American Blind Flange
- Standard: ASME B16.5, ASME B16.48
- NPS: NPS ½”~60”
- Pressure Rating: Class 150/300/600/900/1500/2500
- Material: carbon steel, stainless steel, alloy steel
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American Blind Flange is a kind of solid flange without hole in the center, which is used to permanently or temporarily block the end of pipeline or equipment interface to prevent medium leakage and ensure the safety of maintenance. Materials include carbon steel, stainless steel and alloy steel, suitable for chemical, petroleum and other high-pressure or corrosive systems.
American Blind Flange
Sealing Face Types and Applicability
- Flat Face (FF):
- Application: Suitable for low-pressure systems (≤1.6 MPa) and non-critical environments, often paired with flat gaskets.
- Raised Face (RF):
- Pressure Range: Class 150–2500, widely used in medium-to-high-pressure systems due to its compatibility with various gaskets (e.g., non-metallic or spiral-wound).
- Ring Joint Face (RJ):
- Features: Utilizes metal ring gaskets (e.g., oval or octagonal) for high-temperature and high-pressure sealing, ideal for extreme conditions in petrochemical and nuclear industries (Class ≥600).
American Blind Flange Size
The following is a cross-reference of blind flange sizes based on the ANSI/ASME B16.5 standard (Class 150 rating)
| NPS | OD, mm | Blind thickness (mm) | Number of bolt holes | Bolt hole diameter (mm) | Bolt hole center circle diameter (mm) |
| 1/2″ | 89 | 11.2 | 4 | 15.9 | 66.7 |
| 3/4″ | 98 | 12.7 | 4 | 15.9 | 82.6 |
| 1″ | 108 | 14.3 | 4 | 15.9 | 88.9 |
| 1.5″ | 127 | 15.7 | 4 | 15.9 | 114.3 |
| 2″ | 152 | 17.5 | 8 | 19.1 | 127 |
| 3″ | 190 | 20.6 | 8 | 19.1 | 152.4 |
| 4″ | 229 | 22.2 | 8 | 19.1 | 190.5 |
| 6″ | 283 | 25.4 | 12 | 22.2 | 241.3 |
| 8″ | 343 | 28.6 | 12 | 22.2 | 298.5 |
| 10″ | 406 | 31.8 | 16 | 25.4 | 362 |
| 12″ | 483 | 35 | 16 | 28.6 | 431.8 |