Principles of laying out water supply system

Principles for laying out the water supply system in a building:

1. Adequate quantity and pressure at every fixture (minimum residual head about 3-5 m); size the pipes for peak demand.
2. Short, direct pipes with few bends and fittings, to reduce friction loss and cost.
3. Storage: sump and overhead tank sized for the demand; the tank placed high enough to give sufficient head at the top floor.
4. Valves: a gate valve at each branch and fixture so that parts can be isolated; air valves at high points and drain valves at low points.
5. Avoid contamination: keep water pipes separate from drains and never in contact with sewers; keep tanks covered; where pipes cross a sewer, lay them at least 0.5 m above it.
6. Protection: pipes in ducts or chases, lagged in cold places, not embedded under foundations or in columns; allowance for expansion.
7. Accessibility for repair; joints exposed or in inspection ducts.
8. Material: non-toxic, durable pipes (GI, HDPE, PVC, CPVC).
9. Grouping of fixtures around vertical shafts (kitchens and toilets stacked) for economy.
10. Hot and cold supply kept separate, with insulation on hot pipes.