How do you know when it’s time to retire your old iron distribution piping? Black iron piping is still commonly used for compressed air distribution, but this type of piping doesn’t last forever—and an aging distribution system could be costing you more than you realize. If you’re wondering about the RIO of upgrading to aluminum piping, read on.
What is the Service Life of Compressed Air Piping?
The service life of your compressed air distribution system depends largely on two factors: the material chosen for the piping system and how well you take care of it. A black iron piping system can last 20 years or longer with proper care or may fail in as few as ten years. A big part of that difference comes down to moisture levels in compressed air.
Iron pipe is prone to corrosion when exposed to moisture—and compressed air, you may remember, can be full of moisture. When iron rusts, you will see corrosion buildup, called scale, on the inside of the pipes. Over time, buildup of scale will narrow the inside diameter of the pipe, constricting airflow. Flakes of rust can also break off inside the pipes and clog inline filters or contaminate the air supply.
You can extend the life of your black iron piping by keeping air as dry as possible through the use of air dryers and filters. However, even with good care, it is virtually impossible to avoid all moisture and the resulting corrosion. Eventually, the pipe will deteriorate to the point where it must be replaced.
Service Life of Black Iron vs. Aluminum Piping
All things being equal, aluminum piping has a longer service life than black iron. Aluminum piping can last for several decades with proper care. What makes the difference? Unlike iron, aluminum does not rust. When exposed to oxygen, aluminum forms a layer of aluminum oxide which is protective against further corrosion. That means that aluminum distribution piping won’t develop the scale problems common with black iron. Under similar working and environmental conditions, you can expect aluminum piping to outlast black iron by years or decades.
When to Replace Compressed Air Distribution Piping
How do you know when to replace your black iron distribution piping? As the piping degrades, you’ll notice several problems, including leaks, excessive pressure drop, blocked filters and contaminated air.
- Leaks: Black iron pipe is highly prone to development of leaks at the joints even before corrosion is a highly visible problem. If corrosion is left long enough, you will start to see pinhole—and eventually larger—leaks in the pipe itself. These leaks can add up to a big problem for your energy bill and your bottom line; on average, compressed air leaks cost manufacturers thousands of dollars a year. And an aging iron distribution system may have dozens of leaks, many too small to detect with human senses. These leaks can be patched and repaired—sometimes even for free!—but eventually, it will become more cost-effective to replace the whole system than to try to stay on top of newly forming leaks. A leaky distribution system also makes your compressor work harder to keep up with air demand, which adds up to more wear and tear on your compressor and a shorter service life. This also increases energy costs for the system.
- Excess pressure drop: When iron rusts, the corrosion on the inside of iron piping narrows the interior diameter of the pipe, constricting airflow. It also makes the interior surface rough instead of smooth, which disrupts the laminar flow of compressed air through the pipes. As a result, you’ll start to notice pressure drop increasing across your distribution system. Excessive pressure drop makes your compressor work harder to push air through the degraded distribution system, which will drive up energy bills and add to the wear on your compressor. If scale buildup gets bad enough, you may even experience a complete blockage in your compressed air piping, as rust and other contaminants get caught in the already constricted pipe. This is especially prone to happen at joins and elbows in the system. A blockage in your compressed air piping can shut down production or even lead to a dangerous pipe failure.
- Blocked filters: We’re all familiar with the red flakes that develop when iron rusts. As tiny flakes of scale break off inside the distribution piping, they get carried along with the airstream. Rust particles that break off prior to an inline filter will get captured by the filter media. That will help prevent contamination of downstream processes, but if you have a lot of scale, filters will quickly become loaded. That means you’ll find yourself replacing them more frequently.
- Contamination in compressed air: Iron particles in your piping system can also end up in the final air supply. Any rust particles that break off after the last inline filter will end up in the air you are using for your processes. Depending on your air quality requirements, this may be a minor inconvenience or a serious problem. Rust particles can damage pneumatic tools and equipment. They can also lead to product quality issues, such as problems with spray application of paints and coatings. If you must maintain a specific air purity level for your application under ISO 8573-1:2010, scale in your air distribution system may put you out of compliance.
