The First-Alarm Chief At Mercantile and Warehouse Fires
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Two factors are immediately obvious about Phoenix, Ariz., and they have an impact on fire protection.
- While several high-rise towers and multistory buildings can be found along the central business corridor, the development of the city is 95 percent single-story construction. This includes a preponderance of medium to large-size mercantile and warehouse occupancies. They are often attached in rows of three to six businesses.
- The climate is very hot and dry. The weather subjects structures and often their contents to extreme drying actions, as can he expected at 112 degrees and 15 percent humidity. Buildings burn much faster and flashover is accelerated. These conditions are also hard on fire fighters, who reach the limits of exhaustion from heat stress in 20 minutes or less when working with full protective clothing.
Rapid interior attack
These conditions have encouraged the Phoenix Fire Department to concentrate on rapid interior attack by the first-alarm crews. The fireground commander attempts to gain control of the mercantile or warehouse fire before the interior becomes untenable and the attack crews need to be replaced with fresh personnel. This translates into very aggressive tactics.
Phoenix is an example of a new and fast-growing Southwestern city. From a population of under 50,000 in 1945, it has grown to over 800,000 and covers 330 square miles of Arizona desert. Continuing growth in population and area are projected for the next 20 years as more and more people are attracted to the warm, dry climate. Phoenix now has the ninth largest population in the United States and a fire department which must be creative and innovative to simply keep up with the city’s growth.
The fire department currently has 923 personnel operating 36 engine companies, eight ladders and one heavy squad. With this highly decentralized environment, the department places a heavy emphasis on maintaining the effectiveness of each individual company, stressing standard company operations and fireground procedures. Staffing is maintained at a minimum of four in each company to provide a standard level of operational capability. The capability of each individual company becomes particularly important when the first-arriving company is often three to five minutes ahead of the next unit, and ladder company coverage is particularly thin.
photos by Nancy Engebretson.
Most of the mercantile and warehouse structures have masonry walls supporting wood truss roof systems, either heavy bowstring trusses or newer lightweight truss roofs, with large undivided areas and frequent gaps in separation walls. Most of the working fires and multiple alarms in Phoenix occur in this type of occupancy.
This translates into aggressive tactics and rapid calls for multiple alarms to get back-up crews into standby positions.
Offensive vs. defensive
Aggressive interior attack operations are referred to as offensive tactics. The department makes a very clear distinction between offensive and defensive modes of operation, primarily as a personnel safety concern. When a fireground operation is in an offensive mode, all efforts must support attack crews advancing interior lines toward the seat of the fire. If the fireground commander determines that the degree of fire involvement or structural conditions have made interior attack unsafe, a defensive operation is initiated. In a defensive mode, water is applied from the outside with heavy stream appliances, while all personnel are withdrawn to safe positions.
The fireground commander must maintain a continuing evaluation of the effect the attack is having on the fire- and the effect the fire is having on the structure. The large-area, single-story buildings tend to deteriorate very rapidly, leading to sudden structural collapse. The fireground commander must be prepared to withdraw interior crews and switch to defensive tactics as soon as it becomes evident that interior attack is not gaining control of the fire. A successful interior attack must be strong, fast and fully supported.
The normal response to reported structure fires in Phoenix is two engine companies, one ladder and a command officer, but dispatchers have the option to double this assignment when a working fire is indicated by callers. Experience has shown that dispatchers can identify-by tone of voice and number of calls-significant working fires with well over 90 percent accuracy, and the optional heavy assignment has saved many buildings. The heavy first-alarm assignment provides the capability to launch a dual position attack with adequate water supply and ladder company support with a minimal delay.
Standard operating procedures
Fireground operations in Phoenix are programmed by standard operating procedures which define specific methods and responsibilities on the scene of an incident. This system depends on the skills of a fireground commander who is responsible for directing and coordinating the actions of all companies on the scene. The officer in command of fireground operations must develop a plan which addresses three priorities-rescue, fire control and property conservation-while providing for the safety of all fire department personnel.
The first-arriving company officer formally assumes command iesponsibility until relieved by a command officer. The command structure can be expanded, depending on the needs of the situation, in a logical system which is defined in the procedures.
The standard operating procedures provide a basic framework for all types of operations. Each procedure defines an approach, a set of objectives and responsibilities and a set of operational guidelines for a specific component of fireground operations. These procedures include command, staging, tactical priorities, communications and safety, among others.
The system provides the fireground commander with options supporting coordinated attack operations. Each company officer knows the standard approach and specific responsibilities of an assignment when it is ordered by the officer in command. Tactical plans for specific types of situations (i.e., high-rise fires, freeway incidents, hazardous materials incidents) give the command officer a standard approach for coordinating and combining the standard operations in complex incidents.
Correct strategy
The fireground commander is responsible for determining and implementing the correct strategy to deal with each situation. This is translated into objectives for each company or group of companies working on the incident. At working fires, sectors are established and companies with a common objective are grouped under the direct supervision of one officer. This reduces the fireground commander’s span of control and delegates responsibility for one specific objective or one area of the scene to each sector officer.
