A Ring Joint Gasket (RTJ) provides a strong and durable metal-to-metal seal between two mating RTJ flanges. As the flanges are bolted together, the softer material of the ring joint gasket is “squeezed” into the flanges grooves (made of a harder material) and closes the connection very tightly.

 

Ring joint gaskets ensure a long lasting and strong seal for flanges, valves, piping spools and vessels at high pressure and temperatures (which are typical conditions for many petrochemical processes). Ring joint gaskets are available in different designs (called “styles”) and dimensions, as illustrated in the picture below (BX, R, and BX).

RING JOINT GASKET STYLE-R, RX, AND BX

Ring Joint Gasket Styles

 

RTJ GASKET TYPE “R” (OVAL, OCTAGONAL)

The most common type of RTJ gaskets is the “style R”. R type ring joint gaskets are available in oval or octagonal cross section and manufactured according to API 6A and ASME B16.20 to suit API 6B and ASME/ANSI B16.5 flanges. This type of RTJ gasket is machined to tight manufacturing tolerances to ensure correct installation with standard ASME B16.5 and API 6B ring joint faced flanges. “R style” oval and octagonal RTJ gaskets can seal pressures up to 6.250 psi by ASME B16.20 and up to 5.000 psi according to the API 6A pressure ratings. Type R RTJ gaskets are frequently used for valves covers.

 

RTJ GASKET TYPE “RX”

The RX type RTJ gasket is manufactured according to API 6A and ASME B16.20 to suit API 6B and ASME/ANSI B16.5 flanges. The RX is a pressure energized version of the R octagonal gasket and fits the R type flat-bottomed groove. The RX has an increased height and utilizes the internal system pressure to energize and improve the seal as internal pressure increases. Some RX sizes have a pressure relief hole to equalize pressure on both sides of the sealing faces.

 

RTJ GASKET TYPE “BX”

The BX type RTJ gaskets are manufactured according to API 6A and are suitable for use in high-pressure API 6BX flanges. The gaskets form a metal to metal seal on assembly and the efficiency improves as internal pressure increases. All BX sizes have a pressure relief hole to equalize pressure across sealing faces.

 

RING JOINT GASKET MATERIALS

The material of RTJ gaskets shall match the flanges material but must have a lower hardness: this to ensure that the gasket, and not the flange, get plastically deformed within the groove of the flange as the two mating flanges are bolted together. In case a harder material for the ring type joint is used, the groove of the flange would be damaged as the flanges are tightened (the hardness values for ring joint gaskets are given below).

