Impact of Ventilation on Fire Behavior in Legacy and Contemporary Residential Construction

Under the United States Department of Homeland Security (DHS) Assistance to Firefighter Grant Program, Underwriters Laboratories examined fire service ventilation practices as well as the impact of changes in modern house geometries.  There has been a steady change in the residential fire environment over the past several decades.  These changes include larger homes, more open floor plans and volumes and increased synthetic fuel loads.  This series of experiments examine this change in fire behavior and the impact on firefighter ventilation tactics.  This fire research project developed the empirical data that is needed to quantify the fire behavior associated with these scenarios and result in immediately developing the necessary firefighting ventilation practices to reduce firefighter death and injury.

Two houses were constructed in the large fire facility of Underwriters Laboratories in Northbrook, IL.  The first of two houses constructed was a one-story, 1200 ft², 3 bedroom, 1 bathroom house with 8 total rooms.  The second house was a two-story 3200 ft², 4 bedroom, 2.5 bathroom house with 12 total rooms.  The second house featured a modern open floor plan, two-story great room and open foyer.   Fifteen experiments were conducted varying the ventilation locations and the number of ventilation openings.  Ventilation scenarios included ventilating the front door only, opening the front door and a window near and remote from the seat of the fire, opening a window only and ventilating a higher opening in the two-story house.  One scenario in each house was conducted in triplicate to examine repeatability. 

The results of these experiments provide knowledge for the fire service for them to examine their thought processes, standard operating procedures and training content.  Several tactical considerations were developed utilizing the data from the experiments to provide specific examples of changes that can be adopted based on a departments current strategies and tactics. 

For more information about this project please see the executive summary or the full report.

Online Training Program

In order to make the results of this study more user friendly for the fire service to examine, UL developed an online interactive training module that can be viewed by clicking here. The program includes a professionally narrated description of all of the experiments, their results and the tactical considerations.  Experimental video is used and graphical data is explained in a way that brings science to the street level firefighter.

Comparison of Modern and Legacy Home Furnishings

An experiment was conducted with two side by side living room fires.   The purpose was to gain knowledge on the difference between modern and legacy furnishings.  The rooms measured 12 ft by 12 ft, with an 8 ft ceiling and had an 8 ft wide by 7 ft tall opening on the front wall.  Both rooms contained similar amounts of like furnishings.

The modern room was lined with a layer of ½ inch painted gypsum board and the floor was covered with carpet and padding.  The furnishings included a microfiber covered polyurethane foam filled sectional sofa, engineered wood coffee table, end table, television stand and book case.  The sofa had a polyester throw placed on its right side.  The end table had a lamp with polyester shade on top of it and a wicker basket inside it.  The coffee table had six color magazines, a television remote and a synthetic plant on it.  The television stand had a color magazine and a 37 inch flat panel television.  The book case had two small plastic bins, two picture frames and two glass vases on it.  The right rear corner of the room had a plastic toy bin, a plastic toy tub and four stuffed toys.  The rear wall had polyester curtains hanging from a metal rod and the side walls had wood framed pictures hung on them.

The legacy room was lined with a layer of ½ inch painted cement board and the floor was covered with unfinished hardwood flooring.   The furnishings included a cotton covered, cotton batting filled sectional sofa, solid wood coffee table, two end tables, and television stand.  The sofa had a cotton throw placed on its right side.  Both end tables had a lamp with polyester shade on top of them.  The one on the left side of the sofa had two paperback books on it.  A wicker basket was located on the floor in front of the right side of the sofa at the floor level.  The coffee table had three hard-covered books, a television remote and a synthetic plant on it.  The television stand had a 27 inch tube television.  The right front corner of the room had a wood toy bin, and multiple wood toys.  The rear wall had cotton curtains hanging from a metal rod and the side walls had wood framed pictures hung on them.

Both rooms were ignited by placing a lit stick candle on the right side of the sofa.  The fires were allowed to grow until flashover.  The modern room transitioned to flashover in 3 minutes and 30 seconds and the legacy room at 29 minutes and 30 seconds.

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