What is the purpose of a trap in plumbing systems?

The purpose of a trap in plumbing systems is primarily to provide a barrier against sewer gases. Traps are U-shaped sections of pipe that create a water seal. This water seal prevents odors and harmful gases from the sewer system from entering the living space through the plumbing. The standing water in the trap acts as a barrier, allowing wastewater to flow out while simultaneously blocking the gases that could emanate from the sewer line.

The design of a trap ensures that when fixtures are used, such as sinks or tubs, wastewater can flow through while still maintaining that vital barrier. This is crucial for maintaining indoor air quality and protecting the health of occupants. The effectiveness of the trap in its role can be compromised by factors like evaporation or if the fixture connected to the trap is not used for a long time.

While traps can assist with the removal of minor clogs when used correctly, their primary function is not filtration or airflow but rather the prevention of sewer gas intrusion. Therefore, the barrier function of a trap is a key component of a safe and healthy plumbing system.