Final answer:
Each plumbing fixture, except for those with integrated traps, shall be connected to the sewer line to ensure waste water removal and prevent sewer gases from entering the building. Plumbing also includes air-filled tubes to prevent vacuum conditions and maintain consistent water flow.
Step-by-step explanation:
Each plumbing fixture, except for those having integral traps, shall be connected to the sewer line. This is necessary for the removal of waste water and to ensure the proper functioning of the plumbing system. Fixtures with integral traps, such as toilets, already have a built-in mechanism to prevent sewer gases from entering the building, while other fixtures require a separate trap to be installed in the drainage system. The purpose of a trap is to hold a small amount of water after the fixture is used, which serves as a seal to keep sewer gases from coming back into the home or facility.
On another note, plumbing systems often include air-filled tubes near water faucets—a detail you might find in technical illustrations like Figure 12.28 in plumbing literature. These air-filled tubes are essential as they act as air admittance valves or vent systems. They help prevent vacuum conditions that could disrupt water flow and are necessary to ensure consistent water flow and to protect the trap seal by equalizing pressure within the drainage system.