Testing & commissioning
Commissioning — flushing and final check
From a passed pressure test to a clean, documented installation in use
Once the pressure test has been passed, the installation must be cleaned, checked and documented before it is handed over. Flushing removes installation debris, the temperature check addresses the legionella concern, and the QA documentation proves that the installation has been built and tested correctly. The guide follows the professional sequence up to commissioning.
Flush the system
Flush the installation in accordance with DS 439:2024 once the pressure test has been passed. Flushing removes swarf, soldering flux, dirt and installation debris that could otherwise lodge in valves, filters and taps and impair water quality.
Complete the flushing record
Document the flushing in a flushing record. It confirms that the system has been cleaned before commissioning and is a standard QA document.
Measure and check legionella temperatures
Measure the temperatures in the hot water system: cylinder ≥ 60 °C, furthest draw-off point ≥ 50 °C within 10–20 seconds of opening, and circulation return ≥ 50 °C. The risk zone for legionella growth is 20–45 °C. The requirements follow DS 439:2024 / BR18 §§ 403–419 / SSI.
Vessel≥ 60 °CFurthest stud≥ 50 °C (10–20 s)Circulation return≥ 50 °CConnect the fittings and carry out the final check
Mount and connect fittings, and check the installation against the design and the inspection plan (QA form). Clarify deviations with the designer before the installation is released.
Gather the QA documentation
Gather all quality assurance: pressure test record, flushing record, legionella log and final inspection. The documentation shows that BR18 and DS 439:2024 are met, and is a requirement in the authorised company's QMS.
Hand over to the client
Hand over the installation to the client together with the operation and maintenance instructions and the complete QA documentation. Go through operation, safety valve, bleeding and any service intervals.
The order is fixed: pressure test → flushing → temperature check → final inspection → QA → commissioning.
Source
Based on the worktree article «DS 439:2024» (professional process) and the templates «Process: plumbing project» + «Legionella log» (DS 439:2024 / BR18 §§ 403–419 / SSI).