Pipe flange specifications define the core parameters for flange design, manufacturing and installation. Correct specification confirmation is critical to match pipeline working conditions, ensure sealing performance and avoid leakage.

Main Specification Items

1. Flange Standard

ASME B16.5, EN 1092-1, GB/T 9112~9124, JIS B2220. Different standards cannot be interchanged directly.

2. Nominal Size

ASME: NPS (Nominal Pipe Size, inch), e.g. NPS 2, NPS 6

EN / GB / JIS: DN (Diamètre Nominal), e.g. DN50, DN150

Nominal size matches the connected pipe diameter, not the actual outer diameter of flange.

3. Pressure Class

ASME: Class 150, 300, 600, 900, 1500, 2500

EN & GB: PN6, PN10, PN16, PN25, PN40, PN63, PN100

JIS: 5K, 10K, 16K, 20K, 30K, 40K

It represents the maximum allowable working pressure under specified temperature.

4. Flange Type

Weld Neck Flange (WN)

Slip On Flange (SO)

Plate Flat Flange (PL)

Blind Flange (BL)

Threaded Flange (TH)

Socket Weld Flange (SW)

Lap Joint Flange (LJ)

5. Sealing Face Type

FF: Full Face

RF: Raised Face (most common)

RTJ: Ring Type Joint, for high pressure

MFM: Male and Female Face

TG: Tongue and Groove

6. Material

Carbon steel (A105, Q235), stainless steel (304, 316L), alloy steel (F11, F22). Material selection depends on medium, temperature and corrosion environment.

7. Other Parameters

Flange thickness, bolt circle diameter, bolt hole quantity & size, bolt length, machining requirement, heat treatment, NDT, MTC material test certificate.