The Predictability of Performance In Structures during Suppression Operations

The essence of fire service suppression operations is predicated upon the deployment and application of water as an extinguishing agent, in sufficient quantities, location and duration to extinguish a fire within an enclosed structural compartment. The universal engine company correlation of: “putting the wet stuff on the red stuff” is fundamental to structural fire suppression operations but is ambiguous at best in the context of today’s modern building construction, occupancies, structural systems and building features. 
 
We used to discern with a measured degree of predictability, how buildings would perform, react and fail under most fire conditions. Implementing fundamentals of firefighting and engine company operations built upon eight decades of time tested and experience proven strategies and tactics continues to be the model of suppression operations. These same fundamental strategies continue to drive methodologies and curriculums in our current training programs and academies of instructions.
 
The lack of appreciation and the understanding of correlating principles involving fire behavior, fuel and rate of heat release and the growth stages of compartment fires within a structural occupancy are the defining paths from which the fire service must reexamine engine company operations in order to identify with the predictability of occupancy performance during fire suppression operations thus increasing suppression effectiveness and firefighter safety.
 
Our buildings have changed; the structural systems of support, the degree of compartmentation, the characteristics of materials and the magnitude of fire loading. The structural anatomy, predictability of building performance under fire conditions, structural integrity and the extreme fire behavior; accelerated growth rate and intensively levels typically encountered in buildings of modern construction during initial and sustained fire suppression have given new meaning to the term combat fire engagement.
 
The rules for combat structural fire suppression have changed, but we have yet to write the rule book from which the new games plans must be derived. We seek the elusive “Rosetta stone” that aligns and interprets the emerging and traditionalist acumen related to fire stream effectiveness, flow rates, cooling capacity, extreme fire behavior and fire dynamics, compartment fire theory, propagation and cooling capacity and tactical deployment all relate towards defining an engineering approach to firefighting tactics versus the manual, labor-driven tactics of line deployment and rudiment placement of water on a fuel source within the fire compartment (room).
 
It's no longer just brute force and sheer physical determination that defines structural fire suppression operations. It begs to suggest that many of today's incident commanders, company officers and firefighters lack the clarity of understanding and comprehension that correlate to the inherent characteristics of today's buildings, construction and occupancies and the need for refined engine company operations within the modern building construction setting. We assume that the routiness or successes of our operations and incident responses equates with predictability and diminished risk to our firefighting personnel.
 
 The work of such notable suppression theory pioneers as P. Grimwood, E. Hartin, S. Särdqvist and S. Svennson and the concepts surrounding 3D firefighting, B-SAHF and other emerging research from the NIST and UL are areas that today’s discerning and progressive fire officer and commanders must become well-informed and conversant. The quantitative scientific data and emerging concepts from continuing research and testing such as the NIST’s Wind Drive Fire Studies and UL’s The Structural Stability of Engineered Lumber in Fire Conditions are providing enlightenment on fire development, fuel controlled and ventilation controlled fire development, operational time-duration parameters and degradation and failure mechanisms related to compromise and structural collapse in occupancies.
 
Our current generation of buildings, construction and occupancies are not as predictable as past conventional construction, therefore risk assessment, strategies and tactics must change to address these new rules of combat structural fire engagement.
 
Building Construction Systems
·        Heritage:   Pre-1919
·        Legacy:     1920-1949
·        Conventional:       1950-1979
·        Engineered:          1980-2009
·        Hybrid
·        Chameleon
 
The fundamental compartment that comprised a typical room configuration in terms of area (square footage), volume (height/Width), furnishings (fire load package) and materials of construction (structural anatomy) found within conventional, legacy or heritage construction provided predictability in terms of fire suppression, fire behavior, operational time and survivability (civilian/firefighter). The dramatic changes since the early 1980’s in the evolution of modern building construction and the institutionalization of engineered structural systems (ESS) have created compartment (room) areas in excess 500 square foot, volumes that are open and spaciously interconnected to other habitable space, fire load packages that create extreme fire behavior, compromising structural stability in shorter time spans creating decreasing interior operational time and requiring increasing fire flow rates and volume to sustain requisite extinguishment demands.  
 
