ISO 9455-9:1993 (R2014)

The principle of the method specified is to distil a prepared flux solution with sodium hydroxide to expel the ammonia present in the flux, to pass the resulting distillate into a standard sulfuric acid solution, to titrate the excess acid with sodium hydroxide solution and to calculate the ammonia content of the flux. Applies to fluxes of class 3.1.1 only, as defined in ISO 9454-1.