Optimizing Cathodic Protection
in Urban Utility Environments

1. (Will)
Thank you very much Gretchen! And welcome everyone to the Webinar. It is a pleasure to be back with the Materials Performance webcast team! As always, many thanks for taking such great care of us!

Today’s topic is Optimizing Cathodic Protection in Urban Utility Environments.

2. (Will)
Now onto introductions and a brief overview of the discussion planned for today.

My name is Will Maize, and I am a Product Manager at Mobiltex. In my role I conduct interviews with customers and colleagues from across the industry to try and understand market trends and ultimately, to influence our product development and go to market strategy. I have a background in Civil Engineering, and I’ve worked across multiple industries related to technology and the management of critical infrastructure. Joining me on the webinar today is none other than Mr. Tony da Costa.

(Tony)
As Will mentioned, my name is Tony da Costa and I’m the VP of Engineering at Mobiltex. My primary role is to take Will’s customer product research information and have my team come up with creative ways to turn that into useful industry-leading products for our customers in a reasonable time frame. My background is in Electrical Engineering with a specialty in communications systems. Over the last 29 years, I’ve put that background to use in various digital radio and remote data acquisition product research and development efforts. That includes many of Mobiltex’s current product offerings.

Back to you Will.

(Will)
Thanks Tony! Now for a brief overview of the webinar.

I’m going to lead off today by defining what exactly we mean when we say ‘Urban Utility Environments’. Which group of companies and operators are we talking about? I’ll then introduce some of the main trends that we, Mobiltex, see within this market segment, and introduce some of the major pain points that surface in our conversations with customers. I’ll then pass the ball to Tony, who will walk through some of the novel approaches to mitigating these pain points, leveraging new technology to improve worker safety and increase efficiency within complex urban networks.

3. (Will)
So, let’s define downstream and distribution markets, and understand the characteristics of these systems that make them so challenging.

4. (Will)
What does Cathodic Protection look like in an urban environment? This illustration provides an overview of some of the assets that downstream and distribution utilities use in their cathodic protection systems, while shining some light into constraints around where they can be located. It really is quite busy, isn’t it? This complexity is representative of the operating environments for many distribution companies!

In this image we have two pipelines, the primary pipeline and a foreign pipeline. In terms of the cathodic protection systems at play here, the primary pipeline is cathodically protected by both impressed current systems, note the rectifier, and also galvanic components, note the three sacrificial anodes. This is a blended system, with both types of CP at play. The primary and foreign pipelines are connected via an electrically continuous bond, which helps balance the electrochemical signature across the two pipelines, and in fact, shares the protection of the primary pipe with the foreign pipe. A foreign pipe is typically an asset that is operated by another company or utility, but, in many urban areas we could also visualize this as an offshoot service line.

In urban settings, pipelines often are installed directly underneath the traffic right of way or along a boulevard, for the simple fact that it is much easier to excavate a road than to underpin a building. Cathodic protection test stations, locations that are used to run cables connected to the buried pipeline up to the surface for easy access, are locations that technicians must visit at least once per year in order to take a potential reading in relation to a reference cell. This reading can tell you whether your level of CP on the pipeline is adequate or not. In many urban settings, test stations are installed at grade, in subgrade or flush mounted test station configurations, meaning that the collection of readings can often involve work in traffic right of ways.

The density of infrastructure in our cities also presents challenges in managing stray currents. In this representation, the presence of a high voltage AC powerline creates the opportunity for induced AC current onto the pipeline, which can cause accelerated corrosion and can become a safety hazard. A light rail transit system is also present, which can create challenges around conducted DC current onto the pipeline at crossings and in locations where the tracks and pipeline are running in parallel.

So with this intro, let’s understand a little more about the types of operators managing the constraints of urban pipeline environments.

5. (Will)
On the O&G side of things, when we talk about downstream and distribution utilities we are primarily talking about natural gas distribution systems, however, oil and petroleum refining operations can often fall within an urban environment as well.

Across the entire O&G pipeline landscape in Canada and the U.S., over 833 thousand miles of steel pipeline are operated by downstream companies, which represents 45% of the total. Therefore, almost half of the cathodic protection market for steel O&G pipelines is in the distribution segment, commonly located within urban areas. These companies are charged with bringing you a reliable source of gas for heating, cooking, and in many cases, power generation. Robust regulation exists in the gas distribution market to ensure a high level of performance around public safety and environmental risks, and this regulation has played a key role in driving innovative practices and technology adoption over the years.

