Size-Up

Size-up is defined in most fire service texts as the on going evaluation of problems confronted within a fire situation.


As a firefighter assigned as a member of the interior search and rescue team, you will be operating with a partner to search the building before the first hose line. Your required tasks include ventilation, entry and search, done to locate and confine the fire as well as search for civilian life hazard. Your primary duty is to find the fire for the advancing hose line.

As the apparatus turns the corner onto South Street, you see frantic civilians signaling to you and pointing toward a specific house.

During your approach to the scene, you observe similarly constructed homes all along St. Johns Place. These homes have an attached one-car garage. As you look at 175 St. Johns Place, you make the observation that there is no garage at this address. Instead, you see windows with an air conditioner in them, which indicates a structural change made to this building, which may indicate a separate apartment or living space within this building. An occupant appears and informs you of a smoke condition on the second floor. You ask this person if there is an apartment within this structure where the garage was. He confirms that there is indeed an apartment with one elderly resident residing there.

You then relay this information to the Incident Commander. He orders you and your partner to gain entry into this area and search for the possible origin of fire and victim before possibly going above the fire.

The origin of the fire was located within the converted garage and an elderly occupant was rescued. A potentially life threatening mistake was avoided by not rushing to the location of the smoke and being above the fire without a hose line to protect your team. This is all a result of an accurate size up.

Since entry into the fire service, most of us have been taught the importance of doing a size-up. What is a size-up and how should it be done? Are you showing your new members how to do it?

Size-up is defined in most fire service texts as the on going evaluation of problems confronted within a fire situation. Size-up starts with the receipt of an alarm and continues until the fire is under control. This process is carried out many times and by many different individuals at each fire or emergency event. The responsibility of size-up initially lies with the first officer of the first unit or company that arrives on scene. This responsibility is passed up the chain of command as other units arrive with higher-ranking personnel.

As firefighting is constantly evolving, so must our procedures for doing a size-up. All members must realize that this is not just a function of command, but also the duty of every firefighter to gain as much information as possible about conditions during a fire

The definition of size-up should be broadened so to state that size-up is a continuing evaluation of information received incorporated with your personal observations at a fire or emergency scene.

Personnel size-up starts every day that you might go to a fire, for the existing weather condition and how they might affect your fire department operations at a fire scene. Fire size-up should start at the receipt of alarm and continue until the last unit leaves the scene. Every firefighter and officer at the scene should constantly be doing a size-up. Any condition encountered or observed that could impact operations or the safety of firefighters, should be immediately passed up the chain of command.

The strategic factors that must be considered in size-up according to most firefighting training manuals are:

  • Time of Day
  • Life Hazards, including all firefighting personnel
  • Area of Building
  • Height of Building
  • Type of Construction
  • Occupancy
  • Location and Extent of the Fire
  • Water Supply
  • Street Conditions
  • Auxiliary Appliances (sprinklers, standpipes)
  • Weather Conditions
  • Apparatus and Equipment
  • Exposures
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