construction



underground utilities


 

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SERVICING RESIDENTIAL & COMMERCIAL


We serve a diverse base of residential and commercial customers with our utility services. Our utility experience ranges from underground utility work, including boring tunnels and replacing and repairing sewer and water lines to installation of new services for individual sites and subdivisions

The installation of underground utilities includes pipe and other structures for the conveyance of water, sewage, gas, electricity, etc. Our underground services include potable and reclaimed waterline, gravity sanitary sewer line/force main, and storm drain.

"POTHOLING" OR DAYLIGHTING


Potholing is the practice of digging a test hole to expose underground utilities and determine the horizontal and vertical location. The horizontal and vertical location of the exposed facility must be tied to an above grade feature or permanent survey benchmark. The position may be identified by GPS or by measuring the distance to permanent features in three directions. The elevation below grade should also be recorded.

Most municipalities and utility companies do not consider potholing to be an option. More accurately, it is viewed as an essential phase of underground construction for all types of excavation including horizontal directional drilling (HDD) operations.

State statutes require excavation within 2' of marked utilities be performed in a careful manner.


It is recommended that potholing be used to expose utilities for any excavation including HDD within the tolerance zone of the marked utility. The tolerance zone (also known as the “approximate location”) is typically a strip of ground equal to the width of the underground utility plus two feet on either side. 


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POTHOLING METHODS


For horizontal directional digging (HDD) operations with a bore path that parallels a utility within 3 feet, potholing should be required at the beginning and end of the bore and every 50 feet along the route. For HDD operations with a bore path that parallels a utility within 5 feet, potholing should be performed at the beginning and end of the bore and every 200 feet along the route. Potholing must also be performed for all utilities crossing the path of HDD operations. Backhoe excavation is not allowed within two feet of existing facilities.

Lines installed using HDD do not disturb the ground or leave a ditch line, so the ground is the same hardness, and it is difficult to know if you are getting close to the line or cable. Since the ground may be hard, you can easily cut a cable line with a shovel. Using a vacuum with air or water at a non-damaging pressure will safely expose the line.

Hand digging a test hole is the method of digging a pothole by manual means with handheld equipment such as a shovel. This method is labor intensive and time consuming. The benefit to hand digging is that it does not require expensive equipment and is reasonably safe for locating most facilities. As with any excavation, extreme caution should be practiced if digging near hazardous utilities such as electric lines.

Using a vacuum or hydro excavator instead of a shovel has its advantages. A shovel against a water pipe is most likely not devastating, but a shovel against a fiber optic line can be extremely problematic.

Utility Line Exposure


Services exposed during potholing must be protected throughout the project. Exposed services can shift or sag when the soil supporting and protecting the utility is removed. Utilities that are unsupported due to potholing should be temporarily supported by shoring or other means. The utility should also be protected from items falling into the excavation which could crush or cut the facility.

Vacuum excavation is the preferred method for non-damaging exposure of buried utilities. Vacuum excavation utilizes either air or water pressure to break up the soil and a vacuum device to collect the spoil.

While locators are becoming more accurate, it is still important to physically see exactly where the line or pipe is located.

 

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Potholing Utilities Saves Time & Money


Vacuum excavators are self-contained units that use pressurized air or water to displace soil and create a dry or wet spoil. The displaced dry or wet spoil is removed from the area through a hose using high-velocity suction and stored in a holding tank on the vacuum.

Since vacuum excavators use low-pressure air or water to remove spoil, they are perfect for potholing or identifying existing utilities during underground construction projects.

Operators can select the amount of air or water pressure appropriate for the utility. A lower pressure of 1,500 psi should be used for gas and fiber lines in order to not damage the line coating. A higher pressure can be used for water lines.


The Payoff


Damaging underground utilities can be expensive in terms of project downtime and potential contractor fines. The hydro and air pressure does not damage existing utilities like a heavy equipment strike will. Air and water can maneuver around the existing utilities, giving the crew a safe and clear view of the items below. Call ARS Asphalt today and let us give you a quote. You need the best to take care of your underground utilities and we are here to make it as simple as possible.