EDM Services’ Trip Wire® system (Patent 6924428) detects and locates third party intrusions, one of the leading causes of pipeline leak incidents. This relatively inexpensive system incorporates a fiber optic Trip Wire®, which is installed twelve to twenty four inches above the pipeline or other critical facility. Optical instruments continuously monitor the integrity of the Trip Wire® cable. Should the cable become damaged or severed (e.g. by a construction contractor, exposure within a stream crossing, etc.) the optical device(s), which can be integrated into the pipeline programmable logic controllers (PLC’s) and supervisory control and data acquisition (SCADA) system, output the location of the cable damage.

Operationally, when the Trip Wire® is damaged or severed, the operator receives a third party intrusion alarm at their control center. This alarm provides the location of the intrusion, within an accuracy of about one meter. In most installations, the system can recognize, locate and alarm the operator of an intrusion or potential pipeline exposure within about thirty seconds.

The alarm, coupled with the precise location of the third party intrusion or potential pipe exposure, allows the pipeline operator to dispatch personnel directly to the intrusion site, often preventing the pipe from being damaged. These personnel can then inspect and repair their facilities before long term corrosion or pipe over pressure leak incidents can occur. When a third party intrusion results in an immediate leak, the precise location information provided by the Trip Wire® system allows the operator to immediately dispatch emergency response personnel directly to the intrusion site, significantly reducing impacts to the environment and human life.

The Trip Wire® system provides several benefits:

Typical Installations

Jacobs Engineering Group, Chlorine Pipeline

This project included the design, fabrication and programming of a complete SCADA and communications system. The system was installed to monitor and provide leak detection on a liquid chlorine pipeline. This installation included: four PLC’s (one at the shipper, and one at each of three delivery points), one personal computer based HMI with Wonderware® graphical users interface control software, fiber optic communications system, and integration of third party pressure point analysis leak detection software. The system employed hot standby redundant hardware in this critical application. To minimize operational risks, EDM services’ fiber optic Trip Wire® system (Patent 6924428) was installed to identify and locate third party intrusions.

Vulcan Chlor Alkali Caustic And Chlorine Pipelines

This SCADA system was designed, fabricated, and programmed by the EDM Services team, under subcontract to Kellogg Brown and Root. It incorporated third party pressure point analysis leak detection on two parallel chlorine pipelines. In addition to the chlorine pipelines, the system oped to provide operator data and system alarms. The system utilized fiber optic communications to provide fast, reliable service. This system also includes EDM services’ fiber optic Trip Wire system (Patent 6924428). This system provides vital third party intrusion and location data.


System Controller

This unit includes a NEMA 4 (weatherproof) enclosure, with a PLC (or interface to the customer’s PLC), interface programming, and the other equipment necessary for a fiber optic or copper wire system. The unit can also be configured to include a basic driver to interface with most plant DCS systems (e.g. with Modbus connection). The cost of these control units is about $38,000. This cost does not include the development of any graphic screens for the human-machine-interface (HMI) in your control room. Each control unit can continuously monitor a length of about 350 miles. However, we generally limit control unit spacing to a maximum of 50 miles; this ensures adequate headroom for future splices and other line losses for the life of the pipeline system. The control unit is normally co-located with an existing pipeline PLC (e.g. at an existing remotely operated block valve or pump/compressor station). We normally include all drivers and PLC interfaces with the control unit. The control unit can be housed within an existing PLC enclosure or in a separate enclosure, which is included. The customer simply needs to modify their control room human machine interface (HMI) to show the new alarm and the alarm location.

Fiber or Metallic Optic Cable

For most installations, we recommend fiber optic cable systems, instead of a metallic cable system. The fiber optic system provides an alarm when the cable is severed or damaged. The metallic system only alarms when the cable is severed or more severely damaged. Most above grade fiber optic cables cost $0.75 to $1.00 per lineal foot, including your Trip Wire® license, plus freight. For longer length systems, with long lead times, the cable costs can be reduced, often significantly. In areas subject to rodent damage, there may be a slightly higher cost for armored cable.

Installation/Commissioning Support

We typically spend a couple of days on-site after the system has been installed by the customer’s construction contractor. During this time, we test the installed cable, complete all fiber optic terminations at the system controller, adjust the field equipment sensitivities to match the field installation, test/modify the PLC and SCADA system interface drivers, and train your personnel to make field cable splices. This work is normally done on a time and material basis at $95.00 per hour, plus travel expenses. If desired, we can also complete any intermediate fiber optic cable splices you may have in your system.

Construction, Direct Burial Versus Duct

Direct burial cable is somewhat less expensive to install than cable inserted into a duct. Contractors have quoted from less than $1.00, to $3.00 per lineal foot to install direct burial cable during pipeline construction. This cost covers the additional pipeline construction costs associated with backfilling the ditch to the appropriate level, stringing the cable, making the splices, and backfilling to the final elevation.