Water Supply Systems and Pipe Fitting
What this domain tests
Water Supply Systems and Pipe Fitting tests how water is stored, distributed, sized, jointed and tested inside a building. You should be able to trace direct and indirect supply, explain pressure and flow, and choose valves and fittings.
Core rules
- Direct supply feeds fixtures from the main; indirect supply fills a storage tank and then distributes by gravity or booster pump.
- A tank needs an air gap or appropriate backflow protection; the inlet must not be submerged.
- Size pipes for demand and velocity, not by eye. Long runs and many fittings add friction loss.
- Keep hot and cold pipes separated and insulated where condensation or heat loss matters.
- Fit isolation valves at tanks, risers and fixture groups so repairs do not shut the whole building.
- Slope horizontal supply runs to air-release points and avoid air traps that cause sputtering.
- Test new supply pipework hydrostatically before concealment.
Worked example
A shower outlet is 10 m below a tank water level. Static pressure is about 9.81 kPa per metre, so 10 m gives about 98 kPa (roughly 1 bar). Friction losses in the pipe and fittings reduce this at the outlet, so a tank only 10 m above the shower may not deliver the required pressure. The reasoning is static head minus friction loss, not tank volume alone.
Traps
Confusing pressure with flow, ignoring water hammer, leaving dead legs, connecting a hose bib without backflow protection, and using drainage fittings on pressure lines all lose marks.