The 360° size-up is a must do task at every structure fire. It provides us with vital information to many factors so we as fire officers can formulate our IAP (incident action plan) to best attack and extinguish the fire. This is accomplished by actually walking around the structure and looking for clues and cues. Simply obtaining a three-sided view from our apparatus upon arrival is not effective and we may be missing the bigger picture.
Here is what I feel are two of the most important factors to look for so we can make the best decisions to bring the situation under control as safely and effectively as possible.
The doors and windows provide the most obvious clues as to what is happening inside of the structure.
What to look for:
- Number of openings
- The locations
- Fire conditions
It’s important to know how many and where they are not only for a secondary means of egress but also what fire conditions can we see. It is important to note if these openings are intact or have failed due to rapid fire progression. If the windows have failed, there is little we can do to control the impending flow path without either closing/controlling the doors or creating a new path for the products of combustion to travel to.
Due to the newer products that are burning in our homes and business these days, flashover is occurring in as little as 3-5 minutes. With modern building construction taking a turn towards cheaper and more energy efficient practices, rapid fire progression and/or collapses will occur more violently and more frequently.
What to look for:
The volume and turbulence of smoke will tell us how much time that we have to extinguish the fire. If the smoke is turbulent and under pressure, this tells us that the heat release rate (HRR) is rapidly increasing and time is critical. Turbulent smoke will look angry and have a boiling effect.
With the newer products that are burning we need to realize that they are made up of frozen class B fuels. Petroleum products will produce black acrid smoke not always associated with high heat.
This leaves the direction or “flow path” of the smoke. Smoke is a product of incomplete combustion that is unburned fuel comprised of particulates of gases and vapors that have yet to meet the right mixture to sustain flaming combustion.
Reading the smoke is like reading an instruction manual. The volume, turbulence, and direction will dictate our future actions.
Here are three ways to become better at size-ups:
- Use the TIC (thermal imaging camera) on the walk around. Look at the heat signatures of the openings. Make a mental note of where the products of combustion are accumulating or traveling.
- If a door is open, close it! This will buy us time to get our attack lines into place without allowing more oxygen into the fire.
- Communicate the information to everyone via radio. Help others to see the bigger picture so we all become safer and more efficient on the fireground.
Using the cover photo, post your size-ups in the comments below. Remember to keep it brief and concise.
Photos courtesy of John Dixon and Brett Dzadik.