Report Release – Analysis of Search and Rescue Tactics in Single-Story Single-Family Homes Part I: Bedroom Fires

This report, Analysis of Search and Rescue Tactics in Single-Story Single-Family Homes Part I: Bedroom Fires, examines the eleven bedroom fire experiments. In six of the bedroom fires, search operations occurred prior to suppression. In four of the bedroom fires search, operations occurred during suppression. The remaining bedroom fire was the baseline experiment where the initial conditions remained fixed for the duration of the experiment. Further, the series of bedroom experiments examined search operations that originated via window (x7) and via front door (x3). In all experiments, hydraulic ventilation was performed following suppression. Temperature, velocity, and pressure were measured throughout each structure to assess the fire dynamics. Heat flux and gas concentrations were employed to assess the impact of tactics on occupant tenability. The table below provides a high-level overview of the search tactics and timing relative to suppression for the eleven bedroom experiments.

Bedroom 4 Ignition Experiments

This report is broken down into three main sections:

• Experimental Configuration
  • Detailed description of the purpose-built structures, experimental procedure, instrumentation used, measurement locations, and fuel packages.
• Experimental Results
  • Fire dynamics-based descriptions on each of the eleven bedroom experiments. The changes in the measured quantities (e.g., temperature, gas concentration, heat flux, etc.) throughout the structure are explained with respect to a change in opening/closing a door, venting a window, and/or suppression.
• Discussion
  • The changes in fire dynamics are assessed across sets of the experiments to examine the impacts of different tactics. Here, the data is analyzed in terms of toxic gas and thermal exposures to firefighters and potentially trapped occupants over three different intervals
    • Prior to fire department intervention
    • During search operations
    • During rescue operations

Abstract:

Prior full-scale fire service research on the residential fireground has focused the impact of ventilation and suppression tactics on fire dynamics. This study builds upon prior research by conducting eleven experiments in a purpose-built single-story, single-family residential structure to quantify the impact of how search and rescue tactics are coupled with ventilation and suppression actions and timing. Each fully furnished structure included four bedrooms, 2 bathrooms and an open-floor kitchen and living room. The structures were instrumented to quantify post-ignition toxic gas and thermal conditions. Temperature, velocity, and pressure were measured to evaluate the fire dynamics. Gas concentrations and heat fluxes were measured to quantify toxic and thermal exposures.

Across this series of experiments, the impact of isolation of fire and non-fire compartments, the timing of search actions relative to suppression actions, and the influence of isolation, elevation, and path of travel during rescue were examined with respect to firefighter safety and occupant tenability.

Similar to previous experiments in both purpose-built and acquired structures, the data showed that prior intervention locations lower in elevation and/or behind closed doors had lower toxic gas and thermal exposures compared to locations at higher elevations or locations that were not isolated. Lower elevations were also shown to have lower toxic gas and thermal exposures during the removal of occupants as part of rescue operations.

For scenarios where search operations occurred prior to suppression, isolation of spaces from flow paths connected to the fire compartment was shown to be effective at reducing the thermal operating class for firefighters and the toxic and thermal exposure rates compared to spaces that were not isolated. Following isolation, exterior ventilation was found to further reduce the toxic gas and thermal exposures in the protected space. Suppression, from either interior and exterior positions, was effective at reducing the thermal operating class for searching firefighters and the rate of thermal exposure increase to occupants. Following suppression, additional exterior ventilation increased the rate at which gas concentrations returned to pre-ignition levels.

The ‘Study of Fire Service Residential Home Size-up and Search Rescue Operations,’ was funded through a grant from the Department of Homeland Security (DHS) Federal Emergency Management Agency's (FEMA) Assistance to Firefighters Grant (AFG) Program under the Fire Prevention and Safety Grants: Research and Development (EMW-2017-FP-00628).

Research Project: Study of Fire Service Residential Home Size-up and Search & Rescue Operations
Report Title: Analysis of Search and Rescue Tactics in Single-Story Single-Family Homes Part I: Bedroom Fires
Report Authors: Craig Weinschenk
Download the Report: https://dx.doi.org/10.54206/102376/DPTN2682
Release Date: May 17, 2022