fall hazards
- the correct procedures for inspecting, erecting, using, and maintaining the ladders to be used
- the correct procedures for using and maintaining any fall protection required
- the maximum load carrying capacities of the ladders to be used
- relevant details of the MIOSHA Part 11: Fixed and Portable Ladder standard
The competent person must have the authority to correct identified hazards. The competent person shall be trained, as listed below, and in the following areas:
- Situations that could result in possible cave-ins, and indications of possible failures of protective systems
- The correct testing methods for the classification of soils
- Identifying hazardous conditions or hazardous atmospheres associated with trenching and excavations
- Sloping and benching requirements, according to the excavation standard
- The different types of excavation protective systems
- Inspection procedures in the excavation and trenching standards