While some new pipeline construction of gas distribution utilities is moving towards plastic pipe, much of the installed pipeline is cathodically protected steel, and most new critical high-pressure lines remain steel as well. Steel pipelines are electrically bonded together, which enable efficient deployment of both galvanic and impressed current cathodic protection systems.

6. (Will)
Another key group of companies operates large pipeline distribution networks within our urban environments – water utilities. In North America, approximately 80% of municipal water utilities remain publicly funded government run organizations, with approximately 20% being privately operated.

Water utilities, while regulated, are not under the same pressures to eliminate loss of product – in this case a water leakage – during the delivery process. This is one factor that has influenced a slower adoption rate of best practices around cathodic protection across much of the water industry.

Another factor is in the types of materials used for water distribution mains. Of the 1.3M miles of water pipeline in Canada and the U.S., just 10% are thought to be made up of steel and pre-stressed concrete cylinder pipe (known as PCCP). These are the two common water pipe material types that are electrically continuously, and therefore applicable for efficient cathodic protection. The majority 90%, largely made up of ductile and cast iron materials, are not electrically continuous unless special fittings are used. Therefore the use of cathodic protection has largely been relegated to galvanic magnesium anodes being directly connected to the pipe, buried, and forgotten. While this passive CP strategy can add years to the pipe’s useful service life, it is often executed poorly during construction, and is also impossible to monitor in terms of remaining protection life of the sacrificial anodes.

However, many leading water utilities are using both active impressed current systems and passive galvanic systems to protect against corrosion on their steel and PCCP pipelines. Increasingly, CP is recognized as a reliable and core-practice to ensure that municipalities get the most service life out of their pipeline assets, which in the constrained world of municipal budgets, is critical.

7. (Will)
Ok, so we’ve set the stage for what we are talking about when we discuss cathodic protection in urban environments. From our discussions with customers in this space, we’ve put together a list of trends and pain points that come up time and time again.

8. (Will)
So what are the key considerations for operating cathodic protection systems within urban utility environments?

[FLIP] The first is worker safety and on its flip side, operating efficiency. As the urban asset slide showed, many downstream and urban utilities use test station locations that are within reach of cars and traffic lanes. These operations can be dangerous, and mitigation measures can be expensive and time consuming.

[FLIP] The second is expanding regulation. PHMSA’s Mega Rule has increased the amount of pipeline that falls within high consequence and medium consequence areas, which generally have a higher and more stringent regulatory requirement. Many HCAs and MCAs are directly correlated to population centers.

[FLIP] The third trend is that dense urban CP programs often consist of blended CP systems. Because of the dense nature of distribution assets, with a pipeline main supporting many service lines and branches, cathodic protection systems have evolved into a piece work of impressed and galvanic current sources. This can present a challenge for operators achieving specific criteria to prove compliance.

[FLIP] The final consideration is dynamic interference. The increased density of urban areas means that co-located infrastructure is commonplace in many pipeline ROWs. High voltage powerlines and light rail transit systems can cause havoc for operators, with major risk that a minor coating holiday could lead to a rapid, concentrated corrosion event.

Let’s dive a little deeper into each topic.

9. (Will)
As this picture indicates, our gas and water distribution customers must manage data collection from very risky locations, which places an immediate burden on their technicians and field staff to manage these activities safely.

Many utilities have tens of thousands of subgrade, or flush-mounted, test stations, an example of which is shown in the image in front of you. On the gas side, these test stations are visited annually as part of the annual level of protection survey to collect compliance readings. At each site, a technician must setup traffic control, gain access to the valve box, take a voltage reading (often an ON and an OFF potential), and record before moving on.

While effectively deployed traffic control can create a safe environment, it is stunning how many construction-related incidents occur on traffic ROWs each year. According to the Federal Highways Authority, the U.S. saw over 800 fatalities in 2019 alone due to accidents within traffic ROWs, and this would only include accidents on Highway infrastructure. The number would be much higher if including local roads and city streets.