RTJ GASKET MATERIAL RING ID ASTM GRADE DIN GRADE WKSTOFF NUMBER AISI
GRADE
BS
GRADE
OTHER SPECS
Soft Iron D 1.1003 / 1.0335 Aramco / StW24
LCS S 1.1003 / 1.0335 Aramco / StW24
CS360 LT CS360LT A516 Gr70
4140 4140 UNS G41400 42CrMo4 1.7225 4140
F5 F5 UNS K42544 12CrMo195 1.7362 5Cr 1/2Mo
SS304 S304 S30400 X5CrNi 18 9 1.4301 304 304S15
SS304L S304L S30403 X2CrNi 18 9 1.4306 304L 304SS12
SS309 S309 S30900 X15CrNiSi2012 1.4828 309 309S24
SS310 S310 S31008 XX15CrNiSi2520 1.4841 310 310S24
SS316 S316 S31600 X5CrNiMo18 10 1.4401 316 316S16
SS316L S316L S31603 X2CrNiMo18 10 1.4404 316L 316S11/316S12
SS316L UREA S316UG S31603 X2CrNiMo 18 14 3 1.4435
SS316Ti S316Ti S31635 X10CrNiMoTi1810 1.4571 316Ti 320S31/320S17
SS321 S321 S32100 X10CrNiTi18 9 1.4541 321 321S12
SS347 S347 S34700 X10CrNiNb 18 9 1.455 347 347S51
SS410 S410 S41000 X10Cr13 1.4006 410 410S21
Monel 400 Monel400 N04400 NiCu30Fe 2.436
Inconel 600 INC600 N06600 NiCr15Fe 2.4816
Inconel 625 INC625 N06625 NiCr22Mo9Nb 2.4856
Inconel 718 INC718 N07718
Incoloy 800 INC800 N08800 X5NiCrAlTi31-20 1.4958
Incoloy 800H INC800H N08810 1.4958
Incoloy 825 INC825 N08825 NiCr21Mo 2.4858
904L 904L N08904 X1NiCrMoCu25-20-5 1.4539
F51 F51 S31803 X2CrNiMoN22-5-3 1.4462 2205 /Duplex
F53 F53 S32750 X2CrNiMoN25-7-4 1.441
F55 F55 S32760 X2CrNiMoCuWN 25 7 4 1.4501 Zeron 100
F60 F60 S32205 Duplex
Titanium Ti R 50400 3.7035
17-4PH 17-4PH S17400 1.4542 630
S254 S254 S31254 X1CrNiMoCuN20-18-7 1.4547 F44 / 6Mo
C276 C276 N10276 NiMo16Cr15W 2.4819 Hastelloy
Alloy 28 Alloy28 N08028 X1 NiCrMoCuN 31 27 4 1.4563 SANICRO 28

 

RING JOINT GASKET MATERIALS: MECHANICAL PROPERTIES

Maximum Hardness of RTJ Gaskets

RTJ Gasket Material

Brinell HRB ID

Soft Iron-S

90 56 D

Low Carbon Steel

120 68 S

4 – 6% Chrome
1/2% Moly

130 72 F5

SS 304
Stainless Steel

160 83 S304

SS 316
Stainless Steel

160 83 S316

SS 347
Stainless Steel

160 83 S347

SS 410
Stainless Steel

170 96 S410

 

RING JOINT GASKET DIMENSIONS ASME B16.20

RING JOINT GASKETS STYLE “R” (FOR RTJ FLANGE ASME B16.5)

Ring joint gasket sizes

RTJ GASKET RING NUMBER Diameter P Width A Height Oct C Oct R1 NPS / CLASS
Oval B Oct H
R 11 34.14 6.35 11.2 9.7 4.32 1.5 1/2
300 / 600
R 12 39.7 7.95 14.2 12.7 5.23 1.5 1/2
900 / 1500
R 13 42.88 7.95 14.2 12.7 5.23 1.5 3/4
300 / 600
1/2
2500
R 14 44.45 7.95 14.2 12.7 5.23 1.5 3/4
900 / 1500
R 15 47.63 7.95 14.2 12.7 5.23 1.5 1
150
R 16 50.8 7.95 14.2 12.7 5.23 1.5 1
300 / 1500
3/4
2500
R 17 57.15 7.95 14.2 12.7 5.23 1.5
150
R 18 60.33 7.95 14.2 12.7 5.23 1.5
300 / 1500
1
2500
R 19 65.1 7.95 14.2 12.7 5.23 1.5
150
R 20 68.28 7.95 14.2 12.7 5.23 1.5
300 / 1500
R 21 72.24 11.13 17.5 16 7.75 1.5
2500
R 22 82.55 7.95 14.2 12.7 5.23 1.5 2
150
R 23 82.55 11.13 17.5 16 7.75 1.5 2
300 600

