Where do gases escape in a sanitary drainage system?

In a sanitary drainage system, gases escape primarily through a vent stack. The vent stack is specifically designed to allow sewer gases to vent outside and enable the equalization of pressure within the drainage system. This is crucial for maintaining the flow of wastewater, as it prevents suction that can lead to slow drainage or the potential for traps to be drained of water, which can allow foul odors to enter the living spaces.

The vent stack extends above the roofline of a building, ensuring that the gases disperse safely away from the structure. This not only contributes to the overall health and safety of the interior environment but also helps prevent issues such as the backflow of odors.

Other components, such as toilets, drain basins, or manholes, do not serve the primary function of allowing gases to escape in the same efficient and controlled manner as the vent stack does. Toilets and drain basins are designed for the discharge of wastewater, while manholes provide access for maintenance but are not a dedicated pathway for venting gases.