Each sector officer’s assignment should have a specific objective, either a tactical mission (“Cut off fire extension to the west”) or a standard function (“salvage”). Such assignments frequently involve an evaluation of conditions and a determination of the resources required to accomplish the objective. The fireground commander is the resource allocator and overall coordinator for the sectors, although the sector officers must coordinate their operations with each other at points of mutual concern (i.e., roof sector must coordinate ventilation with interior).
In a typical situation the fireground commander may determine that an interior attack from front to rear is the best strategy to confine the fire.
The interior sector would be assigned this objective, while the sector officer in the rear would be prepared to support this strategy with ventilation and exposure protection. The rear sector would not attempt an interior attack against the interior sector’s advancing crews. The roof sector officer would go to the roof and perform vertical ventilation in coordination with the attack.
Information relay
Each sector officer relays information back to command and to the other sectors on visual observations of conditions, progress toward objectives, safety, and the need to reevaluate the overall strategy of the operation. The fireground commander must constantly monitor and evaluate this information.
Speed, mobility and offensive power are the most important factors in the Phoenix approach to interior attack. All personnel involved in interior operations use positive pressure SCBA, both for personal safety and to improve the effectiveness in advancing toward the seat of a fire. Preconnected lines provide immediate attack and mobility, with sufficient flow for most interior fire load situations. Most Phoenix engine companies now have 2-inch attack lines with automatic nozzles, providing well over 200 gpm with a 200-foot preconnected line. The remaining engines will be equipped with this capability within a year. These engines also have preplumbed master stream nozzles to allow for a quick knockdown of heavy fire involvement before interior attack begins.
On a mercantile or warehouse fire assignment in Phoenix, the first-arriving engine and ladder company proceed directly to the scene and commence standard operations while all other companies stop short until directed to a specific task by the officer assuming command. This staging system is meant to assure that everyone on the scene is working within the same plan. Companies do not simply rush in and commit thelmselves to the most visible need from their perspective, but rely on the fireground commander to identify and prioritize assignments.
Water supply
In an offensive situation the firstarriving engine company always tries to find the best position to extend preconnected attack lines into the fire area. Phoenix engine companies use 3 1/2-inch supply lines with Humat valves. The first engine company is supplied with a 600-gpm supply as soon as the line is hooked up and at least 1000 gpm when a later arriving engine company connects to the hydrant and pumps the supply line. With four engine companies on a working fire, this capability can be provided at two locations. This type of water supply gives the option of using a master stream device or a combination of hand lines. It allows a company close to the fire building to supply several companies with interior hand lines.
Unless the ladder is needed for rescue, ladder companies are expected to position their apparatus for defensive operations. If interior attack proves ineffective and a change is made to defensive tactics, the ladder company’s apparatus should not have to be repositioned. Most ladders in Phoenix have prepiped high-volume elevated stream appliances which can be placed in operation quickly. Defensive positioning means that the apparatus is in a location where the elevated stream could work effectively on the fire and protect exposures but is out of the range of falling walls. Since most roofs in Phoenix can be reached with a 24-foot extension ladder, the aerial is not usually needed for aboveground access.
While engine companies attempt to reach the seat of the fire through the interior, attacking from the unburned side whenever possible, ladder companies provide a standard set of support functions. In large area warehouses, rooftop ventilation is usually critical to avoid mushrooming and interior flashover. Wood roof assemblies are prone to rapid horizontal fire extension and loss of structural integrity, so ventilation must be accomplished quickly and effectively. The officer in charge of rooftop operations must coordinate efforts with the interior sector officer to locate the position where ventilation is needed and to assess the effectiveness of their efforts. If ventilation cannot be accomplished safely, the fire often forces crews to abandon the attack and switch to a defensive strategy.
Safety
Phoenix takes a very serious approach to fire fighter safety. All fire fighters are provided with complete protective turnout clothing, including Nomex hoods. The use of SCBA is mandatory for all personnel operating inside, on the roof or anywhere that products of combustion are encountered. At major fires, personnel are specifically assigned to monitor safety conditions, including structural stability, to supplement the ability of command officers to assess the ongoing safety of operations.
The decisive action in mercantile and warehouse fires usually takes place in the first few minutes and depends on the ability of interior crews to get inside, operate directly on the seat of the fire and prevent the fire from mushrooming under the roof or through the attic. This type of combat requires a heavy commitment of resources to a coordinated attack plan.
The department’s new computeraided dispatch (CAD) system features mobile digital terminals in each vehicle. These terminals automatically transmit up to 10 pages of stored tactical information on an occupancy to video terminals in all responding units. The command officer receives text information about the contents, special hazards and any temporary conditions affecting the occupancy, plus a map of the surrounding area and diagrams of floors plans. Over 1000 occupancies are already in the system and several thousand more are scheduled to be entered. This is expected to make fireground operations even more effective by providing the command officer with critical prefire planning information during the early stages of an incident.
The three tactical priorities provide the basis for all fire fighting operations in Phoenix. The first objective is always rescue. The fireground commander must focus on that objective and support interior search and rescue operations until the rescue concern is satisfied. While fire attack may be needed to support search and rescue, the control and confinement of the fire is actually the second objective. Once the fire is controlled, the fireground commander moves on to the third priority-minimizing the property loss through salvage and overhaul. This is especially important at warehouse fires. The system has proven very effective with the Phoenix Fire Department.
