Compressed Air Leak Cost Calculator
Estimate how much air a leak wastes and what it costs. Air escaping through a hole at normal plant pressures flows at choked (sonic) conditions, so the flow depends only on hole size and upstream pressure.
- ṁ = Cd × A × P1 × 0.6847 ÷ √(R T) = 8.617 g/s (choked flow, air)
- Free air = ṁ ÷ 1.204 kg/m³ = 0.4294 m³/min
- Power = flow × specific power = 2.791 kW
Choked Flow Through a Hole
For air: ṁ = Cd × A × P1 × 0.6847 ÷ √(287 T)
P1 is absolute pressure, T absolute temperature and A the hole area. Free air is referred to 20 °C and 1.013 bar (1.204 kg/m³). Specific power of 6 to 7 kW per m³/min is typical for screw compressors at 7 bar.
Worked example
A 3 mm hole at 7 bar(g) leaks about 430 L/min of free air. At 6.5 kW per m³/min that is about 2.8 kW, roughly 150,000 per year at 9 per kWh over 6,000 hours.
Frequently Asked Questions
How much does a compressed air leak cost?
A 3 mm leak at 7 bar wastes roughly 2.8 kW of compressor power continuously, which adds up to thousands of kWh per year.
How do I find compressed air leaks?
Use an ultrasonic leak detector during production, or soapy water at joints when the plant is quiet.
Does lowering pressure reduce leakage?
Yes. Leak flow is proportional to absolute pressure, and lower pressure also reduces compressor power per unit of air.
Learn more on the blog
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A practical, field focused guide on instrumentationblog.in that explains the theory behind this calculator and how engineers apply it on real plants.
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