ASME B16.5 / B16.20 — Ring joint (RTJ) gasket — Class 600

ASME B16.5 / B16.20 Ring joint (RTJ) gasket — Class 600 — 20 sizes.

NPS	Ring no.	Pitch dia. P (mm)	Ring width A (mm)	Height oval B (mm)	Height octagonal H (mm)
1/2	R-11	34.14	6.35	11.2	9.7
3/4	R-13	42.88	7.95	14.2	12.7
1	R-16	50.8	7.95	14.2	12.7
1-1/4	R-18	60.33	7.95	14.2	12.7
1-1/2	R-20	68.28	7.95	14.2	12.7
2	R-23	82.55	11.13	17.5	16
2-1/2	R-26	101.6	11.13	17.5	16
3	R-31	123.83	11.13	17.5	16
3-1/2	R-34	131.78	11.13	17.5	—
4	R-37	149.23	11.13	17.5	16
5	R-41	180.98	11.13	17.5	16
6	R-45	211.15	11.13	17.5	16
8	R-49	269.88	11.13	17.5	16
10	R-53	323.85	11.13	17.5	16
12	R-57	381	11.13	17.5	16
14	R-61	419.1	11.13	17.5	16
16	R-65	469.9	11.13	17.5	16
18	R-69	533.4	11.13	17.5	16
20	R-73	584.2	12.7	19.1	17.5
24	R-77	692.15	15.88	22.4	20.6

Class 300 and 600 use identical ring grooves/rings.
Ring-number assignment: Tesco Flanges and Sunpack charts agree (Wermac matches overlapping rows); NPS 14–20 assignments from Sunpack only; NPS 24 from Tesco only.
Ring dimensions (B16.20 Type R): R-11…R-35 Hebei Metals (R-11, R-13 also Wermac/hardhatengineer/amesweb); R-36…R-79 from Wermac, amesweb, Klinger and Hebei Metals rows; null where the ring's dimensions were not found in search results (R-40, 43, 48, 51, 52, 55, 56, 58, 66–68, 70–72, 74–76).
R-34 octagonal height not found. R-46 pitch dia: amesweb 211.65 vs Klinger/others 211.15 — 211.15 kept.
Tolerances: P ±0.18, A ±0.20, B/H +1.3/−0.5 mm (Wermac).