The Initial Size-Up

Nov. 19, 2007
Sizing up of the situation makes an initial defensive attack or a change of tactics from an offensive to a defensive operation justified.

Sizing up of the situation makes an initial defensive attack or a change of tactics from an offensive to a defensive operation justified.

Size-up of the fire building upon arrival is a critical, self-survival technique that must be completed prior to entering the smoke and heat of any interior operation. In the days when there were many fires that would develop a firefighter's experience level we could learn through "on the job " training so it was not necessary to train on size-up. But today, with the lower levels of experience and the explosion of quick-collapse, lightweight truss-constructed buildings, firefighters must train on size-up to survive on the fireground.

Size-up can be broken into four major factors: Construction, Occupancy, Life Hazard along with Location and Extent of the Fire. These factors are critical to understand prior to making any decisions to act on the fireground. They are also inter-related to each other. For example, upon arrival to the fire scene, we cannot get the big picture of the construction style of the fire building without also considering the location and extent of the fire. What is the construction style and where is the fire? What damage has been done to the building prior to our arrival to the scene and what damage is going to be done in the next few minutes? In other words, to understand these two related size-up factors we need to use our fireground experience and book smarts to recognize the current situation and predict what will happen next.

Many times in the distant past, as well as this year, the fire service has seen multiple firefighter deaths and injuries, which could be attributed to the lack of a good size-up. A study of these incidents is likely to reveal a poor assessment done upon arrival and continuing throughout the incident. With the study of past fires such as these we should expect that these types of incidents would stop, but with all the duties that have been given to the fire service in recent years one thing that may have been lost in our training schedules is the size-up drill for fireground survival.

Simply recognizing a deadly situation such as a truss constructed roof or floor assembly that is exposed to fire and then performing a defensive attack will often be enough to bring everyone home. Sizing up of the situation makes an initial defensive attack or a change of tactics from an offensive to a defensive operation justified. Often a change of tactics is brought about by reports made by firefighters on the scene that the incident commander (IC) would not normally be expected to have knowledge of like roof conditions.

Residential Structures
size-up of residences can be deceiving when we arrive to the fire scene. We must always be concerned with truss construction in residential occupancies. The question if any one certain residential fire building is truss constructed is not easily answered. A prime example of this is the way that platform frame and lightweight truss built residences will present themselves on the fireground. They will look very similar, are easy to confuse in fully built form and both types are still being built today. These two building styles will also perform vastly different under the same fire conditions. Without actually witnessing the erecting of the residence it is not easy to know what holds the building up.

In these cases it is best to work on the idea that the building is in fact truss supported until we can confirm or deny it by investigating it further. In this situation the best way to determine the construction is to pull some ceiling with a pike pole at the front door and use a thermal imaging camera (TIC) to look for truss or dimensional wood joists. If a TIC is not available it is best to pull ceiling in a non-smoke filled area of the building to examine how it was built before entering. Any truss exposed to any heat or fire should tell us that at least that section and possibly the entire building is ready to collapse and we should not enter for our safety. Fire in the truss area should also be reported to the IC so everyone on the scene will know the situation.

The last two critical size-up factors that must be recognized upon arrival are occupancy and life hazard. These again are inter-related to each other. For example; is the fire building residential or commercial? If it is residential we can expect that there may be persons inside that need to searched for because they are unable to help themselves. Persons sleeping in bed may not know there is a fire because they are not conscious to begin with.

Although this idea of search and rescue for sleeping persons in a residence at 2 a.m. is not a new idea to the fire service, the size-up of the occupancy prior to entering is beneficial and should be considered. For example is the building a two-unit apartment building or is it a single-family residence? With each of these occupancies where will the bedrooms be located? A single-family house will have all or most of the bedrooms grouped together whereas a two-unit apartment building will have two sets of bedrooms because there are two separate living units inside.

Also with the above occupancy examples, how does this change the primary and secondary egress for searching firefighters? Where will the secondary door be if we cannot drag a civilian back the same way we came in? To ensure our safety, a good understanding of the occupancy will help us determine where the exits of a single-family or a two-unit apartment building would be prior to entry.

Commercial Structures
Commercial occupancies will differ significantly from a residential occupancy concerning life hazard. This is because, in a residence we can expect to perform search and rescue, but in a commercial building fire it can be expected that most or all of the victims will run out (if they can move on their own). The reason for this is that no one is sleeping when the fire started. Commercial occupancies are usually places of business. All the occupants have to do is find out about the fire and they will leave.

So the question on commercial occupancies for firefighter safety is this; do we search a commercial occupancy like we search a residence? Of course the answer is no, but some of the justification for firefighter injuries and deaths in commercial occupancies by the local fire department's media affairs person sounds like this; "We didn't know if everyone was out so we went in". This is certainly not good enough to protect our members and may just be a case of little or no size-up training for first and second due fire companies.

The big thing to remember when we arrive on the scene of any fire emergency is to perform a size-up. This is if you are the first-due company to the scene or you are assigned the task of rescuing injured firefighters. A good size-up consists of at least four factors. They are Construction, Occupancy, Life Hazard along with Location and Extent of the Fire. There may be additional factors for different situations to consider as well. There may be questions to answer like, "What is the manpower on the scene?", "What are weather conditions?", "Where is a good water supply?", "How are street conditions?", "Are there any hazardous materials?", etc. All of these answers will also help ensure the safety and effectiveness of your crew.

The vast majority of the information that you will collect and that will keep you alive while performing an interior operation will be gathered outside the fire building before you enter. The reason for this is when a firefighter gets inside there is an inherent "tunnel vision" because all they can usually see is smoke on the outside of the SCBA mask. That may not be enough information to survive as the situation rapidly deteriorates around you if you don't size-up before entering.

Jim Mason has over 20 years in the fire service and serves as a lieutenant with the Chicago Fire Department. As a firefighter he has been assigned to engines, trucks and heavy rescue squads. He is a lecturer on fireground operations and is currently serving on a International Association of Fire Fighters committee to help develop a firefighter self-survival program.

Voice Your Opinion!

To join the conversation, and become an exclusive member of Firehouse, create an account today!