Some texts suggest that the first officer to arrive at the fire scene is relieved of all size-up responsibility once a chief officer arrives on scene. Is this really the case? What about firefighters operating the line or making a search above the fire? Are they relieved of responsibility for sizing up the fire? Size-up is everyone’s responsibility, whether in command or not. The firefighter with two months on the job may have a piece of information (a piece of the puzzle) the chief officer stationed in front of the building may need to complete the puzzle.

( ity of New York Fire Department Deputy Chief Vincent Dunn, a noted author and lecturer, stresses that firefighters continuously are sizing up a fire. They take in information they hear, see, smell, and touch, whether consciously or subconsciously. If this information is never passed on, it is for all intents and purposes useless as far as mitigating the incident is concerned.


Generally, size-up begins with the receipt of the alarm and continues until the units are in service at the operation’s conclusion. However, information beneficial to a size-up can be gleaned prior to and after these general time boundaries. “Prior to an alarm” means any time a unit is out of quarters. Stop the apparatus, and look at buildings or hazardous areas. Ask questions of individuals at the location; ask questions of each other. Get information into your head. Pass it on to the incoming shifts and to other stations. Your next working fire just might be in the building you stopped to look at the previous day.

Size-up after an alarm and after a unit is in service can be achieved with formal and informal critiques. Discussing an operation and the conditions of the building in effect is performing a size-up in the event another fire occurs at the same location. As a company officer coming to work, I discuss fires and other emergencies occurring on previous shifts with the members involved and relay the information to the company members working with me. We then go to the location and look at the present conditions and perform a size-up for similar future operations at the same or a similar location.

Size-up is a continuous process. Look at buildings, streets, locations, and conditions any time and any place—in effect, size up for possible responses to such locations.


An effective size-up during a response involves the following considerations, which sometimes can influence each other (a severe snowstorm, for example, can affect apparatus placement):

Life. Life hazard is the department’s number one priority, and the life hazard or possible life hazard depends on many variables. On receipt of the alarm, the dispatcher may have given responding units information regarding the life hazard. Knowing your district can help you to better assess the life hazard —is the address in a residential or commercial area, for example? Once on scene, look for indications that people may be in distress —perhaps someone at a window or occupants or neighbors waiting to give you information concerning a life hazard within the structure. Realize also that the biggest known life hazard applies to us, the firefighters.

Time. A fire occurring during the early morning or late evening hours in a residential building means that you must make a strong commitment to search for life. A fire in a commercial occupancy during the same hours in many cases entails committing fewer personnel to searching for occupants, but the fire may have gotten a good headway because of a delay in notifying the fire department. The chief officer’s size-up of a response to a latenight working fire in a residential area should include the possibility of special-calling additional ladder companies to aid in the search for life. The time of the fire or emergency also affects street and traffic conditions. If the fire occurs downtown during business hours, response will be slowed and apparatus may not be able to attain the most effective positioning at the operation.

Occupancy. The first responder may have information concerning the type of occupancy when the alarm is received. If the involved structure is a commercial occupancy, what are the known hazards? If your dispatching system maintains information about buildings in the district, request it while responding. If the involved building is residential or public, life hazards will vary with the time of day or night.

Depending on the local code, the occupancy may have available in a designated area information that describes the automatic extinguishing systems present. Try to get as much information as possible about the occupancy while en route to the scene. The first-arriving unit at a working fire also should give the type of building and occupancy over the radio on arrival so that the other responding units may begin their size-up.

Weather. You know the weather conditions when you leave the fire station, and officers will know how it will affect the response. Weather can pose additional operational problems that become evident once on the scene, such as the possibility of rain during a haz-mat incident involving a spill of a water-reactive chemical. Many of you have worked at fires at which the smoke would not lift because of rain or fog. Size-up might include calling for additional air cylinders early in the operation. What about snow? I’ve been to operations where the apparatus could not get near the building and everything had to be carried through waist-deep snow.

Street conditions. While en route, get a preview of how street conditions will affect operations. For example, will the response of some apparatus be delayed by rush-hour traffic? Again, weather conditions may be a major factor in determining street conditions. At the scene you may encounter problems affecting the incident site. Street excavations, for example, may prevent the placement of the aerial or platform needed for rescue or ventilation. An automobile may be parked in front of the hydrant, delaying water supply to the handlines. Remember: As more apparatus respond to an incident, street conditions in the immediate area of operations are being altered. Spectators also affect street conditions, especially as they pertain to additional responding units.

Life hazard is the number one priority in the size-up process. Do you have adequate on-scene resources to handle the life hazard? If not, call for help—fast.

(Photos by Bob Pressler.)

