ASME B16.5 Flanges

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ANSI/ASME B16.5 Flange Dimensions

ASME B16.5 Class 150 Flange Dimensions

Nominal Size Outside Diameter
(OD)		 Min. Thickness
(T)		 RF Dia.
(R)		 No. of Bolt Holes Diameter of Holes Bolt Circle
(BC)		 SO Bore ID 
(SB)		 WN Bore ID 
(WB)		 Dia. Hub Base 
(HB)		 Dia. of Hub Top 
(HT)		 SO LTH
(SL)		 WN LTH 
(WL)
1⁄2 3.50 0.38 1.38 4 0.62 2.38 0.88 0.62 1.19 0.84 0.56 1.81
3⁄4 3.88 0.44 1.69 4 0.62 2.75 1.09 0.82 1.50 1.05 0.56 2.00
1 4.25 0.50 2.00 4 0.62 3.12 1.36 1.05 1.94 1.32 0.62 2.12
11⁄4 4.62 0.56 2.50 4 0.62 3.50 1.70 1.38 2.31 1.66 0.75 2.19
11⁄2 5.00 0.62 2.88 4 0.62 3.88 1.95 1.61 2.56 1.90 0.81 2.38
2 6.00 0.69 3.62 4 0.75 4.75 2.44 2.07 3.06 2.38 0.94 2.44
21⁄2 7.00 0.81 4.12 4 0.75 5.50 2.94 2.47 3.56 2.88 1.06 2.69
3 7.50 0.88 5.00 4 0.75 6.00 3.57 3.07 4.25 3.50 1.12 2.69
31⁄2 8.50 0.88 5.50 8 0.75 7.00 4.07 3.55 4.81 4.00 1.19 2.75
4 9.00 0.88 6.19 8 0.75 7.50 4.57 4.03 5.31 4.50 1.25 2.94
5 10.00 0.88 7.31 8 0.88 8.50 5.66 5.05 6.44 5.56 1.38 3.44
6 11.00 0.94 8.50 8 0.88 9.50 6.72 6.07 7.56 6.63 1.50 3.44
8 13.50 1.06 10.62 8 0.88 11.75 8.72 7.98 9.69 8.63 1.69 3.94
10 16.00 1.12 12.75 12 1.00 14.25 10.88 10.02 12.00 10.75 1.88 3.94
12 19.00 1.19 15.00 12 1.00 17.00 12.88 12.00 14.38 12.75 2.12 4.44
14 21.00 1.31 16.25 12 1.12 18.75 14.14 13.25 15.75 14.00 2.19 4.94
16 23.50 1.38 18.50 16 1.12 21.25 16.16 15.25 18.00 16.00 2.44 4.94
18 25.00 1.50 21.00 16 1.25 22.75 18.18 17.25 19.88 18.00 2.62 5.44
20 27.50 1.62 23.00 20 1.25 25.00 20.20 19.25 22.00 20.00 2.81 5.62
22 29.50 1.75 25.25 20 1.38 27.25 22.22 21.25 24.25 22.00 3.07 5.82
24 32.00 1.81 27.25 20 1.38 29.50 24.25 23.25 26.12 24.00 3.19 5.94

ANSI B16.5 Class 300 Flange Dimensions in mm, ANSI/ASME B16.5 Class 300 Flange Dimensions