Related to efficiencies, many jurisdictions make it mandatory to have a combination of crash trucks, flaggers, crews with pilons, and paid duty officers onsite for the duration of any work in the vicinity of a traffic ROW. These expenses can be considerable especially when you consider the scale of annual surveys spanning tens of thousands of flush-mounted locations.

10. (Will)
In retrospect, much of the CP and pipeline integrity industry will look back on the summer of 2020 as the summer of High Consequence Areas.

In July of last year, PHMSA’s new legislation, the Mega Rule, came into effect. It broadened the scope for high consequence areas (HCA), effectively increasing miles of pipeline under stricter regulatory requirements. It also introduced moderate consequence areas (MCA) as well. The industry has been abuzz since then trying to get a feel for how CP programs should respond to the new guidelines.

PHSMA considers HCAs to be areas where a pipeline release is of greater consequence to health, safety, and the environment. Specific to Natural Gas pipelines, HCAs are identified by applying an equation which estimates the death and property damage from a potential explosion. The equation calculates the potential impact radius, essentially a buffer, along a pipeline. Generally, this radius is about 660 feet on each side of the pipeline.

Any buffer areas are then defined as HCA when they contain:
• 20 or more human occupied structures;
• Buildings housing populations of limited mobility;
• Slow evacuating properties such as nursing homes or schools;
• Buildings or outside areas occupied by 20 or more people at least a few days a week (this includes baseball fields, parks, etc.).
• HCAs also encompass areas with high ecological and environmental impact, drinking water impact, and industrial and or economic impact.

Therefore, as our urban footprints continue to expand so do the higher consequences of pipeline failure, and this results in more HCAs. To give you a feel for the total scale of this, overall, approximately 9% of all PHMSA regulated pipelines in the U.S. are categorized as HCAs.

11. (Will)
A major pain point common in dense urban environments is the challenge of managing blended CP systems. Due to the dense nature of urban infrastructure, many operators have ended up with what the CP industry refers to as blended CP system. A blended system is essentially any combination of an impressed current system (one using rectifiers) with sacrificial galvanic anodes interspersed throughout. In the illustration, we see both a rectifier as well as two sets of three galvanic anodes, both supplying current to the pipeline. [FLIP]

Blends can happen for many reasons, for example:
• A distribution main that is protected via impressed current, with many offshoot service lines which could have local galvanic sources. Because electrically continuous, the galvanic sources will contribute to the total CP level and potentially have influence onto the main pipeline.
• Repairs can also lead to blended systems, as galvanic anodes are added as a safety factor to any exposed pipe from the repair.
• Proximity to other infrastructure (e.g. protected water mains, or protected underground electricity cabling) can also lead to blended systems, particularly when these assets are bonded to the main pipeline.

Blended systems create a challenge for operators that are trying to isolate the specific influence of each and every protection asset, or for achieving the interruption necessary to complete an OFF potential survey. Because many galvanic, or sacrificial CP sources are directly connected and buried, it is often impossible to access these connection points and interrupt the current flow.

This ties me to the next point.

12. (Will)
Shifting regulation means more interruption!

In the U.S., Canada, and in many other countries, NACE SP169-2007 has long been the reference specification in the CP industry for pipelines. The document outlines three main criteria that should be considered when setting out to prove that sufficient cathodic protection is being applied on the pipeline structure.

These are:
• 1. A cathodic (negative) potential of at least 850mV with CP applied, between the structure and a reference. This assumes that voltage drops have been properly accounted for.
• 2. A negative polarized potential (commonly known as the OFF potential) of at least 850mV between the structure and a reference.
• 3. A minimum of 100mV of cathodic polarization between the structure and the reference.

Because the first criteria requires a detailed understanding of IR drop at each local testing site, which can be a logistical challenge, many operators have relied on the second and third criterion. Achieving the OFF potential requires remote interruption of current sources, and this has been a large driver for adoption of remote monitoring and interruption equipment over the last 20-years.

However, some regulators, specifically in the Southeastern United States and in many dense urban areas, have historically accepted the first criteria as a passing metric – an 850mV ON potential reading. These values do not require an interrupted survey to achieve them, and therefore are easier to pull off efficiently in blended systems, for example. There is some risk here as the reading will include the IR drop, which roughly translates to the resistivity of local soil conditions. Over the past decade or so, the industry has seen an increasingly rapid shift of regulators – federal, state, and municipal – requiring all operators to provide the 850mV criteria with an OFF potential reading.

