ABSTRACT
This chapter discusses makeup air systems to satisfy the needs of workroom air exhausted where natural ventilation air changes are insufficient. When the amount of air exhausted from a work room or building exceeds three times the cubical contents per hour of such a room or building, consideration should be given to provide clean, outside air through a fan and duct system to make up the difference between the amount exhausted and at least three times the cubical contents exhausted for maintaining a slight positive pressure inside the building. The maintenance and operating costs are quite favorable. Only occasional cleaning of heat exchanger surfaces and burners are required. Since the basic need for a makeup air system is to supply replacement air to a space, they need to operate only when needed, when exhaust systems are in use. The benefits obtained through the installation of a makeup air system are well worth the investment.
