What are the excavation hazards? Exposure to underground utilities and wastes often endanger the crew during an excavation. It’s especially the case when powerful heavy equipment hit the ground and possible subsurface infrastructure.
This results to serious worker injuries (and fatalities). In addition, there will be delays in the project and possible interruptions to the residences and commercial facilities in the area. For instance, accidentally hitting an underground storage tank might cause a fire or explosion. This could be the scenario if the area was an industrial site or a facility that stores volatiles.
Is it safe to dig in your site?
In highly urbanised areas such as Sydney and Melbourne, there’s a complex underground network of pipes and cables that make progress possible above the ground. Kilometres of water lines and electrical cables make the subsurface scenery much more complex than the tall buildings we see.
Due to the complexity, additional concerns become present before starting any excavation activity. Is there a main transmission line in the site? Do we have to remove significant wet and dry wastes first? Is there a way to make excavation safer? Is it really safe to use certain heavy equipment on the site? Which are the areas where we can safely dig?
Whether it’s new construction or utility placement and repair, knowing where to safely dig is crucial to worker safety and project progress. Continuing with our example earlier about underground storage tanks, certified Service Locators use Ground Penetrating Radar Technology to determine the exact position of the tank. This will allow the excavation crew to know where it’s safe to dig (and avoid hitting the tank and prevent release of volatiles).
Damages in underground gas pipes also release volatiles. This could lead to fires and explosions as with the storage tanks. Noxious gases might also harm the workers and the community in general. To identify and detect gas pipes, certified Service Locators may use the electromagnetic method. This allows accurate mapping of the trajectory of the pipes.
Aside from storage tanks and gas pipes, power lines and water pipes also make the excavation site risky. Accidentally hitting a power line can result to electrocution. This can also lead to expensive damage to the excavation equipment. On the other hand, hitting a water pipe can result to site flooding. This will cause a delay because you’ll have to remove the water first before you can proceed with the excavation. More importantly, the sudden release of water might injure workers (might result to falls, slips, propelled debris).
The electromagnetic method is also used for detecting power lines. This can be a reliable way whether it’s a dry or wet soil. Many times, conditions are unfavourable which can affect the signal’s accuracy. That’s why certified Service Locators often choose an appropriate method based on the target utility line and the prevailing conditions and environment.
Other possible excavation hazards
The excavation activity is a hazard itself. Whether it’s just a trench or major land depression, the actual digging can expose the workers to various risks and dangers.
For example, trenches can collapse due to the instability of the surrounding soil and rocks. This gets worse when there’s a lot of activity in the area wherein vibrations can make the area more unstable. This could result to falls and injuries. One or a few workers might fall or it’s also possible that tools and heavy equipment will fall or tip over (e.g. might pin down or crush the workers below).
It’s always recommended to maintain a safe distance between the trench edges and heavy equipment. Protective systems should also be in place that can depend on the depth of cut, type of soil, vicinity operations and other factors. For instance, shoring is implemented to prevent soil cave-ins and movements. This is accomplished by installing a support system (e.g. aluminium hydraulics). Other methods can also be implemented such as shielding (use of trench boxes) and sloping (use of angles).
Trenches and other man-made excavations should be inspected daily. Often new risks appear in the duration of an excavation activity. Vibrations, slight movements and increasing activity in the area can introduce new hazards and dangers to the workers.
Aside from physical hazards (falls, tipovers, slips, injuries), engineers and workers also have to deal with possible chemical and biological hazards. Breaking up the soil and opening up the site can release certain chemicals into the air. This will make the site unsanitary which will endanger the workers and nearby residences and businesses.
Underground there might be accumulated sludge, storm water and slurry. These might contain substances that can cause lung and nasal problems to people and animals. Toxins from the chemicals themselves or the by-products of microbes might harm all the creatures in the vicinity. This occurs during manual digging, usage of backhoes and other traditional methods of excavation.
Fortunately, modern methods have been developed to make excavation a safer activity. For instance, hydro vacuum excavation is non-destructive (doesn’t break or open up the soil too much) which allows for faster, more efficient and safer digging. It uses pressurised water to penetrate and an air vacuum to transfer the waste from under the ground into the tank.
It’s an eco-friendly and less labour intensive method. It’s a straightforward way of getting the waste. This makes the exposure to waste minimal while getting the job done more efficiently. Hydro vacuum excavation is also recommended in dense areas where accessibility is an issue.
Aside from making the operations safer, hydro vacuum excavation also offers cost and speed benefits. Due to its straightforward technique, there will be a less need for repairs and backfilling. As a result, your team will save time and resources.
Identifying & addressing excavation hazards in your site
Excavation (although it seems a labour intensive process) is actually a delicate activity that requires special precautions. Engineers and other officers are tasked with identifying the risks present in the site. They have to consider the possible hazards and dangers both above and below the ground. They also have to study and analyse the vicinity.
New risks also appear before, during and after excavation. Before digging, people and equipment will move into the area first. Can the site handle the weight above it? During excavation, activities of people and equipment will cause vibrations and other movements in the site. Is the area stable enough to handle those vibrations? Are there protective systems in place to support the unstable ground?
After the excavation, were the repairs and backfilling properly done? What do you need to do with the building site waste? Were the slurry and sludge properly removed and disposed? Will there be no risk to the community once the project is done?
These are just some of the most important questions engineers consider. Depending on the nature of the site (e.g. type of soil, type and extent of excavation to be done, proximity to other structures, urgency of the project), there might be risks unique to the area and project.
For instance, highly urbanised and people-dense areas often have a complex and extensive underground network of pipes and cables. This should be mapped promptly and accurately before initiating any kind of digging. Aside from improving workplace safety, this can also help in speeding up the work because workers know beforehand where to dig safely.
On the other hand, relatively remote areas might have been used as an industrial site (e.g. oil refinery, transport depot, service station). There might be underground storage tanks that still contain diesel, petrol and volatiles. Accidentally hitting these tanks (especially with powerful heavy equipment) might cause leaks, fires and explosions.
There are also certain sites where sludge and slurry might have accumulated. These should be removed first before proceeding to further work. However, breaking up the ground could release gases into the atmosphere and immediate surroundings. One way to prevent this (or minimise it) is through hydro vacuum excavation.
It’s recommended to get a whole picture of the site (above ground, subsurface and the vicinity) so you can identify all the risks. It’s especially the case when you’re dealing with subsurface infrastructure because they are hidden from view. This kind of task requires specialist tools and expertise to ensure accurate utility mapping.
Here at One Search Locators we can accomplish that. As a reputable service locating firm, we’ve already handled assignments in Sydney, Newcastle, Wollongong, Melbourne and surrounds. Our certified Service Locators will conduct the detection of underground utilities in your site.
Call us today at 1300 530 420 and we’ll arrive on your site within 24 hours upon your request. We can also provide you a free quote once you’ve discussed your required services.