Inclusive Guide to Flange Dimensions and Specifications

Precision Hose & Expansion Joints provides easy-to-understand information about various flange dimensions for use in specific areas. This page is a useful source for engineers, contractors, and anyone engaged in the flanges business to detail specifications of flanges. A flange is used extensively for joining pipes, valves, pumps, and other fittings, and to guarantee the proper connection without leakage. This guide is aimed at such types of flanges as mil-spec flanges (military specifications) the aim of which is to meet high standards which are typical of the military and aerospace industries.

The pipe flange size chart provided on this page has seamlessly categorized pipe flanges along with detailed measures so it does not take much to find the right one for a particular application. Due to the differences in the flange sizes depending on the pressure class and standard, the chart enables the users to get the appropriate solution for their projects. Each dimension is carefully listed showing bolt holes, outer diameter, thickness, and other relevant information that users may need to apply in the installation of these types of conduits.

Whether for new construction, repair, or maintenance this flange standard guide eases the selection process. This flange allows for the ASME targets to be met safely since the page ensures that the flange connections meet the necessary standards. The Precision Hose & Expansion Joints mirrors its slogan of precision and accuracy by offering important technical information to individuals and companies in the industry who require only the finest of materials for hose assemblies and expansion joints. To anyone who requires standard sizes of flanges for piping systems, this page provides accurate dimensions of flanges that would be suitable for the system in question.

Nominal Pipe Size 25/125/150 LB. DRILLING 250/300 LB. DRILLING NAVY DRILLING
COMMON SIZE BOLT HOLE DIAMETER
Drilling Column
   
