NCC 2025 Volume One F1D3 (Class 2 to 9); Volume Two H2D2(1)(a) (Class 1 and 10) · AS/NZS 3500.3:2025 Clause 5.4 (rational method), Figure 5.4.11.2, Clause 6.3.3 and Table 6.3.4
Under NCC 2025, site stormwater drainage is designed to AS/NZS 3500.3 (Volume One F1D3 for Class 2 to 9 buildings, Volume Two H2D2(1)(a) for houses and Class 10 buildings), and this calculator applies that Standard's pipe sizing method.