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Size-up is all about gathering and evaluating information in order to make good fireground decisions. At the scene of a fire we gather and evaluate information at a rapid pace. Seldom is there time to thoroughly process and evaluate this information before we start making important decisions. Making quick decisions with incomplete information can create gaps in the decision-making process. What can we do to close the gap between making quick decisions and making accurate decisions?
One tried-and-true method we can use to close the gap is pre-planning our district. We can pre-load valuable information and knowledge about our district and the buildings we respond to in a controlled and deliberate manner, which will improve our ability to retain and quickly recall the information during an emergency. On the fireground, we will be able to make quick and accurate decisions with more complete information.
Who conducts the size-up? Everybody on the engine company should be conducting a size-up. Each member of the engine has a specific function or role at the scene of a fire, based on rank or riding position, and as such each has a purpose for conducting a size-up:
• The officer in charge (OIC) conducts a size-up to determine strategy, tactics, line selection and placement
• The driver/operator conducts a size-up to determine the best apparatus position and water-supply needs
• Firefighters conduct a size-up to make a successful stretch and advance to extinguish the fire
During the size-up, each member of the engine gathers and evaluates information about the structure in which we will be operating and about the fire within it. The information needed to size-up the structure can be pre-loaded ahead of time:
1. Occupancy (residential, commercial, industrial, etc.)
2. Construction (wood frame, ordinary, non-combustible, etc.)
3. Height (number of floors)
4. Size or area (square feet)
The information needed for the following part of your size-up will be different for each incident:
1. Stage of the fire (incipient, growth, fully developed or decay)
2. Location of the fire (Where is it? Where is it going?)
3. Extent of the fire (What portion or percentage of the structure is on fire – 25%, 50% or fully involved?)
4. Potential of the fire (What types of materials are burning and what is the fire load?)
5. Smoke (If no fire is visible, what is the smoke telling you?)
The size-up process
Size-up begins the moment the box is transmitted with the information heard from the radio dispatcher and the information read on the printout or mobile data terminal. Size-up continues while responding and on arrival:
1. While responding, are we sharing information and trying to paint a picture of what we will face?
2. Once we arrive, what are we seeing compared to what we pictured?
3. What are we hearing from people on scene, radio reports and fireground noise?
Size up is ongoing and takes place throughout the incident:
1. What action are we taking and what effect is it having?
2. Is it getting better or worse? Under control or out of control?
3. Are we applying water at the appropriate rate?
4. Is our stream reaching the seat of the fire?
Sizing-up for the stretch
The most critical portion of the size-up affecting the stretch starts on arrival at the scene:
1. Are you first due, second due, etc.? Your order of arrival on scene will determine your primary responsibility.
• Are you stretching the primary line to the fire floor?
• Are you stretching a backup line to the floor above?
• Or will you be stretching into an exposure to cut off fire extension?
2. What are the occupancy, construction, height and size of the structure? This information will tell you a lot about the fire’s potential:
• Is the fire in the attic of a row of lightweight-constructed, wood-frame dwellings?