MFA #25: The Ventilation Revolution - New information brings new understanding

(Author’s Note: As I was writing this series of posts, there appeared here on the Fire Engineering Training Community another blog on this same subject by Nicholas Papa [http://community.fireengineering.com/profiles/blog/show?id=1219672%3ABlogPost%3A627047].  Obviously, I decided to publish mine anyway, as there are enough facets to this discussion to fill entire textbooks, much less a few web pages.  The first installment of Lt. Papa’s series demonstrates it to be a careful review of Ventilation techniques, while I intend to provide a more general reassessment of the entire tactic.  Time will tell whether our perspectives are complimentary or contradictory, but it is the discussions we engage in that are the path to learning from each other, so let’s start the conversation.)

The late Tom Brennan, former Editor in Chief of Fire Engineering Magazine, who blessed our profession with the unusual combination of extraordinary knowledge, extensive experience, and the ability to share those gifts with those willing to learn, spoke often about the need to “make the building behave” in regards to ventilation at a structure fire.  As a seasoned FDNY truck officer, he was an articulate proponent and instructor of the art and science of creating openings at the correct place and time in order to facilitate a fire attack.  I would not presume to know what he would think about the information that has come out of the fire dynamics research regarding this tactic, contradicting as it does prior dogma and practice, but I am certain he would not stand for it being ignored.  With that said, how do we put this newfound knowledge to use? 

My own perspective on ventilation for fire control did a 180-degree turn after I developed an understanding of the fire dynamics research performed over the past few years, including Analysis of One and Two-Story Single Family Home Fire Dynamics and the Impact of Firefighter Horizontal Ventilation at http://newscience.ul.com/wp-content/uploads/2014/04/Analysis_of_One_and-_Two_Story_Single_Family_Home_Fire_Dynamics_and_the_Imapct_of_Firefighter_Horizontal_Ventilation.pdf) and Study of the Effectiveness of Fire Service Vertical Ventilation and Suppression Tactics in Single Family Homes at http://ulfirefightersafety.com/category/projects/effectiveness-of-fire-service-vertical-ventilation-and-suppression-tactics/.  The Governors Island burns produced similar results.  Most powerful was the consistent finding that ventilation invariably increased the heat output of a fire, regardless of the timing or location of the creation of the exhaust path.  Yes, there could be a brief lifting of the smoke layer, but the concomitant acceleration of combustion quickly overcame any benefit by elevating temperatures within the structure.  So much for ventilation improving conditions.

While this was a radical change in my beliefs, it certainly was not sudden.  I initially viewed the research findings as a curiosity; phenomena requiring further study.  As I had been taught the value of ventilation for improving interior conditions for both firefighting and victim survival, and had participated in operations that went poorly because of perceived inadequate or ill-performed ventilation, these experimental results seemed an anomaly.  Upon further study and reflection, though, some of those situations that we had blamed on incorrect ventilation practices likely would have gone badly regardless, and that particular shortfall had often been used as a scapegoat.  A delay in water application was a more consistent issue, while others could have turned out even worse with the addition of air to the burning mix.  I had also seen flames emanate from a window or roof that was opened near a fire, assuming, along with every other firefighter, that it signaled a reduction of the heat within the structure.  We since have come to understand that the flames coming from an opened roof or window were not so much being released, but created.  Ventilation merely provided the missing leg to the fire triangle: oxygen to allow the already hot gas (fuel) to burn, essentially making everything even hotter.  

As we now know that providing ventilation to a fire will increase heat output, and that, essentially, makes everything inside a burning structure worse, we either need to avoid that tactic until after fire control or, if we determine that its use is still indicated while burning continues, then have a plan for managing its predictable effects to prevent a deterioration of conditions.  This subject has been touched upon in this series previously (See MFA #7:Vertical Vandalism? at

http://community.fireengineering.com/profiles/blog/show?xg_source=a...), though in a limited manner that looked only at its risk/benefit ratio.  In upcoming postings on this subject, I will attempt to apply our new understanding of this process to its overall use on the fireground, and thereby help to "bring the science to the street".

(In the ongoing process of researching MFA issues, specifically the need to revise much of our tactical dogma, I have been reading a lot of older Fire Engineering articles, some written by experts still actively participating in these discussions (e.g., Ray McCormack in March 1997, and Bob Pressler in November 1992).  One of the things that strikes me in these decades-old lessons are the authors' consistent warnings about the dangers of ventilation, given its propensity to increase fire intensity.  While they also went on to discuss the various techniques of the time intended to realize its benefits, their instructions were always prefaced with warnings as to its hazards, a hallmark of a good instructor.  To a great extent, we have collectively become complacent with the capabilities of our PPE to shield us from much of the ill effects of poorly-chosen or -performed ventilation, and forgotten this key caveat.)

Next installment: MFA #26: Redefining Ventilation - Putting theory into practice