Trenching and Excavation Procedures and Safety: A Practical Guide

Did you know that the fatality rate for excavation work is 112% higher than general construction work?

There’s no doubt that trenching and excavation are among the most dangerous activities in the world of construction. The good news is that there are plenty of ways to secure these sites (and the workers inside them).

Whether you’re overseeing a site or you’re the one down in the dirt, trench safety is of paramount importance. In this article, we’ll review some basic OSHA excavation standards. We’ll also discuss practical steps you can take to keep everyone safe during the excavation work.

Read on to learn more—it could mean someone’s life.

Trenching and Excavation Safety Concerns

Before we discuss safety procedures, let’s briefly outline the 5 major risks associated with trenching and excavation.

  1. Cave-Ins

One cubic yard of soil can weigh as much as a car. Even a minor cave-in could be enough to seriously injure someone (or worse).

Before the project begins, a qualified professional must evaluate the soil type and design a system to prevent cave-ins. This involves a detailed knowledge of shields, supports, and slope designs.

  1. Falls & Falling Loads

OSHA excavation standards require that all job site materials be stored at least 2 feet away from the edge of an excavation.

This prevents a potential disaster if dirt or a piece of equipment falls into the trenched area. There should be barriers and signage around the excavation area alerting everyone to the fall hazards.

  1. Hitting Utility Lines

One of the worst things you can do while excavating is digging into buried utility lines. Not only could this spell disaster for your municipality, but it could also expose workers to electrocution or deadly gases.

Don’t leave this one to chance. Contractors need to call 811 and wait to hear from all utility operators before excavation begins.

  1. Hazardous Environment

If your excavation depth exceeds 4 feet, OSHA requires you to order atmospheric testing. This will alert you to any toxic chemicals or gases, as well as depleted oxygen levels.

If there are any atmospheric hazards, all workers need to wear the respiratory protection equipment appropriate for the situation.

  1. Accidents With Mobile Equipment

Dump trucks, backhoe loaders, and other heavy equipment present more potential hazards on the site. Equipment operators might have an obstructed view that limits their awareness of trench perimeters and depth.

Every worker should maximize their visibility with appropriate protective apparel, including a hard hat and reflective vest.

Trench Safety Before & During Excavation

Now that you know the most common hazards during excavation work, let’s talk about how to keep everyone safe.

Prepare With Safety in Mind

Safety begins long before your crew ever breaks ground. You should have already checked local legislation and mapped out buried utility lines.

You should note any overhead power lines as well as nearby vehicles or equipment that could disrupt the soil. This is also the time to review the atmospheric tests and gather all the safety apparel and equipment you’ll need.

Competent Person Responsibilities

Your site’s competent person must make many important determinations, starting with soil classification. The type of soil you’re excavating will determine which protective systems you’ll use for the project.

It’s up to the competent person to:

  • Classify soil type
  • Inspect protective systems
  • Design structural ramps
  • Monitor water removal & equipment
  • Conduct site inspections

The competent person to identify and existing or potential hazards and put necessary safety measures into place. It’s up to them to promptly use corrective measures to control or eliminate these dangers.

Use the Right Protective System

Depending on the soil, you’ll use one of the following ways to secure the site.

Sloping involves slanting the soil away from the trench. This is done by cutting back the trench wall at an angle that’s inclined away from the excavation. Trench slope design is a key factor in longevity.

Shoring involves using support systems like hydraulic cylinders to create a protective barrier between the trench walls and the workers. This prevents both soil movement and cave-ins.

Shielding involves using systems like trench boxes (or other types of support) to protect workers from cave-ins.

When deciding which trenching and excavation system to use, factor in the depth of the cut and the water content of the soil. You should also be aware of changing weather conditions and other work in the area that could potentially impact your site.

Reevaluate & Monitor Conditions

Soil conditions will vary during a project due to weather changes, movement of materials, and other factors.

For this reason, daily inspections of the worksite are not optional. Full inspections should be made every morning and especially if it rained or snowed overnight.

Always have someone watching out above ground for potential dangers. They can alert workers to any hazards and provide emergency support if needed.

Speaking of emergencies, every worker should know the details of the emergency plans and rescue procedures. The first aid box and other emergency supplies should be easily accessible (and everyone should know exactly where to find it).

On a final note, no one should be allowed on site without the proper safety apparel and equipment. No exceptions.

Doing Excavation Work? Keep this in mind.

When it comes to trenching and excavation work, you can never be too careful.

Make sure you (and everyone on your site) are fully aware of the potential hazards. Do plenty of pre-excavation preparations to ensure the area is safe. Proper trenching is fundamental for infrastructure, trench drainage and utilities.

And before anyone goes down to begin working, make sure every safety precaution is already in place. There should always be at least one competent person overseeing the site, as well as first aid equipment nearby.

If you have any doubts about OSHA excavation standards or other safety concerns, take some time to review the guidelines. A few minutes of preparation could (quite literally) make the difference in someone’s life.

This article was written by Ankit Sehgal, President and Head of Engineering at Swiftdrain Inc., a global drainage and infrastructure products manufacturing company. He oversees all product design and development at the firm, including engineering, materials sourcing and production.

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