Stack vents are an essential component of a plumbing system, helping to prevent the buildup of pressure and sewage gases within the drainage pipes. They work by creating a continuous column of air within the plumbing system, which allows wastewater to flow freely and prevents the formation of vacuum or pressure that could impede drainage.

Stack vents are usually connected to individual branch lines and extend upward through the building to terminate above the roofline. They may be concealed within walls or enclosures, but they must be properly vented to the exterior to ensure effective ventilation and odor control.

In addition to providing ventilation, stack vents also serve as access points for maintenance and cleaning of the plumbing system. They are typically sized and positioned according to building codes and plumbing standards to ensure proper function and compliance with regulations.