For ventilating discharge pipes you should use air admittance valve of Silent-db20 system. It can be used in gravity drainage systems.The air admittance valve is equipped with thermal insulation integrated in housing. Comes with connection sleeve. Operating temperature ranges from -20°C to +60 °C.
Operating temperature: -20 - +60 °C
Air-flow rate (atmospheric air) at -250 Pa: 32 l/s