This European Standard is applicable to " sodium dichloroisocyanurate, anhydrous" used directly or used to prepare commercial formulations for disinfecting swimming pool water. It describes the characteristics of " sodium dichloroisocyanurate, anhydrous" and specifies the requirements and the corresponding test methods for " sodium dichloroisocyanurate, anhydrous" . It gives information on its use for treating swimming pool water and determines the rules relating to safe handling and use (see Annex B).