Calculator Inputs
Example Data Table
| Hole Size | Pressure | Leaks | Runtime | Energy Price | Typical Use |
|---|---|---|---|---|---|
| 1 mm | 7 bar | 2 | 12 h/day | 0.12 per kWh | Small fitting leak |
| 3 mm | 100 psig | 1 | 16 h/day | 0.12 per kWh | Open tube or worn seal |
| 0.125 in | 90 psig | 4 | 24 h/day | 0.15 per kWh | Multiple plant leaks |
Formula Used
The calculator estimates air flow through a circular leak as an orifice. It first converts gauge pressure to absolute pressure. Then it checks the pressure ratio against the critical pressure ratio for air.
For choked flow: m = Cd × A × P × √(γ / R / T) × (2 / (γ + 1))^((γ + 1) / (2 × (γ - 1)))
For subsonic flow: m = Cd × A × P × √((2γ / (R T (γ - 1))) × ((Pr)^(2/γ) - (Pr)^((γ + 1)/γ)))
The mass flow is converted to standard CFM. Cost is then estimated with: Annual Cost = Total CFM ÷ 100 × Specific Power × Annual Hours × Load Factor × Energy Price.
How to Use This Calculator
- Measure or estimate the leak hole diameter.
- Enter your system gauge pressure and pressure unit.
- Adjust the discharge coefficient if the leak shape is known.
- Add the number of similar leaks found during inspection.
- Enter compressor power, runtime, energy price, and repair cost.
- Press the calculate button to view flow, cost, energy, and payback.
- Use CSV or PDF buttons to save the result.
Compressed Air Leak Loss Guide
Why Leak Loss Matters
Compressed air is useful, but it is costly to produce. A small leak can run for many hours without notice. That lost flow makes the compressor work harder. It also reduces pressure at tools and machines. Lower pressure can slow production and create quality issues.
What This Tool Estimates
This calculator estimates leak flow through a round opening. It also estimates power demand, yearly energy use, annual cost, and repair payback. The result helps teams rank leaks by cost. Large leaks should be repaired first. Many small leaks can also create a major loss.
Important Inputs
Hole diameter has a strong effect on the answer. A larger diameter increases area quickly. Pressure also changes the flow rate. When pressure is high enough, air reaches sonic speed at the leak. The calculator marks this condition as choked flow.
Energy and Cost Planning
Specific power links air flow to compressor energy. Many plants use kW per 100 CFM for this value. If your compressor audit gives a different number, enter that value. Runtime is also important. A leak on a system running all year can be very expensive.
Repair Decisions
The payback value compares repair cost with yearly savings. A short payback means the repair is attractive. Use the repair cost field for parts, labor, access equipment, and downtime. For a plant survey, repeat the calculation for each leak group.
Practical Leak Control
Use ultrasonic testing, pressure checks, and routine walkdowns. Tag each leak during inspection. Record location, size, pressure, and repair status. After repairs, confirm that pressure and compressor loading improve. Keep a log so future leaks are easier to control.
FAQs
What does this compressed air leak calculator measure?
It estimates leak flow, wasted compressor power, annual energy cost, air volume loss, repair cost, payback time, and emissions.
What leak diameter should I enter?
Enter the best estimated opening size. Use ultrasonic findings, visual inspection, or a measured hole size when available.
What is discharge coefficient?
It adjusts the ideal orifice flow for real leak shape. Sharp leaks often use about 0.60 to 0.70.
What is choked flow?
Choked flow happens when air reaches sonic velocity at the leak. More downstream pressure drop will not increase mass flow.
What is compressor specific power?
It is the compressor energy needed for each 100 CFM of delivered air. Use audit data when possible.
Can I calculate many leaks together?
Yes. Enter the count of similar leaks. For different leak sizes, calculate each group separately and add the results.
Why is repair payback useful?
Payback shows how quickly energy savings may recover repair cost. It helps prioritize maintenance work.
Is this result exact?
No. It is an engineering estimate. Actual loss depends on leak shape, pressure stability, temperature, compressor control, and system demand.