Effectiveness of Fire Service Positive Pressure Ventilation

Effectiveness of Fire Service Positive Pressure Ventilation

Enhancing the understanding of how positive pressure attack and positive pressure ventilation affect fire dynamics in residential structures.

Overview

This project addresses concerns expressed by the firefighter community and provides a baseline for choosing the most appropriate type or types of ventilation on the fireground by providing science-based comparisons between the three types of ventilation used everyday across the country. The FSRI team acquires experimental data from full-scale house fire experiments and examines positive pressure ventilation (PPV) used during fire attack, suppression techniques and the resulting fire dynamics. 

The study draws from and enhances previous DHS AFG sponsored research (EMW-2008-FP-01774) which studies the impact of horizontal ventilation through doors and windows and (EMW-2010-FP-00661) which studies the impact of vertical ventilation through the roof. By utilizing residential structures that mirror those used in the Horizontal Ventilation project (EMW-2008-FP-01774) and Vertical Ventilation project (EMW-2010-FP-00661), the team is able to make direct comparisons. 

The experiments are broken into two phases. The first phase incorporates testing both the electric and gas powered 18” fan from six major manufactures to compare their performance capabilities. The fans are ranked according to their total flow and pressure capabilities. The fan which most closely matches the average flow of all fans is selected for phase two, the full scale fire experiments. Twenty-five full-scale fire experiments are conducted, fifteen in the single story and ten in the two-story structure.

The experimental results are used to develop a comprehensive fire service outreach program to ensure the science meets the streets including tactical considerations outlining firefighting ventilation and suppression practices to help reduce firefighter death and injury

Context

There is a continued tragic loss of firefighter and civilian lives, as shown by fire statistics. One significant contributing factor is the lack of understanding of fire behavior in residential structures resulting from the use of ventilation as a firefighter practice on the fire ground. The changing dynamics of residential fires as a result of the changes in home construction materials, contents, size and geometry over the past 30 years compounds our lack of understanding of the effects of ventilation on fire behavior. Positive Pressure Ventilation (PPV) fans were introduced as a technology to increase firefighter safety by controlling the ventilation. However, adequate scientific data is not available for PPV to be used without increasing the risk to firefighters.

For questions about this project, please contact:

Conclusions

This study provided the evidence needed to examine existing standard operating procedures and make sound decisions on the fireground related to the use of positive-pressure ventilation and positive-pressure attack.

The research demonstrated that positive-pressure attack can provide increased visibility and tenability for firefighters and potential trapped occupants while fire suppression efforts are underway. Fans can also be used to pressurize the structure to remove products of combustion after a structure fire has been controlled (i.e., positive-pressure ventilation).

These results have been translated into tactical considerations, which can be accessed in the TECHNICAL REPORT and in the ONLINE TRAINING COURSE.

Researcher's Top Picks