Blended systems, with a combination of ICP and galvanic sources, are a thorn in the side of operators that need to provide an interrupted OFF reading. While the interruption of ICP sources, like a rectifier, can be easily automated using a modern remote monitoring platform, for galvanic sources, the shear volume of assets can cause a headache in terms of quantity of portable interrupters required, and the time it takes to install and configure all of them to operate in a synchronized way.

Now to the final trend.

13. (Will)
Dynamic and stray current interference occurs when an asset, object, or activity outside of the cathodic protection system creates a current that strays onto the pipeline, influencing the electrochemical dynamics of the pipe and designed CP system.

These sources of current can present some of the most challenging and dangerous conditions for cathodic protection engineers and pipeline operators, due to their concentrated nature. Both DC and AC dynamic stray currents are present in the typical urban environment.

On the DC side, the most common source of dynamic DC interference is from DC powered Light Rail Transit systems, or LRTs. As a train passes through a pipeline corridor, it is not uncommon to see a short-duration influence on the DC current and voltage on steel assets in the vicinity. If these effects are large amplitude and frequent, they can cause considerable damage to a pipeline coating and potentially lead to rapid corrosion. Grounding cells can be installed to offer a low resistance pathway to ground to the DC current spikes, minimizing the effect on the pipeline itself.

On the AC side, co-location of pipeline corridors within existing high voltage AC corridors, and vice-versa, has created many challenges. Inductive coupling from the HVAC will create an induced AC current on the pipeline, which immediately looks for a path to ground. This AC will always find the path of least resistance at locations where the coating has weakened – known as holidays. AC corrosion at a small holiday can be extremely concentrated, causing rapid wall loss.

14. (Will and Tony)
So that concludes the key trends affecting operators in urban environments. I’ll now turn it over to Tony for the next section.
Thank you Will. Let’s take a look at how we can improve worker safety with a new product that is just about to be released.

15. (Tony)
Here we see a typical urban configuration for pipelines where those pipelines are coincident with roadways. With the two assets being collocated, we also see test points being installed in subgrade test station boxes, which quite often are in the middle of the roadway.

This creates a challenge for access given the vehicle traffic that may be present on the roads at any given moment. To attain critical measurements from the test points, it is required to attain permits and then block off traffic flow while measurements are being taken. But even blocking off a lane of traffic can still lead to dangerous interactions with vehicles on adjoining lanes.

In the US alone in 2019, there were 135 worker fatalities and numerous other accidents in work zones. The prior three year average was similar. This is an unacceptable risk that can be mitigated through the installation of automated remote monitoring units in the valve boxes. A remote monitoring unit alleviates the need to visit those test points on a yearly or more often basis while acquiring data at frequencies that were previously not possible.

As a means to that end, Mobiltex has created a new remote monitoring unit that is purpose built for the harsh environment found in this below grade installation environment. Drum roll

16. (Tony)
We are happy to present the latest addition to our RMU family, the RMU1-SUB.

Like our existing RMU1 product for standard test stations, the RMU1-SUB is capable of monitoring all signals applicable to test point potential, coupon and bond monitoring. Especially important for monitoring test point potentials, its digital signal processing capability allows for capture of both on and off DC potentials with only the attachment of an additional reference cell. By cycling the impressed current rectifiers and galvanic anodes attached to the protected structure, it’s now possible to attain a validation of your asset’s protection level—all without leaving the comfort of your office. The fine time granularity of the readings gives new insights into the varying protection levels throughout the year.

The RMU1-SUB is designed to fit within a standard Bingham and Taylor valve box that is in common use across many urban areas as a test station. A tough high density polyethylene custom lid allows communication signals to propagate through while supporting necessary traffic loads. This lid has been validated by an independent lab to comply with AASHTO M306 HS-20 traffic load ratings, ensuring that the unit can be deployed where heavy vehicles are expected to pass.

The subgrade environment is a harsh one. This environment can experience extreme heat, flooding conditions, freezing water, road oils and road salts depending on geographic region and time of year. It’s important that a remote monitoring unit that’s installed in these types of conditions be capable of surviving for many years to minimize onsite service requirements. The RMU1-SUB was designed from the ground up (or is that from the ground down?) to address each of these conditions. Significant testing has been performed both in lab settings and in actual field deployments to validate operation.

