What is the required minimum slope for horizontal ducts exceeding 75 feet in length?

The required minimum slope for horizontal ducts exceeding 75 feet in length is 1 unit vertical in 12 units horizontal. This standard slope helps to ensure proper drainage of condensation that may accumulate within the ductwork. When ducts are not sloped adequately, moisture can collect and potentially lead to issues such as mold growth, reduced efficiency, and even structural damage over time. By adhering to this 1:12 slope, designers and installers facilitate effective drainage and maintain the integrity and function of the HVAC system. Having this slope is particularly critical in longer duct runs to ensure that any condensate is directed away efficiently.