Loose flange standards, dimensions and usage environment
What is a loose flange
A loose flange refers to a flange that is loosely attached to the flange of a container or pipe.
Flange is a part that connects shafts to each other and is used to connect pipe ends; it is also used as a flange on the inlet and outlet of equipment to connect two pieces of equipment.
The looper flange is a loose flange. The flange can be made by flanging, directly turning it out or additionally welding the ring.
The advantage is that no additional moment is generated on the container or pipe when the flange is deformed, and it is easy to manufacture.
It can be made of different materials from the container or pipe, which saves precious metals.
The disadvantage is that the flange thickness is larger. Suitable for applications where containers or pipes are lined with brittle materials and the pressure is not high.
What is the size model of the looper flange?
| Sealing surface type | Nominal pressure | ||||
| Class 150 | Class 300 | Class 600 | Class 900 | Class 1500 | Class 2500 |
| Raised face (RF) | NPS/2（DN 15）~ NPS 24（DN 600） | NPS/2（DN 15）~ NPS 12（DN 300） | |||
| Ring junction (RJ) | NPS 1（DN 25）~ NPS 24（DN 600） | NPS/2（DN 15）~ NPS 24（DN 600） | NPS/2（DN 15）~ NPS 12（DN 300） |
Sealing surface type and applicable nominal pressure and nominal size range of butt welding ring plate loose steel pipe flange marked with PN
| Flange type | Sealing surface type | Nominal pressure | ||||
| PN 2.5 | PN 6 | PN 10 | PN 16 | PN 25 | PN 40 | |
| Type A butt welding ring plate loose sleeve steel pipe flange (PL/W-A) | Raised face (RF) | – | – | DN 10 ~ DN 600 | ||
| Concave and convex surface (MF) | – | – | DN 10 ~ DN 600 | |||
| Tongue and groove surface (TG) | – | – | DN 10 ~ DN 600 | |||
| O-ring face (OSG) | – | – | DN 10 ~ DN 600 | |||
| Type B butt welding ring plate loose sleeve steel pipe flange (PL/W-B) | Raised face (RF) | DN 10 ~ DN 1000 | DN 10 ~ DN 1200 | DN 10 ~ DN 1000 | DN 10 ~ DN 800 | DN 10 ~ DN 400 |
Loose flange production standards
| Country | Standard Organization | Standard Name | Description |
|---|---|---|---|
| United States | ASME | ASME B16.5 | Flanges and Flanged Fittings |
| European Union | CEN | EN 1092-1 | Flanges and their joints – Circular flanges for pipes, valves, fittings, and accessories, PN designated |
| United Kingdom | BSI | BS 4504 | Circular flanges for pipes, valves, fittings, and accessories, PN designated |
| Germany | DIN | DIN 2501 | Flanges for pipes, valves, and fittings |
| Japan | JIS | JIS B2220 | Steel pipe flanges |
| China | GB | GB/T 9112 | Steel flanges for pressure purposes |
| India | IS | IS 6392 | Steel flanges |
Scope of application of loose flange
Widely used in chemical industry, construction, water supply, drainage, petroleum, light and heavy industry, refrigeration, sanitation, plumbing, fire protection, electric power, aerospace, shipbuilding and other basic projects.