2500
R 24 95.25 11.13 17.5 16 7.75 1.5 2
900 / 1500
R 25 101.6 7.95 14.2 12.7 5.23 1.5
150
R 26 101.6 11.13 17.5 16 7.75 1.5
300/ 600
2
2500
R 27 107.95 11.13 17.5 16 7.75 1.5
900 / 1500
R 28 111.13 12.7 19.1 17.5 8.66 1.5
2500
R 29 114.3 7.95 14.2 12.7 5.23 1.5 3
150
R 30
*
117.48 11.13 17.5 16 7.75 1.5 3
300 / 600
R 31 123.83 11.13 17.5 16 7.75 1.5 3
300 / 900
R 32 127 12.7 19.1 17.5 8.66 1.5 3
2500
R 33 131.78 7.95 14.2 12.7 5.23 1.5
150
R 34 131.78 11.13 17.5 16 7.75 1.5
300 / 600
R 35 136.53 11.13 17.5 16 7.75 1.5 3
1500
R 36 149.23 7.95 14.2 12.7 5.23 1.5 4
150
R 37 149.23 11.13 17.5 16 7.75 1.5 4
300 / 900
R 38 157.18 15.88 22.4 20.6 10.49 1.5 4
2500
R 39 161.93 11.13 17.5 16 7.75 1.5 4
1500
R 40 171.45 7.95 14.2 12.7 5.23 1.5 5
150
R 41 180.98 11.13 17.5 16 7.75 1.5 5
300 / 900
R 42 190.5 19.05 25.4 23.9 12.32 1.5 5
2500
R 43 193.68 7.95 14.2 12.7 5.23 1.5 6
150
R 44 193.68 11.13 17.5 16 7.75 1.5 5
1500
R 45 211.15 11.13 17.5 16 7.75 1.5 6
300 / 900
R 46 211.15 12.7 19.1 17.5 8.66 1.5 6
1500
R 47 228.6 19.05 25.4 23.9 12.32 1.5 6
2500
R 48 247.65 7.95 14.2 12.7 5.23 1.5 8
150
R 49 269.88 11.13 17.5 16 7.75 1.5 8
300 / 900
R 50 269.88 15.88 22.4 20.6 10.49 1.5 8
1500
R 51 279.4 22.23 28.7 26.9 14.81 1.5 8
2500
R 52 304.8 7.95 14.2 12.7 5.23 1.5 10
150
R 53 323.85 11.13 17.5 16 7.75 1.5 10
300 900
R 54 323.85 15.88 22.4 20.6 10.49 1.5 10
1500
R 55 342.9 28.58 36.6 35.1 19.81 2.3 10
2500
R 56 381 7.95 14.2 12.7 5.23 1.5 12
150
R 57 381 11.13 17.5 16 7.75 1.5 12
300 900
R 58 381 22.23 28.7 26.9 14.81 1.5 12
1500
R 59 396.88 7.95 14.2 12.7 5.23 1.5 14
150
R 60 406.4 31.75 39.6 38.1 22.33 2.3 12
2500
R 61 419.1 11.13 17.5 16 7.75 1.5 14
300 600
R 62 419.1 15.88 22.4 20.6 10.49 1.5 14
900
R 63 419.1 25.4 33.3 31.8 17.3 2.3 14
1500
R 64 454.03 7.95 14.2 12.7 5.23 1.5 16
150
R 65 469.9 11.13 17.5 16 7.75 1.5 16
300 600
R 66 469.9 15.88 22.4 20.6 10.49 1.5 16
900
R 67 469.9 28.58 36.6 35.1 19.81 2.3 16
1500
R 68 517.53 7.95 14.2 12.7 5.23 1.5 18
150
R 69 533.4 11.13 17.5 16 7.75 1.5 18
300 600
R 70 533.4 19.05 25.4 23.9 12.32 1.5 18
900
R 71 533.4 28.58 36.6 35.1 19.81 2.3 18
1500
R 72 558.8 7.95 14.2 12.7 5.23 1.5 20
150
R 73 584.2 12.7 19.1 17.5 8.66 1.5 20
300 600
R 74 584.2 19.05 25.4 23.9 12.32 1.5 20
900
R 75 584.2 31.75 39.6 38.1 22.33 2.3 20
1500
R 76 673.1 7.95 14.2 12.7 5.23 1.5 24
150
R 77 692.15 15.88 22.4 20.6 10.49 1.5 24
300 600
R 78 692.15 25.4 33.3 31.8 17.3 2.3 24
900
R 79 692.15 34.93 44.5 41.4 24.82 2.3 24
1500