Nominal Size Outside Diameter
(OD)		 Min. Thickness
(T)		 RF Dia.
(R)		 No. of Bolt Holes Diameter of Holes Bolt Circle
(BC)		 SO Bore ID 
(SB)		 WN Bore ID 
(WB)		 Dia. Hub Base 
(HB)		 Dia. Hub Top 
(HT)		 SO LTH
(SL)		 WN LTH 
(WL)
1⁄2 3.75 0.50 1.38 4 0.63 2.62 0.88 0.62 1.50 0.84 0.81 2.00
3⁄4 4.62 0.56 1.69 4 0.75 3.25 1.09 0.82 1.88 1.05 0.94 2.19
1 4.88 0.62 2.00 4 0.75 3.50 1.36 1.05 2.12 1.32 1.00 2.38
11⁄4 5.25 0.69 2.50 4 0.75 3.88 1.70 1.38 2.50 1.66 1.00 2.50
11⁄2 6.12 0.75 2.88 4 0.88 4.50 1.95 1.61 2.75 1.90 1.13 2.63
2 6.50 0.81 3.62 8 0.75 5.00 2.44 2.07 3.31 2.38 1.25 2.69
21⁄2 7.50 0.94 4.12 8 0.88 5.88 2.94 2.47 3.94 2.88 1.44 2.94
3 8.25 1.06 5.00 8 0.88 6.62 3.57 3.07 4.62 3.50 1.63 3.06
31⁄2 9.00 1.12 5.50 8 0.88 7.25 4.07 3.55 5.25 4.00 1.69 3.13
4 10.00 1.19 6.19 8 0.88 7.88 4.57 4.03 5.75 4.50 1.82 3.32
5 11.00 1.31 7.31 8 0.88 9.25 5.66 5.05 7.00 5.56 1.94 3.82
6 12.50 1.38 8.50 12 0.88 10.62 6.72 6.07 8.12 6.63 2.00 3.82
8 15.00 1.56 10.62 12 1.00 13.00 8.72 7.98 10.25 8.63 2.38 4.32
10 17.50 1.81 12.75 16 1.12 15.25 10.88 10.02 12.62 10.75 2.56 4.56
12 20.50 1.94 15.00 16 1.25 17.75 12.88 12.00 14.75 12.75 2.82 5.06
14 23.00 2.06 16.25 20 1.25 20.25 14.14 13.25 16.75 14.00 2.94 5.56
16 25.50 2.19 18.50 20 1.38 22.50 16.16 15.25 19.00 16.00 3.19 5.69
18 28.00 2.31 21.00 24 1.38 24.75 18.18 17.25 21.00 18.00 3.44 6.19
20 30.50 2.44 23.12 24 1.38 27.00 20.20 19.25 23.12 20.00 3.69 6.32
22 33.00 2.57 25.25 24 1.63 29.25 22.22 21.25 25.25 22.00 3.93 6.43
24 36.00 2.69 27.62 24 1.63 32.00 24.25 23.25 27.62 24.00 4.13 6.56

