Air Consumption Table: Suction and Pressure

Generally speaking, a pressure blasting system consumes more air than a suction blasting system – up to four times more. For instance, in order to maintain a pressure at the nozzle of 100 psig using a 5/16″ blast nozzle, a suction system consumes approximately 42 cfm and a pressure system consumes approximately 137 cfm.

The main reason for this is that, in a suction system, the nozzle air jet which creates the Venturi effect is usually half the size of the nozzle. For example, a 5/16″ ID nozzle uses a 5/32″ ID air jet, so the air volume demand is set by the air jet. However, in a pressure system, a 5/16″ ID nozzle really requires the air volume for a 5/16″ orifice.

ISTblast - Working Principle of Pressure and Suction Nozzles

Furthermore, in pressure systems, the pressure vessel must be depressurized each time it runs out of media, so the air volume used to build the pressure within the vessel is tossed away and wasted. In suction systems, nearly 100% of the compressed air is driven to the nozzle to propel the media using the Venturi principle.

Read our article HOW TO PROPERLY SIZE YOUR COMPRESSOR FOR YOUR SANDBLASTING APPLICATION in order to understand how to properly size your compressor according to your compressed air demand at the nozzle.

Here is an approximation of the air consumption tables for both systems.

AIR CONSUMPTION TABLE FOR SUCTION SYSTEMS (CFM)1

 PRESSURE (psig)2
NOZZLE ID440506070801000
1/4″121517192126
5/16″192327303442
3/8″273338434858
7/16″384652606580
1/2″495867768594

AIR CONSUMPTION TABLE FOR PRESSURE SYSTEMS (CFM)1

  PRESSURE (psig)2
NOZZLE ID4UNITS20253035404550607080901000120
1/8″cfm17789101213141517192025
lb/h34848556269737782110127140154192
3/16″cfm115161820222426303338414555
lb/h394101114127140153166192220243268297363
1/4″cfm127303437414549556168748197
lb/h3174193219251276303329369398460504556666
5/16″cfm14246535765707688101113126137152
lb/h32542783203453944254625286807568329101010
3/8″cfm15563768291100109126143161173196220
lb/h33744285175586206827448609701080118412961454
7/16″cfm17285100112124137149170194217240254300
lb/h3488576678759840835908116013201476163017822104
1/2″cfm196112129146165179195224252280309338392
lb/h3629734845976110311971305150017001890208822772640
5/8″cfm1173195212239260282308356404452504548611
lb/h31081121913251470160017161875214024222690297332503623

LEGEND

0Optimal working pressure
1cfm: Compressed air required expressed in cubic feet per minute
2psig: Working pressure expressed in pounds per square inch gauge
3lb/h: Abrasive consumption expressed in pounds per hour
4Nozzle ID: Interior diameter of nozzle

Comment bubble

Got Questions?

Contact one of our exerts today to help you chose the right equipment for your application.

Contact us
Speak to an expert