Interrupting & Managing Bonds Safely and Effectively - Virtual Brew 01/16/25

In this episode of Virtual Brew, our free monthly webinar, we’ll cover best practices for interrupting bonded pipeline structures in Cathodic Protection systems, focusing on PHMSA regulations and compliance. Learn strategies for accurate measurements during Close Interval Surveys and discover how remote monitoring units can improve efficiency and precision.

Transcript

Introduction and Agenda

[Presenter]
Thank you all for joining — excited to kick off the first Virtual Brew of 2025. Today’s topic is really about managing and interrupting bonds safely and efficiently.

Here’s what we’ll go through: what actually is a bond, if you’re not familiar — these are very common items used in various CP systems to help make sure the CP system is working effectively. We’ll go through what an interference bond is, what a critical bond is and what might make a bond critical — especially looking at what PHMSA cites as a bond that would be considered critical — as well as performing interrupted surveys with bonds. Finally, we’ll look at how we can improve efficiency performing these surveys and managing your bonds with remote monitoring units.

Poll: Who’s Managing Bonds

To kick us off, I wanted to run a quick poll — just to gauge how many of you in the audience are managing bonds in your CP system. Looks like over 60% of our audience are managing bonds — that’s fantastic, so that tells me you’re probably pretty familiar with bonds. If not, I’m still going to go into more detail for the whole audience, but that’s great to know. Thank you all for engaging with me and bearing with me on a new platform.

What Is a Bond

Let’s go over what a bond is. It may seem simple, and in basic terms it is — an interference bond, often also called a resistance bond depending on the application, is quite literally a connection, usually a wire or a resistor, often a shunt, between one pipeline and another pipeline, used to help prevent corrosion between the two.

This is really common in an area where you have crossings between two or more pipelines, or in very crowded corridors where you have a lot of pipelines in one right-of-way — and since there’s less and less open land, more and more pipelines are being built every day in these same corridors, some of which have been around for 50 years or longer. There’s a lot of situations where this comes up.

How Current Flows Without a Bond

Here’s an example: Company A’s pipeline has a CP system, with its rectifier and anode bed. There’s another operator’s pipeline crossing in that same area — very common, I’d guess almost everybody watching has this happening on their pipelines.

When Company A’s CP system is on, current is flowing through the rectifier to the anode bed, applying CP and protecting that pipeline. But since there’s a crossing, and in this scenario Company B’s pipeline isn’t protected, depending on the resistance of the soil around the pipeline and the different voltage potentials between the two pipes, that current might find Company B’s pipeline more appealing — less resistance — and jump over to it, flowing along the crossing pipeline.

When that happens, at some point that current wants to jump back off of Company B’s pipeline — maybe due to the crossing, or less resistance somewhere else — and current is going to flow wherever there’s the least resistance. In this scenario, it jumps back to Company A’s pipeline. But wherever that current jumps off, that’s a potential area for corrosion to start — corrosion on Company B’s pipeline at that spot, or, if the current flips directions, corrosion on Company A’s pipeline instead. Either way, that’s a problem we don’t want happening.

How an Interference Bond Fixes This

To mitigate this, a lot of people add an interference bond — hooking up Company A’s pipeline to Company B’s pipeline with a resistor of some kind, in this case a shunt. Once that’s hooked up, the current now has a path of least resistance through that wired resistor, so it flows through the bond and back onto Company A’s pipeline. In theory, this prevents corrosion from occurring on either pipeline and keeps the current flowing consistently in the same direction. That’s the main reason these bonds exist.

PHMSA Inspection Requirements

Per PHMSA, this type of bond has to be checked at least once a year, not exceeding every 15 months — the citation is PHMSA 49 CFR § 192. Just like your other CP assets, you have to check these bonds at least every 15 months, and that’s why they’re out there — to help prevent corrosion.

What Makes a Bond Critical

You’ve probably also heard the term “critical bond.” Per PHMSA, what makes a bond critical is if that bond, if removed or disconnected, would cause a loss of cathodic protection on any of the affected pipelines, allowing corrosion to occur and jeopardizing the safe operation of either bonded pipeline.

Take away that interference bond, and now there’s a new hot spot and potential area for corrosion. This can vary a bit by operator, since it can be considered somewhat vague — but PHMSA’s guidance is essentially: any interference bond that, if it failed, would jeopardize structure protection has to be checked and is deemed a critical, or more important, bond.

Critical Bond Inspection Requirements

Since it’s considered critical, it must be checked at least six times a calendar year, at intervals of roughly every two and a half months — you’d have to go inspect that critical interference bond to make sure there’s no metal loss and no corrosion. It’s treated similarly to the requirement for checking your rectifier assets.

Why Bonds Matter for Current Direction

Briefly recapping: a critical bond is one where, if it were disconnected, you’d probably lose adequate cathodic protection and jeopardize the safe operation of your pipeline. These bonds are also important because they help determine the direction of current flow. Going back to the example — with the bond intact, current flows from Company A to Company B and back to A, so I know the direction it’s flowing in. If that bond is removed, or I’m not checking it, I may not notice when the current decides to flip directions, which could cause corrosion on either pipeline if it’s not bonded.

