Dimensions
JIS B2220 20K flanges

Updated May 2026

JIS 5K B2220

JIS 10K B2220

JIS 16K B2220

JIS 20K B2220

JIS 30K B2220

Weld Neck (RF)

Slip On (FF)

Socket Weld (FF)

Lap Joint

Blind (FF)

NPS MM IN		OD	T	T1	L	L1	PCD	BH#	BHØ
10	3/8	90	14	14	20	33	65	4	15
15	1/2	95	14	14	20	34	70	4	15
20	3/4	100	16	16	22	36	75	4	15
25	1	125	16	16	24	38	90	4	19
32	1 1/4	135	18	18	26	41	100	4	19
40	1 1/2	140	18	18	26	41	105	4	19
50	2	155	18	18	26	42	120	8	19
65	2 1/2	175	20	20	30	48	140	8	19
80	3	200	22	22	34	51	160	8	23
90	3 1/2	210	24	24	36	54	170	8	23
100	4	225	24	24	36	58	185	8	23
125	5	270	26	26	40	64	225	8	25
150	6	305	28	28	42	73	260	12	25
200	8	350	30	30	46	77	305	12	25
250	10	430	34	34	52	87	380	12	27
300	12	480	36	36	56	94	430	16	27
350	14	540	40	40	62	110	480	16	33
400	16	605	46	46	70	123	540	16	33
450	18	675	48	48	78	134	605	20	33
500	20	730	50	50	84	136	660	20	33
550	22	795	52	52	90	143	720	20	39
600	24	845	54	56	96	149	770	24	39

Notes..

Dimensions are in millimeters unless otherwise indicated
NPS = Nominal Pipe Size
OD = Outside Diameter of flange
T = Thickness min of all flanges
T1 = Thickness min of blind flange
L = Height of Slip On, Socket Weld and Lap Joint flange
L1 = Height of Weld Neck flange
PCD = Pitch Circle Diameter
BH# = Bolt Hole numbers
BHØ = Bolt Hole diameter
D = Depth of Socket Weld flange (currently unavailable)
Threaded flanges are currently not available

Flange Facing Dimensions in MM

Raised Face design

Flat Face design

NPS	RF large										RF small
	5K		10K		16K		20K		30K		RF small
	G	B	G	B	G	B	G	B	G	B	G1	B1
10	39	1	46	1	46	1	46	1	52	1	35	1
15	44	1	51	1	51	1	51	1	55	1	42	1
20	49	1	56	1	56	1	56	1	60	1	50	1
25	59	1	67	1	67	1	67	1	70	1	60	1
32	70	2	76	2	76	2	76	2	80	2	68	2
40	75	2	81	2	81	2	81	2	90	2	75	2
50	85	2	96	2	96	2	96	2	105	2	90	2
65	110	2	116	2	116	2	116	2	130	2	105	2
80	121	2	126	2	132	2	132	2	140	2	120	2
90	131	2	136	2	145	2	145	2	150	2	130	2
100	141	2	151	2	160	2	160	2	160	2	145	2
125	176	2	182	2	195	2	195	2	195	2	170	2
150	206	2	212	2	230	2	230	2	235	2	205	2
175	232	2	237	2
200	252	2	262	2	275	2	275	2	280	2	260	2
225	277	2	282	2
250	317	2	324	2	345	2	345	2	345	2	315	2
300	360	3	368	3	395	3	395	3	405	3	375	3
350	403	3	413	3	440	3	440	3	450	3	415	3
400	463	3	475	3	495	3	495	3	510	3	465	3
450	523	3	530	3	560	3	560	3
500	573	3	585	3	615	3	615	3
550	630	3	640	3	670	3	670	3
600	380	3	690	3	720	3	720	3
650	735	3	740	3	770	5	790	5
700	785	3	800	3	820	5	840	5
750	840	3	855	3	880	5	900	5
800	890	3	905	3	930	5	960	5
850	940	3	955	3	980	5	1020	5
900	990	3	1005	3	1030	5	1070	5
1000	1090	3	1110	3	1140	5

Raised Face (RF) JIS flange
is a pipe flange conforming to the Japanese industrial standard (JIS B2220) in which the gasket surface is positioned higher than the plane of the bolt circle. This design concentrates the bolt pressure on a smaller gasket surface, resulting in a stronger, tighter, and more reliable leak-free seal.

Flat Face (FF) JIS flange
is a pipe flange that conforms to the Japanese Industrial Standard (JIS) and has a completely smooth, flat sealing surface. Unlike raised surface (RF) flanges, they use gaskets that cover the entire flange surface, from the inner bore to the outer bolt circle.

Dimensions JIS B2220 20K flanges

Flange Facing Dimensions in MM

Dimensions
JIS B2220 20K flanges