In the Indian Standard for flanges and flanged fittings, fundamental importance is given to different industry piping installation requirements. While Indian Standards have been curated by taking inspiration from the British Standards, they focus upon the coordination among various international standards too.
The requirements for cast iron fittings with spigots, sockets or flanges, used in pressure pipes for water, gas, and sewage are specified under the IS 1538 standard. This standard also applies to other fittings with dimensions falling under IS 1538. IS 1538 flanges are widely used in the petroleum, chemical, and oil, gas, electric power and, construction fields.
Nominal Diameter | Outer Diameter | Inner Diameter | Thickness | Bolt Circle | Holes | Diameter of Bolts | |
DN | D | d | t | C | Diameter | Number | |
80 | 200 | 91 | 21 | 160 | 19 | 4 | 16 |
100 | 220 | 117 | 22 | 180 | 19 | 8 | 16 |
125 | 250 | 144 | 22.5 | 210 | 19 | 8 | 16 |
150 | 285 | 171 | 23 | 240 | 23 | 8 | 20 |
200 | 340 | 222 | 24.5 | 295 | 23 | 8 | 20 |
250 | 395 | 276 | 26 | 350 | 23 | 12 | 20 |
300 | 445 | 327 | 27.5 | 400 | 23 | 12 | 20 |
350 | 505 | 361 | 29 | 460 | 23 | 16 | 20 |
400 | 565 | 410 | 30 | 515 | 28 | 16 | 24 |
450 | 615 | 462 | 31.5 | 565 | 28 | 20 | 24 |
500 | 670 | 513 | 33 | 620 | 28 | 20 | 24 |
600 | 780 | 616 | 36 | 725 | 31 | 20 | 27 |
700 | 895 | 716 | 38.5 | 840 | 31 | 24 | 27 |
750 | 960 | 765 | 40 | 900 | 31 | 24 | 27 |
800 | 1015 | 819 | 41.5 | 950 | 34 | 24 | 30 |
900 | 1115 | 920 | 44 | 1050 | 34 | 28 | 30 |
1000 | 1230 | 1020 | 47 | 1160 | 37 | 28 | 33 |
1050 | 1258 | 1065 | 1194 | 37 | 28 | 33 | |
1100 | 1340 | 1124 | 50 | 1270 | 37 | 32 | 33 |
1200 | 1455 | 1223 | 53 | 1380 | 40 | 32 | 36 |
1500 | 1800 | 1530 | 61 | 1710 | 43 | 40 | 39 |
IS 6392 covers the requirements for cast, forged, plate, and flat steel pipe flanges for application in oil, water, air, steam, gas, and prominent chemical environment. For application in temperature up to 450o C, carbon steel is used as the material, and for more than 450o C, alloy steel of different grades is used. Depending on the rated pressure, bore size, type, and grade, we have the below types of flanges available under IS 6392 standard.
IS 9523 standards apply to ductile iron fittings used in pressure pipes for carrying water, gas, and sewage. This standard is also applicable to flanged and mechanical joints, covering sizes from 80 mm to 2000 mm. The products under IS 9523 are categorized as per the Nominal Pressure ratings as below –