A factory’s water system serves several purposes at once: drinking, toilets, production, cooling, and emergency services. A clear drawing should show which system serves each purpose and how contamination is prevented. Bangladesh National Building Code (BNBC) 2020 provides the building-services context for that work.
Where to start reading
Begin with Part 8, Chapter 5, Water Supply, and Chapter 6, Sanitary Drainage. The gazetted code covers building water supply, plumbing, sanitation, and drainage responsibilities. Industrial effluent treatment also requires the applicable environmental rules and clearance conditions. Confirm the occupancy, approved design, and relevant authority requirements before selecting a provision or table.
Review three connected drawings
| Drawing | Questions for the review |
|---|---|
| Water supply | Where does water enter? Which treatment, storage, pumps, valves, and outlets serve each use? |
| Sanitary drainage | Where do soil and waste lines go? How are vents, traps, inspection access, and treatment/disposal arranged? |
| Stormwater and site drainage | Can rainfall enter a sewage or effluent line? Can a polluted area contaminate clean runoff? |
Protect the potable network from cross-connections. Where treated wastewater is proposed for suitable non-potable uses, show a separate, identifiable system and the required protective arrangements. Verify the water-quality requirement at the actual point of use; a compliant STP outlet does not by itself establish safe drinking water.
Keep the design basis visible
- Use the approved occupancy and applicable code criteria for water demand and sanitary facilities. Record the source and clause for every allowance.
- Distinguish daily volume, peak flow, storage, pump duty, pipe sizing, and treatment capacity. They answer different design questions.
- Review the effects of added floors, production, shifts, or staff on the existing system.
- Keep as-built drawings, inspection access, maintenance instructions, test records, and responsible persons together.
Try a drawing walk-through
Choose one drinking-water tap and one toilet. Trace each back to its supply source and forward to its drainage destination. Mark every uncertainty for verification on site. This simple exercise often makes a complicated drawing much easier to understand. Design approval and specialist checks should follow the relevant authority’s process.
The official gazette records BNBC 2020 under S.R.O. No. 55-Law/2020, published 11 February 2021. Use the complete gazetted document, including the relevant tables, appendices, definitions, and any applicable amendments.
Official sources and further reading
Related practical resources
ECR 2023 downloads · Excel workbooks and checklists · RSC Safety for ETP, STP and WTP · ISO for Water and Wastewater Management
Practice downloads
Use the bilingual PDF worksheets in print or alongside the editable Excel files. Examples are for learning; adapt the records to the approved procedures and requirements at your site.
- Environmental aspects and compliance register (PDF · English / বাংলা)
- 3R water planning and permissions worksheet (PDF · English / বাংলা)
Bangladesh Water Act, Water Rules and WARPO · 3R Water Planning in the Textile Industry · Environmental Aspects and Impacts in Treatment Plants
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