NCC 2025 Volume One F1D3 (Class 2 to 9); Volume Two H2D2(1)(a) (Class 1 and 10) · AS/NZS 3500.3:2025 Equations 5.4.10.1 and 5.4.12.2, Clause 5.4.10.2 and Table 7.5.2.1
NCC 2025 calls up AS/NZS 3500.3 for stormwater drainage (Volume One F1D3 for Class 2 to 9 buildings, Volume Two H2D2(1)(a) for houses and Class 10 buildings), and this calculator applies its sag and on-grade pit, surcharge outlet and pit size provisions.