 

RING JOINT GASKETS STYLE R (FOR RTJ FLANGE ASME B16.47 SERIES A)

RTJ GASKET RING NUMBER Dia
P
Width
A
Height Oct
C
Oct
R1
NPS
CLASS
Oval
B
Oct
H
R 93 749.3 19.05 23.9 12.32 1.5 26
300 600
R 94 800.1 19.05 23.9 12.32 1.5 28
300 600
R 95 857.25 19.05 23.9 12.32 1.5 30
300 600
R 96 914.4 22.23 26.9 14.81 1.5 32
300 600
R 97 965.2 22.23 26.9 14.81 1.5 34
300 600
R 98 1022.35 22.23 26.9 14.81 1.5 36
300 600
R 100 749.3 28.58 35.1 19.81 2.3 26
900
R 101 800.1 31.75 38.1 22.33 2.3 28
900
R 102 857.25 31.75 38.1 22.33 2.3 30
900
R 103 914.4 31.75 38.1 22.33 2.3 32
900
R 104 965.2 34.93 41.4 24.82 2.3 34
900
R 105 1022.35 34.93 41.4 24.82 2.3 36
900

 

RING JOINT GASKETS STYLE RX

RTJ GASKET RING NUMBER 720-960 2900# 3000# 5000# OD HEIGHT WIDTH GASKET Wt. ( kg )
RX20 1 ½ 1 ½ 1 ½ 76.2 19.05 8.74 0.24
RX23 2, 2 1/16 93.27 25.4 11.91 0.52
RX24 2, 2 1/16 2, 2 1/16 105.97 25.4 11.91 0.6
RX25 3 1/8 109.55 19.05 8.74 0.5
RX26 2 ½ , 2 9/16 111.91 25.4 11.91 0.64
RX27 2 ½, 2 9/16 2 ½, 2 9/16 118.26 25.4 11.91 0.68
RX31 3 , 3 1/8 3, 3 1/8 134.54 25.4 11.91 0.78
RX35 3, 3 1/8 147.24 25.4 11.91 0.86
RX37 4 , 4 1/16 4, 4 1/16 159.94 25.4 11.91 0.95
RX39 4, 4 1/16 172.64 25.4 11.91 1.03
RX41 5, 5 1/8 5, 5 1/8 191.69 25.4 11.91 1.15
RX44 5, 5 1/8 204.39 25.4 11.91 1.23
RX45 6, 7 1/16 6, 7 1/16 221.84 25.4 11.91 1.34
RX46 6, 7 1/16 222.25 28.58 13.49 1.66
RX47 8 245.26 41.28 19.84 3.88
RX49 8, 9 8, 9 280.59 25.4 11.91 1.72
RX50 8, 9 283.36 31.75 16.66 2.43
RX53 10, 11 10, 11 334.57 25.4 11.91 2.06
RX54 10, 11 337.34 31.75 16.66 2.92
RX57 12, 13 5/8 12, 13 5/8 391.72 25.4 11.91 2.42
RX63 14 441.73 50.8 27 11.96
RX65 16, 16 3/4 480.62 25.4 11.91 3
RX66 16, 16 3/4 457.99 31.75 16.66 4.25
RX69 18 544.12 25.4 11.91 3.41
RX70 18 550.06 41.28 19.84 9.12
RX73 20, 21 1/4 596.11 31.75 13.49 5.27
RX74 20, 20 3/4 600.86 41.28 19.84 10.01
RX82 1 67.87 25.4 11.91 0.36
RX84 1 ½ 74.22 25.4 11.91 0.4
RX85 2 90.09 25.4 13.49 0.4
RX86 2 ½ 103.58 28.58 15.09 0.81
RX87 3 113.11 28.58 15.09 0.9
RX88 4 139.29 31.75 17.48 1.46
RX89 3 ½ 129.77 31.75 18.26 3.09
RX90 5 174.63 44.45 19.84 7.75
RX91 10 286.94 45.24 30.18 1.5
RX99 8 8 245.67 25.4 11.91 2.2
RX201 1 3/8 51.46 11.3 5.74 0.1
RX205 1 13/16 62.31 11.1 5.56 0.13
RX210 2 9/16 97.64 19.05 9.53 0.35
RX215 4 1/16 140.89 25.4 11.91 0.8

