This European Standard is a method for determining the unidirectional non-steady state chloride diffusion and surface concentration of conditioned specimens of hardened concrete. The test method enables the determination of the chloride penetration at a specified age, e.g. for ranking of concrete quality by comparative testing. Since resistance to chloride penetration depends on the ageing, including the effects of continual hydration, then the ranking may also change with age. The test procedure does not apply to concrete with surface treatments such as silanes and it may not apply to concrete containing fibres, see E.1.