1.Scope
This Standard specifies steel pipe flanges (hereafter referred to as “flanges”) of nominal size 10A to 1500A for nominal pressure 5K, 10K, 10K light type,16K, 20K and 30K which are used to join parts for piping, such as steel pipes and valves, in ordinary(1)，pressure (2), high pressure (3), high temperature (4), alloy steel pipes (5), strainless steel pipes (6) piping for steam, air, gas, water, oil, etc. (7).
Notes:
- Piping using Carbon steel pipes for ordinary piping of JIS G 3452 and arc welded carbon steel pipes of JIS G 3457.
- Piping using Carbon steel pipes for pressure service of JIS G 3454.
- Piping using Carbon steel pipes for high pressure service of JIS G 3455.
- Piping using Carbon steel pipes for high temperature serivce of JIS G 3456.
- Piping using Alloy steel pipes of JIS G 3458.
- Piping using stainless steel pipes of JIS G 3459 and large diameter welded stainless steel pipes of JIS G 3468.
- Integral flange, which is to be used as part of some other equipment or components, shall also be within the scope of this Standard.
Weld Neck Flange
Integral Flange
Blind Flange
Socket Weld Flange
Threaded Flange
Plate Flange
Slip On Flange Type A
Slip On Flange Type B
Slip On Flange Type C
Loose Flange/Lap Joint Flange
Classification of flanges and the designation
| Classification of flange | Designation | Figure | |
| Welding flange | Silp on plate flange | SOP |  |
| Slip on hubbed flange | SOH |  | |
| Socket welding flange | SW |  | |
| Welding neck flange | WN |  | |
| Lap joint flange | LJ |  | |
| Threaded flange | TR |  | |
| Intergral flange | IT |  | |
| Blank flange | BL |  | |
Types of nominal pressure 20 K and 30 K slip on hubbed flanges
| Classification of flange | Type | Figure |
| Slip on hubbed flange | Type A |  |
| Type B |  | |
| Type C |  |