This European Standard specifies methods for the aerodynamic testing and rating of constant and variable flow rate terminal units suitable for use with air distribution systems.The terminal units consisted are:single and dual duct;induction;fan assisted induction(parallel and series);sing duct with integral diffuser.The tests for each type of unit are summarized in Figure 1.The tests in this standard are designed to detemine fully the aerodynamic performance of terminal units in an air distribution system.