Flange Facing Types Explained
The flange facing (sealing surface) is critical for creating a leak-tight joint. Different facing types are designed for specific pressure ranges, temperatures, and sealing requirements.
Raised Face (RF)
Most Common Type
- Raised sealing surface (1.6mm or 6.4mm height)
- Concentric or spiral serrations for gasket grip
- Suitable for Class 150-2500
- Works with soft, semi-metallic, and metallic gaskets
- Applications: General service, oil and gas, chemical processing
Flat Face (FF)
Full Surface Sealing
- Entire flange face is sealing surface
- Requires full-face gasket
- Limited to Class 150 and Class 300
- Prevents flange bending under bolt load
- Applications: Low-pressure water, cast iron flanges, plastic-lined systems
Ring Type Joint (RTJ)
High Pressure Metal-to-Metal Seal
- Groove for metal ring gasket (oval or octagonal)
- Metal-to-metal contact for superior sealing
- Suitable for Class 600 and above
- Handles extreme temperatures and pressures
- Applications: High-pressure steam, oil and gas wellheads, refineries
Male-Female Face (MFM)
Self-Aligning Sealing
- One flange has raised male portion, other has recessed female
- Gasket sits in female recess for better alignment
- Reduced gasket blowout risk
- Applications: Pump and valve connections, heat exchangers
Tongue-Groove Face (TG)
Premium Sealing Performance
- Tongue on one flange fits into groove on mating flange
- Excellent gasket containment
- Superior sealing for hazardous media
- Higher cost due to precision machining
- Applications: Toxic gases, high-pressure hydraulic systems
Facing Selection Guide
| Facing Type | Pressure Range | Temperature | Cost |
|---|---|---|---|
| Flat Face (FF) | Low (Class 150-300) | Moderate | Low |
| Raised Face (RF) | Medium-High (Class 150-2500) | Wide | Medium |
| MFM | Medium-High | Wide | Medium-High |
| TG | High | Wide | High |
| RTJ | Very High (Class 600+) | Extreme | High |
Gasket Compatibility
- RF/FF: Non-asbestos, graphite, PTFE, spiral wound
- RTJ: Soft iron, stainless steel, Inconel ring gaskets
- MFM/TG: Sheet gaskets, spiral wound with centering ring
Choosing the correct flange facing type is essential for ensuring leak-free operation and optimal sealing performance in your piping system.
WhatsApp: +86-18658777855
Email: 1007788887@qq.com
You may also like
Socket Weld Flange Guide High Pressure Small Bore Piping Applications
What is a Socket Weld Flange A Socket Weld Flange is designed for small-bore, high-pressure piping systems. The pipe is inserted into a recessed socket area and fillet welded to the flange hub, creating a strong, leak-proof connection. Key Features Socket bore matches pipe outer diameter for precise fit Fillet weld provides strong mechanical connection […]
Lap Joint Flange Stub End Assembly Easy Alignment Piping Systems
Understanding Lap Joint Flanges A Lap Joint Flange consists of two components: a stub end and a backing flange. The stub end is butt-welded to the pipe, while the backing flange rotates freely around it, allowing for easy bolt hole alignment during assembly. Design Features Two-piece construction: stub end + backing flange Backing flange rotates […]
Threaded Flange No Welding Quick Connection Piping Solutions
Threaded Flange Overview A Threaded Flange connects to pipes using internal threads, eliminating the need for welding. This makes threaded flanges ideal for applications where welding is impractical or where quick installation and disassembly are required. Design Characteristics Internal threads match pipe external threads (NPT or BSP) No welding required for installation Tapered threads create […]