Excavation Safety - Part 2
Excavation Safety - OSHA Requirements – Read Part 1
Shoring
Shoring, unlike shielding, is a system that applies pressure against the excavation’s walls to prevent collapse, rather than protection from collapse. Shoring applies pressure to members placed against the excavation’s walls by use of hydraulic, pneumatic, or mechanical means creating a constant outward force. As with shields or trench boxes, shoring is set in place after excavation and before any work is performed. Shoring is then removed after work in the excavation has occurred. Access to the shored excavation needs to be within the protection of the shoring as well.
Once work starts on an excavation, a competent person needs to inspect any work performed at least daily before the work starts and throughout the day as needed. Also, when the condition of an excavation is subject to changes (such as a rainstorm), an excavation is required to be reinspected before work resumes or continues. OSHA frequently cites contractors for failure to perform these inspections, and to have a competent person onsite. Other common OSHA citations to be aware of are; not having egress points (ladders, ramps, or other means) a maximum of fifty (50 ft.) apart to allow quick exits for workers; not keeping spoils, tools, equipment, and materials at least two feet (2 ft.) from the excavation’s edge; and not having any excavation work twenty feet (20ft.) or greater in depth designed by a registered professional engineer.
While OSHA requires personnel protection in excavations more than five feet (5 ft.) in depth, OSHA regulations may also require (in certain circumstances) the same protection methods for excavations of lesser depths. OSHA regulation 1926.652(a)(I)(ii) exempts use of personnel protection in excavations less than five feet (5 ft.) in depth when “…examination of the ground by a competent person provides no indication of cave-in.”
For example, if work is being performed in a four foot (4 ft.) deep trench with vertical walls and with non-cohesive soils or where cracking, weakening, or crumbling soil conditions exist (as with type B or C soils), then a potential hazard exists for workers within the trench, especially those who may be bent over or on their knees working. This situation, therefore, would require use of personnel protection at an excavation depth of less than five feet.
Although this may seem an obscure, or rare occurrence, I found in conversation with OSHA Compliance Safety and Health Officers (CSHO’s), that citations have been issued for no personnel protection in excavations less than five feet. CSHO’s however, would likely address each situation on a case-by case basis. Therefore, all excavations regardless of depth need to be assessed by the competent person before a decision is made whether or not to provide personnel protection.
Attention to forming a work plan before excavating will benefit workers and contractors alike by creating a safe work environment free from potential hazards and liability for the worker, and the contractor alike.