Trench shoring refers to the support system that includes props either timber or steel, and other support mechanisms installed to strengthen the walls of a trench to protect workers inside of it while performing activities such as construction, maintenance, or repairs.
According to statistics, 25 workers are being killed each year in excavation and trenching works, wherein 3 out of 4 are due to cave-ins or soil collapse. The number of fatalities in excavation and trenching is surprisingly the most from all types of construction operation.
Due to the alarming rise of fatalities and serious injuries, OSHA has intensified its long-standing endeavor by undertaking a national emphasis campaign and stepping up the enforcement of the regulations at hand. Below are some of the general excavation and trench shoring rules set by Organization:
1. Heavy equipment to be kept away from the edges of the trench
When working in the trench especially in the process of shoring, safety measures that ensure the welfare of the people working there are maintained are key. Heavy equipment falling inside trenches is a common phenomenon that has proved to be hazardous to workers. The safety measure that should always be taken towards it is to avoid placing them at the edges of the trenches since the instances of soil slip can lead to fatal accidents.
2. Avoid working under raised loads
Environments that entail raised loads, hanging equipment, and kentledge tend to experience falls especially as a result of a failure of the lifting treads or a piece falling. Working in a trench environment presents dangers with the raised loads especially where it involves many workers concentrated in a specific location. The competent worker should be informed about the risks involved with the raised and suspended loads and should inform colleagues of their dangers.
3. The trench should be inspected at every start of a shift
Different workers operate with different approach, whatever common denominators are at hand. For this reason, every time a new shift of workers comes to the site, they should ensure that the trench is structurally sound regarding the tools, equipment, and misalignments. This ensures that the process is continued conveniently. Therefore, inspection is key after every shift to ensure that the safety of every worker is not at stake.
4. All the surcharge load must be kept at a safe distance
Surcharge loads pose a threat in the event of trench shoring in that they increase the soil’s outward pressure. In the event of shoring of trenches, the surcharge loads should be kept at least 2 meters away from the site. This ensures that the load that will act on the trench is reduced, consequently, the less likelihood of a slip or even failure.
5. Testing the area for toxic fumes
Depending on the piping systems that were embedded within it, there can be toxic fumes, gases, and insufficient oxygen conditions that may be unfit for the workers. Provided this is tested and the trench is safe, the workers can just do their job, while in the situation of unsafety, the gears that enable it can be put for convenient working condition.
6. Check the location of the underground utilities
Utilities including water systems, sewer lines, oil, and gas may exist alongside a trench. To repair it and ensure that it is sound, damage to the existing utilities should be avoided. In the processes of shoring and underpinning of the structures, a plan of the trench should be analyzed first and the operations should be strict as stipulated by the engineer. This helps in the protection of the utilities and hence reduces the potential accidents and even the accumulation of more cost.
7. Inspection after a heavy downpour
Heavy rains have the effects of increasing the pore pressure and triggering the effects of liquefaction. This can lead to soil creep. To ensure that the safety of the workers is catered for, the trench should be inspected to confirm the potential creep or damage. The process of shoring exposes the structures associated with the trench to additional loading, for the situations of heavy downpour, when the phreatic surface is raised, prior inspection is paramount before the operations can continue.
8. Educate the workers on the dangers associated with the trenches
Operations of a trench especially a damaged one or the one that has surpassed the lifespan has associated risks. These risks can be shown to the workers before their operation, this ensures that each of them can avoid any dangers that can arise. The most common risk in the trench shoring process is the cave-ins. Safety precautions that ensure that the distance workers keep while at the site are safe and if possible, a barrier to block the soil creep can be made.
Conclusion
Trenching pose serious risks to the workers and utilities associated with it. Understanding the above risks and others as identified by the engineer in charge can help a lot when comes to prevention. The above tips can be taken by default in most trench shoring situations especially conventional process.
ESC offers trench shields which are a heavy-duty and robust, designed and manufactured in compliance with both national and International Standards. All shields are certified by third-party professional engineers, following the guidelines and requirements of the European Standards, NAXSA (North American Excavation Shoring Association) and complies with OSHA Standards.
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