The Fundamentals of Excavation and Trench Safety

This overview offers the basics for a safe approach to excavating and trenching

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Safety and quality are two of the most inseparable components to success on a job site. You can't have one without the other.

And without a solid foundation of safe practices, you'll suffer from more than a deficit of quality. Safety isn't just a quota — it's the thing that keeps employees safe, happy and productive.

You should have a profound understanding of the tenets of excellent safety. It should be a pillar of your utility's identity. Most of all, you should know that there are always ways to improve upon what you already have. But without the fundamentals, you'll find yourself struggling to maintain consistent quality and high productivity.

Understanding excavation safety

OSHA has already done the hard work to collect, organize and explain the various components to keeping a safe excavation site. For free on its website, OSHA even has a “Trenching and Excavation Safety” manual for anyone to download. In this manual, OSHA goes over the fundamentals of excavation and trench safety, such as understanding the various classifications of soil:

Stable Rock — Natural solid mineral matter that can be excavated with vertical sides and remain intact while exposed.

Type A — Cohesive soils with an unconfined compressive strength of 1.5 tons per square foot (tsf) (144 kPa) or greater. Examples include: clay, silty clay, sandy clay, and clay loam. Certain conditions preclude soil from being classified as Type A. For example, no soil is Type A if it is fissured or has been previously disturbed.

Type B — Includes cohesive soil with an unconfined compressive strength greater than 0.5 tsf (48 kPa) but less than 1.5 tsf (144 kPa) and granular cohesionless soils (such as angular gravel, similar to crushed rock, silt, silt loam, sandy loam, and, in some cases, silty clay loam and sandy clay loam).

Type C — Cohesive soil with an unconfined compressive strength of 0.5 tsf (48 kPa) or less, granular soils (including gravel, sand, and loamy sand), submerged soil or soil from which water is freely seeping, submerged rock that is not stable, or material in a sloped, layered system where the layers dip into the excavation or with a slope of four horizontal to one vertical (4H:1V) or steeper.

Keep a site safety checklist

For any excavation job, it’s best to create a safety checklist to be completed by a “competent person.” As defined by 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.

OSHA also lists the types of tasks that a “competent person” should be performing on a job site:

  • Classifying soil
  • Inspecting protective systems
  • Designing structural ramps
  • Monitoring water removal equipment
  • Conducting site inspections

It's best to create a custom checklist based on your specific requirements and even tailor individual checklists to your various job sites. But to get started, this excavation safety checklist created by the University of Delaware is helpful.

Use proper PPE

OSHA outlines the “general PPE” required for most excavation, but the more protected your crew is, the safer and more productive you’ll be. From OSHA’s trenching and excavation worksheet, it outlines the following PPE:

  • Hard hat for overhead impact or electrical hazards
  • Eye protection with side shields
  • Gloves chosen for job hazards expected (e.g., heavy-duty leather work gloves for handling debris with sharp edges and/or chemical protective gloves appropriate for chemicals potentially contacted)
  • ANSI-approved protective footwear
  • Respiratory protection as necessary — N, R, or P95, filtering facepieces may be used for nuisance dusts (e.g., dried mud, dirt and silt) and mold (except mold remediation). Filters with a charcoal layer may be used for odors.

Two popular sources for hardy, cost-effective PPE are and

Know your site inside and out

Understanding where you’re working is an incredibly important part of the job. You should have an understanding of what lies below ground well before you begin excavating. There can be utility lines, old infrastructure, or any number of hazards waiting below to surprise your crew if they’re not careful.

OSHA comes to the rescue once again with a helpful list of precautions to take to avoid below-ground surprises:

  • Determine the approximate location(s) of utility installations, including sewer, telephone, fuel, electric, and waterlines. One common industry practice is to call 811, the “Call Before You Dig” number, to establish the location of any underground utility installations in the work area.
  • Contact and notify utility companies or owners involved to inform them of the proposed work within established or customary local response times.
  • Ask utility companies or owners to establish the location of underground installations prior to the start of excavation work. If they cannot respond within 24 hours (unless the period required by state or local law is longer) or cannot establish the exact location of the utility installations, employers may proceed with caution, which includes using detection equipment or other acceptable means to locate utility installations.
  • Determine the exact location of underground installations by safe and acceptable means when excavation operations approach the approximate location of the installations.
  • Ensure that while the excavation is open, underground installations are protected, supported or removed as necessary to safeguard workers.

Choose the safest tools

Not every power tool is created equal. There are easy ways to increase your safety by being more mindful of the tools your crew is utilizing.

For example, one easy way to reduce air compressor noise and the various other hazards that come with a compressor is to switch to a more portable gas-powered jackhammer. They’re more efficient than the standard pneumatic variety of jackhammer and produce less noise, dust and vibration. With less equipment needed and less to haul to and from a site, making use of power tools with more portability will have a positive effect on the overall site safety.

Safety is always changing

The idea of “safety” is largely intangible. It’s a multi-faceted effort that should constantly evolve on both the micro and macro levels.

As your organization matures, so too should its understanding of safety. Day-to-day safety on a job site should evolve as well to accommodate the changing landscape, the different weather, and the stage of construction. If you follow these basic tenets, you’ll be well on your way to a safer job site.

About the author: Chris Galloway is the owner of US Hammer Jackhammers and Post Drivers. A lifelong contractor, he runs US Hammer and Pioneer Machinery, his rental equipment company, from Woodland, California.


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