Final answer:
Engine crews should wait to ensure the fire is extinguished, follow instructions, and have proper safety equipment before opening doors.
Step-by-step explanation:
Engine crews should wait for a few important things before opening doors into the fire area. First, they need to ensure that the fire has been fully extinguished or controlled, and there is no immediate danger of the fire spreading or reigniting.
This can be determined by assessing the heat, smoke, and flame conditions in and around the fire area. Second, they should wait for instructions from their superiors or incident commanders, who have a better understanding of the overall situation and can provide guidance on the safest approach to opening the doors.
Finally, engine crews should also wait for the appropriate personal protective equipment, such as fire-resistant clothing and breathing apparatus, to ensure their safety while operating in the fire area.