O.D. B.C. DIA. No. B.H. 1 2 3 4 O.D. B.C. DIA. No. B.H. B.H. DIA. O.D. B.C. DIA. No. B.H. B.H. DIA.
1/4 2-1/2 1-11/16 4 7/16 3-1/4 2-1/8 3 9/16
3/8 2-1/2 1-11/16 4 7/16 3-3/8 2-1/4 3 9/16
1/2 3-1/2 2-3/8 4 5/8 5/8 3-3/4 2-5/8 4 5/8 3-9/16 2-7/16 3 9/16
3/4 3-7/8 2-3/4 4 5/8 5/8 4-5/8 3-1/4 4 3/4 3-13/16 2-11/16 4 9/16
1 4-1/4 3-1/8 4 5/8 5/8 4-7/8 3-1/2 4 3/4 4-1/4 3-1/8 4 9/16
1-1/4 4-5/8 3-1/2 4 5/8 5/8 5-1/4 3-7/8 4 3/4 4-1/2 3-3/8 4 9/16
1-1/2 5 3-7/8 4 5/8 5/8 6-1/8 4-1/2 4 7/8 5-1/16 3-15/16 6 9/16
2 6 4-3/4 4 3/4 3/4 6-1/2 5 8 3/4 5-9/16 4-7/16 6 9/16
2-1/2 7 5-1/2 4 3/4 3/4 7-1/2 5-7/8 8 7/8 6-1/8 5 6 9/16
3 7-1/2 6 4 3/4 3/4 8-1/4 6-5/8 8 7/8 6-5/8 5-1/2 8 9/16
3-1/2 8-1/2 7 8 3/4 3/4 9 7-1/4 8 7/8 7-3/16 6-1/16 8 9/16
4 9 7-1/2 8 3/43/4 3/4 3/410 7-7/8 8 7/8 7-11/16 6-9/16 8 9/16
4-1/2                     8-3/16 7-1/16 10 9/16
5 10 8-1/2 8 7/83/4 7/8 3/411 9-1/4 8 7/8 9-1/16 7-13/16 10 11/16
5-1/2                      9-9/16 8-5/16 10 11/16
6 11 9-1/2 8 7/8 3/4 7/8 3/4 12-1/2 10-5/8 12 7/8 1 0-1/8 8-7/8 12 11/16
6-1/2                       10-5/8 9-3/8 12 11/16
7                       11-5/16 10 12 11/16
7-1/2                       11-7/8 10-9/16 12 11/16
8 13-1/2 11-3/4 8 7/8 3/4 7/8 3/4 15 13 12 1 12-3/8 11-1/16 14 11/16
8-1/2                       12-15/16 11-5/8 14 11/16
9                       13-15/16 12-3/8 14 13/16
9-1/2                       14-1/2 12-15/16 14 13/16
10 16 14-1/4 12 1 3/4 1 3/4 17-1/2 15-1/4 16 1-1/8 15 13-7/16 15 13/16
11                       16-9/16 15 16 13/16
12 19 17 12 1 3/4 1 3/4 20-1/2 17-3/4 16 1-1/4 17-5/8 16-1/16 18 13/16
14 21 18-3/4 12 1-1/8 7/8 1-1/8 7/8 23 20-1/4 20 1-1/4 19-1/8 17-3/8 19 15/16
16 23-1/2 21-1/4 16 1-1/8 7/8 1-1/8 7/8 25-1/2 22-1/2 20 1-3/8 21-3/16 19-7/16 20 15/16
18 25 22-3/4 16 1-1/4 7/8 1-1/4 7/8 28 24-3/4 24 1-3/8 23-1/4 21-1/2 22 15/16
20 27-1/2 25 20 1-1/4 7/8 1-1/4 7/8 30-1/2 27 24 1-3/8 25-13/16 23-13/16 24 1-1/16
22 29-1/2 27-1/4 20     1-3/8 7/8 33 29-1/4 24 1-5/8 27-7/8 25-7/8 26 1-1/16
24 32 29-1/2 20 1-3/8 7/8 1-3/8 7/8 36 32 24 1-5/8 30 28 28 1-1/16
25                       31-1/2 29-1/4 29 1-3/16
26 34-1/4 31-3/4 24     1-3/8 7/8 38-1/4 34-1/2 28 1-3/4 32-9/16 30-6/16 30 1-3/16
28 36-1/2 34 28     1-3/8 7/8 40-3/4 37 28 1-3/4 34-11/16 32-7/16 32 1-3/16
30 38-3/4 36 28 1-3/8 1 1-3/8 1 43 39-1/4 28 2* 36-13/16 34-9/16 35 1-3/16
32 41-3/4 38-1/2 28     1-5/8 1 45-1/4 41-1/2 28 2 39 36-3/4 36 1-3/16
33                       40 37-3/4 36 1-3/16
34 43-3/4 40-1/2 32 1-5/8 1 47-1/2 43-1/2 28 2 41 38-3/4 36 1-3/16
35                   42-7/8 40-3/8 36 1-5/16
36 46 42-3/4 32 1-5/8 1 1-5/8 1 50 46 32 2-1/4* 43-7/8 41-3/8 36 1-5/16
38 48-3/4 45-1/4 32     1-5/8 1 56 43 32 1-5/8 46-1/8 43-5/8 36 1-5/16
40 50-3/4 47-1/4 36 1-5/8 1-1/8 1-5/8 1 48-3/4 45-1/2 32 1-3/4 48-1/8 45-5/8 36 1-5/16
