Knowing the building that is on fire is more important than knowing the fire that is in the building. The construction of the building will have a major impact on the characteristics of the spread of the products of combustion and is the key to both understanding and forecasting the most effective paths of least resistance for both fire spread and fire control.
Factors such as the location of the fire in the building in relation to the location of vertical arteries will aid in determining strategy and tactics. For instance, barring any wind condition that might adversely affect fire spread, a fire in an apartment near a window is more likely to vent out that window (creating an autoexposure problem). A fire in proximity to the entry door is likely to vent out the entry door, into the hallway, and up the stairs. These are the paths of least resistance. A fire deeper in an apartment not in proximity to these arteries will also look to spread upward, but may more easily find areas such as bathrooms and kitchens where the largest pipe chases in the building will provide the most effective path of least resistance for fire spread upward.
Understanding the types of building construction and the inherent weaknesses in each will guide the fire strategist in determining tactics regarding where to vent, attack, force entry, conduct overhaul and salvage, as well as predicting how the building is going to fall apart. If you are unclear on building construction and how it influences the fire, you are merely guessing (non-educated guessing) in regard to your operations.