ROFA is a second generation Over Fire Air (OFA) system. The volume of the furnace is set in rotation via special asymmetrically placed air nozzles. The unique positioned air nozzles generates turbulence and rotation in the entire furnace. Rotation prevents laminated flow and the whole volume of the furnace can be used more effectively for the combustion process. The ROFA dramatically reduces fly ash, i.e. unburnt content in the flue gas.

With the ROFA technique surplus air can be reduced without increasing CO or other unwanted substances. The combustion air is mixed more effectively. The result is less cooling of the furnace due to unused combustion air, thereby increasing efficiency.