ANSI B16.5 Class 400 Flange Dimensions

Nominal Size
Outside Diameter
(OD)
Min. Thickness
(T)
RF Dia.
(R)
No. of Bolt Holes
Diameter of Holes
Bolt Circle
(BC)
SO Bore ID 
(SB)
Dia. Hub Base 
(HB)
Dia. Hub Top 
(HT)
SO LTH
(SL)
WN LTH 
(WL)
* WN Bore ID 
(WB)
1⁄2
3.75
0.56
1.38
4
0.63
2.62
0.88
1.5
0.84
0.88
2.06
*
3⁄4
4.62
0.62
1.69
4
0.75
3.25
1.09
1.88
1.05
1.00
2.25
*
1
4.88
0.69
2.00
4
0.75
3.50
1.36
2.12
1.32
1.06
2.44
*
11⁄4
5.25
0.81
2.50
4
0.75
3.88
1.70
2.50
1.66
1.12
2.62
*
11⁄2
6.12
0.88
2.88
4
0.88
4.50
1.95
2.75
1.90
1.25
2.75
*
2
6.50
1.00
3.62
8
0.75
5.00
2.44
3.31
2.38
1.44
2.88
*
21⁄2
7.50
1.12
4.12
8
0.88
5.88
2.94
3.94
2.88
1.62
3.12
*
3
8.25
1.25
5.00
8
0.88
6.62
3.57
4.62
3.50
1.81
3.25
*
31⁄2
9.00
1.38
5.50
8
1.00
7.25
4.07
5.25
4.00
1.94
3.38
*
4
10.00
1.38
6.19
8
1.00
7.88
4.57
5.75
4.50
2.00
3.50
*
5
11.00
1.50
7.31
8
1.00
9.25
5.66
7.00
5.56
2.12
4.00
*
6
12.50
1.62
8.50
12
1.00
10.62
6.72
8.12
6.63
2.25
4.06
*
8
15.00
1.88
10.62
12
1.12
13.00
8.72
10.25
8.63
2.69
4.62
*
10
17.50
2.12
12.75
16
1.25
15.25
10.88
12.62
10.75
2.88
4.88
*
12
20.50
2.25
15.00
16
1.38
17.75
12.88
14.75
12.75
3.12
5.38
*
14
23.00
2.38
16.25
20
1.38
20.25
14.14
16.75
14.00
3.31
5.88
*
16
25.50
2.50
18.50
20
1.50
22.50
16.16
19.00
16.00
3.69
6.00
*
18
28.00
2.62
21.00
24
1.50
24.75
18.18
21.00
18.00
3.88
6.50
*
20
30.50
2.75
23.12
24
1.62
27.00
20.20
23.12
20.00
4.00
6.62
*
22
33.00
2.88
25.25
24
1.75
29.25
22.22
25.25
22.00
4.25
6.75
*
24
36.00
3.00
27.25
24
1.88
32.00
24.25
27.62
24.00
4.50
6.88
*

ASME B16.5 Class 600 Blind Flange Dimensions, ANSI B16.5 Class 600 Flange Dimensions

Nominal Size
Outside Diameter
(OD)
Min. Thickness
(T)
RF Dia.
(R)
No. of Bolt Holes
Diameter of Holes
Bolt Circle
(BC)
SO Bore ID 
(SB)
Dia. Hub Base 
(HB)
Dia. Hub Top 
(HT)
SO LTH
(SL)
WN LTH 
(WL)
* WN Bore ID 
(WB)
1⁄2
3.75
0.56
1.38
4
0.63
2.62
0.88
1.50
0.84
0.88
2.06
*
3⁄4
4.62
0.62
1.69
4
0.75
3.25
1.09
1.88
1.05
1.00
2.25
*
1
4.88
0.69
2.00
4
0.75
3.50
1.36
2.12
1.32
1.06
2.44
*
11⁄4
5.25
0.81
2.50
4
0.75
3.88
1.70
2.50
1.66
1.12
2.62
*
11⁄2
6.12
0.88
2.88
4
0.88
4.50
1.95
2.75
1.90
1.25
2.75
*
2
6.50
1.00
3.62
8
0.75
5.00
2.44
3.31
2.38
1.44
2.88
*
21⁄2
7.50
1.12
4.12
8
0.88
5.88
2.94
3.94
2.88
1.62
3.12
*
3
8.25
1.25
5.00
8
0.88
6.62
3.57
4.62
3.50
1.81
3.25
*
31⁄2
9.00
1.38
5.50
8
1.00
7.25
4.07
5.25
4.00
1.94
3.38
*
4
10.75
1.50
6.19
8
1.00
8.50
4.57
6.00
4.50
2.12
4.00
*
5
13.00
1.75
7.31
8
1.12
10.50
5.66
7.44
5.56
2.38
4.50
*
6
14.00
1.88
8.50
12
1.12
11.50
6.72
8.75
6.63
2.62
4.62
*
8
16.50
2.19
10.62
12
1.25
13.75
8.72
10.75
8.63
3.00
5.25
*
10
20.00
2.50
12.75
16
1.38
17.00
10.88
13.50
10.75
3.38
6.00
*
12
22.00
2.62
15.00
20
1.38
19.25
12.88
15.75
12.75
3.62
6.12
*
14
23.75
2.75
16.25
20
1.50
20.75
14.14
17.00
14.00
3.69
6.50
*
16
27.00
3.00
18.50
20
1.63
23.75
16.16
19.50
16.00
4.19
7.00
*
18
29.25
3.25
21.00
20
1.75
25.75
18.18
21.50
18.00
4.62
7.25
*
20
32.00
3.50
23.00
24
1.75
28.50
20.20
24.00
20.00
5.00
7.50
*
22
34.25
3.75
25.25
24
1.88
30.63
22.22
26.25
22.00
5.25
7.75
*
24
37.00
4.00
27.25
24
2.00
33.00
24.25
28.25
24.00
5.50
8.00
*

