NCC 2025 Volume One F1D3 (Class 2 to 9); Volume Two H2D6(1)(a) (Class 1 and 10) · AS/NZS 3500.3:2025 Clause 3.7, Figure 3.7.4(B) and Appendix H (Figures H.4 to H.6)
A box gutter sump and its side overflow are designed to AS/NZS 3500.3 under NCC 2025, called up by Volume One F1D3 for Class 2 to 9 buildings and by Volume Two H2D6(1)(a) for Class 1 and 10 (Part 7.4 excludes box gutters, H2D6(3)(b)).