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- ISO 9001 - 2015 Certified
- PED 2014/68/EC
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- NACE MR0175/ISO 15156-2
- NORSOK M-650
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- MERKBLATT AD 2000 W2/W7/W10
ASME B16.5 Pipe Flange Dimensions and Pressure Ratings
Dimensions, Classes, and Pressure Ratings for Pipe Flanges
For 316 stainless flange-bolt material, see ASTM A193 B8M Class 1 (sour-service qualified), Class 2 (higher preload), or the ASME SA-193 equivalent.
ASME B16.5 Standard defines the dimensions, pressure classes, and specifications for pipe flanges and flanged fittings used in piping systems. It covers flange types, bolt patterns, pressure-temperature ratings, and facing dimensions. Here, you will find complete ASME B16.5 flange dimensions, pressure class tables, and technical data for piping design and installation.
Pipe Flange Dimensions and Pressure Class Ratings
ASME B16.5 Pipe Flange Dimensions (mm)
| Nominal Size | Diameter, D | Chamfered Thread Distance, U | |||||
|---|---|---|---|---|---|---|---|
| UNC Threads | UNF Threads | 8UN Threads | |||||
| Min. | Max. | Min. | Max. | Min. | Max. | ||
| 1/4 | 6.350 | 1.270 | 2.540 | 0.914 | 1.803 | … | … |
| 5/16 | 7.938 | 1.422 | 2.819 | 1.067 | 2.108 | … | … |
| 3/8 | 9.525 | 1.600 | 3.175 | 1.067 | 2.108 | … | … |
| 7/16 | 11.113 | 1.829 | 3.632 | 1.270 | 2.540 | … | … |
| 1/2 | 12.700 | 1.956 | 3.912 | 1.270 | 2.540 | … | … |
| 9/16 | 14.288 | 2.134 | 4.242 | 1.422 | 2.819 | … | … |
| 5/8 | 15.875 | 2.311 | 4.623 | 1.422 | 2.819 | … | … |
| 3/4 | 19.050 | 2.540 | 5.080 | 1.600 | 3.175 | … | … |
| 7/8 | 22.225 | 2.819 | 5.639 | 1.829 | 3.632 | … | … |
| 1 | 25.400 | 3.175 | 6.350 | 2.134 | 4.242 | … | … |
| 1 1/8 | 28.575 | 3.632 | 7.264 | 2.134 | 4.242 | 3.175 | 6.350 |
| 1 1/4 | 31.750 | 3.632 | 7.264 | 2.134 | 4.242 | 3.175 | 6.350 |
| 1 3/8 | 34.925 | 4.242 | 8.458 | 2.134 | 4.242 | 3.175 | 6.350 |
| 1 1/2 | 38.100 | 4.242 | 8.458 | 2.134 | 4.242 | 3.175 | 6.350 |
| 1 5/8 | 41.275 | … | … | … | … | 3.175 | 6.350 |
| 1 3/4 | 44.450 | 5.080 | 10.160 | … | … | 3.175 | 6.350 |
| 1 7/8 | 47.625 | … | … | … | … | 3.175 | 6.350 |
| 2 | 50.800 | 5.639 | 11.278 | … | … | 3.175 | 6.350 |
| 2 1/4 | 57.150 | 5.639 | 11.278 | … | … | 3.175 | 6.350 |
| 2 1/2 | 63.500 | 6.350 | 12.700 | … | … | 3.175 | 6.350 |
| 2 3/4 | 69.850 | 6.350 | 12.700 | … | … | 3.175 | 6.350 |
| 3 | 76.200 | 6.350 | 12.700 | … | … | 3.175 | 6.350 |
| 3 1/4 | 82.550 | 6.350 | 12.700 | … | … | 3.175 | 6.350 |
| 3 1/2 | 88.900 | 6.350 | 12.700 | … | … | 3.175 | 6.350 |
| 3 3/4 | 95.250 | 6.350 | 12.700 | … | … | 3.175 | 6.350 |
| 4 | 101.600 | 6.350 | 12.700 | … | … | 3.175 | 6.350 |
ASME B16.5 Pipe Flange Dimensions Length Tolerances (mm)
| Range, LT | Tolerance |
|---|---|
| From 19.05 through 63.5 | ±1.016 |
| Over 63.5 through 101.6 | ±2.032 |
| Over 101.6 through 203.2 | ±2.540 |
| Over 203.2 through 406.4 | ±3.048 |
| Over 406.4 | ±4.572 |
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