Flange/Bolt Chart

Number & Size of Bolts for Flanged Joints

Primary Service Pressure Rating Bolting Flange Facing NOMINAL PIPE SIZE
1/2 3/4 1 2 3 4 5 6 8 10 12 14 16 18 20 24
Class 150 Number 4 4 4 4 4 4 4 4 8 8 8 8 8 12 12 12 16 16 20 20
Diameter ½ ½ ½ ½ ½ 5/8 5/8       5/8       5/8       5/8 ¾ ¾ ¾ 7/8 7/8 1 1 1 1/8 1 1/8
Length of Stud Bolts 1/16” RF 4 5 1/4 5 1/4
RTJ 3 4 4 4 4 5
Lth Mach Bolts 1/16” RF 2 2 3 3 3 3 3 1/4 3 1/4 4 4 5 6
Ring No. R15 R17 R19 R22 R25 R29 R33 R36 R40 R43 R48 R52 R56 R59 R64 R68 R72 R76
Class 300 Number 4 4 4 4 4 8 8 8 8 8 8 12 12 16 16 20 20 24 24 24
Diameter ½ 5/8 5/8 5/8 ¾ 5/8 ¾ ¾ ¾ ¾ ¾ ¾ 7/8 1 1 1/8 1 1/8
Length of Stud Bolts 1/16” RF 3 3 4 4 3/4 7 8 9
RTJ 3 4 4 4 1/2 5 5 6 8 10
Lth Mach Bolts 1/16” RF 3 3 8
Ring No. R11 R15 R16 R18 R20 R23 R26 R31 R34 R37 R41 R45 R49 R53 R57 R61 R65 R69 R73 R77
Class 400 Number 4 4 4 4 4 8 8 8 8 8 8 12 12 16 16 20 20 24 24     24
Diameter ½ 5/8 5/8 5/8 ¾ 5/8 ¾ ¾ 7/8 7/8 7/8 7/8 1 1 1/8 1 3/8 1 3/8     1¾
Length of Stud Bolts ¼” RF 3 5 6 8 9     10½
M&F T&G 3 1/2 4 4 8     10¼
RTJ 3 5 6 7 1/2 8 9     11
Ring No.     R11     R13     R16     R18     R20     R23     R26     R31     R34     R37     R41     R45     R49     R53     R57     R61     R65     R69     R73     R77
Class 600 Number 4 4 4 4 4 8 8 8 8 8 8 12 12 16 20 20 20 20 24     24
Diameter ½ 5/8 5/8 5/8 ¾ 5/8 ¾ ¾ 7/8 7/8 1 1 1 1/8 1 3/8 1 5/8 15/8 1     7/8
Length of Stud Bolts ¼” RF 3 5 10 10¾ 11¼ 13
M&F T&G 4 4 9 10½ 11     12¾
    RTJ 3 5 10 10¾ 11½     13¼
Ring No.     R11     R13     R16     R18     R20     R23     R26     R31     R34     R37     R41     R45     R49     R53     R57     R61     R65     R69     R73     R77
Class 900 Number 4 4 4 4 4 8 8 8 8 8 12 12 16 20 20 20 20 20 20
Diameter ¾ ¾ 7/8 7/8 1 7/8 1 7/8 1 1/8 1 1/8 1 3/8 1 3/8 1 3/8 1 5/8 1 7/8 2
Length of Stud Bolts ¼” RF 5 5 10 10¾ 11¼ 12¾ 13¾ 17¼
M&F T&G 4 6 9 10½ 11 12½ 13½ 17
RTJ 5 5 10 11 11½ 13¼ 14¼ 18
Ring No. R12 R14 R16 R18 R20 R24 R27 R31 R37 R41 R45 R49 R53 R57 R62 R66 R70 R74 R78
Class 1500 Number 4 4 4 4 4 8 8 8 8 8 12 12 12 16 16 16 16 16 16
Diameter ¾ ¾ 7/8 7/8 1 7/8 1 1 1/8 1 3/8 1 5/8 1 7/8 2 3
Length of Stud Bolts ¼” RF 5 5 7 10 1/4 11½ 13 1/4 14¾ 16 17½ 19½ 21¼ 24¼
M&F T&G 4 6 10 11¼ 13 14½ 15¾ 17¼ 19¼ 21 24
RTJ 5 5 7 10½ 12¾ 13½ 15¼ 16¾ 18½ 20¾ 22¼ 25½
Ring No. R12 R14 R16 R18 R20 R24 R27 R35 R39 R44 R46 R50 R54 R58 R63 R67 R71 R75 R79
Class 2500 Number 4 4 4 4 4 8 8 8 8 8 8 12 12 12
Diameter ¾ ¾ 7/8 1 1 1/8 1 1 1/8 2 2
Length of Stud Bolts ¼” RF 5 6 7 10 11¾ 13½ 15 19¼ 21¼
M&F T&G 11½ 13¼ 14¾ 19 21
RTJ 5 6 7 8 9 10¼ 12¼ 14 15½ 20 22
Ring No. R13 R16 R18 R21 R23 R26 R28 R32 R38 R42 R47 R51 R55 R60

Stud-Bolt lengths do   not include the height of the points.

Lengths of studs and   bolts, when used with lap joints flanges, are dependent upon the thickness of   the lap of the stud end.