Garden Hero burning town home

Technical Report Released: Multi-Family Dwellings Experiments

June 23, 2020

Funded by the U.S. Department of Homeland Security (DHS) and Federal Emergency Management Agency (FEMA) Assistance to Firefighters Grant Program, Analysis of the Coordination of Suppression and Ventilation in Multi-Family Dwellings is the third report issued as part of the Study of Coordinated Fire Attack Utilizing Acquired Structures project.

The report is broken down into 4 main sections:

  • Experimental Setup - description of the garden-style apartment buildings, instrumentation, and fuel packages
  • Results - fire dynamics based descriptions of the data from each of the thirteen experiments
  • Discussion - examination of fire growth and spread, impact of ventilation, examination of apartment and stairwell tenability, and impact of suppression tactics
  • Tactical Considerations - assessments of the data for fire service members to consider with respect to actions on the fireground

This study builds upon previous residential fireground research by examining the coordination of ventilation and suppression tactics in acquired three-story multi-family dwellings. Experiments were conducted in four separate garden-style buildings. Each building had two lower-level units, four first-floor units, and four second-floor units. Each apartment was approximately 800 sq ft with a single bedroom. The apartments were connected through a central, common enclosed stairwell.

Bedroom, kitchen, and living room fires were studied across the different levels of the structure with four experiments conducted in lower-level apartments, seven conducted in first-floor apartments, and two conducted in second-floor apartments. Firefighter intervention included both exterior fire control and interior suppression with ventilation tactics that included horizontal ventilation, PPV, PPA, hydraulic ventilation, and door control. Fire sizes varied depending on the amount of ventilation provided prior to ignition as well as additional ventilation provided prior to suppression.



The majority of the existing full-scale fire service research studied the impact of tactics on the residential fireground, specifically in single-family structures. This study builds upon prior research by conducting thirteen experiments in three-story, multi-family dwellings to quantify the impact of coordination between ventilation and suppression actions. Experiments were conducted in four, garden-style apartment buildings; each of which had two lower-level units, four first-floor units, and four second-floor units. The apartments shared a common stairwell that was enclosed for all of the experiments in this study.

To examine the effectiveness of tactics in the fire apartment, common stairwell and applicable exposure apartments, four experiments were conducted in lower-level apartments, seven were conducted in first-floor apartments, and two were conducted in second-floor apartments including both bedroom and kitchen/living room fires. The fire size varied based on the amount of initial ventilation provided. The main control variables included the location of initial water application, the ventilation method, and the timing of ventilation relative to water application. The suppression tactics included interior water application, exterior water application followed by interior water application, and a combined interior and exterior water application. The ventilation tactics examined in these experiments included horizontal, vertical, positive pressure, and hydraulic ventilation.

Similar to previous experiments in acquired single-family structures, there was no meaningful increase in temperature outside of fire rooms when ventilation tactics were executed in close coordination with (shortly after or shortly before) the onset of suppression. In contrast, for experiments where ventilation occurred with delayed suppression, temperature exposures increased throughout the fire apartment, and in experiments where the apartment door was left open, temperatures and carbon monoxide exposures increased throughout the common stairwell.

Suppression actions, whether interior or exterior, resulted in a decrease in temperatures and gas concentrations at locations where occupants may potentially be located. The enclosed common stairwell, a unique feature of this experimental series, acted as capture of combustion products. Opening the apartment door to gain access should be thought of as an important ventilation action, both in terms of its potential to cause fire growth and its potential for smoke movement into the stairwell, limiting the egress for potentially trapped occupants in exposure units. Tactics such as door control, positive pressure ventilation, and hydraulic ventilation which were used both simultaneous with and sequentially post-suppression were shown to limit gas flows into the stairwell. After effective suppression, structure ventilation operations should similarly be cognizant of gas flows, with the aim of establishing flow throughout all areas where occupants may be located.

Research Project: Study of Coordinated Fire Attack Utilizing Acquired Structures
Report Title: Analysis of the Coordination of Suppression and Ventilation in Multi-Family Dwellings
Report Authors: Keith Stakes, Julie Bryant, Nick Dow, Jack Regan and Craig Weinschenk
Download the Report:
Release Date: June 23, 2020

Study of Coordinated Fire Attack Utilizing Acquired Structures