ISO 16925-2014 pdf free download

ISO 16925-2014 pdf free download.Paints and varnishes — Determination of the resistance of coatings to pressure water-jetting
Peintures et vernis — Determination de la résistance des revétements a un jet d’eau sous pression.
4 Principle
The resistance of a coated test specimen to the loss of adhesive strength is tested by means of defined pressure water-jetting.
The extent oithe damage of the test specimen primarily depends on, besides the adhesive strength, the space between nozzle and test piece, the volumetric flow rate0 the test time1 the geometry of the nozzle, the impact area, the angle of impact, and the water temperature of the jet, as well as the cutting and scribing tool.
The evaluation is carried out by means of a visual comparison of pictures, in which characteristic values are related to the peeled-off areas.
The parting line (plane) of the peeling shall be indicated in the test report (e.g. substrate/priming coat).
5 Apparatus and materials
Ordinary laboratory apparatus, together with the following:
5.1 Pressure water-jet. consisting of a high-pressure pump and a nozzle.
A high-pressure pump conveys the water from a storage bin. To avoid influences from variations In pressure, it is necessary that the pressure and the volumetric flow rate be adjustable at the nozzle described below.
The water temperature shall be adjustable to ± 2 °C.
The temperature shall be adjusted in accordance with AnnexA. Necessary safety devices on the pressure side oithe unit, as e.g. pressure relief valve and by-pass valve, shall exist lithe jetting is unsteady, a flow calming section may be installed in front of the nozzle. A pulsation of the water Jet at the opening of the pump is Inadmissible. In order to reach a reproducible result, the nozzle shall be solidly mechanically fixed and the test specimen shall be secured against slipping. For the adjustment of the volumetric flow rate, a nozzle with a jet angle of 25° and a volumetric flow rate of 6 1/mm at 2 MPa (20 bar) is required (see Annex A).ISO 16925-2014 pdf free download.