 

RING JOINT GASKETS STYLE BX

RTJ GASKET RING NUMBER 2000# 3000# 5000# 10000# 15000# 20000# OUTSIDE DIA HEIGHT 
OF THE RING
WIDTH 
OF THE RING
RTJ GASKET 
WEIGHT KG
BX 150 1 11/16 1 11/16 72.19 9.3 9.3 0.13
BX 151 1 13/16 1 13/16 1 13/16 76.4 9.63 9.63 0.15
BX 152 2 1/16 2 1/16 2 1/16 84.68 10.24 10.24 0.19
BX 153 2 9/16 2 9/16 2 9/16 100.94 11.38 11.38 0.29
BX 154 3 1/16 3 1/16 3 1/16 116.84 12.4 12.4 0.4
BX 155 4 1/16 4 1/16 4 1/16 147.96 14.22 14.22 0.55
BX 156 7 1/16 7 1/16 7 1/16 237.92 18.62 18.62 1.87
BX 157 9 9 9 294.46 20.98 20.98 2.97
BX 158 11 11 11 352.04 23.14 23.14 4.35
BX 159 13 5/8 426.72 25.7 25.7 6.53
BX 160 13 5/8 402.59 23.83 13.74 3.06
BX 161 16 ¾ 491.41 28.07 16.21 5.35
BX 162 16 3/4 16 3/4 16 3/4 475.49 14.22 14.22 1.94
BX 163 18 3/4 556.16 30.1 17.37 6.9
BX 164 18 3/4 18 3/4 570.56 30.1 24.59 5.86
BX 165 21 ¼ 624.71 32.03 18.49 8.76
BX 166 21 ¼ 640.03 32.03 26.14 12.82
BX 167 26 3/4 759.36 35.86 13.11 8.53
BX 168 26 3/4 765.25 35.86 16.05 10.54
BX 169 5 1/8 173.51 15.85 12.93 0.73
BX 170 6 5/8 6 5/8 218.03 14.22 14.22 1.03
BX 171 8 9/16 8 9/16 267.44 14.22 14.22 1.24
BX 172 11 5/32 11 5/32 333.07 14.22 14.22 1.56
BX 303 30 30 852.75 37.95 16.97

 

HOW TO ORDER RING JOINT GASKET

The following tables shows how to select the correct ring joint gasket depending on the flange size (NPS), manufacturing norm (ASME or API) and flange rating:

