Excavation safety isn’t just a legal requirement or a box to tick in the construction industry; it’s life-and-death serious. The hidden perils that can lurk during excavation work have devastating consequences for people and businesses alike.
Level Ground Excavation involves complying with regulations and ensuring workers have proper equipment. It’s about valuing the lives of people who work in these dangerous environments and creating systems that promote a culture of safe practices. From traditional shoring and shielding to cutting-edge technologies, the construction industry continually develops ways to improve excavation safety.
PCBUs must control risks associated with excavation work to prevent harm so far as is reasonably practicable. This includes managing the risk of ground collapse by ensuring appropriate precautions are in place.
The Occupational Safety and Health Administration sets standards for excavation workers, including specifics on cave-in protection and other safety measures. These rules and precautions ensure workers can complete their work without endangering themselves or others. However, putting those precautions into practice takes work. Construction firms must ensure their workers receive the training to apply them consistently and effectively.
Proper protective systems can mean the difference between an unsafe working environment and a project finished on time and within budget. However, choosing the right defensive system for a specific job can be complex and require expert input.
For example, the type of machinery available on a particular job site can influence the type of protective system appropriate for an excavation. If a steel trench shield is required, but the only machine is a backhoe that cannot handle the weight of such a shield, another protective system must be chosen.
When selecting a protective system, a competent person must consider several factors, including soil classification, depth of cut, water content of the soil, changes caused by weather or climate, surcharge loads (e.g., spoil or other materials to be used in the trench) and other operations nearby. A certified professional engineer may be needed to design the appropriate protection system for each excavation.
Shielding is the most common method of protecting workers from cave-ins, with trench boxes and other supports preventing soil collapse. Sloping and benching are also used to preserve excavations from collapse by cutting trench walls away from the bottom of the excavation at a safe angle. However, sloping and benching must be carefully designed to minimize the risk of collapsing material or creating a hazardous atmosphere at the bottom of an excavation.
The key to safe excavation work is identifying hazards and determining the best controls. This includes protecting workers from falls, cave-ins, inhalation hazards from contaminants that take oxygen from the environment (such as hydrogen sulfide gas and carbon monoxide), water ingress, and flooding. Providing a safe means of entry into and exit from excavations is also important. Using the risk management process, PCBUs should consider these hazards and plan to control them before work starts. They should also regularly review the hazards and their controls.
Hazard identification includes assessing the work site, including ground conditions and existing services. The competent person should consult with relevant people to determine the appropriate method and safe system of work for each site. They should also train workers and monitor the excavations for signs of a potential collapse or other hazards.
Before work begins, underground services such as power, water, and sewer lines must be located. This can be done by contacting the local utility supplier to find out the location of these lines. Then, workers should dig away from these lines and check each trench before and after work to ensure they are not buried or otherwise affected by the excavation.
Workers should wear high-visibility clothing around excavations to make them easily identifiable by drivers of heavy vehicles. They should also be provided with warning signs to indicate the proximity of an excavation. In addition, all excavations should be inspected daily to assess the soil’s condition and to check protective systems. The competent person should immediately remove workers from an excavation if they detect a situation that could lead to a cave-in, such as flooding or deteriorating soil conditions.
Other hazardous conditions associated with excavation include vibration and noise, water ingress and flooding, struck-by hazards, mobile equipment accidents, and confined spaces. A competent person should implement controls to minimize these hazards and keep workers safe, such as ensuring the area is properly fenced, monitoring noise levels and vibration, training employees on safe work practices, providing adequate ventilation, and limiting exposure times.
Training is a critical component of excavation safety. It teaches workers how to identify and avoid hazards, as well as how to use excavating equipment safely. It also covers the relevant work health and safety (WHS) regulations for the job and demonstrates how to follow emergency response protocols.
In addition to training, a qualified supervisor or competent person must always be present when an employee works at an excavation. This ensures that someone can always communicate with and supervise the work. It is also important that this person knows the ins and outs of emergency response procedures and equipment.
Regularly inspecting the excavation site before each shift starts is a good practice. This can help prevent issues such as unsafe soil or the collapse of walls or sides of an excavation. The competent person can then take the appropriate action to address these issues.
Another crucial aspect of excavation safety is ensuring that all workers know the location of underground services and know not to strike them. This includes gas, water, stormwater, sewerage, electricity, telecommunications lines, chemicals, fuel, and refrigerant in pipes or ducting. It is a good idea to consult the service owners and the relevant authority before starting work near these services.
Other controls for working around services include identifying, marking, and recording the position of all existing underground services using cable, pipe, and service plans. PCBUs should also consider other engineering controls such as benching, battering, or shoring to reduce the risk of ground instability during excavation work.
When a worker is working in a trench, they must be protected from potential collapse. To do this, the excavation must be sloped or shored to hold back soil. A qualified person must carry out these operations, and they should be conducted in conjunction with an emergency response plan that includes personal protective equipment such as face masks and respirators.
Moreover, a competent person must inspect all trenches and excavations daily before work is done on-site. Additionally, they must check them as conditions change. This means that they must not only look at the depth of the ditch but also ensure that any hazards, such as underground utility lines or heavy equipment, are kept a significant distance away from the edge of the trench.
In addition, a competent person must ensure that the excavated area is properly ventilated. This prevents hazardous fumes from collecting and putting workers at risk. Additionally, they must ensure that electrical equipment in the trench is properly grounded and tagged or marked as dangerous. Moreover, they must have systems to ensure that the lockout/tag-out procedures are consistently followed.
Finally, a competent person must ensure that all equipment in the excavation is tested for flammable gas and liquids and that the results are recorded before work begins. A continuous monitoring system (audible alarm preferred) should also alert workers of rising % LEL levels. Furthermore, a new gas test should be performed before the excavation resumes if a permit is suspended for any reason.
Ultimately, it’s clear that safety in excavation and trenching is more than just a regulatory concern. It’s about more than just compliance and legal responsibilities; it’s an ethical responsibility that should be prioritized in construction companies of all sizes. When it comes to protecting human life, there are few things more important than following OSHA standards and fostering a workplace safety culture. By reflecting on the statistics, examining comparative scenarios, and acknowledging the immense human impact of an accident like a trench collapse, it becomes clear that there is no room in the construction industry for neglecting excavation safety.