Testing & commissioning
Pressure testing a water installation
Tightness testing of empty pipes and full pressure test before commissioning
Pressure testing documents that the installation is tight before it is put into service and concealed. DS 439:2024 sets a stricter requirement that conduits are leak tested BEFORE they are built in or cast in. The guide covers preparation, equipment, test pressure, holding time and documentation.
Leak test conduits before concealment
Leak test the pipes before they are concealed (built in, cast in or covered). This is a stricter requirement in DS 439:2024 and catches leaks while they can still be reached. Document findings and deviations.
Fill the system and bleed it completely
Fill the installation with water well before the test — as a guide at least 24 hours before — and make sure the system is completely bled. Trapped air compresses and gives a misleading (soft) test result.
Pre-filling≈ 24 hours before (guideline)Connect calibrated measuring equipment
Monitor the test pressure with two reliable pressure gauges, at least one of which must be a calibrated test gauge of class 1 or better (DS/EN 837). The pressure test must be carried out by a person familiar with the task.
Apply the test pressure
The system is tested at an increased pressure. Industry practice is typically 1.5 × operating pressure, while BR18 practice for water is 1.3 × the nominal pressure class for the first 6 hours, so that a drop can clearly be read. The exact test pressure and procedure must be verified against DS 439:2024 before being quoted as normatively binding.
Industry practice1.5 × operating pressureBR18 (water), phase 11.3 × pressure class for 6 hObserve the holding time
Leave the pressure on and read it over the specified holding time. The holding time can never be less than 10 minutes unless the standard states otherwise — for a water installation, follow the procedure in DS 439:2024, which extends over several hours.
Min. holding time10 min (unless the standard specifies otherwise)Assess the pressure drop
Read the pressure at the start and end. An acceptable result is that the pressure holds within the standard's permitted limit. If the pressure drops, there is a leak (or trapped air/temperature fluctuation) — find and remedy the cause.
Remedy and repeat if it fails
If the test is not passed, locate the leak (e.g. by listening, feeling or applying soap to joints), fix it and run the test again from the start. Allow for the fact that temperature changes in the water can also shift the pressure.
Document in the pressure test record
Complete the pressure test record with system type, test pressure, duration, start and end readings, result, date and signature. The record is a mandatory QA element of the authorised company's quality management system (KLS).
Pressure testing without a signed record does not count — the documentation is part of the job.
Source
Based on Arbejdstilsynet's AT-vejledning B.4.2 (pressure testing, pressure gauge requirements, holding time), the BR18 guidance on water / Wavin FAQ (pre-filling + venting) and the worktree templates (DS 439:2024, QA/pressure test record). Verify the exact test pressure against DS 439:2024.