For a lot of districts, working in trenches or excavations is just part of the job. While excavations and trench work may be another routine part of the job, following proper protocol is paramount for your coworkers’ safety. Negligence can mean serious injuries or worse—fatalities. The US Bureau of Labor Statistics’ data show that 271 workers died in trenching or excavation cave-ins from 2000 through 2006.
In a review of multiple national databases, researchers from the National Institute for Occupational Safety and Health found that trenching and excavation hazards during construction activities resulted in 488 deaths between 1992 and 2000. That’s an average of 54 fatalities each year. Although these statistics are astounding, there are lessons to be learned. Having appropriate policies in place can help prevent future injuries or deaths.
Pool members have had more than their share of such injuries. These have been the result of collapse, jumping into a trench without access established, and even an employee jumping over trenches and falling in. Some districts have had multiple trench failures over the years. Luckily, the worst injuries included a hurt knee and a fractured wrist, but these incidents could easily have been fatal.
Even if an excavation cave-in doesn’t seem serious because the debris only goes up to your knees, the pressure will start reducing circulation in your body almost immediately. Also, while you and your coworkers are digging you out, the rest of the excavation may collapse and you might not be able to get out in time. Every excavation and trench should be conducted safely and seriously every time.
The majority of trenching and excavation fatalities revolve around cave-ins. The soil you are excavating weighs a lot more than you may think. Depending on the soil, one cubic yard of earth can weigh up to a ton. This means that even a small accident can become a serious situation very quickly. This is why each excavation and trench needs to utilize one of the four following safety precautions before completion of the work: benching, sloping, shoring, and shielding. Each of these methods has it own pros and cons, so it will require an experienced professional to decide which method is right for your specific task and location.
There are a few things you should consider before choosing what type of protection is best. First, any excavation that is between five and twenty feet in depth must be protected with the right system. Anything deeper than twenty feet must be designed by an engineer. Before deciding which method of protection you are going to utilize, you’ll need to figure out which type of soil you are dealing with. Each soil type comes with different forms of protection as well as sloping requirements. There is a science behind this, for which we included a general outline on the next page.
Benching and sloping are great protection methods when you have the room. They require cutting the slope back and utilizing more space. Shoring and shielding are much more conducive to working in tight environments like repairing a water line by the side of a road. Shoring can be installed very quickly with very little effort. Two people can easily put the needed shoring into a trench to protect workers in less time than it takes to use the benching or shoring methods. Trench boxes, which are placed around an excavation site, can come in basic configurations as well as customizable boxes that fit many different excavations. When utilizing a trench box or shielding methods, make sure you are always following the manufacturer’s recommendations and not customizing anything on your own.
During every excavation activity, it is important that you have someone on site who is designated as what OSHA defines as “competent person.” OSHA defines a competent person as an individual capable of identifying existing and predictable hazards or working conditions that are hazardous, unsanitary, or dangerous. This person should also be able to identify soil types at the site and which protective systems are required. Lastly, this person should be authorized to take prompt corrective measures to eliminate these hazards and conditions.
If you are the designated competent person, you will have a lot of responsibility. The lives of everyone working in the excavation are in your hands. Those working in the excavation will rely on your expertise and may need some training to identify issues while they work. If there is a crack in the trench box or shoring, or dirt sloughing off the side of the slope they need to be able to identify the issue and remove themselves from the situation.
In many workplace scenarios, factoring emotion into the equation can cause a bunch of headaches. Conversely, it’s exactly the right thing to do when thinking about safety. Emotion allows you to remove cost or time concerns from the scenario and have a more human perspective about the people you are working with. Before entering a trench or excavation. Ask yourself if you would feel comfortable putting your son or daughter to work in that hole. If your answer is no, then you should address the issues before proceeding with your work, and if the answer is yes, you should be safe to proceed.
Thinking about all of these situations with this perspective will force you to address safety hazards. The lives of your employees are your top priority. Once again, there is no infrastructure project or repair of any kind that is more important than anyone’s life or safety.
As you are getting ready to plan your next excavation or trench operation, remember the following issues:
- All trenches must be shored if 5 feet or greater in depth
- Spoil piles must be kept back at least 2 feet from the leading edge of the trench
- Ladders and access ramps must be within 25 feet of employees at all times
- Trenches 20 feet or deeper require engineering
- Identify all sources that might affect trench stability
- Make sure to identify any utility lines that might be underground
- Inspect your trench before you start your day
- Inspect your trench after a rainstorm or water event
There are good resources about safety guidelines online at osha.gov, and cdc.gov/niosh/topics/trenching. There are a handful of organizations that offer competent person training in the Colorado area as well. Trench and Shoring Services (shoring.com) offers free classes every month, and provides a certificate upon completion.
One last reminder, a good rule of thumb is that speed never supersedes safety. Even if a task, repairing a damaged water line for example, may be extremely urgent, skipping safety protocols for the sake of speed turns a simple project into a life-and-death scenario. No broken pipe is worth someone’s life.
