"Water-cooling towers are heat removal devices used to transfer waste heat from various sources such as machinery or heated process material to the atmosphere. Common applications include cooling the circulating water used in oil refineries, chemical plants, power plants, and building cooling. Smaller towers are normally factory-built, while larger ones are constructed on site. The water-cooling tower in today's illustration is an 'induced draft' device that pulls air through the tower. The fan induces hot moist air out the discharge. This produces low entering and high exiting air velocities, reducing the possibility of recirculation in which discharged air flows back into the air intake, but also affects potential fire behavior."
Coffee Break Training - Fire Protection Series No. FP-2011-13
United States Fire Administration: http://www.usfa.fema.gov/