What is a "trap arm" in plumbing?

A "trap arm" in plumbing refers to the horizontal pipe that extends from the trap to the vent. This section of pipe is crucial in ensuring proper drainage and venting of a plumbing fixture.

The trap itself serves to block sewer gases from entering a building while allowing wastewater to flow through. The trap arm connects the trap to the vent system, which helps maintain atmospheric pressure in the drainage system and allows air to enter. This air pressure is necessary for the smooth flow of wastewater and prevents issues like backflow or gurgling sounds in the plumbing system.

In the context of plumbing, the design and placement of the trap arm must comply with the National Plumbing Code to ensure that it meets safety and performance standards. The correct slope and length of the trap arm are also essential for effective drainage.

Other choices relate to different components of a plumbing system but do not accurately define a trap arm. For instance, a vertical section of pipe is not specific to a trap arm, as is a type of valve used in drainage, which serves a different function. Similarly, a seal to prevent sewer gas pertains more to the function of the trap itself rather than the trap arm.