What is Excavation Safety?
Excavation Safety is a standardized set of safety precautions for trenching and excavation to eliminate hazards and control risks in compliance with regulations. It is also referred to as Trenching and Excavation Safety as often cited by the U.S. Occupational Safety and Health Administration (OSHA).
What are OSHA Excavation Standards?
OSHA excavation standards are specifications of requirements for trenching and excavation, including protective systems. In U.S. federal regulations, OSHA standards for excavations and backfilling are specifically found in Title 29 (Labor) Part 1926 (Safety and Health Regulations for Construction) Subpart P (Excavations), or 29 CFR 1926 subpart P. The excavation regulation also contains appendices for the following:
- Soil Classification;
- Sloping and Benching;
- Timber Shoring for Trenches;
- Aluminum Hydraulic Shoring for Trenches;
- Alternatives to Timber Shoring; and
- Selection of Protective Systems.
What is the Difference Between Trenching and Excavation?
The scope and application of excavation standards states that excavations include trenches which means that a trench is a type of excavation. Moreover, a trench is further defined as a narrow excavation in relation to its length, and it is generally greater in depth than width. The main difference is that excavation is the umbrella term that encompasses any man-made cut in an earth surface, including trenches. While a trench can be called a trench excavation and all trenches are excavations, not all excavations are made up of trenches only.
What are the Hazards in Excavation?
As any man-made cut, cavity, trench, or depression in the Earths surface formed by earth removal, according to the OHSA definition, excavations involve many hazards. Here are some of the dangers brought by excavations:
- The collapse of the sides of the excavation
- Materials falling onto people
- Falls, either people or vehicles
- Nearby structures collapsing into the excavation
- Electrocution, explosion, blasts, gas leak, or flooding, caused by damage to underground services
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What are the Safety Measures for Excavation?
An OSHA investigation reported that the main reason why trenches collapse is that they are not properly protected. Protective systems such as sloping the ground, benching the ground, shoring the trench with supports such as planking or hydraulic jacks, and shielding the trench using a trench box should be properly implemented at all times. Other excavation safety measures include:
- Collapsing should be avoided by supporting the sides by either battering them or supporting them with sheets.
- Materials from the excavation should be stored at a safe distance from the excavation, this will help reduce the risk of them falling onto people.
- Adding barriers to excavation is an essential precaution to avoid people falling into the excavation.
- It is safer if vehicles are kept completely out of the excavation area, but if required the use of barriers and stop-blocks should help mitigate that danger.
- Cable, pipe, and service plans should be used to ensure that underground services are known so they can be marked on the ground or, ideally, the area avoided entirely.
- Around the areas where there are underground services, mechanical equipment should be avoided and instead use spades and/or shovels.
- Picks and forks should be avoided as they are more likely to pierce cables and pipes.
- Flooding can be avoided by ensuring that there is appropriate pumping equipment so that any water that seeps into the excavation can be easily pumped out to a safe area.
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FAQs About Excavation Safety
A competent person in excavation safety is an individual, designated by the employer, who has the authorization to take immediate corrective actions to eliminate excavation-related hazards that are dangerous to workers. Moreover, an excavation competent person should be able to classify soil, clear sites safely, inspect protective systems, design structural ramps, monitor water removal or dewatering equipment, and perform site inspections.
The 5-foot rule in excavation is a safety practice that states that unless the pit is made entirely in stable rock, trenches 5 feet deep or greater require the use of a protective system. If, however, the excavation is under 5 feet, a competent person may decide whether a protective system is necessary or not.
The 5 4 3 2 1 rule is a safety guideline for excavation work that helps prevent accidents and injuries. They are as follows
- 5 feet deep trenches must have a protective system in place
- Trenches greater than 4 feet must have a ladder for exit and egress
- Ladders should extend at least 3 feet from the excavation for easy access and easy exit
- Place excavated materials 2 feet away from the edge of the excavation
- 1 competent person must be present at all times to monitor safety and eliminate hazards
A cave-in is probably the deadliest excavation hazard, where walls can suddenly collapse without warning, workers do not have time to move out of the way, and cubic yards of dirt can fatally crush and suffocate. U.S. Bureau of Labor Statistics data reveals that 3 out of 4 excavation-related fatalities are caused by cave-ins.
Jona Tarlengco