The install and forget capability along with remote readings allows for improved operational efficiencies. No longer do you have a need to pull traffic control permits every time you have to get a level of protection reading. At the same time, corrosion technicians and other support personnel are no longer exposed to a dangerous traffic setting to get those readings.

17. (Tony)
Here we see three different field trial installations of the RMU1-SUB. The installation in the Southwest U.S. represents a hot weather zone that is typically dry, but could be subject to flash flooding.

In Western Canada, the unit is installed in what we consider our rain capital. The lower mainland area in British Columbia sees rain on average 174 days out of the year with an accumulation of 5’. That leads to a lot of flooded subgrade chambers. Luckily, the RMU1-SUB has been designed to handle that with its IP68 ingress protection level.

The last installation shown is in Eastern Canada on a roadway. The installation was performed over the winter, which yielded exposure to snow and ice. After asking them to treat the unit with the worst field conditions they could think of, the same field trial customer subjected the unit to their version of the ice bucket challenge, where they dunked the unit in a pail of water and allowed it to freeze. The unit performed flawlessly.

18. (Tony)
The challenges for test point monitoring, whether manual or remote, don’t end in urban areas. Installations in rural areas also suffer from their own set of problems. Unfortunately, above ground test stations are often targets, literally, for inconsiderate firearms users. Cows, bears, and other wildlife have also been known to damage test stations whether by biting or overzealous itch scratching. But let’s also not forget landowners that are not overly accommodating of access to pipeline easements on their property.

Subgrade test stations and associated remote monitors are an excellent solution for each of these problems. The lack of visibility makes them an innocuous piece of hardware that attracts less attention whether it be from humans or animals, while the remote monitoring capability allows for less interactions with land owners. The same design characteristics mentioned before allow the remote monitor to survive the harsh subgrade environment.

19. (Tony)
Let’s move on to another challenge that is experienced while surveying protection levels—assets that are protected with galvanic anodes and blended systems that use both impressed current and galvanic anodes.

20. (Tony)
Shown here is a pipeline asset where an impressed current rectifier system and galvanic anodes are being used to protect the pipeline. For the most representative off potential readings, all current sources must be disconnected. While remote monitors on rectifiers have been available for years with GPS synchronized interruption, the same can’t be said for galvanic anodes. Remote monitors for galvanic anodes with interruption capability are now just being deployed. GPS synchronized interruption allows for clean wave forms when taking instant disconnect potentials.

For those galvanic anodes that still require interruption capability during survey events, the solution is to deploy portable interrupters to break the bonding connection between the anodes and the structure. With anodes and their associated test stations often being located away from power sources, a battery-operated solution is required. Ideally the portable interrupter is also self-contained to allow for easy migration from one test installation to the next.

21. (Tony)
Here is our solution for that purpose. This is the Pi-1 pocket interrupter, an award-winning product that was originally designed by Taku Engineering. Mobiltex is excited to have partnered with Taku to take over development and manufacturing of the Pi-1. The unit has been redesigned for cost optimization and to allow for future enhancements in functionality.

The completely self-contained unit is powered by a large capacity battery allowing it to run through full multi-day survey tasks. Through the use of two internal solid-state relays, each capable of switching up to an amp of current, the unit is easily able to interrupt two anode sets or even an anode along with a small bond. The waterproof case makes it an ideal apparatus to deploy in locations where flooding may occur. With all of that, it still fits in your pocket.

For flexibility, an expansion port also allows for the ability to interface with standard Mobiltex accessories.

22. (Tony)
Some of the accessories that are compatible with the Pi1 and enhance its functionality are:

The SRL1 smart relay that gives the Pi1 the capability of interrupting high current bonds or rectifiers at up to 60V/50A.

The SRL2 which gives the same high current interruption capability, but at up to 100V/100A on rectifiers.

Finally, a direct wire-in cable allows for permanent installation of the Pi1 in a rectifier, or prewiring of the rectifier for portable use of the Pi1.

Additional accessories, such as a rapid sample datalogger are planned for the future.

23. (Tony)
For the last topic, we’ll explore how technology can help urban infrastructure operators get a better feel on dynamic events impacting their assets.

