• Effective cross sectional area (with 15mm free board): 33,550mm²
• Flow capacity: 727 litres/min
• Minimum recommended fall: 1:500
• Minimum downpipe size: 
• Circular: 150mm
• Rectangular: min. cross sectional area of 18,500mm²

Catchment area per downpipe based on the above flow capacity is given in Table 3.1.I below. Use Table 3.1B (Section 3.1.4) to determine the Rainfall Intensity to be used.

table 3.1.I