Section 126.96.36.199, "The Presumption of conformity", of The ‘Blue Guide’ on the implementation of EU product rules states the following:
"Harmonised standards provide a presumption of conformity with the essential requirements they aim to cover, if their references have been published in the Official Journal of the European Union."
Nonetheless, rather than relying purely on the normative content, users of standards should also always examine all of the available information concerning how exhaustive the standards are. Even the fact that a standard’s reference has been published in the Official Journal does not guarantee that the standard covers all the necessary aspects. To be completely on the safe side and to minimize the possibility of unpleasant surprises, users of standards should also carry out a risk assessment, especially if such an assessment is required by law anyway for the product in question.