Sioux Chief 250 series TurboVent air admittance valves shall be installed in either branch or stack applications as vent terminal for secondary venting within the plumbing system. Valve shall incorporate an actuating device which spins upon activation to keep the elastomeric sealing surface clean and free of debris. During drainage, actuating device shall raise a designed distance under negative line pressure to allow optimal air flow into the DWV system. Valve shall provide a positive seal at 0 psi and under any positive line pressure to prevent sewer gasses from entering the living space. Valve shall comply with IPC model code and be certified to ASSE 1050 and 1051 standards.