Table 14.3a. Calculated Rated Internal Working Pressures for Copper Tube: Type K*

Nominal or standard size, in inchesAnnealedDrawn**
S= 6,000 psi 100FS= 5,100 psi 150FS= 4,900 psi 200FS= 4,800 psi 250FS= 4,700 psi 300FS= 4,000 psi 350FS= 3,000 psi 400FS= 10,300 psi 100FS= 10,300 psi 150FS= 10,300 psi 200FS= 10,300 psi 250FS= 10,000 psi 300FS= 9,700 psi 350FS= 9,400 psi 400F
1⁄4 1074 913 877 860 842 716 537 1850 1850 1850 1850 1796 1742 1688
3⁄8 1130 960 923 904 885 753 565 1946 1946 1946 1946 1889 1833 1776
1⁄2 891 758 728 713 698 594 446 1534 1534 1534 1534 1490 1445 1400
5⁄8 736 626 601 589 577 491 368 1266 1266 1266 1266 1229 1193 1156
3⁄4 852 724 696 682 668 568 426 1466 1466 1466 1466 1424 1381 1338
1 655 557 535 524 513 437 327 1126 1126 1126 1126 1093 1061 1028
11⁄4 532 452 434 425 416 354 266 914 914 914 914 888 861 834
11⁄2 494 420 404 396 387 330 247 850 850 850 850 825 801 776
2 435 370 355 348 341 290 217 747 747 747 747 726 704 682
21⁄2 398 338 325 319 312 265 199 684 684 684 684 664 644 624
3 385 328 315 308 302 257 193 662 662 662 662 643 624 604
31⁄2 366 311 299 293 286 244 183 628 628 628 628 610 592 573
4 360 306 294 288 282 240 180 618 618 618 618 600 582 564
5 345 293 281 276 270 230 172 592 592 592 592 575 557 540
6 346 295 283 277 271 231 173 595 595 595 595 578 560 543
8 369 314 301 295 289 246 184 634 634 634 634 615 597 578
10 369 314 301 295 289 246 184 634 634 634 634 615 597 578
12 370 314 302 296 290 247 185 635 635 635 635 617 598 580

* Based on maximum allowable stress in tension (psi) for the indicated temperatures (°F).

** When brazing or welding is used to join drawn tube, the corresponding annealed rating must be used. For more information, see Pressure Ratings and Burst Strength