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TECH SHEET -
PROPER PIPE SIZING
Selecting the proper wall thickness is critical for safety. No longer is ultimate burst strength sufficient for determining the suitability of the pipe.
Below you will find a chart of safe working pressures for the common sizes from .25" through 8.00" in the different grades and schedules which are available. Please note that there are various conditions such as bending, threading, etc. that will downrate the safe working pressure. The formula for downrating pipe is found in A.S.M.E. B 31.1. Article Safe Working Pressure Using ASME. Also keep in mind that allowances for mechanical wear and erosion may be necessary, depending on operating conditions oultined in this article.
A.S.M.E. B31. 1. Safe Working Pressures
A.S.T.M. A106 Grades B & C Seamless Pipe
| Nominal Size (inches) |
Pressure (P.S.I.) | Flow in Gallons / Mi @ | ||||
|---|---|---|---|---|---|---|
| A106B | A106C | 15'/sec | 20'/sec | 25'/sec | ||
| 0.25 | SCH 40 | 4828 | 5633 | 4 | 6 | 8 |
| SCH 80 | 6839 | 7698 | 3 | 4 | 5 | |
| 0.375 | SCH 40 | 3907 | 4464 | 8 | 11 | 14 |
| SCH 80 | 5636 | 6574 | 6 | 8 | 10 | |
| 0.50 | SCH 40 | 3746 | 4370 | 14 | 18 | 23 |
| SCH 80 | 5235 | 6106 | 10 | 14 | 18 | |
| SCH 160 | 6922 | 8075 | 7 | 10 | 13 | |
| SCH XXH | 12168 | 14195 | 2 | 3 | 3 | |
| 0.75 | SCH 40 | 3055 | 3563 | 24 | 33 | 41 |
| SCH 80 | 4290 | 5005 | 20 | 26 | 33 | |
| SCH 160 | 6376 | 7439 | 13 | 18 | 23 | |
| SCH XXH | 9689 | 11303 | 6 | 9 | 11 | |
| 1.00 | SCH 40 | 2857 | 3333 | 40 | 53 | 67 |
| SCH 80 | 3949 | 4607 | 33 | 44 | 56 | |
| SCH 160 | 5756 | 6715 | 24 | 32 | 40 | |
| SCH XXH | 8828 | 10299 | 13 | 17 | 21 | |
| 1.25 | SCH 40 | 2352 | 2744 | 69 | 93 | 116 |
| SCH 80 | 3284 | 3833 | 60 | 80 | 100 | |
| SCH 160 | 4419 | 5155 | 49 | 65 | 82 | |
| SCH XXH | 7200 | 8400 | 29 | 39 | 49 | |
| 1.50 | SCH 40 | 2116 | 2468 | 95 | 126 | 158 |
| SCH 80 | 2982 | 3480 | 82 | 110 | 137 | |
| SCH 160 | 4330 | 5051 | 65 | 87 | 109 | |
| SCH XXH | 6481 | 7561 | 44 | 59 | 74 | |
| 2.00 | SCH 40 | 1783 | 2080 | 155 | 207 | 259 |
| SCH 80 | 2574 | 3004 | 137 | 183 | 229 | |
| SCH 160 | 4217 | 4920 | 104 | 139 | 174 | |
| SCH XXH | 5529 | 6450 | 82 | 110 | 138 | |
| 2.50 | SCH 40 | 1949 | 2274 | 223 | 298 | 372 |
| SCH 80 | 2701 | 3151 | 198 | 264 | 330 | |
| SCH 160 | 3767 | 4395 | 165 | 220 | 276 | |
| SCH XXH | 5822 | 6792 | 129 | 173 | 216 | |
| 3.00 | SCH 40 | 1693 | 1975 | 345 | 460 | 575 |
| SCH 80 | 2393 | 2792 | 308 | 411 | 514 | |
| SCH 160 | 3591 | 4189 | 253 | 337 | 421 | |
| SCH XXH | 5113 | 5965 | 194 | 258 | 323 | |
| 3.50 | SCH 40 | 1544 | 1801 | 461 | 615 | 769 |
| SCH 80 | 2209 | 2577 | 415 | 553 | 692 | |
| SCH XXH | 4696 | 5479 | 273 | 364 | 455 | |
| 4.00 | SCH 40 | 1435 | 1674 | 594 | 793 | 991 |
| SCH 80 | 2074 | 2420 | 537 | 716 | 895 | |
| SCH 160 | 3376 | 3938 | 433 | 578 | 722 | |
| SCH XXH | 4392 | 5124 | 364 | 486 | 607 | |
| 5.00 | SCH 40 | 1258 | 1467 | 934 | 1246 | 1558 |
| SCH 80 | 1857 | 2045 | 850 | 1133 | 1416 | |
| SCH 160 | 3200 | 3734 | 682 | 910 | 1137 | |
| SCH XXH | 3907 | 4558 | 605 | 807 | 1009 | |
| 6.00 | SCH 40 | 1143 | 1333 | 1349 | 1799 | 2249 |
| SCH 80 | 1793 | 2092 | 1217 | 1623 | 2030 | |
| SCH 160 | 3078 | 3591 | 988 | 1317 | 1646 | |
| SCH XXH | 3767 | 4395 | 880 | 1173 | 1466 | |
| 8.00 | SCH 40 | 1006 | 1173 | 2337 | 3116 | 3896 |
| SCH 80 | 1586 | 1850 | 2133 | 2844 | 3556 | |
| SCH 160 | 2976 | 3434 | 1703 | 2271 | 2839 | |
| SCH XXH | 2866 | 3344 | 1734 | 2312 | 2891 | |
