Installation, Testing, Commissioning and Maintenance
Installation, Testing, Commissioning and Maintenance tests the sequence from setting out to handover. The exam asks about pressure testing, disinfection, flushing, snag correction and planned maintenance.
Sequence
- Set out and check levels; fix supports and sleeves.
- Install pipework and fittings; keep open ends capped.
- Pressure-test before concealment; repair and retest failures.
- Flush and disinfect potable water systems; flush drainage.
- Commission fixtures, check flow and adjust.
- Hand over records, as-built drawings and maintenance instructions.
Testing rules
- Water supply: test at 1.5 times the working pressure, or the specified test pressure, for at least one hour with a calibrated gauge; no visible leakage.
- Drainage: test with water or air as specified; a smoke test can locate leaks.
- Disinfection: chlorinate the tank and pipework, then flush until the residual chlorine is acceptable.
Worked example
A system works at 4 bar. Test pressure = 1.5 × 4 = 6 bar. Hold for one hour, inspect all joints, and record the gauge reading. If the pressure drops, find the leak; do not simply top up the gauge and pass the test.
Traps
Testing before solvent cement cures, using an uncalibrated gauge, or concealing pipe before inspection costs marks. Maintenance is not only repair: it includes scheduled flushing, valve exercise and leak checks.