Environmental Health & Safety Excavation Safety

Definitions

Benching / Bench System - One or a series of horizontal levels or steps, with vertical or near-vertical surfaces between levels.

Competent Person - Person who is capable of identifying existing and predictable hazards or working conditions, and that has the authority to correct or eliminate them.

Excavation - A cut, cavity, trench or depression that was made be a person into the earth’s surface, through the removal of the earth .

Faces / Sides - Vertical or inclined earth surface formed by excavation work.

Hazardous Atmosphere - A location that is or has the potential to be hazardous from an explosive, fire or IDLH standpoint.

• Sewer Gas / Carbon Monoxide / Oxygen Deficient

Protective System - A system to protect employees from cave-ins, collapse, or from material or equipment falling in to.

1. Support Systems
2. Sloping
3. Benching
4. Shield Systems
5. Guardrails
6. Warning Barriers

Sheeting - Members of a shoring system that retain the earth in position, and are also supported by other members of the shoring system.

Shield/Trench Box - A structure that is capable of withstanding forces that may be imposed by faces and walls of an excavation to properly protect the occupants of the excavation.

Shoring - A metal hydraulic, mechanical or timber shoring system that supports the side of an excavation.

Sloping - Inclined faces and walls of an excavation, excavated in such a fashion to properly protect the occupants of the trench.

• Angle is dependent on soil type and disturbance.

Stable Rock - Solid mineral material that can be excavated with vertical sides, and will remain in tact while exposed.

Wales vs. Bracing - Horizontal members of a shoring system placed parallel to the excavation face whose sides bear against the vertical members of the shoring system or earth.

Dig Safe Notification Required

1. Any public or private way
2. Any company right of way or easement
3. Any public or privately owned land or way
4. Until the appropriate Dig Safe Permit is acquired. 

 

“ Each employer shall provide a place of employment which is free from recognized hazards that would cause or is likely to cause death or serious physical harm to their employees.”

- Section 5 (a) (2)

1. Ladder
2. Ramp
3. Stairway
4. Vehicular Traffic 

1. Barricades set-up in a manner that properly warns vehicle operators of personnel in close proximity to the excavation.
2. Signage (i.e. Personnel in Roadway etc.)
3. Wearing of Warning Vests or, Reflecterized Garments
4. Adequate and appropriate lighting in accordance with DOT requirements 

1. Exception - Toeboards or other suitable barricade is used.
2. Boulders, Stumps and other material that could roll into the trench must be removed.

1. They must be located away from the vehicle being loaded or unloaded, so as not to be struck by falling debris.
2. In all construction areas where there is an overhead hazard, the appropriate personal protective equipment shall be worn.
3. Operators of vehicles receiving the loads can remain in the cab of the vehicle, provided with proper overhead protection.

1. Barricades
2. Hand or Mechanical Signals
3. Stop logs
4. Other suitable Warning Devices 

Potential or Known Hazards

• Excavations > 4’

4 Gas Monitors

• Lower Explosive Level (LEL)
• Carbon Monoxide (CO)
• Hydrogen Sulfide (H2S)
• Oxygen Deficiency or Enrichment (O2)

Ventilation Modifications

Hot Work Activities

Surface Water - Drainage

Should excavation interrupt water flow...

Physical Protection

Pits, shafts and wells can be covered.

• Must be able to withstand (4x) heaviest potential load. 

Type B

Type C

Exception

If employees at lower levels are properly protected from falling, rolling, sliding material or equipment

Exception to the Exception

Equipment above the excavation making the slope or trench