The Ultimate Guide to Pipe Locators

The oldest known pipelines recorded by archaeologists are in the Indus Valley and are over 5,000 years old. These early pipelines were made of terracotta clay and were built to carry water to homes and fields. As other civilizations rose and fell, many invented pipeline technologies independently or borrowed the concept from neighbors. Over the following millennia, pipeline technology evolved into a major industry that supports commerce and commodities transportation around the globe.

Today, pipelines carry everything from water, to oil, and much more. Without networks of pipelines connected to our homes and businesses, our modern society would look very different. With the increasing reliance on and expansion of these lines, the ability to accurately and efficiently locate underground pipelines has become essential in maintaining and repairing modern utility delivery systems.

Locating the Different Types of Pipeline Materials

The first pipelines were made of terracotta, wood, clay, and stone. While ceramic lines are still found on some systems today, most pipeline utility systems use more modern materials. The following is a brief description of some of the more common pipeline materials that can be found on utility networks today.

Ceramic Pipelines: Ceramic pipelines are still in use, primarily in older water and sewer systems. Ceramic pipes won’t oxidize, corrode, or degrade in sunlight and are resistant to abrasion. They are, however, prone to cracking or breaking under pressure or vibration. In addition, joints between pipeline segments can be difficult to make waterproof.

Plastic Pipelines: Plastic pipelines can be made of a myriad of plastic materials such as PVC, PEX, CPVC, ABS, Polyethylene, and HDPE. The material used will depend on the liquid or gas being transported and the environment in which the pipeline will be operating. Plastic pipelines are typically used for liquid and gas transportation.

Iron Pipelines: Iron pipelines have a long history. The first iron pipelines were made of cast iron. Many municipal pipeline systems still have a cast iron component, especially in older parts of town. Most new pipelines that incorporate iron are now built with ductile iron. Ductile iron is less brittle than cast iron and can be machined easier. Both types of iron pipeline are not easy to weld, and connections and joints can be difficult to make waterproof. Iron pipelines are typically used in water and sewer systems.

Steel Pipelines: Steel pipelines can be used for most pipeline applications. Steel is strong, easy to machine, weld, and thread. Air and watertight seals can easily be made at joints on steel pipelines. Downsides to steel can be, weight, cost of installation, and the potential for oxidation.

Copper Pipelines: Copper pipelines are used primarily for hot and cold-water systems. Copper is easy to work and to weld. Air and watertight seals can be made easily on copper lines. Downsides to copper piping can be the cost of materials and installation, along with the potential for corrosion.

Concrete Pipelines: Concrete pipelines are used primarily for water transportation. They are most used in sewer systems and storm drainage systems. Concrete is an inexpensive material, fairly strong, and can be installed quickly. However, concrete pipelines can be brittle if impacted and joints can be difficult to make water tight.

Pipe Locating Equipment

With networks of pipes beneath every city and town, the ability to accurately locate pipelines for repair and replacement is essential to maintaining our modern utility systems. A variety of pipe locating equipment is available to utility workers. These locators can help reduce time consuming guesswork on repair and replacement projects and can save large expenses due inaccurate or unnecessary excavations.

The type of utility locator appropriate for the job is dependent on several factors including the type of pipeline material being located, the presence or absence of trace wires along the line, and the setting of the buried pipeline.

Locating Traced and Non-Traced Pipelines

For the purposes of locating pipelines, piping materials can be divided into two broad categories: conductive and non-conductive. Conductive pipeline materials allow the transfer of electrical signals along the length of a pipeline. Materials for these lines include metals such as ductile iron, cast iron, copper, lead, aluminum, and brass. Non-conductive materials are resistant to the transfer of electromagnetic signals and include plastic, ceramic, concrete, and asbestos.

A common practice with non-conductive pipeline installations is the addition of trace wires. These are usually made of thin copper wire and are installed along the length of the new line. This allows future pipeline workers to easily trace the route of the installation. Unfortunately, trace wires were not always installed on older lines, and the thin copper wires can sometimes break during installation or with the passage of time.

The presence of conductive or non-conductive pipeline materials will have a strong bearing on the type of pipe locating equipment that can be used when tracing underground pipelines.

