ASME B16.20 Ring Joint Gasket Dimensions

Ring Specifications — Pitch Diameter, Width, Height & Flat Width

About

ASME B16.20 defines dimensions for metallic ring joint gaskets used with pipe flanges. The table below contains data from Table 5.1 of ASME B16.20-2017, covering ring specifications for ring numbers R-11 through R-105.

Ring joint gaskets are used with ring-type joint (RTJ) flanges in high-pressure and high-temperature services. Both oval and octagonal cross-section heights are provided where applicable.

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Ring Joint Gasket Table

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Ring Number

Units

94 rows

Ring No.	Pitch Dia. (in)	Width (in)	Height Oval (in)	Height Oct. (in)	Flat Width (in)	Radius (in)
R-11	1.344	0.25	0.44	0.38	0.17	0.06
R-12	1.563	0.313	0.56	0.5	0.206	0.06
R-13	1.688	0.313	0.56	0.5	0.206	0.06
R-14	1.75	0.313	0.56	0.5	0.206	0.06
R-15	1.875	0.313	0.56	0.5	0.206	0.06
R-16	2	0.313	0.56	0.5	0.206	0.06
R-17	2.25	0.313	0.56	0.5	0.206	0.06
R-18	2.375	0.313	0.56	0.5	0.206	0.06
R-19	2.563	0.313	0.56	0.5	0.206	0.06
R-20	2.688	0.313	0.56	0.5	0.206	0.06
R-21	2.844	0.438	0.69	0.63	0.305	0.06
R-22	3.25	0.313	0.56	0.5	0.206	0.06
R-23	3.25	0.438	0.69	0.63	0.305	0.06
R-24	3.7	0.438	0.69	0.63	0.305	0.06
R-25	4	0.313	0.56	0.5	0.206	0.06
R-26	4	0.438	0.69	0.63	0.305	0.06
R-27	4.25	0.438	0.69	0.63	0.305	0.06
R-28	4.375	0.5	0.75	0.69	0.341	0.06
R-29	4.5	0.313	0.56	0.5	0.206	0.06
R-30	4.625	0.438	0.69	0.63	0.305	0.06
R-31	4.875	0.438	0.69	0.63	0.305	0.06
R-32	5	0.5	0.75	0.69	0.341	0.06
R-33	5.188	0.313	0.56	0.5	0.206	0.06
R-34	5.188	0.438	0.69	0.63	0.305	0.06
R-35	5.375	0.438	0.69	0.63	0.305	0.06
R-36	5.875	0.313	0.56	0.5	0.206	0.06
R-37	5.875	0.438	0.69	0.63	0.305	0.06
R-38	6.188	0.625	0.88	0.81	0.413	0.06
R-39	6.375	0.438	0.69	0.63	0.305	0.06
R-40	6.75	0.313	0.56	0.5	0.206	0.06
R-41	7.125	0.438	0.69	0.63	0.305	0.06
R-42	7.5	0.75	1	0.94	0.485	0.06
R-43	7.625	0.313	0.56	0.5	0.206	0.06
R-44	7.625	0.438	0.69	0.63	0.305	0.06
R-45	8.313	0.438	0.69	0.63	0.305	0.06
R-46	8.313	0.5	0.75	0.69	0.341	0.06
R-47	9	0.75	1	0.94	0.485	0.06
R-48	9.75	0.313	0.56	0.5	0.206	0.06
R-49	10.625	0.438	0.69	0.63	0.305	0.06
R-50	10.625	0.625	0.88	0.81	0.413	0.06
R-51	11	0.875	1.13	1.06	0.583	0.06
R-52	12	0.313	0.56	0.5	0.206	0.06
R-53	12.75	0.438	0.69	0.63	0.305	0.06
R-54	12.75	0.625	0.88	0.81	0.413	0.06
R-55	13.5	1.125	1.44	1.38	0.78	0.09
R-56	15	0.313	0.56	0.5	0.206	0.06
R-57	15	0.438	0.69	0.63	0.305	0.06
R-58	15	0.875	1.13	1.06	0.583	0.06
R-59	15.625	0.313	0.56	0.5	0.206	0.06
R-60	16	1.25	1.56	1.5	0.879	0.09
R-61	16.5	0.438	0.69	0.63	0.305	0.06
R-62	16.5	0.625	0.88	0.81	0.413	0.06
R-63	16.5	1	1.31	1.25	0.681	0.09
R-64	17.875	0.313	0.56	0.5	0.206	0.06
R-65	18.5	0.438	0.69	0.63	0.305	0.06
R-66	18.5	0.625	0.88	0.81	0.413	0.06
R-67	18.5	1.125	1.44	1.38	0.78	0.09
R-68	20.375	0.313	0.56	0.5	0.206	0.06
R-69	21	0.438	0.69	0.63	0.305	0.06
R-70	21	0.75	1	0.94	0.485	0.06
R-71	21	1.125	1.44	1.38	0.78	0.09
R-72	22	0.313	0.56	0.5	0.206	0.06
R-73	23	0.5	0.75	0.69	0.341	0.06
R-74	23	0.75	1	0.94	0.485	0.06
R-75	23	1.25	1.56	1.5	0.879	0.09
R-76	26.5	0.313	0.56	0.5	0.206	0.06
R-77	27.25	0.625	0.88	0.81	0.413	0.06
R-78	27.25	1	1.31	1.25	0.681	0.09
R-79	27.25	1.375	1.75	1.63	0.977	0.09
R-80	24.25	0.313	—	0.5	0.206	0.06
R-81	25	0.563	—	0.75	0.377	0.06
R-82	2.25	0.438	—	0.63	0.305	0.06
R-84	2.5	0.438	—	0.63	0.305	0.06
R-85	3.125	0.5	—	0.69	0.341	0.06
R-86	3.563	0.625	—	0.81	0.413	0.06
R-87	3.938	0.625	—	0.81	0.413	0.06
R-88	4.875	0.75	—	0.94	0.485	0.06
R-89	4.5	0.75	—	0.94	0.485	0.06
R-90	6.125	0.875	—	1.06	0.583	0.06
R-91	10.25	1.25	—	1.5	0.879	0.09
R-92	9	0.438	0.69	0.63	0.305	0.06
R-93	29.5	0.75	—	0.94	0.485	0.06
R-94	31.5	0.75	—	0.94	0.485	0.06
R-95	33.75	0.75	—	0.94	0.485	0.06
R-96	36	0.875	—	1.06	0.583	0.06
R-97	38	0.875	—	1.06	0.583	0.06
R-98	40.25	0.875	—	1.06	0.583	0.06
R-99	9.25	0.438	—	0.63	0.305	0.06
R-100	29.5	1.125	—	1.38	0.78	0.09
R-101	31.5	1.25	—	1.5	0.879	0.09
R-102	33.75	1.25	—	1.5	0.879	0.09
R-103	36	1.25	—	1.5	0.879	0.09
R-104	38	1.375	—	1.63	0.977	0.09
R-105	40.25	1.375	—	1.63	0.977	0.09

Data sourced from ASME B16.20-2017, Table 5.1.

How to Use This Chart

Select a ring number to view its dimensions. The chart includes:

Pitch Diameter — average pitch diameter of the ring
Width — width of the ring cross-section
Height (Oval) — height for oval cross-section rings (not available for all ring numbers)
Height (Octagonal) — height for octagonal cross-section rings
Flat Width — width of the flat on octagonal rings
Radius — radius in the octagonal ring profile