A335 P11 Pipe MAWP Calculator ASTM A335 -P11 Alloy Steel Pipe SMLS 1 1/4Cr-1/2Mo-Si
Material Properties Description
ASTM A335 -P11 Alloy Steel Pipe SMLS 1 1/4Cr-1/2Mo-Si
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 6,659 6,160 5,860 5,594 5,394 5,227 5,028 4,795 1/4 0.54 6,438 5,955 5,666 5,408 5,215 5,054 4,861 4,635 3/8 0.675 5,210 4,819 4,585 4,377 4,220 4,090 3,934 3,751 1/2 0.84 4,995 4,621 4,396 4,196 4,046 3,921 3,772 3,597 3/4 1.05 4,074 3,768 3,585 3,422 3,300 3,198 3,076 2,933 1 1.315 3,810 3,524 3,352 3,200 3,086 2,991 2,876 2,743 1 1/4 1.66 3,137 2,902 2,761 2,635 2,541 2,463 2,368 2,259 1 1/2 1.9 2,822 2,610 2,483 2,370 2,286 2,215 2,130 2,032 2 2.375 2,377 2,199 2,092 1,997 1,926 1,866 1,795 1,712 2 1/2 2.875 2,600 2,405 2,288 2,184 2,106 2,041 1,963 1,872 3 3.5 2,258 2,088 1,987 1,896 1,829 1,772 1,704 1,625 3.5 4 2,059 1,905 1,812 1,730 1,668 1,616 1,554 1,482 4 4.5 1,914 1,770 1,684 1,608 1,550 1,502 1,445 1,378 5 5.563 1,678 1,552 1,476 1,409 1,359 1,317 1,267 1,208 6 6.625 1,524 1,410 1,341 1,280 1,235 1,197 1,151 1,098 7 7.625 1,421 1,314 1,250 1,194 1,151 1,115 1,073 1,023 8 8.625 1,342 1,241 1,181 1,127 1,087 1,053 1,013 966 9 9.625 1,275 1,180 1,122 1,071 1,033 1,001 963 918 10 10.75 1,217 1,126 1,071 1,023 986 956 919 876 12 12.75 1,051 972 925 883 851 825 794 757 14 14 955 884 841 803 774 750 721 688 16 16 834 771 734 701 676 655 630 600 18 18 740 684 651 622 599 581 559 533 20 20 665 615 585 559 539 522 502 479 22 22 604 559 531 507 489 474 456 435 24 24 553 511 487 464 448 434 417 398 26 26 510 472 449 428 413 400 385 367 28 28 473 438 416 397 383 371 357 341 30 30 441 408 388 371 358 346 333 318 36 36 367 340 323 308 297 288 277 264 42 42 314 291 277 264 255 247 237 226 44 44 300 278 264 252 243 236 227 216 46 46 287 265 253 241 232 225 217 207 48 48 275 254 242 231 223 216 208 198
Allowable Stress vs Temperature 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 1000 1100 1200 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 
