Roof Sump Lateral
Effective contributing area (m2) 246 48 19
Flow volume under IRF (m3) 2.89 1.54 1.63
Flow volume per unit area (m) 0.012 0.032 0.084
IRF weighting coefficients 3,359 14,663 19,985
Total contributing volume (m3) 9,701 22,653 32,543
Contributing volume / total RDII volume (%) 15 35 50