In general, the total pressure drop between your compressor room and your point of use shouldn't be more than 1 bar. In theory, new systems are designed with a maximum pressure drop of only 0.1 bar over the fixed piping, to reduce energy costs.
But I have seen 1 bar, or even 1.5 bar, many many times. And 2 bar is not uncommon.
The budget
Don't think of that 1 bar as one number. Think of it as a budget, where every component gets a share:
| Component | Typical pressure drop |
|---|---|
| Air main (compressor room to distribution) | 0.03 bar |
| Distribution piping | 0.03–0.05 bar |
| Connection / service piping | 0.04 bar |
| Fixed pipework, total | ≈ 0.1 bar |
| Air dryer | 0.1–0.2 bar |
| Filters (new and clean) | 0.1–0.2 bar |
| Filters (due for replacement) | up to 0.5 bar |
| Hose, couplings and FRL unit at the machine | 0.3–0.5 bar |
| Everything together | 0.8–1.0 bar, maximum |
If your system spends more than that, something is eating more than its share. Usually it's the filters, or piping that is too small for the flow.
Filters deserve special attention
A dirty compressed air filter creates a much bigger pressure drop than a new, clean one. In fact, the amount of pressure drop is an indicator of how dirty the filter is! A filter starts with a low pressure drop, and it grows over time. Replace them at the recommended pressure drop.
The same goes for the oil separator inside your screw compressor: anything above 0.2 to 0.3 bar under load means it's time to replace it.
Working backwards from the tool. If we need 6 bar of air pressure for our consumer to work correctly, and the system takes 1 bar of pressure drop, we need to set our air compressor to 7 bar. Every 0.1 bar costs 0.7% in energy. So a system with only 0.5 bar of pressure drop can run at 6.5 bar instead: 3.5% less energy, every hour it runs.
Written by Cas · Updated Aug 2026