Compressors here deliver roughly 43 to 47 CFM. It is the 15 HP piston class: the Champion RV series 15 HP two stage, ABAC AB7 and Champion R series duplex sets, and the Chicago Pneumatic RCP-C Iron duplex all land here at 175 PSI. Alongside them sit 15 HP variable speed rotary screws from Quincy and Chicago Pneumatic and the smaller oil free multi scroll packages from Quincy, Atlas Copco and Chicago Pneumatic.

Piston, screw or scroll at 45 CFM

A 15 HP two stage piston unit on a 120 gallon tank is the value choice for a shop that runs tools in bursts and can accept a 60 to 70 percent duty cycle. A duplex set adds redundancy and lets one pump carry the shop on a slow day. A 15 HP variable speed screw is the pick when the compressor runs all shift and demand moves around; it holds a steady pressure and cuts power at partial load. Oil free multi scroll units cost the most but deliver Class 0 air at about 60 dB, which is why they show up in labs, food packaging and dental or medical settings.

Power

Everything on this page is three phase, 208 to 230 or 460 volt. Budget a 60 amp circuit for a 15 HP piston motor at 230 volt and a 50 amp circuit for a 15 HP screw. Piston units need clearance for cooling air and a solid floor; scroll and screw packages are enclosed and can sit closer to a wall.

Dryer sizing

Size the refrigerated dryer at 50 to 60 CFM. For a piston compressor add an aftercooler so inlet air to the dryer stays under 100 degrees F.

Related pages

• 40 CFM air compressors
• 50 CFM air compressors
• Oil free scroll air compressors
• Shop all sizes by CFM