Which statement about a vent pipe is TRUE?

Vent pipes play a crucial role in plumbing systems by providing necessary ventilation to drainage systems. This ventilation is essential because it allows air to enter the plumbing system, thereby preventing the formation of vacuum conditions that can impede or block the flow of wastewater. Essentially, venting maintains proper pressure in the drainage system, ensuring that wastewater can flow freely and that sewer gas does not accumulate within the building.

Adequate ventilation helps in preventing siphoning of traps, which could lead to unpleasant odors or potential health hazards due to exposure to sewer gases. Furthermore, vent pipes facilitate the release of gases produced by decomposing waste, making them vital for the safe operation of the plumbing system.

Other options do not accurately represent the function of vent pipes, as they do not serve decorative purposes, are not exclusively for waste disposal, and do not have a requirement to be attached to foundation walls. Their primary and vital role is ensuring that the drainage system operates correctly and efficiently.