Key Bond Measurements

Next, let’s briefly go into what interrupted surveys look like with your bonds, and some critical measurements you’ll want to take to capture the actual health of your bond.

First, we always recommend getting your pipe-to-soil measurement for the structures at that bond while they’re bonded together — this measures the potentials on your structure while connected to your foreign structure, which is key to understanding whether your structure is adequately protected while connected to it.

The next measurement we recommend is that same pipe-to-soil reading, but with the bond disconnected — taking the potential measurements on your structure while the bond is disconnected. That helps you understand the interference your structure might be experiencing from the foreign crossing — key to understanding the actual interference you’d be encountering on that structure.

Lastly, we recommend taking the bond current measurement — if you have a shunt or other resistor bonding your two structures together, you’ll want to measure across that bond, across that resistor. That lets you see which way the current is flowing — a negative potential tells you it’s flowing one way, positive tells you the other — as well as confirming the bond is actually working correctly, since you might see equilibrium between the two structures’ pipe-to-soil readings based on the current on that bond.

Example: Test Post with a Bond Shunt

Here’s an example for those less familiar with what a bond looks like: a 3-inch riser post with a single bond site and a shunt — that red shunt in the middle is bonding the two structures together. When taking those potential measurements, you’ll want to take the bond shunt measurement on the shunt itself with your digital voltmeter and a Mesa tablet, as an example, and then take the pipe-to-soil measurements of whichever structure is yours and whichever is the crossing structure — having all of that data together tells you the true health of your bond, and whether it’s doing what it’s supposed to do: keeping your pipeline protected.

Performing Interrupted Surveys with Bonds

When performing close interval surveys, since a CIS is an interrupted survey, you’ll need to be interrupting the CP system on your pipeline while performing that survey. Most often, this means disconnecting the bond — to remove any interference and get the true health of your pipeline while surveying. After you’ve already captured the measurements from the previous section, go ahead and disconnect the bond — if doing this manually, you’ll disconnect the shunt or bond between the two structures.

Then you perform your close interval survey — now you’re just looking at Company A’s pipeline (your pipeline), performing the survey with your interruption cycle set by your portable interrupter, like your Micromax, or, if using a Bullhorn remote monitor, setting up your interruption cycle that way. Once you disconnect the bond, you go ahead and perform your close interval survey as normal.

The Inefficiency of Manual Bond Management

We’ve talked about what bonds are, their purpose, how to manually disconnect them, and perform surveys, along with the required compliance measurements to ensure your pipeline is healthy. But everything I just described is a lot of manual disconnecting, manually taking things apart, spending time on manual measurements — that’s not very efficient in the field. I’ve been out there myself and done this, and it can sometimes take upwards of 15 minutes just to remove one — especially with multiple bonds in one box, it can take a long time to manually disconnect all of them and get your interruption cycle set up for your survey.

Using Remote Monitors to Capture Bond Measurements

By using Bullhorn remote monitors, you’re able to capture all of those measurements remotely. PHMSA requires these to be visited every few months to capture measurements, especially if it’s a critical bond — using a remote monitor for these reduces how often you have to physically go into the field to take these measurements, letting you build a long-term look at the health of your bond and pipeline, all from your desk — I can do it right here from where I’m giving this presentation.

Especially if you’re using our 520 interruptible bond monitor, you’re able to capture the pipe-to-soil measurements for your bond, your bonded structure, and your shunt current measurements, all with one button click. A really big additional value from using a remote monitor and improving efficiency is that you don’t have to manually interrupt your bonds anymore.

Real-World Story: Forgetting to Reconnect Bonds

I’ve heard this story before, and I imagine everyone in the audience has one similar. I remember talking to some customers and technicians who were performing an interrupted survey in a really crowded corridor — they had a bond box with multiple bonds in it, and to perform their survey correctly, they disconnected all their bonds, performed their whole survey over the course of a week, and left — but forgot to reconnect their bonds. It didn’t cause any problems for them since they caught it early, but this happens all the time. If anyone’s like me, I forget small things all the time too, so forgetting to reconnect bonds happens often.

Interrupting Bonds Remotely

If you’re using a remote monitor — whether or not you’re familiar with the Bullhorn line, if you’ve used portable interrupters in the past, it’s just like setting up your interruption cycle, say three-on, one-off — all you have to do is use the remote monitor to interrupt that bond remotely. I go to our web page and click Interrupt, and while interrupting your whole pipeline as normal for performing interrupted surveys, you’re interrupting the bond at the same time.

That saves a whole lot of time at the actual bond site while performing your survey, letting your crew finish a bit faster, as well as letting you capture the same measurements I mentioned earlier — instant-on and instant-off — while interrupting, with the CP system on and off. Using remote monitors on your bonds saves a ton of time and saves your crew a lot of headache trying to remember which bond was which, or whose pipe is whose — it’ll make your survey work a lot more efficient, while also giving you an extended, healthy look at your pipeline and your bonds, especially critical ones.

Closing

That’s the end of my content for today, so I want to open up the floor to questions — thank you all for having me. As a brief recap: we talked about what an interference bond is, what critical bonds are, what PHMSA declares those as and the reporting cadence for checking on them, performing interrupted surveys with bonds, and finally, improving efficiency with remote monitors on your bonds. Feel free to send questions in the chat, or we can follow up with you after the event.