In plumbing, what is the purpose of a trap in drainage systems?

The purpose of a trap in drainage systems is to prevent fumes from escaping. Traps are designed to hold a small amount of water at all times, which creates a seal that blocks sewer gases from entering buildings. This is crucial for maintaining indoor air quality and preventing the spread of unpleasant or potentially harmful odors. The water seal acts as a barrier, allowing wastewater to flow out while simultaneously preventing harmful gases from coming back up through the drain. Understanding this design is essential for ensuring safe and effective plumbing systems in residential and commercial settings. While traps also play a role in allowing the passage of wastewater, their primary function is the protection from sewage gases.