eStoreAir 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.
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 ID4 | 40 | 50 | 60 | 70 | 80 | 1000 |
| 1/4″ | 12 | 15 | 17 | 19 | 21 | 26 |
| 5/16″ | 19 | 23 | 27 | 30 | 34 | 42 |
| 3/8″ | 27 | 33 | 38 | 43 | 48 | 58 |
| 7/16″ | 38 | 46 | 52 | 60 | 65 | 80 |
| 1/2″ | 49 | 58 | 67 | 76 | 85 | 94 |
AIR CONSUMPTION TABLE FOR PRESSURE SYSTEMS (CFM)1
| PRESSURE (psig)2 | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NOZZLE ID4 | UNITS | 20 | 25 | 30 | 35 | 40 | 45 | 50 | 60 | 70 | 80 | 90 | 1000 | 120 |
| 1/8″ | cfm1 | 7 | 7 | 8 | 9 | 10 | 12 | 13 | 14 | 15 | 17 | 19 | 20 | 25 |
| lb/h3 | 48 | 48 | 55 | 62 | 69 | 73 | 77 | 82 | 110 | 127 | 140 | 154 | 192 | |
| 3/16″ | cfm1 | 15 | 16 | 18 | 20 | 22 | 24 | 26 | 30 | 33 | 38 | 41 | 45 | 55 |
| lb/h3 | 94 | 101 | 114 | 127 | 140 | 153 | 166 | 192 | 220 | 243 | 268 | 297 | 363 | |
| 1/4″ | cfm1 | 27 | 30 | 34 | 37 | 41 | 45 | 49 | 55 | 61 | 68 | 74 | 81 | 97 |
| lb/h3 | 174 | 193 | 219 | 251 | 276 | 303 | 329 | 369 | 398 | 460 | 504 | 556 | 666 | |
| 5/16″ | cfm1 | 42 | 46 | 53 | 57 | 65 | 70 | 76 | 88 | 101 | 113 | 126 | 137 | 152 |
| lb/h3 | 254 | 278 | 320 | 345 | 394 | 425 | 462 | 528 | 680 | 756 | 832 | 910 | 1010 | |
| 3/8″ | cfm1 | 55 | 63 | 76 | 82 | 91 | 100 | 109 | 126 | 143 | 161 | 173 | 196 | 220 |
| lb/h3 | 374 | 428 | 517 | 558 | 620 | 682 | 744 | 860 | 970 | 1080 | 1184 | 1296 | 1454 | |
| 7/16″ | cfm1 | 72 | 85 | 100 | 112 | 124 | 137 | 149 | 170 | 194 | 217 | 240 | 254 | 300 |
| lb/h3 | 488 | 576 | 678 | 759 | 840 | 835 | 908 | 1160 | 1320 | 1476 | 1630 | 1782 | 2104 | |
| 1/2″ | cfm1 | 96 | 112 | 129 | 146 | 165 | 179 | 195 | 224 | 252 | 280 | 309 | 338 | 392 |
| lb/h3 | 629 | 734 | 845 | 976 | 1103 | 1197 | 1305 | 1500 | 1700 | 1890 | 2088 | 2277 | 2640 | |
| 5/8″ | cfm1 | 173 | 195 | 212 | 239 | 260 | 282 | 308 | 356 | 404 | 452 | 504 | 548 | 611 |
| lb/h3 | 1081 | 1219 | 1325 | 1470 | 1600 | 1716 | 1875 | 2140 | 2422 | 2690 | 2973 | 3250 | 3623 | |
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
