What Is a Blind Flange?

A blind flange is a solid flange used to seal or terminate the end of a piping
system, vessel nozzle, or pressure-containing opening. Unlike other flange
types, a blind flange has no center bore and does not allow fluid to pass
through it.

How It Works

A blind flange is bolted to a mating flange with a gasket installed between
the flange faces. When the bolts are tightened, the gasket is compressed,
creating a pressure-tight seal that blocks the flow of fluid through the
connection.

Typical Applications

• Closing the end of a pipeline
• Isolating sections of piping for maintenance or testing
• Sealing vessel and equipment nozzles
• Providing future expansion points in a piping system
• Pressure testing and hydrostatic testing operations

Advantages

• Provides a secure, pressure-containing closure
• Allows easy access to piping systems when removed
• Facilitates future system modifications and tie-ins
• Available in a wide range of sizes, pressure classes, and materials
• Can withstand high pressures due to its solid construction

Considerations

• Typically heavier than other flange types of the same size
• Requires proper gasket selection and bolt tightening procedures
• May require additional support in larger sizes due to weight
• Must be rated for the system’s design pressure and temperature

Blind Flange vs. Weld Neck Flange

Summary

A blind flange is a solid flange used to close off the end of a piping system
or equipment connection. It provides a pressure-tight seal, allowing systems
to be isolated, tested, maintained, or prepared for future expansion.