This European Standard is applicable to trichloroisocyanuric acid used for emergency treatment of water intended for human consumption. It describes the characteristics of trichloroisocyanuric acid and specifies the requirements and the corresponding test methods for trichloroisocyanuric acid. It gives information on its use in water treatment. It also determines the rules relating to safe handling and use of trichloroisocyanuric acid (see Annex B).