Low Pressure Orifice Chart

GAS USE IN BTUS PER HOUR AGAINST A GIVEN ORIFICE SIZE (DRILL SIZE)
DRILL SIZE Decimal Equivalent Natural Gas Natural Gas LP Gas
Gas Pressure→ 4" WC 7"WC 11" WC
    Gas use in Btus/hr Gas use in Btus/hr Gas use in Btus/hr
75 0.021 1200 1600 3080
70 0.028 2125 2825 5475
65 0.035 2240 4400 8560
60 0.040 4350 5750 11175
3/64" 0.047 5975 7900 15360
55 0.052 7350 9710 18890
50 0.070 13300 17590 34250
45 0.082 18250 24150 46975
3/32" 0.094 23875 31600 61460
40 0.098 26075 34500 67095
7/64" 0.109 32490 42980 83600
35 0.110 32850 43450 84525
1/8" 0.125 42415 56100 109150
30 0.129 44820 59300 115345
9/64" 0.141 53660 71000 138090
25 0.150 60670 80260 156150
5/32" 0.156 66310 87725 170650
20 0.161 70360 93075 181075
11/64" 0.172 80200 106100 206425
15 0.180 87950 116350 226350
3/16" 0.188 95430 126250 245575
10 0.194 101630 134450 261575
13/64" 0.203 111950 148100 288000
5 0.206 114640 151640 295000
7/32" 0.219 129940 171900 334450
1 0.228 141110 186675 363150

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