Air leaks happen all the time when working with air compressors. The key is to know how to detect and to fix them before it becomes a very costly mistake.
How common are compressed air leaks?
Compressed air leaks are widespread in practical applications. Not only do they seem to be frequent, but they also are time-consuming to find and fix on a regular basis. In an average manufacturing plant, 20-30% of their total energy consumption is compressed air. Of that figure, there is an average of 30% leakage.
How costly are compressed air leaks?
Here are 2 examples to put your cost into perspective:
Possible Annual Cost
Let’s say you have a 100,000 sq foot manufacturing facility. According to Madison Gas and Electric, the average manufacturing facility uses 95.1 kWh of energy per square foot, per year. That means your facility would use approximately 9.51 million kWh with approximately 2,377,500 million kWh (25%) used for compressed air. If 30% of this use gets wasted on leaks, you are wasting about 713,250 kWh per year. If you pay $0.05/kWh for your energy, this means you are wasting approximately $35,662.50 annually on compressed air leakage. Imagine if you could fix most of those leaks and use that money for investing in the growth of your business!
Below in Figure 1, we show how much one specific leak could cost you annually, depending on the size of the leak and the PSI that you are running at.
Detecting your compressed air leaks
There are a few ways to identify compressed air leaks:
1. Listen – Sometimes you can walk around the plant, following the compressed air lines, and hear the hissing of a leak as you walk by it. Unfortunately, this isn’t always effective because factories are usually noisy and piping may be fixed to a high ceiling that is far away from your general walkway.
2. Ultrasonic acoustic detector – This type of detector picks up the high-frequency noise waves that a leak makes. This equipment often includes directional microphones, amplifiers, audio filters, and then either a visual indicator or headphones to see or hear leaks.
The way it works:
- When compressed air is flowing through a pipe, it is moving in what is called laminar flow. This type of flow means all particles are streaming all in the same direction – in a parallel manner. When there is a leak in the pipe, the airflow around the leak changes to turbulent flow, meaning that the air is not all moving in the same direction. See figure 2 for a visual representation.
- This turbulent air creates a noise that can be interpreted by ultrasonic detectors. The detector will either connect to headphones and produce a sound that gets louder when a leak is present, or else have a screen that the ultrasonic waves will show on. The wave will change a lot when the sound gets louder.
- These type of detectors usually filter out any other background noises so that leaks can be heard or seen even in very noisy environments.
- This method is a speedy, comfortable, and accurate way to look for compressed air leaks.
How to Fix Leaks
Depending on the complexity of the leak, this determines how involved the repair will be.
Quick Fix for Some Leakage:
- Tightening connections
More Involved Fixes:
- Pipe Sections
How to Reduce Future Compressed Air Leakage
- Ensure that fittings, disconnects, hoses, and tubing are all high quality
- Make sure thread sealant is properly applied
- All non-operating equipment should be isolated with a valve in the distribution system
- Lower the air pressure of the system
- This is effective because the flow rate decreases when the system pressure drops. The pressure differential across a leak will be lower, meaning less air will leak out.
- Once your repair any outstanding leaks, you should take another look at your compressor control system and reanalyze it so that you make sure to realize your total savings opportunities.
Compressed air leaks are a common issue but can easily be detected and fixed. It’s important to run routine checks for leaks and if one is present, to fix immediately to prevent costly mistakes. If you have any other leak or general air compressor questions, please contact us at: