ASME B16.5 blind flange is well suited to be used for higher pressure temperature applications. Apart from several aspects covered by this standard such as pressure-temperature ratings, materials, Carbon Steel BLRF Flange Dimensions, tolerances, marking, testing, and methods of designating openings. The ASME B16.5 standard also takes into account requirements and recommendations regarding flanges gaskets, flanges bolting, and flanges joints.
Specification of ASME B16.5 Blind Flange
Blind flanges manufactured in accordance with ASME B16.5 can be provided in Class 150 through Class 2500. It is basically a circular disc that does not have a hub or bored center. Bolts holes are drilled and aligned symmetrically along the circumferential edge of the solid disc. Whereas the Blind Flange is produced in sizes NPS 1/2 through NPS 24, with the requirements of these flanges mentioned in both metric and U.S units.
Size Range:1/2″- 24″/ DN15 – DN600
Pressure:CLASS 150/CLASS 300/CLASS 600/CLASS 900/CLASS 1500/Class2500
Materials:ASTM A105/ASTM A350 LF2; ASTM A694 F42 / 46 / 56 / 60 / 65; STM A182 F11 / 22 / 5 / 9 / 91; ASTM A182 F304/304L/304H/316/316L/310S/904L/F51
Manufacturing standards: ASME B16.5
Sealing Face: RF, FF, RTJ, LMF, SMF
Material for Blind Flange
We are specialized in various steel flanges, the materials including carbon steel, alloy steel and stainless steel.
| Carbon Steel | ASTM A105 / A105N, ASTM A350 LF2/LF3, ASTM A694 F42 / 46 / 56 / 60 / 65, P235GH, P265GH, P280GH, P355GH |
| Alloy Steel | ASTM A182 F11 / 12 / 5 / 9 / 91 / 92 |
| Stainless Steel | ASTM A182 F304/304L/304H, 316/316L, 321, 310S, 317,347,904L， 1.4404, 1.4437. |
| Duplex Stainless Steel | ASTM A182 F51, F53, F55 |
Carbon steel flange, that is, the body material is carbon steel plate or end flange connection. Stainless steel flange, also called SS flange, it means the material of flange is stainless steel. Common material standards and Grades are ASTM A182 Grade F304/L and F316/L. It used in more industries than carbon steel. Stainless steel has better resistant performances on corrosion environment and always provides with a good appearance.
Carbon Steel Blind Flange
The chemical composition of ASTM A105 material mainly includes elements such as carbon (C), silicon (Si), manganese (Mn), phosphorus (P), sulfur (S), copper (Cu), nickel (Ni), molybdenum (Mo), vanadium (V), and chromium (Cr), and the content of each element is within a certain range, ensuring the stability and reliability of the material. This balanced chemical composition gives ASTM A105 material excellent mechanical properties and corrosion resistance.
Chemical Composition
| CHEMICAL | LIMITS | C | Mn | P | S | Si | Cu | Ni | Cr | Mo | V |
| ASTM A105 | MIN | 0.60 | 0.10 | ||||||||
| MAX | 0.35 | 1.05 | 0.035 | 0.040 | 0.35 | 0.40 | 0.40 | 0.30 | 0.12 | 0.08 |
Mechanical Properties
| MATERIAL | T.S (MPA) | Y.S (MPA) | EL % | R/A % |
| ASTM A105 | 485 min | 250 min | 22 min | 30 min |
ASTM A182 F304 BL Flange
ASTM A182 F304 BL flanges are made up of a chromium nickel austenitic stainless steel. The material has carbon, manganese, phosphorus, silicon, sulfur with 18% chromium and 8% nickel in the composition. ZIZI Engineering is a leading manufacturer and supplier of the ASTM A182 F304 flanges in various types and sizes.
Chemical Composition
| CHEMICAL | LIMITS | C | Mn | P | S | Si | Ni | Cr | N |
| ASTM A182 F304 | MIN | 8.00 | 18.00 | ||||||
| MAX | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 11.00 | 20.00 | 0.10 |
Mechanical Properties
| MATERIAL | T.S (MPA) | Y.S (MPA) | EL % | R/A % |
| ASTM A182 F304 | 515 min | 205 min | 30 min | 50 min |
ASTM A182 F51 Forged Blind Flange
ASTM A182 F51 forged blind flange is made up of a duplex steel material. The material has both ferritic and austenitic qualities in the metallurgic microstructure. The tensile strength of the material is 620MPa and the minimum yield strength is 450MPa.
Chemical Composition
| CHEMICAL | LIMITS | C | Mn | P | S | Si | Ni | Cr | Mo | N | Cu |
| ASTM A182 F51 | MIN | 4.50 | 21.00 | 2.50 | 0.08 | ||||||
| MAX | 0.03 | 2.00 | 0.030 | 0.020 | 1.00 | 6.50 | 23.00 | 3.50 | 0.20 |
Mechanical Properties
| MATERIAL | T.S (MPA) | Y.S (MPA) | EL % | R/A % |
| ASTM A182 F51 | 620 min | 450 min | 35 min | 45 min |
How to Inspection of ASME B16.5 Blind Flange
During the dimensional inspection of the flange, you should check for the following;
Outer Diameter of body
Bolt Circle & Bolt hole Diameter
Straightness and alignment of the bolt hole
The thickness of the Blind
BL Flange Dimension and Weight
Blind flange dimensions are covered in ASME B16.5 – which covers Pipe Flanges and Flanged Fittings for size NPS 1/2” to 24” for above NPS 26” to 60” it should be as per ASME B16.47.
Class 150
| Nominal Pipe Size | A | C | G | H | I | J | Weight | |
| inch | mm | mm | mm | mm | Number of Holes |
mm | mm | kg/piece |
| 1/2 | 21.3 | 88.9 | 11.2 | 35. 10 | 4 | 15.7 | 60.45 | 0.42 |
| 3/4 | 26.7 | 98.6 | 12.7 | 42.9 | 4 | 15.7 | 69.85 | 0.61 |
| 1 | 33.4 | 108 | 14.2 | 50.8 | 4 | 15.7 | 79.25 | 0.86 |
| 11/4 | 42.2 | 117.3 | 15.7 | 63.5 | 4 | 15.7 | 88.9 | 1.17 |
| 11/2 | 48.3 | 127 | 17.5 | 73. 15 | 4 | 15.7 | 98.6 | 1.53 |
| 2 | 60.3 | 152.4 | 19. 10 | 91.9 | 4 | 19.1 | 120.7 | 2.42 |
| 21/2 | 73.0 | 177.8 | 22.4 | 104.6 | 4 | 19.1 | 139.7 | 3.94 |
| 3 | 88.9 | 190.5 | 23.9 | 127 | 4 | 19.1 | 152.4 | 4.93 |
| 31/2 | 101.6 | 215.9 | 23.9 | 139.7 | 8 | 19.1 | 177.8 | 6.17 |
| 4 | 114.3 | 228.6 | 23.9 | 157.2 | 8 | 19.1 | 190.5 | 7.00 |
| 5 | 141.3 | 254 | 23.9 | 185.7 | 8 | 22.4 | 215.9 | 8.63 |
| 6 | 168.3 | 279.4 | 25.4 | 215.9 | 8 | 22.4 | 241.3 | 11.3 |
| 8 | 219.1 | 342.9 | 28.4 | 269.7 | 8 | 22.4 | 298.5 | 19.6 |
| 10 | 273.0 | 406.4 | 30.2 | 323.9 | 12 | 25.4 | 362 | 28.8 |
| 12 | 323.8 | 482.6 | 31.75 | 381 | 12 | 25.4 | 431.8 | 43.2 |
| 14 | 355.6 | 533.4 | 35. 10 | 412.8 | 12 | 28.4 | 476.3 | 58.1 |
| 16 | 406.4 | 596.9 | 36.6 | 469.9 | 16 | 28.4 | 539.8 | 76.0 |
| 18 | 457.2 | 635 | 39.6 | 533.4 | 16 | 31.75 | 577.9 | 93.7 |
| 20 | 508.0 | 698.5 | 42.9 | 584.2 | 20 | 31.75 | 635 | 122 |
| 24 | 609.6 | 812.8 | 47.8 | 692.2 | 20 | 35.1 | 749.3 | 185 |
Class 300
| Nominal Pipe Size | A | C | G | H | I | J | Weight | |
| inch | mm | mm | mm | mm | Number of Holes |
mm | mm | kg/piece |
| 1/2 | 21.3 | 95.2 | 14.2 | 35.1 | 4 | 15.7 | 66.55 | 0.64 |
| 3/4 | 26.7 | 117.3 | 15.7 | 42.9 | 4 | 19 | 82.5 | 1.11 |
| 1 | 33.4 | 123.9 | 17.5 | 50.8 | 4 | 19 | 88.9 | 1.39 |
| 11/4 | 42.2 | 133.3 | 19 | 63.5 | 4 | 19 | 98.5 | 1.79 |
| 11/2 | 48.3 | 155.4 | 20.6 | 73.15 | 4 | 22.3 | 114.3 | 2.66 |
| 2 | 60.3 | 165. 1 | 22.3 | 91.9 | 8 | 19. 10 | 127 | 3.18 |
| 21/2 | 73.0 | 190.5 | 25.4 | 104.6 | 8 | 22.3 | 1.493 | 4.85 |
| 3 | 88.9 | 209.5 | 28.4 | 127 | 8 | 22.3 | 168.1 | 6.81 |
| 31/2 | 101.6 | 228.6 | 30.2 | 139.7 | 8 | 22.3 | 184.1 | 8.71 |
| 4 | 114.3 | 254 | 31.7 | 157.2 | 8 | 22.3 | 200.1 | 11.5 |
| 5 | 141.3 | 279.4 | 35 | 185.7 | 8 | 22.3 | 234.9 | 15.6 |
| 6 | 168.3 | 317.5 | 36.5 | 215.9 | 12 | 22.3 | 269.7 | 20.9 |
| 8 | 219. 1 | 381 | 41.10 | 269.7 | 12 | 25.4 | 330.2 | 34.3 |
| 10 | 273.0 | 444.5 | 47.7 | 323.9 | 16 | 28.4 | 387.3 | 53.3 |
| 12 | 323.8 | 520.7 | 50.8 | 381 | 16 | 31.7 | 450.8 | 78.8 |
| 14 | 355.6 | 584.2 | 53.8 | 412.8 | 20 | 31.7 | 514.3 | 105 |
| 16 | 406.4 | 647.7 | 57.15 | 469.9 | 20 | 35 | 571.5 | 137 |
| 18 | 457.2 | 711.2 | 60.45 | 533.4 | 24 | 35 | 628.6 | 175 |
| 20 | 508.0 | 774.7 | 63.5 | 584.2 | 24 | 35 | 685.8 | 221 |
| 24 | 609.6 | 914.4 | 69.85 | 692.2 | 24 | 41. 10 | 812.8 | 339 |
Class 400
| Nominal Pipe Size | A | C | G | H | I | J | Weight | |
| inch | mm | mm | mm | mm | Number of Holes |
mm | mm | kg/piece |
| 1/2 | 21.3 | 95.2 | 14.2 | 35. 10 | 4 | 15.7 | 66.55 | 0.76 |
| 3/4 | 26.7 | 117.3 | 15.7 | 42.9 | 4 | 19.1 | 82.6 | 1.28 |
| 1 | 33.4 | 123.9 | 17.5 | 50.8 | 4 | 19.1 | 88.9 | 1.60 |
| 11/4 | 42.2 | 133.3 | 20.6 | 63.5 | 4 | 19.1 | 98.6 | 2.23 |
| 11/2 | 48.3 | 155.4 | 22.3 | 73. 15 | 4 | 22.4 | 114.3 | 3.25 |
| 2 | 60.3 | 165.1 | 25.4 | 91.9 | 8 | 19.1 | 127 | 4.15 |
| 21/2 | 73 | 190.5 | 28.4 | 104.6 | 8 | 22.4 | 149.4 | 6.13 |
| 3 | 88.9 | 209.5 | 31.7 | 127 | 8 | 22.4 | 168.1 | 8.44 |
| 31/2 | 101.6 | 228.6 | 35 | 139.7 | 8 | 25.4 | 184.2 | 11.0 |
| 4 | 114.3 | 254 | 35. 10 | 157.2 | 8 | 25.4 | 200.2 | 13.7 |
| 5 | 141.3 | 279.4 | 38. 10 | 185.7 | 8 | 25.4 | 235 | 18.5 |
| 6 | 168.3 | 317.5 | 41. 10 | 215.9 | 12 | 25.4 | 269.7 | 25.5 |
| 8 | 219.1 | 381 | 47.8 | 269.7 | 12 | 28.4 | 330.2 | 42.6 |
| 10 | 273 | 444.5 | 53.8 | 323.9 | 16 | 31.75 | 387.4 | 64.5 |
| 12 | 323.8 | 520.7 | 57. 15 | 381 | 16 | 35.1 | 450.9 | 94.30 |
| 14 | 355.6 | 584.2 | 60.45 | 412.8 | 20 | 35.1 | 514.4 | 124 |
| 16 | 406.4 | 647.7 | 63.5 | 469.9 | 20 | 38.1 | 571.5 | 162 |
| 18 | 457.2 | 711.2 | 66.55 | 533.4 | 24 | 38.1 | 628.7 | 205 |
| 20 | 508 | 774.7 | 69.85 | 584.2 | 24 | 41.1 | 685.8 | 254 |
| 24 | 609.6 | 914.4 | 76.2 | 692.2 | 24 | 47.8 | 812.8 | 386 |
Class 600
| Nominal Pipe Size | A | C | G | H | I | J | Weight | |
| inch | mm | mm | mm | mm | Holes | mm | mm | kg/ piece |
| 1/2 | 21.3 | 95.2 | 14.2 | 35.1 | 4 | 15.7 | 66.55 | 0.76 |
| 3/4 | 26.7 | 117.3 | 15.7 | 42.9 | 4 | 19. 10 | 82.6 | 1.28 |
| 1 | 33.4 | 123.9 | 17.5 | 50.8 | 4 | 19. 10 | 88.9 | 1.60 |
| 11/4 | 42.2 | 133.3 | 20.6 | 63.5 | 4 | 19. 10 | 98.6 | 2.23 |
| 11/2 | 48.3 | 155.4 | 22.3 | 73.15 | 4 | 22.4 | 114.3 | 3.25 |
| 2 | 60.3 | 165. 1 | 25.4 | 91.9 | 8 | 19. 10 | 127 | 4.15 |
| 21/2 | 73 | 190.5 | 28.4 | 104.6 | 8 | 22.4 | 149.4 | 6.13 |
| 3 | 88.9 | 209.5 | 31.7 | 127 | 8 | 22.4 | 168.1 | 8.44 |
| 31/2 | 101.6 | 228.6 | 35 | 139.7 | 8 | 25.4 | 184.2 | 11.0 |
| 4 | 114.3 | 273. 1 | 38.1 | 157.2 | 8 | 25.4 | 215.9 | 17.3 |
| 5 | 141.3 | 330.2 | 44.5 | 185.7 | 8 | 28.4 | 266.7 | 29.4 |
| 6 | 168.3 | 355.6 | 47.8 | 215.9 | 12 | 28.4 | 292.1 | 36.1 |
| 8 | 219. 1 | 419. 1 | 55.6 | 269.7 | 12 | 31.75 | 349.3 | 58.9 |
| 10 | 273 | 508 | 63.5 | 323.9 | 16 | 35. 10 | 431.8 | 97.5 |
| 12 | 323.8 | 558.8 | 66.55 | 381 | 20 | 35. 10 | 489 | 124 |
| 14 | 355.6 | 603.3 | 69.85 | 412.8 | 20 | 38. 10 | 527.1 | 151 |
| 16 | 406.4 | 685.8 | 76.2 | 469.9 | 20 | 41. 10 | 603.3 | 214 |
| 18 | 457.2 | 743 | 82.6 | 533.4 | 20 | 44.5 | 654.1 | 272 |
| 20 | 508.0 | 812.8 | 88.9 | 584.2 | 24 | 44.5 | 723.9 | 349 |
| 24 | 609.6 | 939.8 | 101.6 | 692.2 | 24 | 50.8 | 838.2 | 533 |
Class 900
| Nominal Pipe Size | A | C | G | H | I | J | Weight | |
| inch | mm | mm | mm | mm | Number of Holes |
mm | mm | kg/piece |
| 1/2 | 21.3 | 120.6 | 22.3 | 35. 10 | 4 | 22.3 | 82.5 | 1.77 |
| 3/4 | 26.7 | 130 | 25.4 | 42.9 | 4 | 22.3 | 88.9 | 2.42 |
| 1 | 33.4 | 149.3 | 28.4 | 50.8 | 4 | 25.4 | 101.6 | 3.57 |
| 11/4 | 42.2 | 158.7 | 28.4 | 63.5 | 4 | 25.4 | 111.2 | 4.15 |
| 11/2 | 48.3 | 177.8 | 31.7 | 73. 15 | 4 | 28.4 | 123.9 | 5.75 |
| 2 | 60.3 | 215.9 | 38. 10 | 91.9 | 8 | 25.4 | 165.1 | 10.1 |
| 21/2 | 73 | 244.3 | 41. 10 | 104.6 | 8 | 28.4 | 190.5 | 14.0 |
| 3 | 88.9 | 241.3 | 38. 10 | 127 | 8 | 25.4 | 190.5 | 13.1 |
| 4 | 114.3 | 292.1 | 44.5 | 157.2 | 8 | 31.7 | 234.9 | 26.9 |
| 5 | 141.3 | 349.2 | 50.8 | 185.7 | 8 | 35 | 279.4 | 36.5 |
| 6 | 168.3 | 381 | 55.6 | 215.9 | 12 | 31.7 | 317 | 47.40 |
| 8 | 219.1 | 469.9 | 63.5 | 269.7 | 12 | 38.1 | 393.7 | 82.5 |
| 10 | 273 | 546.1 | 69.85 | 323.9 | 16 | 38.1 | 469.9 | 122 |
| 12 | 323.8 | 609.6 | 79.25 | 381 | 20 | 38.1 | 533.4 | 173 |
| 14 | 355.6 | 641.3 | 85.8 | 412.8 | 20 | 41.1 | 558.8 | 206 |
| 16 | 406.4 | 704.8 | 88.9 | 469.9 | 20 | 44.4 | 615.9 | 259 |
| 18 | 457.2 | 787.4 | 101.6 | 533.4 | 20 | 50.8 | 685.8 | 367 |
| 20 | 508 | 857.2 | 107.9 | 584.2 | 20 | 53.8 | 749.3 | 463 |
| 24 | 609.6 | 1041.4 | 139.7 | 692.2 | 20 | 66.55 | 901.7 | 876 |
Class 1500
| Nominal Pipe Size | A | C | G | H | I | J | Weight | |
| inch | mm | mm | mm | mm | Number of Holes |
mm | mm | kg/piece |
| 1/2 | 21.3 | 120.6 | 22.3 | 35.1 | 4 | 22.3 | 82.5 | 1.77 |
| 3/4 | 26.7 | 130 | 25.4 | 42.9 | 4 | 22.3 | 88.9 | 2.42 |
