How to Reduce Trenching and Excavation Safety Hazards

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The work involved in exposing underground utilities can be intricate in nature. There is a lack of vision, due to the infrastructure being underneath the ground, meaning that accurately locating the target piping or cabling is difficult. This problem makes it incredibly important to gather as much intelligence as you can on the area in which you are working.

Finding underground schematics for the area is one of the first things that should be done when preparing to start work on a new site. The responsible contracting company that installed the infrastructure will have created detailing documentation for workers to use when performing repairs on the piping and cabling laid beneath the ground. You can use this information to speed along your utility potholing process.

utility potholing

Trenching for Repairs

Trenching is something that can be avoided by using vacuum excavation contractors. However, in some instances, it may be necessary to dig a trench to access the subsurface infrastructure. The proper definition of a trench, defined by the Occupational Safety & Health Administration, is a narrow excavation beneath the ground that is deeper than it is wide while being no wider than 15 feet.

It is crucial to have a competent person perform a survey of the area, aiming to find out the types of soil and rocks in the ground, as well as inspecting your protective systems and conducting regular site inspections. This person will be required by law to inspect trenches at the start of each shift, as well as following a rainstorm.

It is essential to decipher the type of ground materials you are working with, as this can affect the precautions you need to take before starting work. Some important factors that should be taken into account include the soil classification, water content of the soil, use of heavy digging equipment, depth of cut and other changes which can be caused by weather and climate. According to the Occupational Safety & Health Administration, or OSHA website, there is a range of safety precautions that need to be taken when trenching. The most common threat when trenching is the risk of collapse, which can result from the surrounding ground materials being too weak to hold up machinery and other items.

Generally, unless the excavation is performed in entirely solid rock, you will need to have a trench protection system in place. The first is called Sloping, which involves cutting the trench wall back at an inclined angle to ensure that debris does not fall into the trench. The second method is called Shoring and requires more work, such as the installation of support, items such as an aluminum hydraulic to prevent soil movement and cave-ins. The third and final method is Shielding, which protects workers by using trench boxes or other types of support that avoid soil cave-ins.

Overall, trenching and excavation are some of the most hazardous construction operations that you can undertake. This danger is why it is critical to take the necessary precautions to ensure the safety of workers on-site.

Expose Underground Utilities with Vacuum Excavation

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Underground utilities are particularly susceptible to damage, especially when worked upon in more traditional ways such as manual digging and using a backhoe.

Manual Digging is the most labor-intensive method of exposing underground utilities, requiring significant worker numbers to accomplish the job. This kind of work can also take days to complete, requiring both the removal and replacement of soil, meaning that projects can fall behind schedule. Another significant risk encountered when manually digging is that hand tools can come into contact with electrical wiring beneath the surface, which can pose a significant threat to human life, causing either severe injury or even death. Due to these reasons, other modern methods have become more commonly used.

A backhoe requires the use of machinery in order to dig up the ground and expose buried underground utilities. This piece of machinery has a large bucket which digs into the ground, in much the same way as a hand shovel. Additionally, due to the larger size of these machines, this means that the job can be completed more quickly. The problem with this method, much like with hand digging, is the lack of vision that the machine operator has underground. This lack of visual information means that underground cabling can be damaged during the excavation process, incurring significant costs and project delays while repairs are made to the existing infrastructure.

These older methods of potholing utilities have been replaced by a quicker, more cost-effective method called Vacuum Excavation.

utility potholing

What is Vacuum Excavation?

As the name suggests, vacuum excavation involves the removal of ground materials through suction. This method of excavation can be done in two different ways.

The first type of vacuum excavator uses water; highly-pressurized water is used to dislodge and remove soil. A vacuum is then applied over the area to suck up and store debris. Water excavation can be useful in situations where the ground would otherwise be too hard to simply vacuum. The high-pressure water helps to increase the moisture of the soil and make it easier to break up. Water vacuum excavation is suitable as it is non-destructive and allows for more accurate excavation of underground utilities.

The second method is simply air vacuum excavation. This method is suited to areas with loose soil and ground materials, which are quickly drawn up through an intake nozzle into a dry debris container. From here, you can unearth the underground utilities that you need to work on without causing any damage, similarly to the water excavation process. Once the work has been completed, a driver will dump the dry soil back into the hole you’ve created.

Overall, both of these methods are hugely useful at increasing safety on the worksite. Hand Digging is labor and time intensive, but it is also dangerous as workers can come into contact with live electrical wiring. The same can occur when using a backhoe. This danger is why you will now commonly find a Vacuum Excavator being used to expose underground utilities.