This part of ISO 9455 specifies a method for the determination of the zinc content of water soluble fluxes of type 3, as defined in ISO 9454-1. The method is intended to apply to an aqueous solution of flux containing approximately 25 % of zinc, expressed as zinc chloride (ZnCI2). For solid fluxes and for solutions whose concentrations differ appreciably from those stated above, an appropriate adjustment should be made to the amount of sample taken for the test.