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Useful Formulas & Charts
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If you attended Cummins-Wagner's
Seminar on Air Compressors,
you probably remember our promise
to
get some of the useful charts and formulas on our webpage.
Without further
ado....
click on
the following links to see some of the most noteworthy tidbits from the seminar.
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Air System Question and Answer Sheet |
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Leak Detection and Prevention Chart |
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How to Select an Air Compressor Chart
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Loss of Air Pressure Due To Friction Tables
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Electrical Power Cost of Compressed Air Formula
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How to Convert SCFM to ICFM Formula and Vapor Pressure Table |
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Click here to visit the Compressed Air Sourcebook!
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Air Flow Table
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Develop
A Leak
Detection & Prevention Program!!
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Cost
Of Air Leaks: |
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1/16" |
$604.00 |
/ |
year |
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1/8" |
$2,223.00 |
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year |
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1/4" |
$9,691.00 |
/ |
year |
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3/8" |
$21,805.00
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/ |
year
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Back
To Top
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AIR FLOW TABLE
Volume of free air in C.F.M.
that will flow thru round holes from a receiver into the atmosphere.
Cubic feet of air per minute
measured at absolute pressure of 14.7 lbs. per sq. in. and 70°F.
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Dia. of
Orifice
Inches |
GAUGE PRESSURE IN
RECEIVER - POUNDS |
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2 |
5 |
10 |
15 |
20 |
25 |
30 |
35 |
40 |
45 |
50 |
60 |
70 |
80 |
90 |
100 |
125 |
150 |
200 |
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1/64 |
.04 |
.062 |
.077 |
.105 |
.123 |
.140 |
.158 |
.176 |
.194 |
.211 |
.229 |
.267 |
.300 |
.335 |
.370 |
.406 |
.494 |
.583 |
.75 |
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1/32 |
.158 |
.248 |
.311 |
.420 |
.491 |
.562 |
.633 |
.703 |
.774 |
.845 |
.916 |
1.06 |
1.20 |
1.34 |
1.48 |
1.62 |
1.98 |
2.32 |
3.18 |
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3/64 |
.356 |
.568 |
.712 |
.944 |
1.10 |
1.26 |
1.42 |
1.58 |
1.75 |
1.91 |
2.06 |
2.38 |
2.70 |
3.0 |
3.33 |
3.66 |
4.44 |
5.25 |
6.86 |
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1/16 |
.633 |
.993 |
1.24 |
1.68 |
1.96 |
2.25 |
2.53 |
2.81 |
3.10 |
3.38 |
3.66 |
4.23 |
4.79 |
5.36 |
5.92 |
6.49 |
7.90 |
9.31 |
12.17 |
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3/32 |
1.43 |
2.23 |
2.80 |
3.78 |
4.41 |
5.05 |
5.69 |
6.31 |
7.0 |
7.63 |
8.25 |
9.5 |
10.8 |
12.0 |
13.3 |
14.6 |
17.8 |
20.9 |
27.35 |
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1/8 |
2.53 |
3.97 |
4.98 |
6.72 |
7.86 |
8.98 |
10.1 |
11.3 |
12.4 |
13.5 |
14.7 |
16.9 |
19.2 |
21.4 |
23.7 |
26.0 |
31.6 |
37.3 |
48.7 |
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3/16 |
