As a facility manager, you’re responsible for the smooth operations of all the systems within your Chicago building, and this includes all the plumbing and piping systems. Over time, these systems can corrode, leaving you with leaking pipes and potential water and chemical damage, depending on the contents flowing through the pipe. Here at NuFlow, we want to help you prevent corrosion in order to extend the useful life of your plumbing systems and prevent leaks as well as catastrophic pipe blowouts.

Causes of Corrosion in Metal Plumbing Pipe Systems

Metal plumbing pipes are most susceptible to corrosion, and today there are more types of metal plumbing pipes than ever before, including cast iron, copper, brass, galvanized steel, corrugated stainless steel tubing, black iron and carbon steel as well as many other types of steel pipes. Unfortunately, all types of metal plumbing pipes are susceptible to corrosion due to a number of factors, and the corrosion rate of plumbing pipes has only increased over the last two to three decades. Here are the four most common reasons for the increase in corrosion rates of metal plumbing pipes.

1. Modern Steel Plumbing Pipes Are Not as Corrosion Resistant as Their Predecessors

The steel plumbing pipes of today are not as corrosion resistant as the pipes that were manufactured 30 to 40 years ago. Part of this is due to using pipes with lower pipe schedules. For example, the pipes used more than 30 years ago for cooling tower operation were schedule 80 pipes. Today, those pipes are more likely to be schedule 40 pipes, which have thinner pipe walls. When this is combined with less effective corrosion inhibitors, limited corrosion monitoring programs and total reliance on corrosion calculations and estimated useful lives, pipe leaks and failures become more common.

2. Engineering Practices that Are Not as Tolerant as in the Past

The tolerances for certain plumbing pipe systems have been relaxed since the 1950s. This is especially true when it comes to HVAC systems. According to ACHRNews, facility managers and building owners could rely on an average corrosion rate of 1-2 MPY a year, with MPY standing for mill penetration per year. One MPY is equal to 1/1000 of an inch every year, and the standard rate is often used in calculating the coupon corrosion rate. The corrosion rate today is closer to 3 to 5 MPY.

3. Increasing Operating Demands on the Pipes

Plumbing and processing piping are subjected to higher demands today than in the past. Metal pipes today can have almost anything flowing through them from water to paint and even food and drinks. Buildings are also larger and are occupied by more people today than they were in the past. This means that plumbing pipes of all types and for all manufacturing and water distribution practices are put under greater stress, resulting in an increased rate of corrosion. If these factors aren’t taken into the coupon rate calculations, facility managers many find themselves in need of emergency repairs and pipe replacements far sooner than they anticipated.

4. Corrosion Inhibitors that Are Less Effective

Corrosion inhibitors are designed to reduce the rate of corrosion in certain piping applications, including HVAC chillers and cooler as well as some boiler systems. With the increase in environmental protections and codes, the corrosion inhibitors today are not as effective as they were several decades ago. While this is good for the environment, it means faster rates of corrosion.

Understanding Corrosion Inhibitors

Businesses use corrosion inhibitors because they are extremely cost-effective when compared to other types of corrosion controls. They are implemented by adding a certain amount of the inhibitor to the system at predetermined intervals.

Types of Corrosion Inhibitors

There are three different types of corrosion inhibitors available on the market.

  • Anodic – These inhibitors are designed to react with oxygen to form a thin layer on top of the metal surface. You can think of this in relation to the way copper forms a patina and turns green over time. The patina protects the copper from corrosion.
  • Cathodic – Cathodic inhibitors slow corrosion reactive elements, like hydrogen and oxygen, usually with the addition of a poison, including selenium ions and arsenic.
  • Mixed – Mixed corrosion inhibitors use both anodic and cathodic inhibitors to slow pipe corrosion.

Selecting the Right Corrosion Inhibitor for Your Plumbing Pipes

Since corrosion inhibitors are considered extremely affordable, you may want to consider using them in order to extend the useful life of your process piping systems, especially in closed systems, like your HVAC chiller. Of course, it’s not recommended to source your own corrosion inhibitor and purchase it because the one you choose may not be correct or safe for your system. Instead, we recommend finding an expert that is NACE certified. An experienced and NACE certified pipe corrosion expert can evaluate your pipes and recommend or develop the right corrosion inhibitor for your needs.

Understanding Corrosion Coupons

Corrosion coupons are another tool in your corrosion prevention and pipe maintenance toolbox. These coupons are designed to determine the rate of corrosion within your plumbing pipes and to help you determine the proper maintenance schedule and the estimated repair costs as well as the entire expected useful life on your piping system under the current and future estimated operating loads. You’ll sometimes hear facility managers and engineers refer to corrosion coupons as corrosion monitoring coupons.

The reason they are called coupons is because they are small pieces of metal, usually strips or discs, that are manufactured using the same material as your plumbing pipes. Through careful observation of the rate of corrosion on the coupon, calculations can be performed to determine the rate of corrosion in your piping system. However, the effectiveness of this method depends on the vigilance of the team monitoring the coupon.

Epoxy Pipe Lining to Inhibit Corrosion of Metal Piping Systems

When it comes to preventing corrosion in plumbing systems and certain types of process piping systems, epoxy pipe lining has proven to be an effective method. This is because inserting an epoxy coating or pipe liner prevents the water or contents flowing through the pipe from coming into contact with the metal pipe walls. Since the product flowing through the pipe no longer comes into contact with the pipe wall, corrosion is eliminated, and the expected useful life of your plumbing system and/or process piping system in extended.

It all starts with a Building Pipe Assessment from our Chicago pipe lining technicians at NuFlow. Our building pipe assessments are designed to tell us how old your plumbing pipes are and how much corrosion is present on your plumbing pipes, and it starts with a thorough camera inspection that is recorded and displayed on an LCD monitor. Once we know the condition of your plumbing pipes, we will write a detailed report of everything that was found, explain the report to you and provide you with a copy. We will also tell you if your pipes are good candidates for the pipe lining process. If they are, we will provide you with an estimate so that you can make an informed decision.

If you decide to go ahead with pipelining in order to prevent future corrosion in your pipes, we will explain the process to you and create a pipelining schedule. To determine whether or not your process piping or plumbing pipes are good candidates for the pipe lining process, give us a call at 815-790-9000.