Impact of Ventilation on Fire Patterns

Impact of Fixed Ventilation on Fire Damage Patterns in Full-Scale Structures Report Released

April 18, 2019

Over the past 30 years, home construction materials, contents, size and geometry have changed drastically - and consequently, so has fire behavior. Today’s fires, thriving as they do on predominantly synthetic materials, tend to become ventilation-limited. How and where a fire receives oxygen greatly impacts the fire dynamics and subsequent fire patterns.

Knowledge of fire dynamics is critical for fire investigators to properly identify a fire’s origin. Fire dynamics depend on the relationship of the fuel, heat, and ventilation during a fire event. A ventilation change as simple as a door left open by an occupant fleeing the fire, a window open remote from the fire, or a window that fails as a result of fire growth could greatly impact the fire damage inside the structure. 

Executive Summary

During the past decade, research conducted for the purpose of examining firefighting tactics has brought focus to the impact that on-going changes in home construction materials, contents, size, and geometry have on a fire incident. Current residential structure fires are predominantly fueled by synthetic contents and commonly become ventilation-limited. How and where the fire receives oxygen, especially with a ventilation-limited fire, impacts the fire growth and subsequent fire dam- age patterns. A review of the state of forensic science in the United States was published in 2009. The report, entitled Strengthening Forensic Science in the United States: A Path Forward, by the U.S. National Academy of Sciences, indicated that ‘...more research is needed on the natural variability of burn patterns and damage characteristics...’.

The NIJ supported Fire and Arson Investigation Technology Working Group developed a list of research needs to support the operational requirements of fire investigations. The research needs identified included: 1) understanding of the effects of ventilation on fire damage and patterns; 2) repeatability and reproducibility of test measurements of large-scale structure fires, and 3) development of materials property data for accurate computer model inputs.

Objectives The goal of this study was to improve the capabilities of the fire investigation community by adding to the knowledge base and transferring the findings as widely as possible in order to “get the science to the street.” The primary objectives of this series of experiments as presented in this report include:

  • To examine how differences in ventilation to full-scale structure fires result in changes to the fire damage and fire patterns within the structure. 

  • To measure the fire environment within the structures and compare the data with the fire damage in the structures. 

  • To document the repeatability or lack thereof of the fire conditions and fire patterns within a structure based on the available ventilation. 

  • To provide a discussion of basic fire dynamics in structures, specifically with regard to the impact of ventilation on the resulting fire patterns. 

Research Project: Impact of Ventilation on Fire Patterns
Report Title: Impact of Fixed Ventilation on Fire Damage Patterns in Full-Scale Structures
Report Authors: Daniel Madrzykowski and Craig Weinschenk
Download the Report:
Release Date: April 18, 2019

Impact of Ventilation on Fire Patterns