Quality of information is key.
C Below offers professional utility locating and mapping services throughout the South West. Our highly experienced technicians utilize the most advanced equipment in the industry to gather information for your project. Accurate information is vital in planning and can prevent costly delays from damages caused by cutting, coring, drilling or digging in areas congested by unseen hazards in concrete, masonry and underground. The tools we use and our approach will be tailored to the quality level of information you require.
Quality levels may be thought of as degrees of risk, or how much information is really needed to adequately design or construct a project. Plans typically contain disclaimers as to the accuracy of the utility information. The use of quality levels allows project owners to decide what level of information they need to appropriately manage the level of risk for the project. Information can be provided in the form of pull box or electrical reports, potholing reports, underground mapping, 3D modeling or simply surface markings.
There are four recognized quality levels of underground utility information ranging from Quality Level D (the lowest level) to Quality Level A (the highest level).
Quality Level D is the most basic level of information for utility locations. It comes solely from existing utility records or verbal recollections, both typically unreliable sources. It may provide an overall "feel" for the congestion of utilities, but is often highly limited in terms of comprehensiveness and accuracy. QL-D is useful primarily for project planning and route selection activities.
Quality Level C involves surveying visible utility facilities (e.g., manholes, valve boxes, etc.) and correlating this information with existing utility records (QL-D information). When using this information, it is not unusual to find that many underground utilities have been either omitted or erroneously plotted. Its usefulness, therefore, is primarily on rural projects where utilities are not prevalent, or are not too expensive to repair or relocate.
Quality Level B involves the application of appropriate surface geophysical methods to determine the existence and horizontal position of virtually all utilities within the project limits. It addresses problems caused by inaccurate utility records, abandoned or unrecorded facilities, and lost references. Decisions regarding location of storm drainage systems, footers, foundations and other design features can be made to successfully avoid conflicts with existing utilities. Slight adjustments in design can produce substantial cost savings by eliminating utility relocations.
Quality Level A is the highest level of accuracy and involves the full use of the subsurface utility investigation method. It provides information for the precise plan and profile mapping of underground utilities through the nondestructive exposure of underground utilities, and also provides the type, size, condition, material and other characteristics of underground features.
Electromagnetic locating is often the most common and cost effective method for locating utilities. It is often the first step in a comprehensive investigation that may employ more than one method. We use a combination of many different tools to electronically locate utilities. There are four common methods electromagnetic locating.
Method 1 | Direct connect method involves the technician directly connecting a transmitter to the line. A signal is sent down the utility or tracer wire buried with the utility and located with a receiver from above the surface. This is ideal for electrical, communication, and gas lines.
Method 2 | Induction involves sending a signal through the surface to the utility when you cannot directly connect to it for various reasons. The utility then transmits this signal which is picked up by a receiver above the surface in the same manner as the Direct Connect method.
Method 3 | Sonde locating involves inserting a locatable transmitter into a utility or conduit to be located by a receiver above the surface. Some of the tools we use that have locatable sondes in them are crawler cameras, push cameras, and ram rods. This method is often used for storm drains, waste lines and empty conduit.
Method 4 | Passive locating is a method where a receiver is used to pick up naturally produced electromagnetic field emitting from a buried utility.
When utilities are located, our technicians use industry standard colors to mark them directly on the surface. Water based marking paint is used when permitted. When paint is not permitted in cases like finished decorative surfaces or high traffic customer areas, we can use chalk, wax or other marking materials. Flags and whiskers are also used in areas such as grass or dirt when paint markings will not last.
C Below also utilizes GPR to assist during utility locating. With the ability to locate nonmetallic as well as metallic utilities up to 12ft deep, GPR is used in conjunction with traditional methods of locating.
GPR is also the safest, fastest and most accurate method of locating reinforcing steel, prestressing strand (post tensioned / pretensioned cables), conduit (metallic / nonmetallic) and other indications in concrete and masonry structures. With the ability to penetrate up to 18 inches of concrete / masonry, our technicians can mark all indications directly on the scanning surface prior to coring, cutting or drilling operations. The survey results can also be saved and printed in 3-Dimensional detail providing a subsurface map for our client. Our technicians can also determine the thickness of concrete and masonry structures in addition to the spacing and depth of indications.
ADVANTAGE OVER X-RAY | GPR emits about 1% the power of a cell phone signal to perform its functions, therefore there is no need to provide a safety perimeter around work areas. This allows us to work in buildings where temporary evacuation is not an option (i.e. hospitals). Unlike X-ray, GPR can be used with access to only one side of the scanning area, as there is no need to place film on the opposite surface. Scanning and marking of a 2 ft square section can be performed in just a few minutes. The equipment is very portable and can be moved to each location quickly, making scanning of multiple areas per hour possible.
- Concrete/Masonry Structure Scanning
- Locating Post-Tension Cables
- Rebar Locating
- Utility Locating
- Forensic Investigation
- Bridge Deck Inspection
- And many other custom applications