Powered by iReportSource   OSHA Sloping/Benching Diagrams I am sure you may have heard about trenching incidents near you or reading about them on a national level. Managing safety for these operations is quite simple once you know the requirements and understand some of the nuances that go along with the different soils and protective systems we have. Hazards Cave-ins pose the greatest risk with these activities and are much more likely than other excavation-related accidents to result in worker fatalities. Other potential hazards include falls, falling loads, hazardous atmospheres, and incidents involving mobile equipment. One cubic foot of soil can weigh 100 pounds. One cubic yard of soil can weigh as much as a car, and the kinetic energy of soil falling 3, 4, 10 feet, and you can see the danger here. It has been said that an unprotected trench is an early grave. So let me start by stating the obvious: do not enter an unprotected trench. Protective Systems So at what point do we need to protect a trench? According to OSHA, trenches 5 feet (1.5 meters) deep or greater require a protective system unless the excavation is made entirely in stable rock. Oh, and forget about stable rock, I will explain that later. If less than 5 feet deep, a competent person may determine that a protective system is not required. Competent Person OSHA standards require that employers inspect trenches daily and as conditions change by a competent person before worker entry to ensure the elimination of excavation hazards. A competent person is an individual who is capable of identifying existing and predictable hazards or working conditions that are hazardous, unsanitary, or dangerous to workers, soil types and protective systems required, and who is authorized to take prompt corrective measures to eliminate these hazards and conditions. Access/Egress OSHA standards require safe access and egress to all excavations, including ladders, steps, ramps, or other safe means of exit for employees working in trench excavations 4 feet (1.22 meters) or deeper. These devices must be located within 25 feet (7.6 meters) of all workers. Here are some other requirements to follow: Ground Safety Keep heavy equipment away from trench edges. In the fire department, we tried to keep all heavy rigs at least 25 feet away. But this was to prevent vibrations to already unstable trenches during rescue operations. But heavy equipment that could pose a hazard of falling into the trench or even knocking materials into the trench has to be located back at a safe distance. The standard requires that you keep excavated soil (spoils) and other materials (like sand and gravel used for backfill or pipes being installed) at least 2 feet (0.6 meters) from trench edges. Ongoing inspections are needed to ensure this requirement is being met. Underground Safety Know where underground utilities are located before digging. This is a requirement in the OSHA standards, but it requires you to follow State laws that actually govern locating and marking PUBLIC utilities. Private utilities still need to be located and marked as well. So, familiarize yourself with the 811 "call before you dig" system. Test for atmospheric hazards such as low oxygen, hazardous fumes, and toxic gases when > 4 feet deep. This is when you suspect there could be a hazardous atmosphere or one could reasonably be expected to exist, such as in excavations in landfill areas or excavations in areas where hazardous substances are stored nearby. Falls and Falling Objects 
Do not work under suspended or raised loads and materials. This means workers down in the trench and the track hoe bucket swinging over their head to drop gravel, sand or pulling the material out. Also, Walkways have to be provided where workers or equipment are required or permitted to cross over excavations. Guardrails that comply with §1926.502(b) shall be provided where walkways are 6 feet (1.8 m) or more above lower levels. Again, only when workers a