Positive oversight

After reading the article on positive-pressure attack in the January issue, I'm very concerned that the authors downplayed several serious operational and safety concerns in their efforts to promote the use of positive-pressure ventilation. The presentation of the article is clearly intended to refute common PPV apprehensions, however, the potential consequences of misapplication of PPV are very seriously understated.

The title “Positive Reinforcement” and the front-cover headline “PPV Myths Debunked — 20 Reasons to use Ventilation Fans For Positive-Pressure Attack” both emphasize that the objective of the article is to convince firefighters and fire chiefs that they should be using positive pressure in most interior fire attack situations. The authors are entitled to express their opinions; however the article presents their opinions and personal observations as factual information. They provide no scientific information, data or specific observations to support their assertions and, I believe, they are unintentionally providing information that could be misleading and dangerous in certain circumstances.

Several of the so-called “myths” are actually very valid and important factors that should be evaluated whenever the use of PPV is considered. I was very surprised to see some of these serious concerns categorically refuted or expressed as minor cautions.

It's absolutely incorrect to state that PPV will not push fire throughout a building, will not push fire throughout the voids in a building and will not spread fire into the voids of a balloon-frame building. It would be valid to state that PPV will not necessarily or inevitably cause these outcomes; however, each of these outcomes could occur if PPV is employed improperly, inappropriately or in the wrong circumstances.

The assurance that a crew can't make an exhaust opening in the wrong location is a dangerous misstatement. It's true that the excess pressure will always find the path of least resistance to push air, heat and products of combustion out of a building; however it is very possible that the opening could be located in a very undesirable location.

The statements regarding the use of PPV for attic and basement fires fall short of expressing appropriate cautions for these situations. It could be the best decision and it could be the worst decision, depending on the circumstances.

The caution against using PPV when potential backdraft conditions are present falls far short of expressing the extreme consequences of failure to recognize the warning symptoms.

The suggestion that PPV can be used when there is only one opening to the space where the fire is located is foolhardy and likely to result in serious injury or death under the wrong circumstances.

Positive-pressure ventilation is a proven and very effective technique in certain circumstances, beginning with knowing where the fire is located and where it can be vented safely and effectively, directly to the exterior of the building. There are many situations where PPV should not be used or should only be employed with extreme caution. Misapplication of PPV has resulted in many undesirable outcomes. A mild expression of concern is hardly adequate when misapplication of the technique could result in deaths or serious injuries to firefighters and civilians.

It would have been far more appropriate to provide valid qualitative and quantitative information to assist fire officers in determining when it is appropriate to use PPV and how it should be employed in those situations. More importantly, the article should have clearly identified and emphasized the situations where the use of PPV is not appropriate. The potential consequences of using PPV improperly or in the wrong circumstances are much too severe to be brushed aside.

J. Gordon Routley
Fire Protection Engineer

Editor's reply: We went to “Positive Reinforcement” authors Kriss Garcia and Reinhard Kauffman for their response.

The questions that are raised … are valid in regards to many of the precautions that must be considered when using PPA. Hard questions proposed by such a credible source as Mr. Routley are the basis of most of our research. As we have stated in our articles, training and, better yet, knowledge of when and how to use PPA is first and foremost.

In our yet-to-be published third article about PPA precautions, we address many of these concerns in greater depth. Let us assure the readers that the information we are providing is based on hundreds of actual fire tests we conducted in live-fire situations, as well as those of several other agencies and individuals. A vast amount of research regarding pressurized fire attack also has been conducted in Great Britain, where we have presented several White Papers for fire engineers. It is this fairly significant amount of empirical evaluation that leads us to the solid foundation of making the statements that we do.

Besides the empirical evaluations, we've been using this technique while providing fire protection for over a decade and have found that what were originally hypotheses are demonstrable and reproducible results. By no means is PPA without risk, the largest risk being the lack of knowledge and training associated with this very dynamic tactic. We believe an intelligent American fire service is ready for this tactic; it's already being used by hundreds fire departments with reported positive results.

I will briefly address each point [in the order Routley] mentioned.

1. We have conducted many live-fire tests, as well as laboratory tests, related to this topic and have found that the ability to overcome the pressure already created by the fire in the fire area itself with the initial blower is very minimal.

