To provide a piping facility allowing early detection of leakage of liquid chemicals at an initial state to treat waste liquid and capable of storing the leaked liquid without splashing it outside in the case of a serious breakdown accident.

This piping facility has the double pipe structure formed of the interior pipe 1 formed by connecting one end of each interior pipe 12, 13 and 14 to each pipe connection part of an interior branch joint 11 and the exterior pipe 2 arranged to cover the periphery of the interior pipe 1 and formed by connecting one end of each exterior pipe 22, 23 and 24 to each pipe connection part of an exterior branch joint 21 arranged in the periphery of the interior branch joint 11. The exterior branch joint 21 of the double pipe structure and the adjacent part thereof are arranged inside a box-like structure 3, and the other end of each exterior pipes 22 and 23 is led out of the box-like structure 3, passing through the box-like structure, and each exterior pipe 22 and 23 is engaged with the box-like structure 3 at passing through positions thereof in a water-cutting state.