AML / All Material Locators

All Material Locators or “AMLs” are produced by Subsurface Instruments with patented technology. AMLs were designed specifically to locate non-conductive and non-traced underground utilities as well as the traditional conductive materials

AMLs project an ultra-high radio frequency from an antenna on the end of the locator. Changes in density create distortions in the reflected radio waves that are detected by receivers located on either side of the blade. An onboard microprocessor then interprets the signals and alerts the operator to any density change through a combination of LED lights, audio signal, and laser. This technology allows the user to search for buried plastic pipelines based on differences in density.

Utility Locators

Utility Locators can locate pipelines that are made of conductive materials or have an intact trace wire. These locating systems have two components: a transmitter and a receiver. The transmitter is usually a small box used to create an electromagnetic signal along the line that is being traced. The transmitter typically has several frequency options to help with differentiating the signal from electromagnetic interference in the environment.

The second component is a receiver that can be set to the frequency emitted by the transmitter. This device is moved along the route of the pipeline and can “read” or interpret the transmitter signal to determine the precise location of the buried pipeline. The operator is generally alerted to the pipeline’s location by visual and auditory signals.

When using the transmitter of a utility locator, the pipeline to be traced can be energized through either induction or conduction.

Conduction: This form of transmission involves a direct connection between the transmitter and the pipeline or trace wire. This is usually done with alligator clip equipped connector cables. A ground stake is also used to complete the circuit. Direct transmitter conduction is more powerful than induction and allows the pipeline to be traced at a further distance from the transmitter box.

Induction: This form of transmission involves indirect signal transmission. The transmitter box is placed over the pipeline or trace wire and emits an electromagnetic signal into the soil. This signal induces an electromagnetic field in the underground pipeline.

Utility locators are very accurate and can usually provide an estimate of depth. However, they are of limited use if the line is non-conductive (plastic/ceramic/concrete) or if the trace wire has been broken.

If it is believed that a pipeline has a broken trace wire, a ground fault locator such as the A-Frame by Subsurface Instruments can help to locate the trace wire break for repairs.

Sewer Cameras

Sewer cameras are useful tools for locating underground pipelines and for diagnosing damages such as breaks or clogs. Most modern sewer cameras are remote controlled and can be “steered” through a pipeline route. In addition, many sewer cameras can also record video to aid in diagnosing problems or to be shared with workers and clients.

Some sewer cameras are also equipped with sondes. A sonde emits an electromagnetic frequency as it moves through the pipeline. When used in conjunction with a utility locator receiver, the sonde’s path through the pipeline can be traced from the surface.

Similarly, a conductive trace rod or sewer snake can be threaded through a non-conductive line and connected to a utility locator’s transmitter. The locator’s receiver can then be used to trace the pipeline.

Magnetic Locators

Magnetic locators work by reading variations in the Earth’s magnetic field caused by ferrous (iron or steel) objects. If a pipeline is made of iron or steel, or if it has iron valves or joints, a magnetic locator can read these components. Magnetic locators can frequently read ferrous objects at greater depths than traditional metal detectors and make a great addition to any pipeline locating kit.

Subsurface Instruments produces a combination utility locator / magnetic locator known as the PL-TT. This powerful locator incorporates the advantages of both a magnetic locator and traditional utility locator systems.

Choosing the Right Pipeline Locating Equipment

When considering purchasing a pipe locator, the most important considerations are the types of pipeline material you expect to encounter and the environment in which you will be locating. For conductive lines or pipelines equipped with intact trace wires, a utility locator is usually going to be the best choice.

If the pipelines being located are likely to be made of non-conductive materials such as plastic, ceramic, or concrete, the best locating device will be determined by whether the line is equipped with a trace wire. If there is an intact trace wire, a traditional utility locator will still be the best option. If there is no trace wire, or if you suspect that the trace wire is broken, there are two options.

If the utility line has a broken trace wire, a ground fault locator such as the A-Frame by Subsurface Instruments can help to locate the break in the trace wire for repairs.

If there is no trace wire, an All Materials Locator or AML should be considered, especially if the pipeline is not buried in rocky soil or near tree roots.