5.7 |
8.93 |
11.2 |
15.2 |
17.65 |
20.2 |
22.8 |
25.2 |
28.0 |
30.5 |
33.0 |
38 |
43.2 |
48.3 |
53.2 |
58.5 |
71.0 |
84.0 |
109.6 |
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1/4 |
10.1 |
15.9 |
19.9 |
26.9 |
31.4 |
35.9 |
40.5 |
45.0 |
49.6 |
54.1 |
58.6 |
67.6 |
76.7 |
85.7 |
94.8 |
104 |
126 |
149.3 |
195 |
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3/8 |
22.8 |
35.7 |
44.7 |
60.5 |
70.7 |
80.9 |
91.1 |
101 |
112 |
122 |
132 |
152 |
173 |
193 |
213 |
234 |
284 |
336 |
438 |
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1/2 |
40.5 |
63.5 |
79.6 |
108 |
126 |
144 |
162 |
180 |
198 |
216 |
235 |
271 |
307 |
343 |
379 |
415 |
506 |
586 |
777 |
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5/8 |
63.03 |
99.3 |
124.5 |
168 |
196 |
225 |
253 |
281 |
310 |
338 |
366 |
423 |
479 |
536 |
592 |
649 |
790 |
932 |
1216 |
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3/4 |
91.2 |
143 |
179.2 |
242 |
283 |
323 |
365 |
405 |
446 |
487 |
528 |
609 |
690 |
771 |
853 |
934 |
1138 |
1340 |
1750 |
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7/8 |
124 |
195 |
244.2 |
329 |
385 |
440 |
496 |
551 |
607 |
662 |
718 |
828 |
939 |
1050 |
1161 |
1272 |
1549 |
1825 |
2382 |
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1 |
162 |
254 |
318.2 |
430 |
503 |
575 |
648 |
720 |
793 |
865 |
938 |
1082 |
1227 |
1371 |
1516 |
1661 |
2023 |
2385 |
3112 |
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1-1/8 |
205 |
321 |
402.5 |
544 |
637 |
727 |
820 |
910 |
1004 |
1094 |
1187 |
1370 |
1552 |
1734 |
1918 |
2101 |
2560 |
3020 |
3940 |
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1-1/4 |
253 |
397 |
498 |
672 |
784 |
900 |
1019 |
1124 |
1240 |
1352 |
1464 |
1693 |
1917 |
2144 |
2370 |
2596 |
3160 |
3725 |
4860 |
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1-3/8 |
307 |
482 |
604 |
816 |
954 |
1091 |
1230 |
1367 |
1505 |
1643 |
1780 |
2054 |
2330 |
2607 |
2880 |
3153 |
3840 |
4525 |
5910 |
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1-1/2 |
364 |
572 |
716 |
968 |
1132 |
1293 |
1460 |
1620 |
1783 |
1946 |
2112 |
2335 |
2760 |
3081 |
3412 |
3734 |
4550 |
5360 |
7000 |
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1-3/4 |
496 |
780 |
972 |
1318 |
1540 |
1760 |
1985 |
2205 |
2429 |
2650 |
2875 |
3310 |
3755 |
4200 |
4645 |
5085 |
6195 |
7300 |
9530 |
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2 |
648 |
1015 |
1274 |
1720 |
2120 |
2300 |
2594 |
2880 |
3173 |
3460 |
3752 |
4330 |
4915 |
5480 |
6070 |
6650 |
8100 |
9540 |
12450 |
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Table is based on 100
coefficient of flow. For well rounded entrance multiply values
by 0.97.
For sharp edged orifices
a multiplier of 0.65 may be used. This table will give
approximate results only.
For accurate
measurements see Part 1, Section Four, Test Standards.
The formula Q=14.5 PD²,
where Q is C.F.M., P is absolute pressure and D is orifice diameter
in inches,
may be used for any
points not given in table. (Applies only above 15 pounds
gauge.)
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Electrical
Power Cost of Compressed Air |
(BHP)
(.746) (Cost per Kwh) (Hours per Year)
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| Motor
Efficiency |
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Annual Power Cost |
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A
50
HP air compressor, with
a 93% efficient (Epact
standard) motor,
and operating 8,760 hours per year with
power at $.06 per Kwh
costs $21,081 per year
in
electrical consumption.