Commanders and Company Offices need to gain new insights and knowledge related to the modern building occupancy and to modify and adjust operating profiles in order to safe guard companies, personnel and team compositions. Strategies and tactics must be based on occupancy risk not occupancy type and must have the combined adequacy of sufficient staffing, fire flow and nozzle appliances orchestrated in a manner that identifies with the fire profiling, predictability of the occupancy profile and accounts for presumed fire behavior. Today’s engine company operations and fire suppression theory has to progress beyond the pragmatic approaches to fire suppression such as “Big Fire-Big Water principle.
 
When we look at various buildings and occupancies, past operational experiences; those that were successful, and those that were not, give us experiences that define and determine how we access, react and expect similar structures and occupancies to perform at a given alarm in the future. Naturalistic (or recognition-primed) decision-making forms much of this basis. We predicate certain expectations that fire will travel in a defined (predictable) manner that fire will hold within a room and compartment for a predictable given duration of time; that the fire load and related fire flows required will be appropriate for an expected size and severity of fire encountered within a given building, occupancy, structural system; in addition to having an appropriately trained and skilled staff to perform the requisite evolutions
 
Executing tactical plans based upon faulted or inaccurate strategic insights and indicators has proven to be a common apparent cause in numerous case studies, after action reports and LODD reports. Our years of predictable fireground experience have ultimately embedded and clouded our ability to predict, assess, plan and implement incident action plans and ultimately deploy our companies-based upon the predictable performance expected of modern construction and especially those with engineered structural systems.
 
If you don't fully understand how a building truly performs or reacts under fire conditions and the variables that can influence its stability and degradation, movement of fire and products of combustion and the resource requirements for fire suppression in terms of staffing, apparatus and required fire flows, then you will be functioning and operating in a reactionary manner, that is no longer acceptable within many of our modern building types, occupancies and structures. This places higher risk to your personnel and lessens the likelihood for effective, efficient and safe operations. You're just not doing your job effectively and you're at RISK. These risks can equate into insurmountable operational challenges and could lead to adverse incident outcomes. Someone could get hurt, someone could die, it's that simple; it's that obvious.
 
Considerations for changing fire flow rates, the sizing of hose line and the adequacies for fire flow demand and application rates, staffing needs for safe operations, considerations for defensive positioning and defensive operating postures must be considered, and it warrants repeating again; Reckless-Aggressive firefighting must be redefined in the built environment and associated with goal oriented tactical operations that are defined by risk assessed and analyzed tasks that are executed under battle plans that promote the best in safety practices and survivability within known hostile structural fire environments- with determined, effective and proactive firefighting
 
Doctrine of Combat Fire Engagement
·        Predictive Strategic Process
·        Tactical Deployment Model
·        Dynamic Tactical Deployment
·        Performance Indicators and Street Aides
o       Fire Dynamics
o       Resistance
o       Resilience
o       Structural Systems
o       Occupancy Hazard Profiles
 
The traditional attitudes and beliefs of equating aggressive firefighting operations in all occupancy types coupled with the correlating, established and pragmatic operational strategies and tactics MUST not only be questioned, they need to be adjusted and modified; risk assessment, risk-benefit analysis, safety and survivability profiling, operational value and firefighter injury and LODD reduction must be further institutionalized to become a recognized part of modern firefighting operations
 
Aggressive firefighting must be redefined and aligned to the built environment and associated with goal oriented tactical operations that are defined by risk assessed and analyzed tasks that are executed under battle plans that promote the best in safety practices and survivability within know hostile structural fire environments.
 
Our current generation of buildings, construction and occupancies are not as predictable as past conventional or legacy construction and occupancies;
  • Risk assessment, strategies and tactics must change to address these new rules of structural fire engagement.
  • You need to gain the knowledge and insights and to change and adjust your operating profile in order to safe guard your companies, personnel and team compositions.
  • Again strategic firefighting operations; Strategies and tactics must be based on occupancy risk not occupancy type.
The following are quotes from Fire Chief Anthony Aiellos (ret) Hackensack (NJ) Fire Department, Fire Chief during the Hackensack Ford Fire, July, 1988...
 
"If you don't fully understand how a building truly performs or reacts under fire conditions and the variables that can influence its stability and degradation, movement of fire and products of combustion and the resource requirements for fire suppression in terms of staffing, apparatus and required fire flows, then you will be functioning and operating in a reactionary manner. This places higher risk to your personnel and lessens the likelihood for effective, efficient and safe operations. You're just not doing your job effectively and you're at RISK. These risks can equate into insurmountable operational challenges and could lead to adverse incident outcomes”.
 
 

 

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