Pipe Locator Brand Comparisons

There are many brands to choose from when selecting a pipeline locating device. Each brand has its own strengths and product developers tend to concentrate on specific attributes in their line of products.

Pipehorn Pipe Locating Equipment

Pipehorn equipment is designed for intuitive use and rugged reliability. Pipehorn carries three models of pipe locating equipment and they certainly are up to the task. The Pipehorn 800-H is their single frequency pipeline locator, and the 800-HL is their multifrequency pipeline locator. These locators are no frills workhorses designed to get the job done and get it done fast!

In addition to the utility locators mentioned above, Pipehorn also produces a magnetic locator with an ergonomic handle that is unique in the industry. If your locating jobs are going to take more than a few minutes, the handle on the Pipehorn Maghorn will let you swing the locator all day without tiring your grip. All Pipehorn products are proudly Made in the U.S.A.

Subsurface Instruments Pipe Locating Equipment

Subsurface Instruments carries multiple models of utility locators. Their VF-3 and VF-10 locators are equipped with multifrequency options for pipeline locating in urban areas that have high EMF interference. These models also have powerful transmitters for energizing lines at long distances.

In addition to their selection of pipe and cable locators, Subsurface Instruments also carries a transmitter clamp for situations where direct transmitter connection is not possible. They also carry an A-Frame ground fault locator for identifying troublesome breaks in trace wires on non-conductive pipelines.

If you are looking to locate non-conductive pipelines, Subsurface Instruments is the only manufacturer of the AML All Materials Locator. These devices are designed specifically for locating non-conductive and non-traced underground utilities such as PVC, HDPE, Polyethylene, and other plastic pipelines. In addition to locating non-conductive pipelines, the AML can also locate conductive metal pipes. Subsurface Instruments is based in Wisconsin and its products are proudly Made in the U.S.A.

Leica Geosystems Pipe Locating Equipment

Leica Geosystems brings Swiss engineering to its line of pipeline locating equipment. Leica’s systems are centered around data recording and sharing. Some of their locators, such as the DD230 are even Bluetooth compatible, and their DX Shield Software allows locator data to be shared among devices. Leica is committed to bringing cutting edge software integration to the pipeline locating industry.

Should You Locate Pipelines Yourself

Due to the potential for gas, oil, and high-pressure line explosions, line strikes can be very dangerous. Even non-hazardous line strikes such as water lines and cables can be very expensive to repair. Considering this, it is always advisable that all pipelines are located prior to breaking ground on a project.

Utility location services are generally provided free of charge through your state’s 811 telephone line. Calling 811 automatically routes you directly to your local 811 center and each state has its own specific locating guidelines. If your state accepts online contacts from homeowners and contractors, you may be able to file an “online request”.

If you are a contractor, or a utility service provider, pipeline location tools can also be useful devices for double checking locations provided by the 811 service. A second reading is never out of place and ensures that all underground utilities have been located properly. Having a utility locator on hand can also be useful in time sensitive projects where an 811 technician may not be able to arrive immediately.

Contact Us with your Pipe Locator Questions

If you are deciding on whether to purchase a pipeline locating device, please feel free to reach out to us at Precision Outdoor Tech. We will discuss your needs and project specifications and will point you in the right direction to products that can help you to locate your lines. Give us a call with your questions, and we will be happy to help you out. If it is after hours, please use the contact form listed in the municipal contact section below and we will respond shortly.

If you have already decided on the type of pipeline locator that you would like to use for your project, you can find our product collections via the following links.

All Material Locators (AMLs)

For all underground pipeline materials, including non-conductive pipelines. All Material Locators work best in non-rocky soils away from tree roots.

Utility Locators

Utility locators can be used to trace metal pipelines and other conductive utilities. These devices can also be used on trace-wire equipped non-conductive pipelines.

Sewer Cameras

Sewer cameras work great for tracing non-conductive pipelines with the help of a utility locator receiver. They can also record videos of pipeline interiors to inspect for damage.

Magnetic Locators

Magnetic locators are appropriate for steel, iron, or cast-iron pipelines, valves, septic tanks, and pipeline joints. The size of the target determines the depth at which it can be read.