ANSI B16.5 Class 900 Flange Dimensions

Nominal Size
Outside Diameter
(OD)
Min. Thickness
(T)
RF Dia.
(R)
No. of Bolt Holes
Diameter of Holes
Bolt Circle
(BC)
SO Bore ID 
(SB)
* WN Bore ID 
(WB)
Dia. Hub Base 
(HB)
Dia. Hub Top 
(HT)
SO LTH
(SL)
WN LTH 
(WL)
3
9.50
1.50
5.00
8
1.00
7.50
3.57
*
5.00
3.50
2.12
4.00
4
11.50
1.75
6.19
8
1.25
9.25
4.57
*
6.25
4.50
2.75
4.50
5
13.75
2.00
7.31
8
1.38
11.00
5.66
*
7.50
5.56
3.12
5.00
6
15.00
2.19
8.50
12
1.25
12.50
6.72
*
9.25
6.63
3.38
5.50
8
18.50
2.50
10.63
12
1.50
15.50
8.72
*
11.75
8.63
4.00
6.38
10
21.50
2.75
12.75
16
1.50
18.50
10.88
*
14.50
10.75
4.25
7.25
12
24.00
3.12
15.00
20
1.50
21.00
12.88
*
16.50
12.75
4.63
7.88
14
25.25
3.38
16.25
20
1.63
22.00
14.14
*
17.75
14.00
5.12
8.38
16
27.75
3.50
18.50
20
1.75
24.25
16.16
*
20.00
16.00
5.25
8.50
18
31.00
4.00
21.00
20
2.00
27.00
18.18
*
22.25
18.00
6.00
9.00
20
33.75
4.25
23.00
20
2.13
29.50
20.20
*
24.50
20.00
6.25
9.75
24
41.00
5.50
27.25
20
2.63
35.50
24.25
*
29.50
24.00
8.00
11.50

ANSI B16.5 Class 1500 Flange Dimensions

Nominal Size
Outside Diameter
(OD)
Min. Thickness
(T)
RF Dia.
(R)
No. of Bolt Holes
Diameter of Holes
Bolt Circle
(BC)
So Bore ID 
(SB)
Dia. Hub Base 
(HB)
Dia. Hub Top 
(HT)
SO LTH
(SL)
WN LTH 
(WL)
* WN Bore ID 
(WB)
1⁄2
4.75
0.88
1.38
4
0.88
3.25
0.88
1.50
0.84
1.25
2.38
*
3⁄4
5.12
1.00
1.69
4
0.88
3.50
1.09
1.75
1.05
1.38
2.75
*
1
5.88
1.12
2.00
4
1.00
4.00
1.36
2.06
1.32
1.62
2.88
*
11⁄4
6.25
1.12
2.50
4
1.00
4.38
1.70
2.50
1.66
1.62
2.88
*
11⁄2
7.00
1.25
2.88
4
1.12
4.88
1.95
2.75
1.90
1.75
3.25
*
2
8.50
1.50
3.63
8
1.00
6.50
2.44
4.12
2.38
2.25
4.00
*
21⁄2
9.62
1.62
4.13
8
1.12
7.50
2.94
4.88
2.88
2.50
4.12
*
3
10.50
1.88
5.00
8
1.25
8.00
–
5.25
3.50
–
4.62
*
4
12.25
2.12
6.19
8
1.38
9.50
–
6.38
4.50
–
4.88
*
5
14.75
2.88
7.31
8
1.63
11.50
–
7.75
5.56
–
6.12
*
6
15.50
3.25
8.50
12
1.50
12.50
–
9.00
6.63
–
6.75
*
8
19.00
3.62
10.63
12
1.75
15.50
–
11.50
8.63
–
8.38
*
10
23.00
4.25
12.75
12
2.00
19.00
–
14.50
10.75
–
10.00
*
12
26.50
4.88
15.00
16
2.12
22.50
–
17.75
12.75
–
11.12
*
14
29.50
5.25
16.25
16
2.38
25.00
–
19.50
14.00
–
11.75
*
16
32.50
5.75
18.50
16
2.63
27.75
–
21.75
16.00
–
12.25
*
18
36.00
6.38
21.00
16
2.88
30.50
–
23.50
18.00
–
12.88
*
20
38.75
7.00
23.00
16
3.12
32.75
–
25.25
20.00
–
14.00
*
24
46.00
8.00
27.25
16
3.63
39.00
–
30.00
24.00
–
16.00
*

