The pressure rating of an ASTM A105 flange depends on its design standard (e.g., ASME B16.5), pressure class, and operating temperature.
✅ ASME B16.5 Pressure Classes for ASTM A105 Flanges:
| Pressure Class | Max Pressure at 100°F (38°C) |
|---|---|
| Class 150 | 285 psi (1.96 MPa) |
| Class 300 | 740 psi (5.10 MPa) |
| Class 400 | 990 psi (6.83 MPa) |
| Class 600 | 1,480 psi (10.20 MPa) |
| Class 900 | 2,220 psi (15.30 MPa) |
| Class 1500 | 3,705 psi (25.50 MPa) |
| Class 2500 | 6,170 psi (42.50 MPa) |
🔥 Temperature Impact on Pressure Rating (ASTM A105):
As temperature increases, the allowable pressure decreases.
For example, for Class 300 flange:
| Temp (°F) | Max Pressure |
|---|---|
| 100°F | 740 psi |
| 200°F | 640 psi |
| 400°F | 495 psi |
| 600°F | 320 psi |
| 800°F | 165 psi |
(Source: ASME B16.5 pressure-temperature ratings)
📌 Notes:
Ratings apply when the flange is made from ASTM A105, a forged carbon steel suitable for high-temperature service.
Ratings must be matched with gasket type, bolting, and connected piping.