| 1 | 33.4 | 149.3 | 28.4 | 50.8 | 4 | 25.4 | 101.6 | 3.57 |
| 11/4 | 42.2 | 158.7 | 28.4 | 63.5 | 4 | 25.4 | 111.2 | 4.15 |
| 11/2 | 48.3 | 177.8 | 31.7 | 73.15 | 4 | 28.4 | 123.9 | 5.75 |
| 2 | 60.3 | 215.9 | 38.1 | 91.9 | 8 | 25.4 | 165.1 | 10.1 |
| 21/2 | 73 | 244.3 | 41.1 | 104.6 | 8 | 28.4 | 190.5 | 14.0 |
| 3 | 88.9 | 266.7 | 47.7 | 127 | 8 | 31.7 | 203.2 | 19.1 |
| 4 | 114.3 | 311.1 | 53.8 | 157.2 | 8 | 35 | 241.3 | 29.9 |
| 5 | 141.3 | 374.6 | 73.15 | 185.7 | 8 | 41.1 | 292.1 | 58.4 |
| 6 | 168.3 | 393.7 | 82.5 | 215.9 | 12 | 38.1 | 317.5 | 71.8 |
| 8 | 219. 1 | 482.6 | 91.9 | 269.7 | 12 | 44.4 | 393.7 | 122 |
| 10 | 273 | 584.2 | 107.9 | 323.9 | 12 | 50.8 | 482.6 | 210 |
| 12 | 323.8 | 673. 1 | 123.9 | 381 | 16 | 53.8 | 571.5 | 316 |
| 14 | 355.6 | 749.3 | 133.3 | 412.8 | 16 | 60.45 | 635 | 420 |
| 16 | 406.4 | 825.5 | 146 | 469.9 | 16 | 66.55 | 704.8 | 558 |
| 18 | 457.2 | 914.4 | 162 | 533.4 | 16 | 73. 15 | 774.7 | 760 |
| 20 | 508 | 984.2 | 177.8 | 584.2 | 16 | 79.25 | 831.8 | 965 |
| 24 | 609.6 | 1168.4 | 203.2 | 692.2 | 16 | 91.9 | 990.6 | 1558 |
Class 2500
| Nominal Pipe Size | A | C | G | H | I | J | Weight | |
| inch | mm | mm | mm | mm | Number of Holes |
mm | mm | kg/piece |
| 1/2 | 21.3 | 133.4 | 30.2 | 35. 10 | 4 | 22.4 | 88.9 | 2.99 |
| 3/4 | 26.7 | 139.7 | 31.7 | 42.9 | 4 | 22.4 | 95.3 | 3.50 |
| 1 | 33.4 | 158.8 | 35. 10 | 50.8 | 4 | 25.4 | 108 | 4.96 |
| 11/4 | 42.2 | 184.2 | 38. 10 | 63.5 | 4 | 28.4 | 130 | 7.35 |
| 11/2 | 48.3 | 203.2 | 44.5 | 73. 15 | 4 | 31.75 | 146.1 | 10.4 |
| 2 | 60.3 | 235 | 50.8 | 91.9 | 8 | 28.4 | 171.5 | 15.6 |
| 21/2 | 73 | 266.7 | 57. 15 | 104.6 | 8 | 31.75 | 196.9 | 22.6 |
| 3 | 88.9 | 304.8 | 66.55 | 127 | 8 | 35.1 | 228.6 | 34.8 |
| 4 | 114.3 | 355.6 | 76.2 | 157.2 | 8 | 41.1 | 273.1 | 53.9 |
| 5 | 141.3 | 419.1 | 91.9 | 185.7 | 8 | 47.88 | 323.9 | 90.8 |
| 6 | 168.3 | 482.6 | 108 | 215.9 | 8 | 53.8 | 368.3 | 141 |
| 8 | 219.1 | 552.5 | 127 | 269.7 | 12 | 53.8 | 438.2 | 214 |
| 10 | 273 | 673.1 | 165.1 | 323.9 | 12 | 66.55 | 539.8 | 411 |
| 12 | 323.8 | 762 | 184.2 | 381 | 12 | 73.15 | 619.3 | 592 |
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