Group 1.9 Pressure-Temperature Ratings
1.25Cr-0.5Mo alloy steel. The lightest of the common chrome-moly grades, used where carbon steel's 800 °F ceiling is not enough but the service does not justify 2.25Cr-1Mo.
- Standard
- ASME B16.5
- Group
- Group 1.9
- Materials
- A182 F11 Cl. 2, A335 P11, A217 WC6, A387 Gr. 11 Cl. 2
- Class 150 at 100 °F
- 290 psig (20.0 bar)
- Class 150 at 600 °F
- 140 psig (9.7 bar)
| Class | 100 °F | 200 °F | 300 °F | 400 °F | 500 °F | 600 °F | 650 °F | 700 °F | 750 °F | 800 °F | 850 °F | 900 °F | 950 °F | 1000 °F |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Class 150 | 290 | 260 | 230 | 200 | 170 | 140 | 125 | 110 | 95 | 80 | 65 | 50 | 35 | 20 |
| Class 300 | 750 | 750 | 720 | 695 | 665 | 605 | 590 | 570 | 530 | 510 | 485 | 450 | 320 | 215 |
| Class 400 | 1000 | 1000 | 965 | 925 | 885 | 805 | 785 | 755 | 710 | 675 | 650 | 600 | 425 | 290 |
| Class 600 | 1500 | 1500 | 1445 | 1385 | 1330 | 1210 | 1175 | 1135 | 1065 | 1015 | 975 | 900 | 640 | 430 |
| Class 900 | 2250 | 2250 | 2165 | 2080 | 1995 | 1815 | 1765 | 1705 | 1595 | 1525 | 1460 | 1350 | 955 | 650 |
| Class 1500 | 3750 | 3750 | 3610 | 3465 | 3325 | 3025 | 2940 | 2840 | 2660 | 2540 | 2435 | 2245 | 1595 | 1080 |
| Class 2500 | 6250 | 6250 | 6015 | 5775 | 5540 | 5040 | 4905 | 4730 | 4430 | 4230 | 4060 | 3745 | 2655 | 1800 |
Interpolation between listed temperatures is permitted; extrapolation is not.
Common questions
Which materials are in ASME B16.5 Group 1.9?
A182 F11 Cl. 2, A335 P11, A217 WC6, A387 Gr. 11 Cl. 2.
What is a Class 300 Group 1.9 flange rated at 600 °F?
605 psig (41.7 bar). At 100 °F the same flange is rated 750 psig (51.7 bar).