This document specifies general performance requirements for procedures for determination of the concentration of chemical agents in workplace atmospheres as required by the Chemical Agents Directive 98/24/EC (see reference [1]). These requirements apply to all measuring procedures, irrespective of the physical form of the chemical agent (gas, vapour, suspended matter) and of the sampling method and analytical method used. This document is applicable to all steps of a measuring procedure. This document is applicable to measuring procedures with separate sampling and analysis steps, and also to direct-reading devices.