When you think about increasing your compressed air systems and their efficiency, maintaining your air compressor’s consumables, filters, fluids and regulators are most likely what comes to mind. One aspect that gets overlooked are the parts that carry the compressed air from the machine to the tool, which are often referred to as the “dirty thirty”.
The hoses, pipes, and fittings typically run about 30 feet in length and when things aren’t maintained properly, your air compressor can see a drop in pressure which will effect the efficiency of the machine. Dirty thirty pressure drops are typically seen throughout the final stretch of the hoses and the drop typically ranges from 30 to 50 psi, or around 20 times the amount of pressure lost in the earlier sections of the hoses. These findings remained the same when the pipe was over 100 feet in length.
If you suspect the drop in your compressed air systems’s efficiency is resulting from the dirty thirty, try setting up a pressure gauge to double check your air compressor’s performance. If the gauge reads on the lighter side, your problem may be a result of the hoses, pipes, and fittings. When testing this way, gauges can be slow to detect the drop in pressure and might only be showing you a third of the actually loss of pressure. That means if your gauge is reading 10psi, the actual pressure drop could be up to 30psi.
Potential dirty thirty inefficiency issues
A loss in pressure due to the dirty thirty can lead to a series of issues, including:
– Poor product application on paints, polishes, etc.
– Misfires on tools, nailers, drills, screws, staplers
– Poor craftsmanship on cabinets, tables, steel frames
Potential issues with the compressed air system’s efficiency at the dirty thirty
While inefficient leaks and air pressure drops can happen just about anywhere, we usually find more of these problems along the dirty thirty area. The issue, at times, can be pipes that don’t fit correctly due to your flow rate and air demand. If your air compressor is running around 100 psi, a 2% reduction in pressure needs a 1% reduction in input. In order to prevent a drop in pressure, the hoses and filters must be the appropriate size for their dynamic use, as opposed to the cubic feet per minute they deliver.
Another problem you might run into when pressure drops are quick disconnects and hoses that don’t fit properly. Issues with disconnects can be caused by ball and spring assemblies within the female half of the disconnect coupling. When hoses are creating pressure issues, it’s often because the hose isn’t wide enough.
Finally, consider the length of your hose. If it’s too long for the application you might run into dirty areas beyond the 30 feet. While it might seem like a good idea to purchase the longest hose you can get for your money, it’s not worth it in the end when you consider the inefficiencies.
It’s not uncommon for leaks to account for up to 30% of the total amount of compressed air being used. Think about how much that’s costing your facility on a daily basis.
If you suspect your air compressor has leakage issues, start with the most obvious places first, then test for smaller leaks. At Michigan Air we can test your system for leaks and ensure it’s properly installed. A few simple tests can save you a lot of money in the long run.
Michigan Air sells and services air compressors throughout the state of Michigan, from Grand Rapids to Detroit and everywhere in between. We are ELGi Compressor distributor and specialists. Call us today with your compressed air needs.

Rotary Screw Compressor Troubleshooting Guide
Run more efficiently with this quick reference guide that covers issues such as:
- Low pressure
- Excessive vibration
- Low oil pressure
- Overheating
- Excessive oil consumption
- Excessive current draw
- Failure to start or motor stalls