Most atrium smoke control systems are designed using the equation method which is based on a steady analysis. This webinar discusses fundamental concepts of the equation method including the axisymmetric plume, the balcony spill plume, the window plume, preventing plugholing, and airflow to control smoke flow. The relation between the equation method and computational fluid dynamics (CFD) is discussed. AtriumCalc is a spreadsheet application for the analysis of atrium smoke control systems.