Firefighting 101                                                         by:  Dan Howell

Size Up

Firefighting is accomplished through the execution of a series of decisions. In order for these decisions to lead to a safe and successful outcome, they must be based on accurate and complete information. In the fire service, this information is gained through size-up.   Within a matter of seconds, information regarding response, scene layout, building construction, weather, time of day, fire involvement, life safety and water supply must be gathered and used to determine the initial course of action. This information must be gathered in a systematic size-up that evaluates the entire fire scene and takes into consideration the basic fundamental priorities of the fire service. Furthermore, size-up must continue throughout the incident, constantly evaluating the results of decisions made. Accompanied with good size-up is an incident that is far more likely to be professionally and successfully mitigated.

 Size-up begins with the initial alarm and response. Immediately, the type of call, weather, incident location and time of day are known. Based on time of day, volunteer departments may not know the number of available personnel and this should be carefully considered when determining if mutual aid is going to be needed. In addition to this information, there should be a general idea of the available water supply. Priorities at this time should be getting the initial engines en route that will provide for fire attack and water supply. During response, size-up will be assisted by updated information from dispatch and other units arriving on scene. This information will provide further details on water supply, responding personnel, fire conditions and any occupants in danger. This is why the initial report given by the first arriving units or personnel is so important. This report sets the tone for all other responding units.

 Upon arrival, the critical decision of apparatus placement must be made. Careful consideration should be given to radiant heat, collapse zones and any threatening hazards such as traffic and power lines. The placement selected should allow the apparatus to fulfill its role on the fireground. The attack pumper should be placed so that it can effectively launch the fire attack needed and still be supplied by an efficient water source. Tankers and shuttle trucks should not be bottled up, but free to deliver their water and leave to refill. In the instance of an aerial, it should have the access it needs to place its ladder in position to accomplish the task necessary at the time, whether it be a master stream, rescue or ventilation. It is important to remember that once the first hose line is stretched, the apparatus becomes an exposure to be protected. Furthermore, there are few things more disruptive to a fire ground than having to move a truck that has been improperly placed in regards to its safety, or a truck that cannot be effectively supplied with water.  

Beyond placement of apparatus, before effective operations can begin, the entire scene must be thoroughly evaluated by size-up. This size-up is performed by first taking a view of the overall scene. Once this is done a walk-around must be performed. This involves walking around the entire structure or in the case of large industrial buildings having reliable reports for all sides of the building. When this walk-around is performed all six sides of the structure should be examined. The six sides include all four sides, A, B, C and D, the attic and the basement. This walk-around is crucial for the safe operation of the scene; critical information may remain hidden if all six sides are not accounted for.

It only takes a few seconds and its omission can lead to disaster. By the time that the initial size-up and walk-around are complete, information regarding life hazards, dangers to firefighters, building construction, fire conditions, utilities, threatened exposures, likely avenues of fire spread, initial fire attack, ventilation and additional resources needed should be available. This information should allow for decisions to be made about strategy and the tactics needed to accomplish the challenges of the incident.

 As the scene progresses, so must the size-up. Every aspect of the scene must be constantly evaluated. All operations must be monitored for safety and effectiveness. This is tremendously important with the condition of the structure. If interior fire attack is not making rapid progress, do not hesitate to withdraw to safer positions. Furthermore, the dangers of  lightweight construction and trusses cannot be over emphasized. If trusses are burning do not be on them, under them or beside them. Remember, if it is burning, it will fall down! Evaluation of the scene will not end until well after the fire is out and the department has had the opportunity to critique the incident and learn from mistakes, reinforce what went right and make any changes necessary.

To effectively face the challenges of an incident, good information is mandatory. This information is obtained through a systematic and ongoing process called size-up. It involves examining every aspect of the fire scene and making correct intervening decisions. When combined with a well-trained fire department the outcome can only be a scene that was handled safely, professionally and given its best opportunity for a successful conclusion.