Author: Tara Wagner

Do your operations screech to a halt when all the air-powered equipment in your factory is used at the same time? Stoppages due to insufficient volume or pressure suggest the compressed air system was poorly designed.

Many facilities think good design is just a matter of running piping to where it’s needed. However, while the system might run, it’s probably inefficient and costing more than it should.

With that in mind, here are five common design mistakes in compressed air systems and how to avoid them:

Mistake #1. Failing to assess the volume of air needed. Specifications for air-powered equipment list both minimum pressure and minimum volume in cubic feet per minute (cfm) needed. If the equipment doesn’t get both, chances are, it won’t run or operate as expected.

How to Avoid it: Start by calculating total cfm needed and identifying minimum pressure. Confirm piping can meet the volume requirements and design the layout to minimize pressure drops – loop systems are often a good choice. Use CAM Demand Expanders or pressure regulators to avoid delivering more air than particular items require.

Mistake #2. Wrong-sizing the air receiver. When air-powered equipment is turned on, line pressure drops. The compressor needs time to react to this demand, so an air receiver ensures there’s sufficient air available.

How to Avoid it: Consult an expert to determine the optimal size receiver for your system. The receiver must hold enough air to meet peak demand while the compressor spools up. Too small, and you’re starving the tools. Too big, and the compressor may hardly run. Note that storage is only effective if there is a differential between the stored pressure and the point of use pressure. There are two main types of storage in a compressed air system: system storage and point of use storage. Both must be engineered for events and the corresponding compressor response.

Mistake #3. Incorrectly sizing the compressor. If your compressor runs all the time, it’s not keeping the air receiver charged, costing you money and wearing out the compressor. When the compressor is too large for the system, it runs only briefly to recharge the receiver. That says you’ve spent too much on compressor capacity and it could lead to reliability problems and poor efficiency.

How to Avoid it: Don’t make a quick decision on your compressor size. Take the time to figure out the precise need for your facility. Consult with experts if needed.

Mistake #4. Excessive pressure drops. The compressor might deliver 120 psi, but what do the tools at the end of pipe runs get? Friction between flowing air and pipe walls saps pressure from the system. Tight turns and tees take out more, as can quick-disconnect fittings.

How to Avoid it: To help guarantee you get enough psi where it’s needed:

• Minimize the length of pipe runs
• Use large diameter pipe
• Avoid tight radii
• Use threaded joints

Mistake #5. Omitting a Demand Expander controller. This is a fast-acting controller and valve. As air consumption rises, it opens progressively, allowing more air into the piping. This minimizes pressure drops and ensures each piece of equipment gets both the cfm and psi needed. When consumption drops, the flow controller quickly reduces the flow to stop line pressure going higher than needed. The reservoir isn’t depleted as quickly, and the compressor is able to recharge it faster.

How to avoid it Research your options when choosing automation controllers for your system. A full system audit from an expert may help you to better understand what your system needs to be fully optimized.

Get Help to Optimize System Design

It’s easy to make mistakes when designing a compressed air system. These errors lead to unnecessarily high purchase and installation costs, along with excess energy consumption and inefficient operation. The optimal system minimizes total costs and maximizes performance, but achieving that takes in-depth expertise.

The specialists at CAM Technologies have spent years working with compressed air. We can help design and install a system to meet your needs. Call or email CAM Technologies for more information.

Compressed air is critical to the success of every industrial facility. Without it, production comes to a halt and customer expectations aren’t met. Reliability and the ability to meet peak demand are essential, so it all comes down to compressed air system design.

Seeking the Lowest Total Cost

Designing a compressed air system would be straightforward if demand was constant, but unfortunately, it never is. The larger the plant, the wider the swings are between baseline and peak demand. This makes optimizing compressor capacity, air receiver capacity, and distribution pipework a complex task.

It’s easy to design an oversized and expensive system that has no trouble satisfying peak demand, but it’s possible that even this system will become unreliable as components endure duty cycles far from their original design specifications. With a well-designed system, every piece of equipment has just enough compressed air to run efficiently whenever called upon.

Distributed vs. Centralized Systems

When a compact area is being served, a centralized system is the best choice – it’s simpler and less expensive to install. It will also likely be more efficient, more reliable and easier to maintain.

However, as a facility grows larger and more complex, the case for a decentralized system becomes stronger. In a decentralized system, air is compressed close to where it’s needed. Benefits include:

• Shorter pipe runs — less pressure drop, fewer opportunities for leaks and less waste
• Increased flexibility – If some areas of the plant run a single shift while others operate 24/7, why provide air everywhere? In a decentralized system, it’s possible to deliver air only where it’s needed. This can have a significant impact on running costs.

10 Design Guidelines

Now that you understand the type of system that you need to design, keep the following guidelines in mind when you begin the process:

1. Understand demand. Consider a flow monitor, which can be useful for logging consumption patterns.
2. Determine supply requirements. Most operations want clean and dry air, but you should also identify any specific needs. Note the facility size and location of major users.
3. Evaluate ambient conditions. This includes elevation, relative humidity and dust.
4. Determine facility temperatures. Especially in a large facility, pipes can pass through areas where temperatures vary widely. They can even be buried underground or placed near a roof. All of this can be managed, but it needs to be identified first.
5. Choose the most valuable system layout. A loop helps reduce pressure drops but requires additional piping. A straight type of system is typically cheaper to install.
6. Size pipes for demand and distance. Remember that pushing air through a long thin pipe requires a large amount of compression.
7. Size the storage. The air receiver should be sized to handle peak demand. Avoid excessive compressor cycling, which can occur if the receiver is a poor match. Note that storage is only effective if there is a differential pressure between storage and the points of use. Use of CAM Demand Expanders and Regulators are essential to providing proper system storage.
8. Identify future maintenance needs. Incorporating bypass sections during construction makes later maintenance much easier. This is also a good time to consider accessibility of key components and possible future expansion.
9. Select pipe material. Aluminum is a popular choice because it’s lightweight and easy to shape, but it is more expensive than steel. Keep in mind that surface finish affects pressure drop.
10. Evaluate how modern flow control technologies can help improve system performance and lower costs.

Benefit From Our Experience

Designing an efficient compressed air system is a complex task. While you can try calculating and modeling demand, there’s always an element of unpredictability. Someone with experience of designing such systems knows the traps and pitfalls to avoid. That’s why it makes sense to partner with the specialists at CAM Technologies. We can help you design a system that’s efficient, reliable and cost-effective. Call or email for more information.

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