Blinds are flanges without a center bore (hole or opening) and are available in both Raised Face (RF) and Flat Face (FF) styles. While most flange types create a connection point that allows the flow of liquid, gas, or air, blind flanges are used to seal the end of a piping system and prevent flow. Blind flanges may be used when testing pipe pressure, to create an access point in a piping system, to temporarily seal a piping system while modifying or repairing the line, or to create a long-term seal to terminate a piping system.
A blind flange is bolted, rather than welded in place. This allows easier access as needed for pipe system upkeep, inspection, or to allow for future expansion. Pairing with a gasket creates a tight seal: The gasket fills the space between the flange faces, which prevents liquid or gas leaks.
How to Choose the Right Blind Flange
Blind pipe flanges may be produced to match bolt hole measurements for slip-on or welding neck flanges, or if needed, can be custom machined to any other specifications. Either way, when purchasing flanges, choose the appropriate flange features, material, dimensions, and class to meet your application needs.