The Cost of a Failing Compressed Air Distribution System
An aging compressed air distribution system will add to your operating costs in several ways. Some of these costs may include:
- Wasted compressed air due to leaks in your system (and remember, compressed air is your most expensive utility!).
- Higher energy costs because your air compressor must work harder.
- Increased wear and tear on your compressor and a shorter service life.
- Higher maintenance costs, including consumables (e.g., filters) and maintenance time.
- Product quality issues leading to loss of inventory.
- Increased downtime to take care of leaks and blockages.
The ROI of Upgrading to Aluminum Compressed Air Piping
When the time comes to replace your distribution system, it pays to invest in a higher-quality, longer-lasting piping system. Aluminum piping costs a bit more than black iron up front, but it will pay for itself over time. It takes about five to seven years to recoup the cost difference between aluminum and iron through lower operating costs. When you factor in the longer service life—in most cases, much longer—the return on investment (ROI) for aluminum distribution piping is quite high compared to other piping materials.
Aluminum pays for itself in several ways.
- No leaks: A high-quality aluminum piping system, like Unipipe, is leak-free, both at installation and over time. Unipipe’s fittings are designed to eliminate air leaks at the joints. And since aluminum doesn’t rust like iron, you can expect leak-free service for many years to come. That means you keep more of your expensive compressed air for production applications instead of losing it to leaks.
- Lower pressure drop: Since aluminum doesn’t develop scale and rust inside the lines, you won’t experience the gradual pressure drop commonly seen in black iron piping. Air lines stay clean and clear.
- Fewer maintenance problems: Eliminating scale and rust also means fewer problems with your compressed air distribution system. Inline filters don’t have to be changed as often, and you’re much less likely to experience a blockage in your pipes. You’ll also experience less wear and tear on your compressor motor.
- Cleaner air: If air purity is a concern, aluminum is the way to go. Like the high cost of stainless steel, its rust-free operation results in cleaner air. Aluminum is appropriate for all but the highest purity classes (e.g., medical-grade/breathing air). Even for food- and medical-grade applications, aluminum can often be used up to the final filters, resulting in cost savings compared to the higher cost and installation time for stainless steel.
Installation Costs: Aluminum vs. Black Iron Distribution Piping
When you are installing a new compressed air distribution system, or replacing an old one, it is important to look not only at material costs but also installation costs. A modular aluminum piping system like Unipipe is much faster to install and does not require special tools. That leads to savings on two fronts: labor and downtime. These savings may make up a large part of the cost difference between aluminum and iron.
- Unipipe can be installed without special tools or fittings, which means you don’t need a certified plumber or highly skilled technician to install or make changes to the system.
- Its fast install time also results in less downtime during the installation. A Unipipe aluminum piping system can be installed in half the time of a comparable black iron system, so you can get back to production sooner.
The Final Word: When to Upgrade to Aluminum Piping
Replacing your compressed air distribution system is a major investment in both money and time (which is also money). If you currently have an aging black iron piping system, it makes sense to get as much service life as you can from it. But if you are experiencing excessive problems with your compressed air distribution—leaks that develop faster than you can patch them, dirty air, excessive pressure drop, or a compressor that can no longer keep up with air loss and pressure drop—it may be time to think about an upgrade. When that time comes, aluminum may be the smartest choice.
Unipipe is the best compressed air piping system on the market. Its high-quality aluminum construction and innovative fitting design result in years of leak-free service. That’s why Unipipe backs up their systems with a 20-year warranty—the best in the industry. Unipipe is fast and easy to install and is manufactured to the highest standards. In addition to compressed air piping, Unipipe is available for nitrogen, vacuum, high-pressure and multi-fluid applications.
Want to talk about compressed air piping? Contact a Unipipe specialist.