Street conditions are an integral part of the size-up process. Work closely with emergency communications personnel and traffic control personnel to coordinate access to the fire scene. Time of day, weather, street construction, and spectators must be considered. Alternate access routes may be required.

Construction. You may know the construction of the building from the alarm information or may see it for the first time when you arrive. Frame construction has different features than fire-resistive construction. Different locales have different codes for buildings. Fires may spread as a result of the structure’s construction. Consider the collapse potential. Some types of buildings collapse sooner than others under fire conditions. Knowing about the various types of construction can help you to locate voids and possible survivors, and the knowledge can be expanded and reinforced during inspections.

Area. Your first opportunity to examine the area of the building may be on arrival. Do you have a small, onestory private dwelling consisting of 2,000 square feet? Or do you have a large factory complex? At haz-mat operations, what will your area of operations be? You may be dealing with a leak that will necessitate evacuating a square mile of the community.

Height. The height of the building may present problems. Is it within reach of the ladders your department carries? If it is within the ladder’s reach, is the apparatus that carries that ladder responding? Fires located on the upper floors of high-rise buildings necessitate additional staffing to get equipment to the fire location. At emergency operations, height applies to below grade as well as above grade. Well rescues have been in the news during the past few years. Are your units equipped to operate 60 or more feet below grade, or do you have to special-call additional resources from a nearby community?

Location and extent. Where is the fire or emergency located? How large is the fire? What is the scope of the emergency? Is the emergency/fire within the capabilities of the staff and equipment you have on scene or responding? A fire on the 50th floor requires different strategies and tactics than a fire on the first floor. Similarly, a fire involving a trash can is a different operation than one involving three floors.

Exposures. Looking at the exposure problem is important if you are going to prevent a one-building fire from turning into a multiple-building fire. Some of the factors to look at regarding the exposures include the following:

  • Construction — Is the structure brick or wood-frame? How are the exposures separated from the fire building: a 30-foot alley, brick nogging, a fire wall, or no separation at all?
  • Wind —From which direction is it coming? How severe is it?
  • Occupancies—Would you protect a parking lot before protecting crude-oil storage tanks? Evaluate life hazards in exposures.

A complete and early size-up must be performed with regard to all exposures.

Auxiliary appliances. The presence or absence of auxiliary appliances can make or break a fire operation. They include standpipe, sprinkler, foam, halon, and CO> systems. They also may include heating, ventilation, and airconditioning (HVAC) systems for smoke control. When arriving at buildings that have auxiliary systems, you must know whether they are activated manually or automatically.

I remember a fire in a large department store equipped with a sprinkler system throughout. Work was done on the system, and on completion a section was not resupplied with water. A fire erupted in the portion of the building covered by this section of unsupplied sprinklers, resulting in a firefighter’s death.

The presence of an automatic system does not always mean it is operational. Try to locate a building employee familiar with the system; keep him/her close to the incident commander in case assistance is needed.

Remember also that auxiliary appliances can be of great help in exposures. Standpipe systems in exposures, for example, can be used to feed defensive or offensive handlines at large operations.

Water supply. You may be saying to yourself: “We have all the water we need in our hydrant system.” But what about during the summer months? Are many hydrants opened in various areas by people who want to cool off? How do these openings affect the pressure of the hydrant you are using? Members may have to patrol during fire operations to shut down open hydrants in surrounding areas so that sufficient pressure can be maintained on the fireground. In rural communities, all water might have to be brought to the scene by tankers, or drafting operations may be needed. Sometimes private contractors shut down whole grids of hydrant mains to work on a section, without notifying the local fire company. If you are out in your community and see contractors digging up the street, stop and ask questions.

Exposure problems must be addressed early in the size-up process. Wind, type of occupancy, and construction features—such as the asphalt shingle siding of exposure #2—are vital factors in exposure size-up.Continuous size-up is mandated. Fire conditions change—sometimes rapidly—and an ongoing size-up can, among many things, help prevent injudiciously placed apparatus from becoming an exposure problem.

Apparatus and equipment. What apparatus is responding? Do you need any special equipment? How far do the apparatus and equipment have to travel? Do you have enough staffing on the apparatus? With budget cuts affecting many departments, it may take staff crews of two units to perform an assignment once done by one unit. The time to set up mutual-aid policies with other departments with specialized tools is prior to the incident. Dispatchers should have lists of the equipment carried on each apparatus so that when the incident commander requests a special tool, the apparatus carrying it can be dispatched immediately.

The above considerations are just starting points for performing preincident, on-scene, and post-incident size-up. As you know, many areas overlap, and some may not pertain to a particular fire or emergency.

Using these areas to structure your size-up process will help you become proficient in sizing up various kinds of operations.

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