ELK Engineering Associates

CASE STUDY: CP NOT WORKING!

In Texas, many municipalities require cathodic protection (CP) to be installed on metallic waterlines to typically include ductile iron, steel, and concrete pipe. And because of the considerable cost involved, many of the municipalities check or monitor the CP systems periodically to make sure they are protecting the pipe from corrosion that could result in a leak of possibly millions of gallons of processed water. In general, because water is not specifically regulated by any government agency, the need and schedule for monitoring is determined by the municipality.

During one such survey to monitor the CP system by a major Texas city, Technicians measured levels for the CP system that were not consistent with historical performance. The reason was soon discovered, but the cause was a little more elusive.

The water line in question utilized an impressed current CP system to provide protection from corrosion. One of the components used in this type of system is an external electrically powered device referred to as a rectifier. It is essentially a heavy-duty power supply for the system. In this case, the rectifier (through troubleshooting) was found to be the source of the problem. The aforementioned troubleshooting identified a damaged cable that is intended to complete the return path for the CP current. Apparently, the cable in question had been damaged during a refurbishment of the landscaping on and around the area of the waterline, specifically the installation of a bike path. While the exact details resulting in the damage have yet to be revealed, or even the exact cause, methodical troubleshooting found that the cable in question had been re-routed, presumably by a contractor, from the original connection at the waterline to an electrical utility pole ground cable.

This did not fix the problem. The contractor incorrectly identified the damaged cable as a ground cable.

For context, this cable is not related to any alternating current (AC) power source. As a result, the damaged cable does not present a shock hazard, or would anyone necessarily realize an immediate result of the cut cable such as a loss of power at a business or a residence. The result does, however, prevent the waterline from being protected from failure due to corrosion.

Although the necessary repair for the damaged cable will be at a considerable cost the typical question is always, “How could this have been avoided?” “Who is at fault?”

The short and most obvious answer is the contractor. The contractor should have contacted the appropriate agency for a dig check before excavating. But there may be additional blame to go around. The municipality could have advised the contractor of the existence of the CP system, if they didn't. Also, they should have provided an inspector to observe the excavating around the waterline. But ultimately the contractor, according to available records, did not notify the municipality of the incident, probably because of results previously cited. And while accidents happen on many projects with various trades the liability as well as the resulting consequences requires proper reporting of the damage, and/or full time inspection on behalf of the municipality.

Final assessment, repairable and the CP system can be returned to service to protect the municipality utilities.

The prolonged continuous solution would involve development of a periodic inspection program at a regular interval to verify the CP system(s) are operating and providing continuous protection from corrosion failures.

The Year In Review - ELK Engineering

It has been another extremely busy year and once again the activity for ELK Engineering has been extensive.
ELK has been involved in multiple projects for the implementation and verification of systems intended to protect critical infrastructure in support of the recently revealed airport expansion and renovations.
ELK has provided design and installation support for multiple CP groundbeds for major electrical providers in South Texas. This effort is to assure vital assets are capable of safely providing adequate operational capacity during critical high demand events.
ELK completed R&D efforts for the revolutionary Retro-Fill process for deep vertical groundbed replacement. More to follow...
All of this in addition to multiple projects in support of the continuing North Texas growth and improvements as ELK enters its 30th Year of service to the DFW Metroplex, all of Texas, and beyond.
Happy New Year!

Based upon industry trends, internal forecasts, and specific demand for corrosion and other related engineering services, ELK will direct more resources to that end. As a result, the CSS (Construction Support Services) group of ELK is now re-entering the corrosion technology industry as Applied Corrosion Technology Incorporated (ACTi), an independent services provider.
The formation of the CSS group in ELK was as a result of the acquisition by ELK of Applied Corrosion Technology Inc. in 1998. ACT's nature and type of services was easily integrated into the ELK system and became the CSS group.
The CSS group has provided a means for ELK to more effectively assure the proper installation and implementation of ELK designed cathodic protection systems over many years.
ELK looks forward to working with ACTi in the future and recognizes the Corporation as a valued Associate.

ELK Engineering is currently seeking and accepting application for the position of Entry Level Corrosion Technician/CP-1.
This position will work closely with the Engineer(s) with regard to the performance of CP design surveys, facility wide CP surveys, post installation acceptance testing, safety grid continuity survey, and AC mitigation survey and testing.
This position involves a combination of Field and Office work to include data review and analysis. Some over-night travel is required.
ELK offers competitive salary and benefits.
Further details regarding this position can be obtained by contacting ELK Engineering Associates directly.

Despite the interruption in many areas of commerce, growth in North Texas hasn't skipped a beat. As a result, continuous activity over the past year has led us to ask, "Where has the time gone?"
Primary activity over the past three quarters has been water treatment and transmission. It's just part of what we do...