Abstract: A three-dimensional model of a 20 story full-scale office building was built, and the influence of window on the vertical fire spread over the building facade was studied by setting different window area and location. It was found that: When the window area was larger, the vertical spread rate of fire was faster, and the indoor temperature raised faster. The large window-wall ratio accelerated the vertical spread of fire over the building facade. As the window moved upward in the vertical position, the ignition time of each floor increased.

Key words: building fire, facade, fire spread, window sill wall