The On Scene Size Up

Size up begins after a call is dispatched. On the ride to the scene, all members should start to think about all potential impacts that the location will have on the type of incident. Upon arrival of the first due officer in charge he or she should give a detailed description of the incident over dispatch to advised all in coming units of the situation.


The on scene size up should be transmitted in a clear and understandable manner. It should contain specific details regarding the location, type of incident and any other important information that may be a factor in brining the incident under control. There are many different types of templates for the report. The photo below shows a guide that was created for and is used by the Allendale Volunteer Fire Department.3

The Structure Fire guide consists of seven steps; confirm the address, describe the number of floors, occupancy, conditions found, water supply, mode of attack, and finally establish command.

Setting the Scene

When arriving on scene it is extremely important to confirm the dispatch address because you want all incoming units to know the correct address. It may determine certain special tactics such as condo complex or an occupied multiple dwelling.

Announcing the number of floors and occupancy is vital because it will allow for units to begin thinking about what tools and methods they may use at the incident. For example a one story residential type dwelling the truck company may use more ground ladders around the entire structure compared to a high-rise incident. Occupancy is a key component to the report because it will dictate certain operational tactics based on the risk-benefit analysis of life safety.

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Pertinent information is vital due to the fact that it may completely alter your plan of attack. If the dwelling is set far back in a gated area then maybe the rig won’t be able to make it into the property. You can also be faced with a natural factor where the landscape changes in the rear of the structure and what was initially a one-story dwelling is in fact two stories from the rear.

Water Supply and layout info is important for incoming engines because it allows them to get an idea of where the nearest hydrant is or even a static supply such as a pond or river.

Mode of attack describes whether units are investigating the scene, offensively or defensively attacking the fire. 2Investigative mode refers to units arriving to a reported fire and finding nothing visible on arrival however units continue to search before deeming it unfounded. Offensively attacking and making a push allows for incoming units to understand that they will most likely be assisting with interior operations, search, etc. The defensive attack refers to an exterior approach that may require master streams, ladder pipes, and a larger water supply. (The photo to the right shows a well off end unit of a condo complex. Tactical considerations must be made such as setting up master streams to control it while protecting the exposures and potential extension to other units.)

The Auto Accident side follows a similar method as the structure fire card. Again, confirm the dispatch address, and then begin to assess the scene. Announcing how many and the types of vehicles involved can assist with distinguishing the patients mechanism of injury such as with convertible rolling over units may be presented with a more traumatic patient rather than a door pop in the school parking lot. Describing the conditions found is also vital because it will allow for specialty units to think about how they will stabilize the vehicles and what other equipment they made need to safely extricate the patient.


A proper size up benefits everyone on scene and it also allows for the Incident Commander (IC) to set the expectations of the operation. If the IC sounds hyped up then there’s a chance that the responding personnel will also get in the same manner and there is potential for unorganized chaos on scene. If the IC is calm, cool, and collected, then he or she will be able to establish a presence that the incident will be handled in an organized and professional manner.

The size up report is one of the most important components of basic incident stabilization and operation. Make sure to check you department’s SOG regarding the size up and if you don’t have one established yet. Draft something up, suggest it, and start using it. Remember to stay rescue ready and always stay proactive. Remember that the size up is always on going as condition change. Things happen, be prepared for variations. Always have a plan A, a back up plan B, then begin thinking about a plan C, and so on for a successful operation.

Flow and Vent was founded by a couple firefighters who believed that there is more to the fire service than just being a t-shirt fireman. It is a page dedicated to providing some tricks to the firefighting trade. We are going to provide you with drills, methods, and insights on things that we have found effective in performing the job. Our administration is made of a breed of young firefighters, raging from all walks of life and completely different departments. However, we have one thing in common, we love the job.

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