One Size Never Fits All - Positive Pressure Attack

One size fits all, an iconic statement that the American fire service tends to apply to a very dynamic event. Unfortunately, the environment that we respond to and are expected to provide a service in does not fit into a “one size fits all” category. We as a fire service have become a utilitarian service that is expected to utilize a variety of tasks, tactical and strategic operations to accomplish our mission. Like all tactics, we as fire fighters have an emotional connection to the effects of the tactic. That emotional connection can sometimes blind us of the true benefits or the appropriate use of a tactic. The American Fire Service continues to evolve through technology, and the complexity of the environment that we work in does not afford us the opportunity of emotional connections to the tactics, science and facts. Thus the title of this article, “One Size Never Fits All” is a more accurate definition. In the previous two issues we looked unemotionally at the pros and cons of the “Duck and Dive tactic” and “Transitional Attack”, this issue we will take a closer look at Positive Pressure Attack (PPA). If you go to almost any fire station in America you will find a gas powered positive pressure fan either on the engine or the truck. The evolution of the “Fan” over the last twenty years has grown past the use of just a ventilation tool. Vent for life was our motto, the use of the fan was one functional tool in the vent for life motto. The challenge with vent for life is COORDINATION. Since the beginning, the application of water in a coordinated attack was critical for the vent process; failure to do so causes rapid fire growth which jeopardizes the safety of the fire fighters and the victims still inside. We know for a fact that the failure to apply water along with ventilation creates a very dangerous environment. The first order of business is to identify and define Positive Pressure Attack (PPA) versus Positive Pressure Ventilation (PPV). PPA is defined as the use of the mechanical positive pressure fan in a coordinated initial attack into a compartment fire with the fan being used as an aid in the suppression process. PPV has an accepted definition of the use of the mechanical fan for the sole purpose in assisting in ventilation post knock down or fire control. Positive Pressure Attack originated as a means to ventilate a structure after the fire was knocked down. Over the years the use of a positive pressure fan has evolved into using the fan to assist in the extinguishment process. Experts like Kris Garcia, Reinhard Kauffmann and Ray Schelble developed tactical operations which include the use of a coordinated attack with the use of the positive pressure fan. The fan was placed in the intake (airflow) of the structure to provide pressure into the compartment with an exhaust, allowing the super-heated gasses to vent out the exhaust as fire fighters, in a coordinated effort, stretch an attack line from the clean air side of the flow path advancing towards the seat of the fire. The concept was that properly used PPA allows firefighters great control over the interior environment of a fire building to provide increased ventilation (cool fresh air) for potential victims and better visibility for the firefighter to attack the fire. Positive Pressure Ventilation is the tactical use of a mechanical fan to assist in venting the structure post fire control. The need for a single intake, flow path and then an exhaust are used in conjunction with the fan to aid in the removal of the super-heated gasses. Over the last twenty years PPA became a valuable tool that many organizations used consistently for residential structure fires. Over the last ten years some organizations have developed larger truck mounted and elevated fans for the use in commercial and multi-story buildings. Currently, Underwriters Laboratory (UL) is in the final stages of conducting research and testing the benefits and disadvantages of the use of PPA. I am fortunate enough to sit on that committee along with PPA experts from around the world.  Kris Garcia, one of the most prominent PPA experts, is also on the committee. The Data from the UL test is still being digested. Director Steve  Kerber plans to have the data and full report out by spring 2016. For this article I will attempt to be unbiased based on the data of the UL PPA test for the simple reason that the data isn’t final.  What we will use is the other documented test through KTF and NIST. The Tactic: The use of a PPA fan positioned in the inlet of a structure, positioned to maximize the creation of a flow path from the unburned side of the structure to the fire compartment then vented out an exhaust. Crews are to identify the air intake; traditionally the front door, then an exhaust opening must be created. This is traditionally done by taking a window or opening a door closest to the fire. Once the exhaust is established, crews will then move back to the inlet and make their initial attack with the fan blowing at their backs. The Goal: The goal of the fan blowing at your back is to clear a path through the structure to the seat of the fire and out the exhaust. The concept is that the fan clears all the super-heated gasses out of the structure and out the exhaust providing for better visibility and patient survivability. In addition, the thought was that it would provide for less thermal insult on fire fighters as they advance through the structure. The Challenge: One of the critical challenges of PPA is creating the appropriate and effective sized exhaust outlet; the “book” says 2 ½ times the inlet size. With the modern fuels high energy release and expansion rate we are finding that we struggle to create a large enough exhaust to move the volume of super-heated gasses out of the structure fast enough must be accomplished with a larger exhaust. Inaccurately identifying where the fire is located causing fire extension into non fire compartments causing more damage.  The use of PPA is dependent on the following items: The fire occupancy can be identified and is compartmentalized. A large enough exhaust can be created. The fire is compartmentalized and located near an exterior wall. Exhaust vent and fire are located on the same floor. The occupant and fan position are not impacted by wind speed or direction. The use of PPA is another tool for our tool box. I know that is a cliché but we are a dynamic organization that must have multiple tactical options to safely provide the expected service to our community. Aggressive tactical operations that are performed by skilled firefighters under the direction of educated company officers that use tactical knowledge to best provide service is critical. In all cases, tactical operations should not delay the application of water. Water is provided for improved conditions for patient survivability and interior fire operations. The result from the UL PPA study will impact how and when PPA is applied; however, it will not be eliminated from our tool box. Bottom line is that it all depends as there are conditions and situations for each tactic. Next month we will take a look at Vertical Ventilation and the result from UL’s study.   --- Jason is the Fire Chief of Laramie County Fire District #2 in Cheyenne Wyoming and an Adjunct Professor for Laramie County Community College where he teaches a semester course “The principles of fire behavior”.  Prior to arriving in Cheyenne in 2011 he was the Fire Chief of Gore Hill Fire Rescue in Great Falls Montana.  In addition, he spent 10 years working for the Montana Fire Services Training School as a regional instructor and regional training manager for the state of Montana. His fire behavior journey began in 2001 when he was introduced to the English fire service through Jim Mastin and John Taylor (Author of Smoke Burns).  These introductions to the English fire service spurred a curiosity and eventually lead to chief Caughey traveling to Manchester England to participate in the English Fire training system. Chief Caughey has been an active member in the "Kill the Flashover" project lead by Joe Starnes.  He is also a current technical member of the Underwriters laboratory Positive Pressure test committee.

Training Police to Understand Today's Modern Fire Enviornment Friday, October 16th's 3rd educational session at the 2015 ISFSI Fall Instructor Conference, will be presented by Forest Reeder and Brian Kazmierzak.   How many times has your fire department arrived at a house fire only to find the police have beat you in and kicked in the front door.  As the UL/NIST studies have shown over the past several years, opening a door is ventilation.  But has anyone ever trained our police officers on what they should do when they arrive at a fire scene?  Has your department ever talked to your police department about fire behavior or what their expectations are once they arrive ahead of the fire department at a fire scene?  We as the fire service must take it upon ourselves to teach the police.  They are not being taught in the police academy about fire scene response, but they get sent to the regularly nationwide. So from arrival, to positioning, to size-up, and most of all to leaving the BOX intact prior to fire department arrival, we need to be able to stress and teach the correct operations for police officers on the fireground. Just remember we can’t get mad at them for doing something they have never been taught to do the right way in the first place. This program will provide you with a take away Police Roll Call Training Program and Quick Drill to help local fire departments educate their police departments on the hazards of the modern fireground and what are the best tasks to perform prior to the arrival of the fire department.  This program was developed out of necessity after several police close calls at around the same time as the NYPD fire double LODD in the Rockaways.