Excavation and trenching are necessary for most construction projects. It is because they are regular operations in almost all construction projects. However, despite being common, they are quite flawed, making trenching is a prevalent Jobsite hazard. Every year, more than 50 Americans die as a result of trenching and excavating. That said, here are questions and answers to digging a trench safely:
Does the Law Require a Professional to Be Present for All Trenching Activities?
Trenches differ in size and depth. That said, the safety requirements for each trench varies, mainly due to depth. All trenches that exceed a depth of 5ft have to have a protective system installed unless they are in stable rock. Such a protective system needs professional knowledge.
Professional knowledge can be offered by anyone in this case as long as they are familiar with soil types, compositions, and hazardous excavation zones. The rules come from the Occupational Safety and Health Administration (OSHA). They apply for trenches from 5 to 19ft. When it comes to trenches that are above 20ft, a registered professional engineer must authorize trenching.
What Are the Types of Safety Hazards When Digging a Trench?
There are different types of safety hazards during the excavation of a trench. Common ones include cave-ins where the soil collapses inwards: Falls and falling loads whereby equipment and workers fall into an excavated area. Additionally, deep trenches have depleted oxygen levels, which can cause hypoxemia.
Moving machinery on-site can also pose a severe safety hazard. Mobile equipment operators have an obstructed view, so they may not detect when nearing the trench. Last but not least is hitting utility lines. From sewer lines to gas leaks and electrocution from power lines, the list is endless. Other safety hazards include:
- Accidents to members of the public
- Surface Obstructions
- Undermining of nearby structures
- Loose rock and soil
- Ground Water
Before Digging a Trench, What Should Contractors Do?
First, an expert’s history assessment must be done to find out the risks on-site should be carried out. The report includes utility assessments to determine buried underground pipework and overhead powerlines. Moreover are investigations to find out whether there is a dangerous atmosphere is present. In response, an expert will create a work site’s safety process and label it as a confined space. Appropriate emergency equipment should also be on-site as a precaution.
What if Digging a Trench May Reduce the Stability of a Nearby Structure?
If this is the case, authorities must take control measures. First of all, the Excavation process must be looked at to ensure everything is safe for neighboring structures. Note that even small trenches can undermine the foundation of a network, especially if it’s shallow. If this is not possible, it may be necessary to remove the structure.
Besides ripping the building down, the excavation company must temporarily support the structure as the excavation project proceeds. Suppose a neighboring building is involved during an excavation project. In that case, a structural engineer should be contacted to design proper plans for methods to support structures. This way, the stability of the structure will not be compromised during excavation. To add to this, digging a trench near such an arrangement will pose a hazard to employees if safety is not taken seriously.
How Can Contractors Avoid the Accumulation of Water in a Trench?
Drain water management is part of the emergency measures that are set in place before the excavation is started. In case of unprecedented flooding, there should be a plan to evacuate all personnel very fast. Additionally, there should be control measures to address this risk. Such a safety system prevents the accumulation of water.
How Do Professional Excavation Companies guarantee excavation is safe?
Simple: By following all rules and regulations set by OSHA. For example, a professional engineer inspects the soil at the beginning of each shift. Moreover, they inspect the site before, after it rains, and after other extreme weather events. They are completely familiar with potential hazards since moisture and other weather conditions affect soil stability.
They also respond to these site conditions by designing and implementing a protection system. This system shields, slopes, and supports the soil depending on site conditions. Supports prevent cave-ins, which killed two workers a month on average. That said, to prevent Jobsite injury and fatalities, professionals are required.
Other measures include installing a barrier and safety signage around the Excavation perimeter to mark the fall hazard. Professionals also identify areas that have low levels of oxygen. Following this, workers wear appropriate respiratory protection equipment. Finally, professional excavation companies have access to utility maps which prevent hazards caused by hitting utility lines.