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How To
Convert SCFM To ICFM |
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ICFM =
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SCFM X
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14.7 PSIA - (.36 SRH X .339 STD
VP)
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X |
460
+ AIT
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ASP - (ARH X AVP) |
528 |
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ICFM
- |
Inlet
Cubic
Feet
Per Minute
- Actual Site Conditions |
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SCFM -
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Standard
CFM
Defined At 68°F, 0% RH, 14.5 PSIA |
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SRH -
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Standard
Relative
Humidity,
36% |
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STD VP -
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Standard
Vapor
Pressure
@ 68° F = .339 |
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ASP -
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Actual
Or Inlet Suction
Pressure
Expressed In PSIA |
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ARH -
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Actual
Or Inlet Relative
Humidity |
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AVP -
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Actual
Or Inlet Vapor
Pressure
- From Chart |
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AIT -
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Actual
Or Inlet
Ambient Temperature |
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Vapor
Pressure (VP) of Water at Ambient Temperature |
| Temp.°F |
Ambient
Pressure
Lb./Sq.In. |
Temp.°F |
Ambient
Pressure
Lb./Sq.In. |
Temp.°F |
Ambient
Pressure
Lb./Sq.In. |
| 32 |
0.08854 |
68 |
0.3390 |
103 |
1.0382 |
| 33 |
0.0922 |
69 |
0.3509 |
104 |
1.0695 |
| 34 |
0.0960 |
70 |
0.3631 |
105 |
1.1016 |
| 35 |
0.1000 |
71 |
0.3756 |
106 |
1.1345 |
| 36 |
0.1040 |
72 |
0.3886 |
107 |
1.1683 |
| 37 |
0.1082 |
73 |
0.4019 |
108 |
1.2029 |
| 38 |
0.1126 |
74 |
0.4156 |
109 |
1.2384 |
| 39 |
0.1171 |
75 |
0.4298 |
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76 |
0.4443 |
110 |
1.2748 |
| 40 |
0.1217 |
77 |
0.4593 |
111 |
1.3121 |
| 41 |
0.1265 |
78 |
0.4747 |
112 |
1.3504 |
| 42 |
0.1315 |
79 |
0.4906 |
113 |
1.3896 |
| 43 |
0.1367 |
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114 |
1.4298 |
| 44 |
0.1420 |
80 |
0.5069 |
115 |
1.4709 |
| 45 |
0.1475 |
81 |
0.5237 |
116 |
1.5130 |
| 46 |
0.1532 |
82 |
0.5410 |
117 |
1.5563 |
| 47 |
0.1591 |
83 |
0.5588 |
118 |
1.6006 |
| 48 |
0.1653 |
84 |
0.6771 |
119 |
1.6459 |
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| 50 |
0.1781 |
87 |
0.6351 |
121 |
1.7400 |
| 51 |
0.1849 |
88 |
0.6556 |
122 |
1.7888 |
| 52 |
0.1918 |
89 |
0.6766 |
123 |
1.8387 |
| 53 |
0.1990 |
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124 |
1.8897 |
| 54 |
0.2064 |
90 |
0.6982 |
125 |
1.9420 |
| 55 |
0.2141 |
91 |
0.7204 |
126 |
1.9955 |
| 56 |
0.2220 |
92 |
0.7432 |
127 |
2.0503 |
| 57 |
0.2302 |
93 |
0.7666 |
128 |
2.1064 |
| 58 |
0.2386 |
94 |
0.7906 |
129 |
2.1638 |
| 59 |
0.2473 |
95 |
0.8153 |
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96 |
0.8407 |
130 |
2.2225 |
| 60 |
0.2563 |
97 |
0.8668 |
131 |
2.2826 |
| 61 |
0.2565 |
98 |
0.8935 |
132 |
2.3440 |
| 62 |
0.2751 |
99 |
0.9210 |
133 |
2.4069 |
| 63 |
0.2850 |
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134 |
2.4712 |
| 64 |
0.2951 |
100 |
0.9492 |
135 |
2.6370 |
| 65 |
0.3056 |
101 |
0.9781 |
136 |
2.6042 |
| 66 |
0.3164 |
102 |
0.0078 |
137 |
2.6729 |
| 67 |
0.3276 |
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