Trap seals are protected from back pressure and siphonage by what?

Trap seals are protected from back pressure and siphonage primarily through the use of vents and pressure. Vents play a critical role in maintaining the correct pressure balance within plumbing systems. They allow air to enter the drainage system, which helps equalize pressure and prevent the creation of a vacuum that could siphon water out of the trap, thus maintaining the water seal.

When trap seals are intact, they prevent sewer gases from entering the living spaces of a building. Without effective venting, situations can occur where the water seal is compromised due to negative pressure (siphonage) or excessive pressure (back pressure). Therefore, it's essential to have a properly designed venting system in place, as it directly affects the functionality and reliability of the traps throughout the plumbing system.

Other options, while they may relate to plumbing aspects, do not specifically address the mechanisms of preventing siphonage and back pressure related to trap seals.