   We have completed these evaluations in all types of structures, including balloon-constructed buildings. In these tests we actually breach stud spaces and try to force fire into the attic and basement areas. The only time we have seen appreciable fire spread into these spaces is when the roof is opened, creating an area of negative pressure for the fire to travel to.

   Fires will create much more pressure within the structure than any blower ever will. Simply stated, the tactic is to first ensure an adequate exhaust, which, when done correctly, ensures the products of combustion continue exhausting in front of advancing fire crews. This is accomplished by placing blowers at the back of the initial-attack crews, in effect creating a safe anchor point from which the attack can begin. Water application will again increase the pressure within the structure many times more than any blower can.

   If this tactic would have been invented last week, it would not be called PPV or PPA, it would be called negative-assurance ventilation. In effect, this is what the blower accomplishes. The fire has already found the area of less pressure; often times this is the exterior of the structure. Placing blowers and opening exhausts as we stipulate allows the products of combustion to exit ahead of the firefighters, increasing visibility and therefore, safety.

2. Let me answer this concern this way. If you are the victim on the floor in a structure fire, is there any bad location to remove the products of combustion that are going to kill you after firefighters disturb the thermal balance? The answer is no.

   To make viable rescues, we need to remove the super-heated, lethal products of combustion in coordination with the fire attack. During dozens of live-fire tests, we evaluated the environment where victims are likely to be found and have irrefutably found that following PPA, conditions for their survival are improved. We also have found the opposite to be true following water application with inadequate ventilation.

3. We have conducted several attic and basement fire tests and have found PPA to be a viable and dramatic improvement over other ventilation techniques. When accompanied with aggressive interior operations, including rapid and aggressive overhaul and access to the fire area, PPA provides much better results than other or nonexistent ventilation techniques.

4. As our article and training simply state, we do not recommend PPA or PPV for backdraft situations. We also do not advocate placing firefighters on or near what has been determined to be an unexploded bomb — a backdraft. In backdraft situations, it's very doubtful that life or property value remains. Backdraft situations are few and far between, yet have to be handled by the most experienced firefighters, with well-coordinated tactics applied from safe positions to protect our firefighter's safety.

5. If you have only one opening as an option, PPV allows for a more rapid clearing of the interior environment than no ventilation. We do not — nor have we ever — advocated sending firefighters into an interior environment where a blower is operating without an adequate exhaust. In these situations, you are not going to be able to make a coordinated attack unless an exhaust can be made away from the fire attack crews. The exhaust opening is just as important, if not more so, than the blower operating when we have firefighters and/or survivable victims in a structure.

After 15 years of research, practical application and education of firefighters, we understand the passion and appreciate those with questions regarding PPA/PPV. The questions serve to help us explain the concept in an even clearer manner. We also understand Mr. Routley's concerns, as we had some of the same ones when this concept was first presented to us. We base our conclusions on hundreds of empirical evaluations, and after over five decades of combined experience, we feel the American fire service is not only ready but eager for this tactic.

N.Y. state of mind

Newsday's articles on the volunteer fire service and [Philip] Stittleburg's open letter on behalf of the National Volunteer Fire Council [News & Trends, December 2005] both fail to mention a key difference between New York state and the rest of America's states served by fire-rescue volunteers.

New York state, especially Long Island where I lived and worked for three years, is notorious for its abundance of local government bodies with elected “commissioners,” over and above all the elected local government leaders. New York's local fire commissioners determine the extent of apparatus purchases, including all the gigantic rigs that look like landed space ships.

Commission-laden Northeastern states are uncharacteristic of the rest of America, especially the Southern states. Local decision-makers in the industrial northeastern states are village-based, whereas in the agrarian Southern states the decision-makers are based at the county seats and state capital; no villages nor townships exist here.

Fire-rescue volunteers elsewhere in America usually don't have the taxing authority of New York state's local fire districts, thus have to earn their apparatus through fund-raising carnivals, fairs, festivals, bingo games and food sales.

Donald E. White, Firefighter/EMT-B Alexandria (Va.) Volunteer Fire Dept.