57
8.0 Appendix
8.2 Unit Conversions
Flow Rate vs. Test Pressure Conversions
Table 8-4. Maximum Potential Orifice Flow Rate versus Test Pressure (English)
Test Pressure (H
2
O)
Peak Velocity (ft./sec)
Flow/Unit Area* (cfm/sq. in)
1”
66.2
27.6
3”
114.7
47.8
5”
148.0
61.7
7”
175.1
72.9
10”
209.3
87.1
12”
229.3
95.6
15”
256.4
106.9
20”
296.0
123.4
25”
331.0
138.0
28”
350.3
146.0
30”
362.6
151.1
35”
391.6
163.3
40”
418.7
174.6
45”
444.1
185.1
48”
458.6
191.2
50”
468.1
195.2
60”
512.8
213.8
65”
533.7
222.5
* Through a perfectly streamlined orifice (coefficient of velocity and discharge = 1).
