There was a stairway in the living room which goes up to a perpendicular second floor hallway. At both ends of the hallway were bedrooms which had the doors closed, but in the middle of the hallway, almost directly across from the stairway was a bathroom with a .61m by 1.98m doorway wide open. To make matters worse, there was a .61m by .43m open window inside the bathroom; which itself was a 2.26m by 2.23m room.
The open bathroom window acted to ventilate the smoke and fire upstairs and into the bathroom, causing higher temperatures and more damage. This can be backed up by the first floor thermocouple temperature graph which clearly demonstrated that the higher in the room the thermocouple, the higher the temperature; as well as the radiant heat flux measurements which indicated that the heat was most intense near the ceiling and most likely traveled up the staircase and into the second floor bathroom. ("Report of Test, Figs. 5,6") but before it traveled upstairs, the fire started in the corner of the...
But then it traveled both up the staircase as well as into the dining room. And since the dining room was not ventilated, but the upstairs bathroom was, the fire was ventilated into the bathroom at a rate equal to or greater than it spread into the dining room. In other words, the open door and window in the upstairs bathroom caused the smoke and fire to travel upstairs as fast as it traveled through a big opening and into the next room. This clearly demonstrated how air and smoke circulation and ventilation can influence the development and spread of fire.
References
Corbitt-Dipiero, Cathleen. (n.d.). "Fire Investigation Mythunderstandings."
InterFIRE.org. Retrieved from http://www.interfire.org/features/indicators.asp
"Report of Test FR 4009" (1998). InterFIRE.org. Retrieved from http://www.interfire.org/features/fire_experiment.asp