24. (Tony)
As Will mentioned previously, dynamic interference occurs on both the AC and the DC side of cathodic protection. In this illustration, you can see how pipelines crossing or running parallel to HVAC powerlines are at risk from the dynamic events from the powerline. However, we won’t get into detail here and if interested, please check out our full Webinar focusing on AC interference that we hosted with MP back in October 2020.

25. (Tony)
Looking at the DC side, dynamic DC is most often a challenge in close proximity to light rail transit systems. Will mentioned that a passing train, and the electrical current that it is powered by, can cause a very short, dynamic pulse into the soil in the vicinity of the train lines. When a pipeline is in close proximity, there is a good chance that some of that current can pass through to the pipeline and disrupt the cathodic protection balance.

To monitor for these effects, many operators will install a CP coupon in the soil in the vicinity of the pipeline, within the influence area of the LRT line. As the CP coupon can be connected to the pipeline, and therefore share the same protection characteristics as the pipe, it can be used to measure just how much protection there is, and how this is effected by the dynamic DC. Many customers use RMUs to monitor these coupons, and a device like the SUB1 is perfectly suited for these applications. Because it can disconnect the coupon, you can even get an OFF potential reading on the pipeline.

26. (Tony)
However, because these dynamic events can occur in very short duration, many operators will install a portable datalogger to collect and store readings on the coupon. With sample rates of one reading per second, dataloggers record a more granular waveform that is better suited for transient event analysis.

The CorTalk uDL1 and uDL2 data loggers from Mobiltex are our products for these applications, both being widely used across the industry.

27. (Tony)
Now for a practical example from the field. This chart represents a sample of real data collected using an uDL1 data logger on an LRT line located in a major North American city. The horizontal axis represents the local time, the left vertical axis the scale for the DC readings, and the right vertical axis the scale for the AC readings.

The uDL was setup to sample one measurement every second, recording both AC and DC voltages via one measurement channel. The device was installed at a station location, and the engineer in charge was concerned about the impact of DC interference onto their cathodically protected pipe that passed close to the station. This snapshot provides a 30-hour window into the electrical activity on the pipeline. At a very high level, it is interesting to note that both readings – the AC and DC – vary at a relatively small amplitude. A lack of huge variation here is something that would put the engineer or operator at relative ease.

Let’s dive a little deeper.

28. (Tony)
We’ve now isolated the DC voltage on the chart, as DC is the key parameter of interest due to the LRT line running on DC power.

Many of our customers operating near trains and tram lines are always interested to note the differences between AC and DC readings during the operating hours of the LRT, and the hours that the LRT system is not running. This time typically falls between 2 and 4 am in most cities. [FLIP]
From this dataset, we can see a clear example of the system quieting down in terms of low amplitude on DC readings during these hours. Readings taken at this period can help the operator isolate their baseline for cathodic protection on the pipeline.

29. (Tony)
Zooming in a little more on the DC voltages reveals another, potentially more interesting pattern. The horizontal axis is now showing gridlines on a 30-minute spacing.

At this scale, the data indicates consistent and very constant spikes in the DC voltage in the negative direction, occurring every 10 minutes or so. [FLIP] From some research into the train schedule, the data is indicative of a correlation between a train entering the station, and a small spike in DC voltage towards the negative.
Turn it back to Will.

30. (Will)
Thank you very much, Tony.
To wrap up I will conclude with some details on Mobiltex and how you can work with us.
Mobiltex, based up in Calgary, Alberta first started developing remote monitoring products for the cathodic protection industry in 1991. We now offer best-in-class remote monitoring and field-survey products for the cathodic protection and pipeline integrity industries, spanning oil & gas, water, power generation, and civil infrastructure sectors. Our products are depended on by many of the largest pipeline operators and distribution utilities in North America and around the world. We design, manufacture, and assemble our products in our Calgary office, in the same building that houses our world-class customer service, sales, finance and marketing teams.

31. (Will)
Mobiltex is proud to partner with leading Cathodic Protection specialists across the world, and the logos on the screen now represent a selection of our partners. Please reach out to one of our partners, to Mobiltex customer reps and our service team, or to Tony and I directly, in case you have any questions and inquiries into our technologies and services.

32. (Will)
We will now open-up the floor for questions.