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Sizing-up the fire ground

Firefighter safety must be every incident commander’s objective. The first steps toward crew safety on scene are size-up and the 360-degree walk around.

August 28, 2014 
By Neil Campbell

Firefighter safety must be every incident commander’s objective. The first steps toward crew safety on scene are size-up and the 360-degree walk around.

fire ground  
ICs must consider weather and wind, time of day, smoke conditions, find the seat of the fire, look and listen for trapped occupants, check for signs of structural collapse, consider ventilating the structure and, most importantly, consider how all of these factors affect responding firefighters.


Gathering information is the foundation of the decision-making process. Information gathering starts the moment contact is made with dispatchers. Immediately, responding crews know the time of day and the weather. These details are extremely important. A residential structure fire at 1 a.m. can present challenges different from those at 1 p.m.; people are usually home in the early hours of the morning and rescue may be the focus. Weather can affect any incident. Windy conditions, for example, can be unpredictable and wind-driven fires can be extremely challenging. Strong winds can change the IC’s plan for attack, and ventilation must always be considered.

Once on scene, the IC must broadcast what he or she sees to all responding units; simply put, say what you see. An initial size-up report will help build a picture for others who are responding. The initial report should identify the type of building construction, the structure’s height and type of occupancy, the building dimensions and whether smoke or flames are showing. For the incoming units there is a huge difference between hearing “Engine 1 is on scene at 875 Waters St.” instead of “Engine 1 is on scene at 875 Waters St. We have smoke and flames showing on the Bravo side of an apartment building, type-five construction, 50 feet by 200 feet, three storeys tall. We are catching a hydrant at the corner of Waters and Summit Drive. Engine 1 will be command on the Alpha side.”


The goal of the initial report is to help all responding members understand what they may face at the incident.

Command needs to be established by the first-in officer. A report identifying the unit first on scene, conformation of the address, and the location of command need to be relayed to dispatch and all responding units. This information helps to ensure the units are able to stage nearby, secure a secondary water supply if required, or report directly to the IC.

Once the initial on-scene report is complete, the IC must do a 360-degree walk around. This is a fact-finding assessment during which the IC tries to identify many things, mainly the location of the fire. Many firefighters have died after they entered smoke-filled structures unaware of the location of the fire and ended up in the worst place possible – above the seat of the fire.

A thermal imaging camera (TIC) is an excellent tool for the IC to use during the 360-degree walk around. TICs can help to find super-heated conditions inside the structure. Unfortunately, not all fire departments have TICs. An alternate method for finding the seat of the fire is to follow the smoke. Smoke turns from light, wispy laminar smoke to pressurized, boiling smoke when a room or structure can no longer absorb heat. Turbulent smoke is an indicator of super-heated conditions inside the structure. Turbulent smoke is also precursor to flashover and needs to be recognized in its earliest stage. Follow the smoke and you will find the fire. If the IC completes the 360-degree walk around and still isn’t able to locate the fire judging by smoke conditions, then he or she must assume the fire is on the lowest floor of the building or in the basement. It should be the goal of every IC to clearly explain to members of the interior operating teams where the fire is located before they enter the structure.

Also during the 360-degree walk around the IC looks and listens for any signs of a required rescue. A civilian needing rescue becomes a priority and may halt all other fire-ground tasks. Not all rescues require firefighters to enter the structure. More often than not, a civilian rescue can be accomplished with a ground ladder. People inside structures usually attempt to self-evacuate. Those who can not escape will likely be found in staircases, near windows or on balconies.

During the walk around, the IC must also think about ventilating the structure. Ventilation immediately improves the chances of survivability for civilians trapped inside. Opening up the structure as close to the seat of the fire as possible, then incorporating positive-pressure attack with high-pressure fans can create a flow path of fresh air inside the structure to move super-heated fire gases and smoke away from civilians who still may be inside.

One major factor that has the potential to dictate how and where the structure is ventilated is wind. Wind velocity as low at seven kilometres per hour (km/h) can overpower a high-pressure fan and render it useless. Wind velocity as low as 15 km/h can produce a wind-driven fire inside a structure that may result in extreme fire behaviour and rapid fire spread; both are extremely dangerous to firefighters attempting to enter a structure. Wind conditions can change the IC’s plan for an interior attack and force the responding crews to initiate an exterior fire attack instead.

If the situation has progressed past a room-and-contents fire, the IC must look for signs of structural collapse. Two indicators that the IC will always apply to a potential collapse are the presence of brown smoke and the amount of time that has passed since the fire was reported. Brown smoke indicates that unprotected wood is burning, which means the fire is structural: wall studs, floor joists and roof trusses are being attacked by fire and the moment that happens, the structure starts to weaken. The IC must always know how long the fire has been burning and constantly re-evaluate interior operations. After firefighters have spent time inside the structure without establishing fire control, the IC has to consider transitioning to defensive operations.

The IC looks for a multitude of other things, such as the location and securing of utilities and any indication that the fire was intentionally set or the possibility of a clandestine drug lab being located inside the structure.

There is a lot of pressure on the IC to get a plan in place and start tasking the responding manpower. But the IC must ensure the walk around is not rushed; if he or she moves too fast something important may be missed.

Without a proper size-up, the IC will be at a huge disadvantage when trying to keep the crew safe. 

Neil Campbell is a fifth-generation firefighter with the City of Kamloops. Contact him at

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