A335 P1 Pipe MAWP Calculator ASTM A335 -P1 Alloy Steel Pipe SMLS C-1/2Mo
Material Properties Description
ASTM A335 -P1 Alloy Steel Pipe SMLS C-1/2Mo
Min Design Temperature
-20 °F
Y Coefficient
Ref 3 — Ferritic steels
Maximum Allowable Working Pressure (psig) Sch STD Sch XS Sch 160
NPS OD (in) 100 °F 200 °F 300 °F 400 °F 500 °F 600 °F 700 °F 800 °F 1/8 0.405 6,093 6,093 5,993 5,794 5,627 5,461 5,227 4,961 1/4 0.54 5,891 5,891 5,794 5,601 5,440 5,279 5,054 4,796 3/8 0.675 4,767 4,767 4,689 4,533 4,403 4,272 4,090 3,882 1/2 0.84 4,571 4,571 4,496 4,346 4,221 4,096 3,921 3,722 3/4 1.05 3,727 3,727 3,666 3,544 3,442 3,340 3,198 3,035 1 1.315 3,486 3,486 3,429 3,314 3,219 3,124 2,991 2,838 1 1/4 1.66 2,870 2,870 2,823 2,729 2,651 2,572 2,463 2,337 1 1/2 1.9 2,582 2,582 2,540 2,455 2,384 2,314 2,215 2,102 2 2.375 2,175 2,175 2,140 2,068 2,009 1,949 1,866 1,771 2 1/2 2.875 2,379 2,379 2,340 2,262 2,197 2,132 2,041 1,937 3 3.5 2,066 2,066 2,032 1,964 1,908 1,851 1,772 1,682 3.5 4 1,884 1,884 1,853 1,791 1,740 1,688 1,616 1,534 4 4.5 1,751 1,751 1,723 1,665 1,617 1,569 1,502 1,426 5 5.563 1,535 1,535 1,510 1,460 1,418 1,376 1,317 1,250 6 6.625 1,395 1,395 1,372 1,326 1,288 1,250 1,197 1,136 7 7.625 1,300 1,300 1,279 1,236 1,201 1,165 1,115 1,059 8 8.625 1,228 1,228 1,208 1,167 1,134 1,100 1,053 1,000 9 9.625 1,167 1,167 1,148 1,110 1,078 1,046 1,001 950 10 10.75 1,114 1,114 1,096 1,059 1,029 998 956 907 12 12.75 962 962 946 914 888 862 825 783 14 14 874 874 860 831 807 783 750 712 16 16 763 763 751 726 705 684 655 621 18 18 677 677 666 644 625 607 581 551 20 20 608 608 598 579 562 545 522 495 22 22 552 552 543 525 510 495 474 450 24 24 506 506 498 481 467 453 434 412 26 26 467 467 459 444 431 418 400 380 28 28 433 433 426 412 400 388 371 353 30 30 404 404 397 384 373 362 346 329 36 36 336 336 331 320 310 301 288 274 42 42 288 288 283 274 266 258 247 234 44 44 275 275 270 261 254 246 236 224 46 46 263 263 258 250 242 235 225 214 48 48 252 252 247 239 232 225 216 205
Allowable Stress vs Temperature 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 1000 1100 Temperature (°F) 0 5 10 15 20 Allowable Stress (ksi) Disclaimer: This calculator is for guidance only. Results are based on ASME B31.3-2024 allowable stresses for seamless pipe (Ej=1.0, W=1.0). Always verify against the current edition of the standard. The engineer of record is responsible for all design decisions.
References ASME B31.3-2024 — Process Piping, Table A-1 ASME B36.10M — Welded and Seamless Wrought Steel Pipe ASME B16.5-2020 — Pipe Flanges and Flanged Fittings 