RING JOINT GASKET – RTJ STYLE R

NOMINAL PIPE SIZE PRESSURE CLASSES
ASME B16.5 API 6B ASME B16.47 Series A
150# 300# – 600# 900# 1500# 2500# 720# – 960# (1) 2000# 3000# 5000# 10000# 150# 300# – 600# 900#
1/2” R-11 R-12 R-12 R-13
3/4” R-13 R-14 R-14 R-16
1” R-15 R-16 R-16 R-16 R-18 R-16 R-16 R-16 R-16 R-82
1 1/4” R-17 R-18 R-18 R-18 R-21 R-18 R-18 R-18 R-18
1 1/2” R-19 R-20 R-20 R-20 R-23 R-20 R-20 R-20 R-20 R-84
2” R-22 R-23 R-24 R-24 R-26 R-23 R-23 R-23 R-24 R-85
2 1/2” R-25 R-26 R-27 R-27 R-28 R-26 R-26 R-26 R-27 R-86
3” R-29 R-31 R-31 R-35 R-32 R-31 R-31 R-31 R-35 R-87
3 1/2” R-33 R-34 R-37 R-89
4” R-36 R-37 R-37 R-39 R-38 R-37 R-37 R-37 R-39 R-88
5” R-40 R-41 R-41 R-44 R-42 R-41 R-41 R-41 R-44 R-90
6” R-43 R-45 R-45 R-46 R-47 R-45 R-45 R-45 R-46
8” R-48 R-49 R-49 R-50 R-51 R-49 R-49 R-49 R-50
10” R-52 R-53 R-53 R-54 R-55 R-53 R-53 R-53 R-54 R-91
12” R-56 R-57 R-57 R-58 R-60 R-57 R-57 R-57 R-57 R-57
14” R-59 R-61 R-62 R-63 R-61 R-61 R-61 R-61 R-62
16” R-64 R-65 R-66 R-67 R-65 R-65 R-65 R-65 R-66
18” R-68 R-69 R-70 R-71 R-69 R-69 R-69 R-69 R-70
20” R-72 R-73 R-74 R-75 R-73 R-73 R-73 R-73 R-74
22” R-80 R-81
24” R-76 R-77 R-78 R-79 R-77 R-78
26” R-93 R-100
28” R-94 R-101
30” R-95 R-102
32” R-96 R-103
34” R-97 R-104
36” R-98 R-105

 

RING JOINT GASKET – RTJ STYLE RX

NPS PRESSURE RATING
API 6B
720# 960# 2000# 2900# 3000# 5000#
1” RX-82
1 3/8” RX-201
1 1/2” RX-20 RX-20 RX-20 RX-84 RX-20 RX-20
1 13/16″ RX205
2” RX-23 RX-23 RX-23 RX-85 RX-24 RX-24
2 1/2” RX-26 RX-26 RX-26 RX-86 RX-27 RX-27
2 9/16” RX210
3” RX-31 RX-31 RX-31 RX-87 RX-31 RX35
3 1/2” RX-89
4” RX-37 RX-37 RX-37 RX-88 RX-37 RX-39
4 1/16″ RX-215
5” RX-41 RX-41 RX-41 RX-90 RX-41 RX-44
6” RX-45 RX-45 RX-45 RX-45 RX-46
8” RX-49
RX-99 (2)
RX-49 RX-49 RX-49
RX-99 (2)
RX-50
10” RX-53 RX-53 RX-53 RX-91 RX-53 RX-54
12” RX-57 RX-57 RX-57 RX-57
14” RX-63
16” RX-65 RX-65 RX-65 RX-69
18” RX-69 RX-69 RX-69 RX-73
20” RX-73 RX-73 RX-73 RX82

 

RING JOINT GASKET – RTJ STYLE BX

NPS PRESSURE RATING
API 6BX
2000# 3000# 5000# 10000# 15000# 20000#
1 11/16″ BX-150 BX-150
1 13/16″ BX-151 BX-151 BX-151
2 1/16″ BX-152 BX-152 BX-152
2 9/16″ BX-153 BX-153 BX-153
3 1/16″ BX-154 BX-154 BX-154
4 1/16″ BX-155 BX-155 BX-155
5 1/8″ BX-169
6 5/8″ BX-170 BX-170
7 1/16″ BX-156 BX-156 BX-156
8 9/16″ BX-171 BX-171
9″ BX-157 BX-157 BX-157
11″ BX-158 BX-158 BX-158
11 5/32″ BX-172 BX-172
13 5/8″ BX-160 BX-159 BX-159 BX-159
16 3/4″ BX-161  BX-162 BX-162 BX-162
18 3/4″ BX-163 BX-164 BX-164
21 1/4″ BX-165 BX-166
26 3/4″ BX-167 BX-168
30″ BX-303 BX-303