Impact of Fire Attack Utilizing Interior and Exterior Streams

FSRI Releases Part III of the Fire Attack Study: Full-scale Experiments

December 6, 2017

The Fire Safety Research Institute (FSRI), part of UL Research Institutes is pleased to release the scientific report for Part III of the 2013 DHS FEMA Grant, Impact of Fire Attack Utilizing Interior and Exterior Streams on Occupant Survival: Full Scale Experiments.

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“For the first time we’ve specifically implemented and measured conditions during several versions of an interior fire attack. This new data, combined with additional experiments measuring conditions during transitional fire attacks allows us to better understand how our tactics may effect trapped occupants. Implementing the Tactical Considerations we’ve developed with assistance from our technical panel can allow firefighters to be more effective on today’s complex fireground.”

- Steve Kerber, Vice President, Research and Director, FSRI

This report details the results and analysis from 26 full-scale structure fire experiments looking to quantify the differences in interior and transitional fire attack. The experiments were analyzed to look at both victim survivability and tactic effectiveness. The following tactical considerations were developed with assistance from the project technical panel, blending their experience with the research results to aid in application on today’s complex fire grounds.

  • Interior Suppression With Only Smoke Showing
  • Transitional Attack With Fire Showing Near the Entry Point
  • Fire Showing Remote from The Primary Entry Point
  • There Can Be Survivable Spaces on Arrival at a Single-Family Residential Home
  • Fire Attack and Search & Rescue Can Occur Simultaneously
  • Search Consideration: Closed Doors Significantly Increase Occupant Survivability
  • Water in the Fire Compartment Matters, and so Does Timing
  • If You Can Get Water to Where It Needs to Go, You Don’t Need Much
  • Water Flow Can Impact Flow Path
  • Suppression Operations, Both Interior and Transitional, Did Not Increase Potential Burn Injuries to Occupants
  • Speed of Transition is the Enemy of Re-growth
  • Water Converted to Steam Expands, Hot Gases Cooled Rapidly Contract
  • Water Vapor is a Bi-product of Combustion
  • Flow and Move vs. Shutdown and Move
  • You Should Cool as You Advance
  • Understanding the Limitations of a Thermal Imaging Camera Can Increase its Effectiveness
  • A Short Burst of Water Cannot Tell You Gas Temperature
  • Large Volume Gas Cooling Requires a Large Volume of Water


As research continues into how fire department interventions affect fire dynamics in the modern fire environment, questions continue to arise on the impact and implications of interior versus exterior fire attack on both occupant survivability and firefighter safety. This knowledge gap and lack of previous research into the impact of fire streams has driven the need for further research into fire department interventions at structure fires with a focus on hose streams and suppression tactics.

As the third report in the project “Impact of Fire Attack Utilizing Interior and Exterior Streams on Firefighter Safety and Occupant Survival”, this report expands upon the fire research conducted to date by analyzing how firefighting tactics, specifically suppression methods, affect the thermal exposure and survivability of both building occupants and firefighters in residential structures.

Part I: Water Distribution.

Part II: Air Entrainment.


Part III: Full-Scale Residential Fire Experiments.

This report evaluates fire attack in residential structures through twenty-six full-scale structure fire experiments. Two fire attack methods, interior and transitional, were preformed at UL’s large fire lab in Northbrook, IL, in a single-story 1,600 ft ranch test structure utilizing three different ventilation configurations. To determine conditions within the test structure it was instrumented for temperature, pressure, gas velocity, heat flux, gas concentration, and moisture content. Additionally, to provide information on occupant burn injuries, five sets of instrumented pig skin were located in pre-determined locations in the structure. The results were analyzed to determine consistent themes in the data. These themes were evaluated in conjunction with a panel of fire service experts to develop 18 tactical considerations for fire ground operations. As you review the following tactical considerations it is important to utilize both these research results and your per- sonal experience to develop your department’s polices and implement these considerations during structural firefighting.

Research Project: Study of the Impact of Fire Attack Utilizing Interior and Exterior Streams on Firefighter Safety and Occupant Survival
Report Title: Impact of Fire Attack Utilizing Interior and Exterior Streams on Firefighter Safety and Occupant Survival: Full Scale Experiments
Report Authors: Robin Zevotek, Keith Stakes and Joseph Willi
Download the Report:
Release Date: January 25, 2018

Study of the Impact of Fire Attack Utilizing Interior and Exterior Streams on Firefighter Safety and Occupant Survival