Final answer:
The critical factors when dealing with structured fires include having means available for attack, delivering an attack at a favorable moment, and assessing the situation and dressing appropriately.
Step-by-step explanation:
When dealing with structured fires, there are several critical factors to consider. First, it is important to have means available to carry out an attack, such as fire-raising materials. Second, if there is a possibility of an external fire, it is recommended to not wait for it to break out within and instead deliver an attack at a favorable moment. Lastly, there is uncertainty and potential for extreme physical danger during firefighting operations, so it is crucial to assess the situation, report conditions, and dress with appropriate equipment.