Pneumatic breakers and site tools are usually straightforward to size when the actual airflow of each tool is known. The key is to total the tools that will genuinely operate at the same time rather than simply counting every tool on site.
Key points
- Add simultaneous tool demand
- Check each tool manufacturer specification
- Long hoses create pressure drop
- A 185 CFM unit may suit many common site setups
Sizing breakers and pneumatic tools
Reference values for handheld jackhammers are often around 45–90 CFM, but actual tools vary. Two 70 CFM breakers running together represent 140 CFM before allowing for hose losses or other consumers, which explains why the 185 CFM class is common for this kind of work.
Impact wrenches may use much less average air than large breakers, but continuous-use tools should be sized on realistic duty rather than optimistic averages.
How to specify the job
Start with the equipment or process that will consume the air. Record the number of tools that may run at the same time, each tool's required airflow, and the highest operating pressure. For industrial temporary-air jobs, also note required air quality, duty cycle, connection size and whether the process can tolerate interruption.
Airflow, pressure and operating margin
Compressor capacity is usually described by airflow and pressure. In Australia you will commonly see airflow in CFM or m³/min and pressure in PSI or bar. The compressor must meet both requirements at the point of use. Long hose runs, fittings, filters and simultaneous demand can reduce effective performance, so a practical sizing margin is useful.
What to ask the hire supplier
Machine
Confirm rated free-air delivery, working pressure, fuel or electrical requirements and whether the exact model may vary.
Accessories
Ask about hoses, manifolds, aftercoolers, dryers, filtration, receivers, fittings and any tool-specific accessories.
Logistics
Confirm towing or delivery, access, placement, refuelling, collection, operating hours and any site induction requirements.
Safety
Follow the supplier's risk assessment and operating manual. Verify hose, coupling and accessory pressure ratings.
Use the sizing calculator
If your application is based on pneumatic tools, our calculator can total approximate airflow and suggest a compressor class. It is a planning tool only; final selection should be confirmed against the actual equipment specifications.
Open compressor calculator