All You Need to Know About Common Underground Utility Location Methods
Underground utility locations are difficult to find considering the wide network of cables and lines increasing consistently.
There is a growing congestion of lines, which makes it vital to pinpoint their location, including telecommunications, sewer, water, gas, and fibre lines, to ensure safety.
There are some common methods used to locate underground utility, which are now used to provide safety to everyone. Listed below are the most widely used practices.
#1: Electromagnetic Utility Locator
Private utilities are commonly located by a technique called electromagnetic utility locating. The technique involves locating equipment by generating electromagnetic radio frequency.
When the method is applied to the ground, subsurface utilities that contain conductive materials are easily detected on the receiver.
This method is popular for its accuracy and commonly used for detecting:
Generally, gas lines are made of medium and high quality polyethylene pipes, or plastic. As such, tracer wire is used alongside or mounted on top of the pipeline so that the line is easy to locate.
In such instances, it’s required to have access to the system and current can be induced and the tracer wire can be easily located.
However, there are certain lags of this technology:
It can’t locate unmarked asbestos, plastic, non-ductile, tera-cotta or concrete pipes.
It fails to perform beyond 10-15 feet depth
#2: Acoustic Pipe Locator
Acoustic location techniques were commonly applied to locate waterlines. However, with the introduction of SENSIT ULTRA-TRAC APL, even unmarked plastic pipes and sewer and water laterals can be detected.
The instrument can send a series of pings down into the ground, and monitor acoustic wave patterns that ultimately lead to a locate profile.
In fact, APL can locate in grass, soil, gravel, asphalt, and concrete, making it easier to use and detect within minutes. Indeed, it is the most awaited additions to utility location options.
#3: Ground Penetrating Radar
Also called GPR, Ground Penetrating Radar is a technology used subsurface utility locating that utilizes high frequency pulses.
Radio waves are emitted into the ground and the facilities can deflect radio wave back to the operator where objects are displayed on specific equipments.
These locating equipments are commonly used for buried pipes, manholes, tanks, cables and similar buried objects, which cannot be located with other common methods like electromagnetic locating.
To understand and operate this type of equipment it requires extensive training, experience and expertise.
However, GPR also has certain limitations like:
Some types of soil like clay, shale or saline, having higher conductivity, restricts GPR from penetrating the soil.
Most of the high frequency antennas like 300-1000+MHZ can penetrate a short distance only.
A major drawback of GPR is that when the ground penetrating radar is used, for each foot in depth the buried pipe must have an inch diameter. For instance, a 6-foot pipe needs to be 6’ in diameter in order to locate it through GPR.
Environment accessibility, soil density, and crowding of utilities also influence the effectiveness of GPR.
#4: Hydro or Vacuum Excavation
Vacuum excavation, also called potholing, is a fast yet non-destructive way of locating and exposing underground utilities.
In this case, higher pressure air is utilized for breaking up the soils, and vacuumed into the tank.
This method is commonly used in difficult soil conditions such as in case when pressurized water breaks up soil. The method is also called hydro digging, soft digging, or hydro trenching.
There are several methods to be used to locate utilities starting from some state-of-the-art techniques and equipments to most advanced technologies and locators.
Author Bio: Jon Armstrong is an expert in cable fault finding. He uses Geo scan techniques and underground cable locator to find cable location and offers great service. With several years of training and experience in this field, he has excelled in his area of work.