ASME B16.5 Class 2500 Flange Dimensions

Nominal Size
Outside Diameter 
(OD)
Min. Thickness
(T)
RF Dia.
(R)
No. of Bolt Holes
Diameter of Holes
Bolt Circle
(BC)
Dia. Hub Base 
(HB)
Dia. Hub Top 
(HT)
SO LTH
(SL)
WN LTH 
(WL)
* WN Bore ID 
(WB)
1⁄2
5.25
1.19
1.38
4
0.88
3.50
1.69
0.84
1.56
2.88
*
3⁄4
5.50
1.25
1.69
4
0.88
3.75
2.00
1.05
1.69
3.12
*
1
6.25
1.38
2.00
4
1.00
4.25
2.25
1.32
1.88
3.50
*
11⁄4
7.25
1.50
2.50
4
1.12
5.13
2.88
1.66
2.06
3.75
*
11⁄2
8.00
1.75
2.88
4
1.25
5.75
3.12
1.90
2.38
4.38
*
2
9.25
2.00
3.63
8
1.12
6.75
3.75
2.38
2.75
5.00
*
21⁄2
10.50
2.25
4.13
8
1.25
7.75
4.50
2.88
3.12
5.62
*
3
12.00
2.62
5.00
8
1.38
9.00
5.25
3.50
–
6.62
*
4
14.00
3.00
6.19
8
1.63
10.75
6.50
4.50
–
7.50
*
5
16.50
3.62
7.31
8
1.88
12.75
8.00
5.56
–
9.00
*
6
19.00
4.25
8.50
8
2.12
14.50
9.25
6.63
–
10.75
*
8
21.75
5.00
10.63
12
2.12
17.25
12.00
8.63
–
12.50
*
10
26.50
6.50
12.75
12
2.63
21.25
14.75
10.75
–
16.50
*
12
30.00
7.25
15.00
12
2.88
24.38
17.38
12.75
–
18.25
*

ANSI B16.5 Flange Pressure Ratings

ANSI Class
150
300
400
600
900
1500
2500
Temperature oF
Maximum Allowable Non-Shock Pressure PSIG
-20 to 100
285
740
985
1480
2220
3705
6170
200
260
680
905
1360
2035
3395
5655
300
230
655
870
1310
1965
3270
5450
400
200
635
845
1265
1900
3170
5280
500
170
605
805
1205
1810
3015
5025
600
140
570
755
1135
1705
2840
4730
650
125
550
730
1100
1650
2745
4575
700
110
530
710
1060
1590
2655
4425
750
95
505
675
1015
1520
2535
4230
800
80
410
550
825
1235
2055
3430
850
65
320
425
535
640
955
2655
900
50
230
305
460
690
1150
1915
950
35
135
185
275
410
685
1145
1000
20
85
115
170
255
430
715

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