Every month, 2 workers are killed in trench collapses.
How can you prevent these tragedies in your workplace? One step is to ensure your team is performing comprehensive excavation inspections that meet OSHA standards.
A discussion about excavation inspections must begin by defining a competent person. According to OSHA, a competent person is:
an individual, designated by the employer, who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous or dangerous to workers, and who is authorized to take prompt corrective measures to eliminate them.
In relation to the excavation standards, a competent person is required to classify soil, inspect protective systems, design structural ramps, monitor water removal equipment, and conduct site inspections.
Inspections should be conducted by a competent person each day before the shift starts, during the shift, after rainstorms, or after any other occurrence that may impact the stability of the excavation.
The excavations need to be inspected for hazardous conditions that include, but are certainly not limited to:
- Evidence of a potential cave-in,
- Indications of impending failure of protective systems (i.e., shoring, shielding, sloping), and
- Potential hazardous atmospheres.
If any hazardous condition is discovered, an inspector has the authority to remove workers from the excavation until necessary precautions have been made to ensure the safety of the workers.
Soil distress increases the likelihood of a cave-in. Signs of soil distress include:
- Fissures or cracks on excavation face
- Slumping of material, soil or rock, from excavation face
- Bulging or heaving of material at the bottom of the excavation wall that could mean the soil is about to come into the trench
- The edge of the trench begins to sink
- Small pebbles or clumps of dirt suddenly trickle or roll down the excavation wall.
What causes soil distress? These are some of the conditions that can cause a protection system to fail or weaken, signaling that a cave-in is about to occur:
- Nearby vibrating machinery. This can vibrate the soil and cause it to settle down and inward toward the trench.
- Moving heavy loads, such as street traffic, nearby will compress the nearby soil downward, which in turn will push soil inward toward the trench.
- Rain or water suddenly seeping into the trench indicates a changing soil condition and could result in reclassification of the soil type, which might impact the type of protection system needed.
- Hot and dry weather can also affect the stability of the soil.
Don’t let your workplace add to the statistics of trenching incidents. Take time to ensure all excavations are properly inspected in order to prevent tragedy.