Cleanouts shall be designed to be what?

Cleanouts must be designed to be gas-tight and watertight to ensure that they effectively prevent the escape of gases and liquids from the plumbing system. This is crucial for maintaining hygiene and safety standards within a building. Gas-tightness ensures that harmful gases, which can accumulate in drainage systems, do not leak into occupied spaces, posing health risks. Watertightness is equally important because it prevents the leakage of water and other fluids, which can lead to structural damage, mold growth, and other issues. By adhering to these requirements, cleanouts play a vital role in the overall integrity and functionality of the plumbing system.

Other design considerations like flexibility, accessibility, or standardization are important but do not address the core necessity of preventing the escape of gases and liquids, which is essential for safety and performance in plumbing systems.