Abrasive Blasting, Shot Peening & Surface Prep calculator
Abrasive Blast Compressor Air Demand Calculator
Size blast compressor capacity from the measured nozzle orifice and loaded nozzle pressure, not nameplate horsepower. Add every simultaneous nozzle, breathing and auxiliary air, then a reserve.
What this calculator does
- Pressure-blast compressor capacity from nozzle orifice, loaded nozzle pressure, simultaneous nozzles, accessory air and reserve.
Formula used
- Nozzle airflow at 100 psi = interpolated chart value for the measured orifice
- Loaded nozzle demand (cfm) = chart airflow × (psig + 14.7) ÷ 114.7 × simultaneous nozzles
- Required capacity (cfm) = (nozzle demand + accessory air) × (1 + reserve % ÷ 100)
- Headroom (cfm) = available rating − required capacity
Inputs explained
- Measured Nozzle Orifice: Actual bore measured with a nozzle gauge, not the stamped size.
- Loaded Nozzle Pressure: Pressure measured at the nozzle while blasting.
- Simultaneous Nozzles: Nozzles that can be live at the same time.
- Breathing and Auxiliary Air: Respirator, dryer, control and vacuum load on this source.
- Capacity Reserve: Engineering reserve for wear, leakage and operating variation.
- Available Compressor Rating: Delivered capacity at the operating pressure.
How to use the result
- Best suited to compressor rental sizing, multi-nozzle expansion, nozzle wear capacity review.
- Confirm the final compressor selection with the equipment supplier. Does not verify breathing-air quality, alarms or carbon-monoxide controls. Piping, hose and fitting pressure losses need a separate check.
Common questions
- Why is nozzle diameter so important? Airflow rises quickly with orifice area. A small diameter increase from wear can consume the reserve that held nozzle pressure, so gauge the actual bore.
- Is the reserve mandatory? The reserve is an engineering and supplier decision, but zero reserve leaves no capacity for wear, leakage or operating variation.
- Can I size by horsepower? Not reliably. Use delivered cfm at the required pressure; horsepower alone does not establish available air volume.
- Does this check breathing-air safety? No. It includes breathing-air volume only. Air quality, filtration, alarms and respirator compliance need separate verification.
Last reviewed 2026-10-01.