According to the Merriam-Webster dictionary, to personify something means “to conceive of or represent as a person or as having human qualities or powers.” In the story, the house is personified throughout the whole story, and when the fire starts, it becomes a battle for survival between the fire and the house.
The way the author does this is through his use of verbs. He utilizes human actions and attributes them to the fire.
“It (the fire) fed upon Picassos and Matisses...baking off the oily flesh…” (Bradbury 2).
Here, the fire is in a feeding frenzy and baking the contents of the paintings.
“Now the fire lay in beds, stood in windows, changed the colors of drapes” (Bradbury 2).
Now, the fire "lays" in beds, "stands" in windows, and "changes" the color of the drapes. Laying, standing, and changing are all human actions that Bradbury has given to the fire to personify it.
When the blind robots appear and fight the fire by shooting a green chemical at it,
“The fire backed off, as even an elephant must at the sight of a dead snake" (Bradbury 2).
This shows hesitation on the part of the fire and concern for its survival. However, the final personification comes when the author gives the fire the ability to think, and it outmaneuvers the house.
“But the fire was clever. It had sent flames outside the house, up through the attic to the pumps there. An explosion! The attic brain which directed the pumps was shattered….” (Bradbury 2).
After destroying the pumps,
"The fire rushed back into every closet and felt of the clothes hung there” (Bradbury 2).
The fire is rushing and feeling. These are all terms that would be associated with a human being. Finally, the fire, which has systematically killed off the house,
“….burst the house…. puffing out skirts of spark and smoke” (Bradbury 2).