ASME B16.34 Pressure Rating Table
Complete pressure-temperature rating reference for industrial valves per ASME B16.34. Covers Class 150 through Class 2500 for carbon steel, stainless steel, and alloy materials.
What is ASME B16.34?
ASME B16.34 is the American standard for valves that defines pressure-temperature ratings, dimensions, tolerances, materials, and testing requirements for flanged, threaded, and welding end valves. It establishes the maximum allowable working pressure at various temperatures for each pressure class (150, 300, 600, 900, 1500, 2500).
Quick Reference: Maximum Working Pressure at Ambient Temperature (38°C / 100°F)
Material Group 1.1 — Carbon Steel (ASTM A216 WCB / A105)
Class 150
Class 300
Class 600
Class 900
Class 1500
Class 2500
Pressure-Temperature Rating: Carbon Steel (WCB / A105) — Material Group 1.1
Applicable to: ASTM A216 WCB, ASTM A105, ASTM A350 LF2 (cast and forged carbon steel valve bodies)
| Temperature | Class 150 (bar / psi) |
Class 300 (bar / psi) |
Class 600 (bar / psi) |
Class 900 (bar / psi) |
Class 1500 (bar / psi) |
Class 2500 (bar / psi) |
|---|---|---|---|---|---|---|
| -29°C to 38°C (-20°F to 100°F) | 19.6 / 285 | 51.1 / 740 | 102.1 / 1480 | 153.2 / 2220 | 255.3 / 3705 | 425.5 / 6170 |
| 50°C (122°F) | 19.2 / 279 | 50.1 / 727 | 100.2 / 1453 | 150.3 / 2180 | 250.5 / 3633 | 417.5 / 6055 |
| 100°C (212°F) | 17.7 / 256 | 46.6 / 676 | 93.2 / 1352 | 139.8 / 2028 | 233.0 / 3380 | 388.4 / 5633 |
| 150°C (302°F) | 15.8 / 229 | 45.1 / 654 | 90.2 / 1308 | 135.3 / 1962 | 225.5 / 3270 | 375.8 / 5450 |
| 200°C (392°F) | 13.8 / 200 | 44.1 / 640 | 88.3 / 1280 | 132.4 / 1920 | 220.6 / 3200 | 367.7 / 5333 |
| 250°C (482°F) | 12.1 / 175 | 43.2 / 627 | 86.5 / 1254 | 129.7 / 1881 | 216.2 / 3135 | 360.3 / 5225 |
| 300°C (572°F) | 10.2 / 148 | 42.5 / 616 | 85.0 / 1232 | 127.5 / 1849 | 212.5 / 3081 | 354.2 / 5135 |
| 350°C (662°F) | 8.2 / 119 | 41.5 / 602 | 83.0 / 1204 | 124.5 / 1805 | 207.5 / 3009 | 345.8 / 5015 |
| 400°C (752°F) | 6.5 / 94 | 39.8 / 577 | 79.5 / 1153 | 119.3 / 1730 | 198.8 / 2884 | 331.4 / 4806 |
| 425°C (800°F) | 5.5 / 80 | 38.0 / 551 | 75.9 / 1101 | 113.9 / 1652 | 189.8 / 2753 | 316.4 / 4589 |
* Values based on ASME B16.34-2017. For exact design pressures, always refer to the latest edition of the standard. Carbon steel (WCB/A105) max service temperature is 425°C (800°F).
Pressure-Temperature Rating: Stainless Steel (CF8M / F316) — Material Group 2.2
Applicable to: ASTM A351 CF8M (cast), ASTM A182 F316 (forged) — 316 Stainless Steel valve bodies
| Temperature | Class 150 (bar / psi) |
Class 300 (bar / psi) |
Class 600 (bar / psi) |
Class 900 (bar / psi) |
Class 1500 (bar / psi) |
|---|---|---|---|---|---|
| -29°C to 38°C (-20°F to 100°F) | 19.6 / 285 | 51.1 / 740 | 102.1 / 1480 | 153.2 / 2220 | 255.3 / 3705 |
| 50°C (122°F) | 18.3 / 265 | 47.6 / 690 | 95.1 / 1380 | 142.7 / 2070 | 237.8 / 3450 |
| 100°C (212°F) | 15.9 / 230 | 41.4 / 600 | 82.7 / 1200 | 124.1 / 1800 | 206.8 / 3000 |
| 150°C (302°F) | 14.5 / 210 | 37.6 / 545 | 75.2 / 1090 | 112.7 / 1635 | 187.9 / 2725 |
| 200°C (392°F) | 13.4 / 195 | 35.0 / 508 | 70.0 / 1015 | 105.0 / 1523 | 175.0 / 2538 |
| 250°C (482°F) | 12.6 / 183 | 32.8 / 476 | 65.6 / 952 | 98.5 / 1428 | 164.1 / 2380 |
| 300°C (572°F) | 11.9 / 173 | 31.1 / 451 | 62.2 / 902 | 93.3 / 1353 | 155.5 / 2255 |
| 350°C (662°F) | 11.4 / 166 | 29.8 / 432 | 59.5 / 863 | 89.3 / 1295 | 148.8 / 2158 |
| 400°C (752°F) | 10.8 / 157 | 28.3 / 410 | 56.5 / 820 | 84.8 / 1230 | 141.3 / 2050 |
| 450°C (842°F) | 9.4 / 136 | 24.4 / 354 | 48.8 / 708 | 73.2 / 1062 | 122.0 / 1770 |
* Stainless steel 316/CF8M max service temperature per ASME B16.34 is approximately 450°C (842°F).
