1. Size Range
| ASME B16.5 | ASME B16.47 |
|---|---|
| Covers NPS ½" to 24" (DN 15 to DN 600) | Covers NPS 26" to 60" (DN 650 to DN 1500) |
B16.5 is for standard pipe flanges.
B16.47 is for large-diameter flanges not covered by B16.5.
2. Pressure Classes (Rating)
| ASME B16.5 | ASME B16.47 |
|---|---|
| 150, 300, 400, 600, 900, 1500, 2500 | 75, 150, 300, 400, 600, 900 (Series A & B differ slightly) |
B16.5 includes higher-pressure classes (up to 2500#).
B16.47 has a lower max pressure rating (900#) and includes Class 75 (only in Series B).
3. Flange Types
| ASME B16.5 | ASME B16.47 |
|---|---|
| - Weld Neck (WN) - Slip-On (SO) - Socket Weld (SW) - Lap Joint (LJ) - Threaded (THD) - Blind (BL) |
- Weld Neck (WN) only (most common) - Blind (BL) only |
B16.47 is limited to weld neck and blind flanges (no slip-on, lap joint, etc.).
B16.5 includes a wider variety of flange types.
4. Series A vs. Series B (B16.47 Only)
ASME B16.47 is divided into two series, based on historical standards:
| Series A (MSS SP-44) | Series B (API 605) |
|---|---|
| - Thicker, heavier flanges - Higher bolt loads - More common in oil & gas pipelines |
- Lighter, more compact - Similar to older API 605 standard - Used in water, low-pressure systems |
Series A is stronger but more expensive.
Series B is lighter and cheaper but has lower pressure capability.
5. Bolt Hole Patterns & Dimensions
B16.5 has a standardized bolt circle for each size and class.
B16.47 (Series A & B) may have different bolt patterns for the same size, requiring careful selection.
6. Applications
| ASME B16.5 | ASME B16.47 |
|---|---|
| - General industrial piping - Petrochemical plants - Power plants - HVAC systems |
- Large pipelines (oil, gas, water) - Water treatment plants - Low-pressure big bore systems |
Summary Table: Key Differences
| Feature | ASME B16.5 | ASME B16.47 |
|---|---|---|
| Size Range | ½" – 24" | 26" – 60" |
| Pressure Classes | 150 – 2500 | 75 – 900 |
| Flange Types | WN, SO, SW, LJ, THD, BL | WN, BL only |
| Series | N/A | Series A (MSS SP-44) & Series B (API 605) |
| Typical Use | General industrial piping | Large-diameter pipelines |
When to Use Which?
✔ Use B16.5 for standard pipe sizes (up to 24") and higher-pressure systems.
✔ Use B16.47 for large pipelines (26" and above), especially in oil, gas, or water transmission.
