1. Hydraulic Capacity Sizing using the Manning Equation
To ensure zero overflow water dripping onto windshields, each longitudinal and lateral aluminum gutter purlin is sized using the **Manning Hydraulic Formula**:
$$Q = rac{1}{n} A R_h^{2/3} S^{1/2}$$
Where $A$ is the gutter wet cross-sectional area, $R_h$ is the hydraulic radius, $S$ is the purlin slope (minimum 5° inclination), and $n = 0.009$ is the Manning roughness coefficient for extruded smooth AL6005-T5 aluminum. Champion gutters accommodate rainfall intensities exceeding 250 mm/hour without overflow.