These Flanges are used as a termination point to a piping system. Blind-Flanges have a blank surface with bolt point to fit a pipe. A Blind flange is round plate which has all of the relevant boltholes but no center hole, and because of this feature this flange is used to close off the ends of a piping systems and pressure vessel openings. It also permits easy access to the interior of a line or vessel once it has been sealed and must be reopened.
The blind flange is used to close ends of piping systems. It is a kind of round plate with no center hold but with all the proper bolt holes. This blind flange is available in various sizes and materials and is used to provide positive closer on the ends of pipes, valves or equipment nozzles. This flange helps in easy access to a line once it has been sealed. The blind flange is sometimes custom made or machined to accept a nominal sized pipe to which reduction is being made.
Blind Flanges are commonly used in petrochemical, pipe engineering, public services & water works.
Blind pipe flanges are often used for high pressure applications.
This reduction can be a threaded reduction or welded reduction.
Details of Blind flange
- Size: 1/2” to 60”, DN 12mm to DN 1500mm
- Pressure class: Class 150 to Class 2,500, PN 2.5 to PN 250
- Facing: RF / RTJ
- Cabon steel: A105, A350 LF2
- Stainless steel: A182 F304/F304L/F316/F316L/F321
- Alloy steel: F11, F12
Standards, Dimensions & Weight of Blind flanges
- ASME/ANSI B16.5 Class 150 BL
- ASME/ANSI B16.5 Class 300 BL
- ASME/ANSI B16.5 Class 600 BL
- ASME/ANSI B16.5 Class 900 BL
- ASME B16.47 Series A/MSS SP-44 Class 150 BL
- ASME B16.47 Series A/MSS SP-44 Class 300 BL
- ASME B16.47 Series A/MSS SP-44 Class 600 BL
- ASME B16.47 Series A/MSS SP-44 Class 900 BL
- ASME B16.47 Series B/API 605 Class 75 BL
- ASME B16.47 Series B/API 605 Class 150 BL
- ASME B16.47 Series B/API 605 Class 300 BL
- ASME B16.47 Series B/API 605 Class 600 BL
- ASME B16.47 Series B/API 605 Class 900 BL
Blind flange is put at the end of pipe or at the junction that would possibly be a future expansion into that direction.
Piping is easier to drill or weld at the construction stage. Once it was in use, drilling or welding will need prolong cleaning especially when the fluid transferred is combustible. For the mean of future extension, either the blind or valve would be used to seal the end.
Advantage of Blind Flanges
- A much more cost efficient way to seal a pipe when doing repairs
- Blind flanges are convenient to install
- They can save a good amount of time and money