For underground ducts, what is the purpose of maintaining a specific slope?

Maintaining a specific slope for underground ducts is essential primarily for allowing drainage. This is crucial because moisture can accumulate within the ducts due to condensation or groundwater infiltration. If the ducts are not sloped properly, water can pool inside, leading to stagnant water, potential corrosion, and reduced efficiency of the duct system. The slope facilitates the movement of water away from the ducts, ensuring that they remain dry and operational over time.

While proper insulation, airflow, and noise reduction are important considerations in duct design and installation, they do not specifically pertain to the need for a slope in underground applications. Insulation addresses thermal performance, airflow influences how air moves through the system, and noise reduction relates to the sound produced by the air movement; none of these factors directly connect to maintaining a slope for drainage purposes.