A venting system for a direct vent fireplace or other direct vent appliance to direct combustion gases to an exterior area. The direct venting vent pipe facilitates unrestricted lengths of pipe installations. The vent pipe has a double wall construction forming an interior axial passageway and a coaxial outer passageway. The double walls are spaced apart by an insert to maintain coaxial spacing. Sections of the vent pipe are lockingly connected to prevent separation and ensure sealing connection between the pipe sections. Elastic seal members are utilized between the matingly connected sections and a mechanical lock assembly prevents separation.