New report looks at impact of chimney top appurtenances on flue gas flow

The main function of a chimney structure is “draft” through which, flue gases and smoke are removed from the building. Several parameters influence draft including the chimney height and the temperature differences between the outside air and combusted gases inside the flue. Flow resistance decreases the induced draft. Moreover, additional turns and sharper parts in a chimney also influence the process and often maximize the flow resistance and minimize the draft in the system. Furthermore, rain caps and other terminals increase flow resistance depending on the terminals’ materials, geometries, and size. Proper design of a venting system requires information and...