Fire Dynamics and Firefighting Tactics in Multi-Story Residential Structures

According to U.S. Census data on “Starts and Completions by Purpose and Design,” quarters three and four of 2023 represent the highest market share of single-family attached structures on record, with data going back nearly 30 years. In quarter four 2023, townhouses represented almost 20% of housing starts in the U.S. The rise in the number of townhouse buildings, combined with the number of existing but older attached structures commonly known as rowhomes, represent evolving challenges for the fire service. 

Townhouses and rowhomes are both multi-story residential buildings with some commonalities: limited access points, dense fuel loads mostly composed of synthetic fuels, potential for internal vertical fire spread, and exposure concerns. Conversely speaking, the design and construction of townhouses and rowhomes can have several notable differences:

Previous research from the Fire Safety Research Institute (FSRI), part of UL Research Institutes, has studied the residential fire environment in both one- and two-story single-family homes. However, there is a research gap around attached dwellings and three-plus story constructions. Further, townhouses and rowhomes have been the site of recent near misses and line of duty deaths.

To respond to this need, this FSRI study explores fire dynamics and firefighting strategies and tactics specifically designed for multi-story homes. FSRI is building and conducting full-scale experiments on a modern townhouse and traditional rowhome at its test facility in Sharon Hill, PA. Studying both modern and traditional buildings allows researchers to explore the similarities and differences in fire dynamics and the corresponding fire department responses between these two common types of multi-story residential homes.

The experiments in this project explore:

• Fire growth and spread
• Victim survivability
• Ventilation practices (e.g., horizontal, vertical, positive pressure, and hydraulic)
• Suppression practices, including interior and exterior water application
• Search and rescue practices
• Fireground coordination

Context 

This project builds on FSRI’s decades worth of research studying suppression, ventilation, and search and rescue in a range of single-family and multi-family homes. Previous studies have generated numerous evidence-based practices and tactical considerations for firefighters conducting operations on the ever-changing modern residential fireground. 

“Because we’ve extensively studied fundamental fireground tactics and their application to one- and two-story structures, we are well positioned to apply our expertise to multi-story homes. With their unique challenges and increasing prevalence, there’s a pressing need for comprehensive research in this area.”

–Keith Stakes, FSRI Lead Research Engineer II

Objectives

Through this research, FSRI aims to gain a deepened understanding of the most effective strategies and tactics for responding to fires in both modern and traditional multi-story homes. Data collected through these experiments aids in the development of a set of tactical considerations that support firefighters in effectively navigating the complexities of fires in these structures. The findings may also inform changes in strategies and tactics when responding to fires in townhouses and rowhomes. 

Technical Panel 

To improve continuity between fire service research projects, three members of the Size-Up and Search & Rescue Technical Panel were selected to rollover to this panel and continue serving as well.