42 53 49-1/2 36 1-5/8 1-1/8 57* 52-3/4* 36* 2-1/4* 50-1/4 47-3/4 38 1-5/16
44 55-1/4 51-3/4 40 1-5/8 1-1/8 53-1/4 49-3/4 32 1-5/8        
46 57-1/4 53-3/4 40 1-5/8 1-1/8 55-3/4 52 28 2 54-1/2 52 40 1-5/16
48 59-1/2 56 44 1-5/8 1-1/8 1-5/8 1-1/8 65* 60-3/4* 40* 2-1/4*
Specifications: 25/125/150 LB. DRILLING
ANSI B16.1-1975 Class 25 – 2
ANSI B15.1-1975 Class 125 – 1
ANSI B16.24-1971 – 1
ANSI B16.5 Class 125/150 – 3
AWWA C207-78
Tbl 1 & 2, Class D, Tbl 3, Class E – 3
AWW C207-78 Tbl 1 & 2, Class B – 4
MSS SP-44 1975 Class 150 – 1
SS SP-51 1965 MSS 150# – 1
Specifications: 250/300 LB. DRILLING
ANSI B16.1-1975 Class 250
ANSI B16.24-1971 300 lb.
ANSI B16.5-1973 Class 300
MSS SP-44-1975 Class 300
Specifications: NAVY DRILLING
MIL-F-20042C – 50 lb.
MIL-F-20042C – 150 lb.
BU Ships Drawing B.176
PN Flange Specifications
Nominal PN6 PN10 PN16 PN25 PN40
O.D. B.C. DIA. No. B.H. B.H. DIA. O.D. B.C. DIA. No. B.H. B.H. DIA. O.D. B.C. DIA. No. B.H. B.H. DIA. O.D. B.C. DIA. No. B.H. B.H. DIA. O.D. B.C. DIA. No. B.H. B.H. DIA.
DN 25 3.94 2.95 4 0.55 4.53 3.35 4 0.55 4.53 3.35 4 0.55 4.53 3.35 4 0.55 4.53 3.35 4 0.55
DN 32 4.72 3.54 4 0.55 5.51 3.94 4 0.71 5.51 3.94 4 0.71 5.51 3.94 4 0.71 5.51 3.94 4 0.71
DN 40 5.12 3.94 4 0.55 5.91 4.33 4 0.71 5.91 4.33 4 0.71 5.91 4.33 4 0.71 5.91 4.33 4 0.71
DN 50 5.51 4.33 4 0.55 6.50 4.92 4 0.71 6.50 4.92 4 0.71 6.50 4.92 4 0.71 6.50 4.92 4 0.71
DN 65 6.30 5.12 4 0.55 7.28 5.71 4 0.71 7.28 5.71 4 0.71 7.28 5.71 8 0.71 7.28 5.71 8 0.71
DN 80 7.48 5.91 4 0.71 7.87 6.30 8 0.71 7.87 6.30 8 0.71 7.87 6.30 8 0.71 7.87 6.30 8 0.71
DN 100 8.27 6.69 4 0.71 8.66 7.09 8 0.71 8.66 7.09 8 0.71 9.25 7.48 8 0.87 9.25 7.48 8 0.87
DN 125 9.45 9.45 8 0.71 9.84 9.84 8 0.71 9.84 9.84 8 0.71 10.63 10.63 8 1.02 10.63 10.63 8 1.02
DN 150 10.43 8.86 8 0.71 11.22 9.45 8 0.87 11.22 9.45 8 0.87 11.81 9.84 8 1.02 11.81 9.84 8 1.02
DN 175 ---- ---- ---- ---- 12.40 10.63 8 0.87 12.40 10.63 8 0.87 12.99 11.02 12 1.02 13.78 11.61 12 1.18
DN 200 12.60 11.20 8 0.71 13.39 11.61 8 0.87 13.39 11.61 12 0.87 14.17 12.20 12 1.02 14.76 12.60 12 1.18
DN 250 14.76 13.19 12 0.71 15.55 13.78 12 0.87 15.94 13.98 12 1.02 16.73 14.57 12 1.18 17.72 15.16 12 1.30
DN 300 17.32 15.55 12 0.87 17.52 15.75 12 0.87 18.11 16.14 12 1.02 19.09 16.93 16 1.18 20.28 17.72 16 1.30
DN 350 19.29 17.52 12 0.87 19.88 18.11 16 0.87 20.47 18.50 16 1.02 21.85 19.29 16 1.30 22.83 20.08 16 1.42
DN 400 21.26 19.49 16 0.87 22.24 20.28 161.02 22.83 20.67 16 1.18 24.41 21.65 16 1.42 25.98 23.03 16 1.54
DN 500 25.39 23.62 20 0.87 26.38 24.41 20 1.02 28.15 25.59 20 1.30 28.74 25.98 20 1.42 29.72 26.38 20 1.65
DN 600 29.72 27.76 20 0.94 30.71 28.54 20 1.06 33.07 30.31 20 1.30 33.27 30.31 20 1.42 ---- ---- ---- ----

Precision Hose and Expansion Joints can also furnish standards: API Standard 605, British Standard 10:1962, DIN 2633 and ISO 2084 + 2536, and others standards on request.