JIS B2220 flange standard

Updated May 2026

JIS B2220 is the Japanese industrial standard for steel pipe flanges and defines dimensions, pressure ratings, materials, and marking requirements for flanges used in Japanese installations and numerous projects throughout Asia.

JIS flanges use a “K” classification system (.g., 5K, 10K, 16K, 20K, 30K, 40K, 63K, where the number roughly indicates the maximum working pressure in kgf/cm² at ambient temperature. JIS B2220 flanges do not correspond to ASME B16.5, EN 1092-1, and other well known standards in terms of dimensions and some designs. Direct connection of an EU or ASME flange to a B2220 flange is generally not recommended. flanges.

IS B2220 Flange Types

JIS Type	Description	ASME B16.5 Equivalent
WN	Welding neck	Weld neck
SOH	Slip-on hubbed	Slip-on
BL	Blind	Blind
SW	Socket weld	Socket weld
(*)TR	(*)Threaded	(*)Threaded
LJ	(*)Loose (lap joint)	Lap joint
(*) currently no data available

Images of flange types all Flat Face design

Weld Neck

Slip On

Socket Weld

Lap Joint

Blind

JIS B2220 Flange Faces

The JIS B2220 standard specifies various flange face designs, such as raised face, flat face, tongue and groove, and male and female. The dimensions of the flange face depend on the diameter and the pressure class (K) of the flange. The raised flange face (RF) is generally the most commonly used type, as it allows for the easy realization of a leak-free flange connection. The main purpose of an RF flange is to concentrate the contact pressure on the gasket surface, resulting in increased sealing strength.

Raised Face design

The JIS B2220 standard also specifies the scale for the raised face profile and height in relation to the pressure class. Higher pressure classes (e.g. (20K or 30K) often use specific male female face variants to withstand enormous forces without leakage.

The standard also describes two gasket types: a large raised face is suitable for wide, flat ring gaskets, while a small raised face is often used for positioning specific composite flat ring or spiral wound gaskets.

JIS B2220 Flanges Materials

All materials have a JIS standard number to which the material number, also known as the material symbol, is linked.

The most commonly used materials in the production of JIS B2220 flanges are carbon steel, stainless steel, duplex steel, and nickel alloys.

Some other quality and material standards are described below, in the form of the more well known ASTM and API standards.

Carbon steel flanges JIS B2220:

High-temperature carbon steel ASTM A105: A53, A106, API 5L
Low-temperature carbon steel ASTM A350: LF1, LF2, LF3
High-yield strength carbon steel ASTM A694: F42, F52, F60, F65

Stainless Steel JIS B2220 Flanges:

Stainless Steel ASTM A182: F304, F304H, F304L, F304N, F304LN, F309H, F310, F310H, F310MoLN, F316, F316H, F316L, F316N, F316LN, F316Ti, F317, F317L, F321, F321H, F347, F347H, F348, F348H, 904L

Alloy Steel JIS B2220 Flanges:

Alloy Steel ASTM A182: F5, F9, F11, F22, F1, F5/F5a, F91

Duplex Steel JIS B2220 Flanges:

Duplex Steel ASTM A182: Duplex 2205 (UNS S31803 – UNS S32205)
Super Duplex ASTM A182: UNS S32750 – UNS S32760

Nickel Alloy JIS B2220 Flanges:

ASTM B160: Nickel 200 Flange | Nickel 201
ASTM B166: Inconel 600 Flange
ASTM B564: Inconel 625 Flange
ASTM B425: Incoloy 800 Flange
ASTM B564: Incoloy 825 Flange
ASTM B564: Monel K400 Flange | Monel 400
ASTM B564: Hastelloy C276 Flange | Hastelloy B, Hastelloy D, Hastelloy C-276, Hastelloy G

The source for the quality and material standards described above comes from
creativepiping.com