BNBC (Bangladesh National Building Code)

BNBC 2020 is published by the Housing and Building Research Institute (HBRI) and adopted by RAJUK and other development authorities. Key chapters: Part 2 (Administration and Enforcement), Part 3 (General Building Requirements), Part 4 (Fire Protection), Part 5 (Building Materials), Part 6 (Structural Design — references ACI 318 for concrete, AISC 360 for steel), Part 7 (Plumbing), Part 8 (Electrical and Mechanical). Seismic design provisions define four zones: Zone 1 (Z=0.12, Sylhet), Zone 2 (Z=0.20, Dhaka), Zone 3 (Z=0.28, Rangpur), Zone 4 (Z=0.36, highest risk areas). Wind speed maps provide basic wind speeds (195-260 km/h at 10m height). BNBC 2020 substantially updates seismic provisions from the 1993 edition. Enforcement varies significantly — many existing Dhaka buildings predate the 2020 code and were not built to the 1993 edition either.

BNBC is the legally applicable building code in Bangladesh. Understanding its requirements — and critically, the gap between code requirements and typical construction practice — is essential for building due diligence, risk assessment, and compliance planning in the Bangladesh market.