Common Flange Facing Types

When selecting flanges for industrial piping systems, the flange facing is critical for leak-tight performance. Below are the most common flange facing types, their descriptions, and typical applications.

1. Flat Face (FF)

Description:
A Flat Face flange has a gasket surface that lies on the same plane as the bolting circle face.

Applications:

• Low-pressure piping systems (water, air, steam up to about 150–300 psi)
• Connections to cast iron valves, pumps, or fittings
• Low-temperature services

2. Raised Face (RF)

Description:
The gasket surface is raised above the bolting circle plane. Standard heights are 1/16″ (1.6 mm) for Class 150–300 flanges and 1/4″ (6.4 mm) for Class 400 and above.

Applications:

• General industrial piping: oil & gas, petrochemical, chemical plants, refineries
• Pressure ratings from Class 150 to Class 2500
• Wide range of temperatures and media

3. Ring Type Joint (RTJ)

Description:
RTJ flanges feature a precision-machined groove that accommodates a metallic ring gasket. When bolted, the gasket deforms to create a metal-to-metal seal.

Applications:

• High-pressure and high-temperature services (Class 600 to Class 2500+)
• Oil & gas exploration, subsea pipelines, wellhead equipment
• Sour service (H₂S) and highly toxic/flammable fluids
• Refineries and power plants

4. Tongue and Groove (T&G)

Description:
One flange face has a raised tongue, and the mating flange has a matching groove. The gasket sits inside the groove.

Applications:

• Critical services where gasket blowout is unacceptable (toxic or explosive fluids)
• High-vibration systems (compressors, reciprocating pumps)
• Vacuum services

5. Male and Female (M&F)

Description:
Similar to T&G, but with a shallow male protrusion and a matching female recess. The gasket sits inside the female face.

Applications:

• Medium to high-pressure systems (Class 300–1500)
• Steam, water, oil, and chemical services where blowout prevention is desired
• Heat exchangers and pressure vessels

Choosing the Right Flange Facing

Facing Type	Typical Pressure	Typical Applications
FF	Low	Cast iron equipment, low-pressure water/air
RF	Low to high	General industrial piping, oil & gas, chemicals
RTJ	Very high	Subsea, wellhead, high-temperature refineries
T&G	Medium to high	Toxic fluids, high vibration, vacuum
M&F	Medium to high	Heat exchangers, pressure vessels

 

At Hebei Yu Jinduo Co, we supply all standard flange facing types according to ASME B16.5, ASME B16.47, EN 1092-1, DIN, JIS and other international standards. Contact us for a quote or technical consultation.