Underground Service Company provides various methods for locating underground utilities. Each method renders varying degrees of accuracy and intrusiveness. Additionally, access requirements differ between each method. Please review each of the following methodologies below to determine which procedure will meet your specific job requirements. If the results of the survey are to be transposed to a construction document, a survey crew may be mobilized after location work is completed to record findings. The client would need to supply a working print with meets and bounds. A standard survey includes a mark-out on site only.

Electro-magnetic Location

A signal is applied to a desired utility either directly or indirectly with a portable transmitter. An operator then sweeps the area with a receiver, which enables tracking of the utility's course and depth with out potholing. Some conditions known and unknown will affect the accuracy of the results. These conditions may include: soil conditions, utility congestion in a particular area, and points of contact available to utilities.

• Applications: Electrical, telephone, fiber optic, oil, fuel, gas, blank pvc ducts, and metallic water lines.
• Accuracy: If marked by the operator, the depth readings are accurate to +/- 10% of total depth from surface elevation. The lateral reading is accurate to +/- 3% of total depth.
• Requirements: Optimum results are obtained when access is available to points of contact to the desired utility, i.e. manholes, pull boxes, valve stations, etc.
• Time: One operator can average 2 miles of single utility per 8-hour shift.

"Air-knife" Location

This method is ideal for projects where the exact location and elevation of utilities is required. A vacuum trailer and air compressor are mobilized along with two operators. The equipment uses air to excavate the road base, soil, even 1/2 sack slurry, for exposure of the desired utility without the risk of damage to the line. The depth of the utility from existing grade is then recorded, and the hole is backfilled, compacted, and patched if required. When the desired utilities run beneath the public right of way, an encroachment permit, traffic control plan, and inspection requirements must be approved and obtained from the local authority. Underground Service Company can also mobilize a survey crew at an additional cost if the results are to be transposed to a construction document.

• Applications: Any size or type of utility up to 15 feet in depth. A special proposal is required for utilities deeper than 15 feet.
• Accuracy: Exposed utilities can be recorded exactly as to their lateral location and depth.
• Requirements: Approval from local authority (if required), general knowledge of what is to be located or prior mark-out by "dig-alert" if available.
• Time: The crew can expose and close one 12" diameter pothole at a 10-foot depth in ideal conditions within 1 hour.

• Permits, traffic control, and asphalt patchback vary with the scope of work and project requirements. A walkthrough on site with the client is required prior to issuance of a site-specific proposal.

Push Camera / Tractor Camera

A small camera with a built in transmitter allows operators to follow the course of the utility from an entry point to the system through the course of the line. The camera head can be tracked above ground by an operator with a receiver that records the lateral position and elevation of the camera head. The maximum travel distance of the tractor cam is 1,500 linear feet. The push cam is limited to 300 linear feet. Multiple changes in direction adversely affect the travel distance capabilities.

• Applications: Storm drains, waste lines, empty ducts or conduit. 2" through 48" diameter. A special proposal is required for applications greater than 48" in diameter.
• Accuracy: If marked by the operator, the depth readings are accurate to +/- 10% of total depth from surface elevation. The lateral reading is accurate to +/- 5% of the total depth.
• Requirements: Unrestricted access to manholes, catch basins, or clean outs for equipment travel.
• Time: Varies with site conditions.

Every project varies with conditions on site. A supplemental proposal that addresses site-specific criteria can be prepared if work is to be authorized. To schedule service, contact Underground Service Company and request a work authorization form. Once we have received a signed copy, work can be scheduled. Upon completion, we will mail an invoice for services preformed. Payment in full is due within 15 days. If you have any site-specific questions, please do not hesitate to call.