This code of practice provides detailed guidelines for the design, installation, and testing of drainage and sanitation systems within and around buildings. It covers material specifications, pipe sizing using the discharge unit method, trapping, ventilation systems (single stack, one-pipe, etc.), and commissioning tests to ensure a functional and hygienic system. This standard is a modern replacement for the drainage section of the National Building Code.
Covers general requirements, design, installation, and testing of drainage and sanitation systems in buildings.
Quick Reference Values
Minimum trap water seal for WC50 mm
Minimum diameter for a soil pipe serving one or more WCs100 mm
Recommended minimum gradient for 100 mm drain1 in 80
Maximum spacing of manholes on straight run (up to 300mm dia drain)30 m
Air test pressure for drainage system100 mm water gauge for 5 minutes
Minimum diameter of main ventilating pipe50 mm
Key Formulas
Pipe Sizing based on Discharge Units (DU) from Table 4 and Table 7
Practical Notes
The concept of Discharge Units (DU) is fundamental for sizing pipes; accurately calculating the total DU load for a branch or stack is critical to avoid under-sizing.
Proper venting is often overlooked but is crucial to prevent trap siphonage, back pressure, and foul gas entry into the building. Clause 8 provides detailed options.
This standard should be read in conjunction with IS 17429 (Part 1) for water supply to have a complete understanding of the building's plumbing services.