Software interfaces. See also: application binary interface and application programming interface. A software interface may refer to a wide range of different types of interface at different levels: an operating system may interface with pieces of hardware.
The products used to seal these pipe joints are known as gaskets. A flange gasket is the particular style of gasket utilized to create a seal when two flanged pipe ends are bolted together. The most common use for gaskets is in the services industry, where water pipes need to be sufficiently sealed to prevent water leaks, loss of pressure, or external foreign contaminants entering the pipe.
Nearly every type of exhaust, from manifolds to tubular headers, incorporates the exhaust flange in some form to prevent exhaust leaks. Some versions of the flange utilize what is known as a donut gasket to assist in sealing the system. The donut gasket is a round gasket that uses a flat and smooth center hole to ride solidly on the exhaust pipe. The outside diameter of the donut gasket is manufactured with a slight angle on each side that is sandwiched into the flange on the exhaust manifold and the exhaust pipe.