Understanding ASME B16.34 Valve Pressure Classes
What does "Class" mean?
The pressure class (e.g., Class 150, Class 300) is a dimensionless number that defines the pressure-temperature rating of a valve. Higher class numbers indicate higher pressure ratings. The actual working pressure depends on both the class number and the operating temperature.
Why does pressure decrease with temperature?
As temperature increases, the tensile strength and yield strength of metals decrease. ASME B16.34 accounts for this by reducing the maximum allowable working pressure at elevated temperatures, ensuring safe operation throughout the entire temperature range.
ASME B16.34 vs ASME B16.5
| Parameter | ASME B16.34 | ASME B16.5 |
|---|---|---|
| Scope | Valves (flanged, threaded, welding end) | Flanges and flanged fittings |
| Size Range | DN 6 to DN 600 (NPS 1/4 to 24) | NPS 1/2 to NPS 24 |
| Classes | 150, 300, 400, 600, 900, 1500, 2500, 4500 | 150, 300, 400, 600, 900, 1500, 2500 |
| P-T Ratings | Same tables for common materials | Same tables for common materials |
| Special Ratings | Allows "Special Class" ratings for thicker walls | Not applicable |
Common Material Groups per ASME B16.34
| Material Group | Cast (ASTM) | Forged (ASTM) | Common Name |
|---|---|---|---|
| 1.1 | A216 WCB | A105 | Carbon Steel |
| 1.2 | A216 WCC | A350 LF2 | Carbon Steel (higher strength) |
| 1.5 | A217 WC6 | A182 F11 | 1-1/4 Cr - 1/2 Mo Alloy Steel |
| 1.9 | A217 C5 | A182 F5 | 5 Cr - 1/2 Mo Alloy Steel |
| 2.1 | A351 CF8 | A182 F304 | 304 Stainless Steel |
| 2.2 | A351 CF8M | A182 F316 | 316 Stainless Steel |
| 2.3 | A351 CF3M | A182 F316L | 316L Stainless Steel |
| 2.5 | A890 Gr 4A (CD3MN) | A182 F51 | Duplex 2205 |
Frequently Asked Questions
What is the ASME B16.34 pressure rating for Class 150 valves?
For carbon steel (WCB/A105), Class 150 valves are rated at 19.6 bar (285 psi) at ambient temperature. This rating decreases with increasing temperature — for example, at 200°C (392°F), the rating drops to 13.8 bar (200 psi).
How do I select the right valve class for my application?
Identify your maximum operating pressure and temperature. Find the row in the P-T table matching your temperature. The valve class column where the pressure exceeds your operating pressure is the minimum class required. Always apply a safety factor as per your engineering standards.
Does ASME B16.34 apply to all valve types?
ASME B16.34 applies to gate, globe, check, ball, and plug valves with flanged, threaded, or welding end connections. Butterfly valves are covered by separate standards (API 609, MSS SP-67/68).
What is "Special Class" in ASME B16.34?
Special Class ratings allow valves to have higher pressure ratings than "Standard Class" by using thicker valve walls. This is achieved by manufacturing the valve with increased wall thickness beyond the minimum required by the standard class, allowing up to 2x the standard pressure rating.
Need Valves Rated to ASME B16.34?
Supreme Valves India manufactures gate, globe, ball, and check valves in Class 150 through 2500. Carbon steel, stainless steel, and exotic alloys. EN 10204 3.1 material certificates.