International (English)

Pressure test

To provide for enhanced safety and reliability, alpex connectors made of PPSU / brass must be pressure-tested after each installation and before any plaster or screed is applied. Testing can be carried out using water or compressed air and is a two-step process for all potable water and heating installations: Firstly, the installation is tested for leak-tightness and secondly for strength.

Pressure test using water

Work steps

  • Leak test:
    Once the system has been filled with water, fittings/connectors are leak tested from 1 to 6.5 bar according to the DVGW worksheet W534. If left uncrimped, alpex connectors visibly leak. Visual inspection is necessary.
  • Strength test:
    A successful leak test is followed by a strength test using water for potable water installations according to EN 806-4 at 11 bar and for heating systems according to DIN 18380 at 4 to max. 6 bar.

The VDI directive 6023 specifies that potable water systems should be put into operation immediately after water pressure testing and subsequent flushing, i. e. without downtime, for reasons of hygiene. For reasons of potable water hygiene, corrosion and freeze protection, potable water installations should only be filled just before being started. If water rests in a filled or partially filled system for a long time frame, this will have adverse effects on the future quality of potable water and should be avoided.

We recommend a pressure test using compressed air if installations are started later. Pressure-testing the system with compressed air does not only prevent freeze damage. It also avoids adverse effects on the hygiene of all system components due to water resting in the pipes.

Pressure test report (water)
Pressure test report (water)
Technical information PDF
533,70 KB
Rinsing report drinking water
Rinsing report drinking water
Technical information PDF
507,10 KB

Pressure test using compressed air

For physical and safety reasons, due to gas compression, pressure tests using compressed air are subject to other requirements than pressure tests using water.

The tests should be carried out according to the ZVSHK bulletin "Pressure Tests Using Compressed Air or Inert Gases for Potable Water Installations according to DIN 1988 (TRWI)" For more information, please refer to the "Pressure testing using compressed inert gas" form.


Work steps

  • Leak test:
    Leak testing is carried out at 150 mbar according to the ZVSHK bulletin. Test time for 100 litres of pipe volume is at least 120 minutes. Test time is extended by 20 minutes for every additional 100 litres.

  • Strength test :
    A successful leak test is followed by a strength test according to the ZVSHK bulletin for potable water installations and for heating systems at max. 3 bar – test duration: 10 min.
Pressure test report (compressed air or inert gases)
Pressure test report (compressed air or inert gases)
Technical information PDF
525,93 KB