A blind assembly for use in a piping circuit that includes a blind element and an injection system. The blind element has a planar portion that is transversely mounted in the piping circuit to block flow through the piping circuit. When the blind element is installed, it has one or more flat surfaces that are in sealing contact with another component of the piping circuit, such as a flange face, to define a sealing interface. A primary seal is provided between the blind element and the other component of the piping circuit and which circumscribes at least a portion of the sealing interface. The injection system is in communication with the sealing interface, and selectively injects a sealant material into the sealing interface to form a redundant seal in the sealing interface and around the primary seal. An injection fitting can mount to the flange for injecting the sealant.