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.
Blind pipe flanges are typically provided with a raised face, flat face, or RTJ facing. When a raised face is necessary for blind pipe flanges, the standard height is 1/16″ for blind pipe flanges under 400#. For blind pipe flanges of 400# and up, the standard blind pipe flange raised face height is 1/4″.
Blind flanges are often used in chemical, petroleum, marine, paper making, shipbuilding, metallurgy, boiler, electric, power, and natural gas.
Blind pipe flanges are recommended for high-pressure applications and commonly used to seal the end of pressure vessel openings or piping systems.