What is a common vent?

A common vent functions as a venting system that serves two or more sanitary fixtures which are trapped but located on the same level. This type of vent is critical in plumbing design as it allows for the efficient removal of sewer gases and helps maintain proper atmospheric pressure in the drainage system. By connecting the two fixtures through a single vent pipe, it minimizes the materials required for installation and optimizes space within the plumbing layout.

In contrast, options referring to different levels or a single fixture do not accurately describe the specific function of a common vent. Connecting to multiple stacks also diverges from the definition, as it implies a more complex arrangement that goes beyond what is required for a common vent. Thus, the correct representation of a common vent is its role in supporting two trapped fixtures situated at the same level, emphasizing both functionality and efficiency in plumbing design.