Red Seal Carpenter Practice Exam 2025 - Free Carpenter Practice Questions and Study Guide

A plumbing "trap" specifically refers to a U-shaped section of pipe installed beneath sinks, showers, and other fixtures. Its primary function is to hold a small amount of water, which creates a barrier that prevents sewer gases from infiltrating living spaces. This is critical for maintaining indoor air quality and ensuring the health and safety of the occupants. The design of the trap allows wastewater to flow out while simultaneously retaining enough water to form an effective seal against odors and dangerous gases.

The other options do describe certain plumbing functions but do not accurately define what a plumbing trap is. Water flow regulation pertains to devices like valves or flow restrictors, a filter would refer to a system that removes particulates or contaminants from water, and heated pipes generally refer to systems for preventing frozen pipes in colder climates, which are unrelated to the purpose of trapping sewer gases.