Understanding and Fighting Basement Fires: The ISFSI & UL FSRI 2017 Joint Research Project: Brian Kazmierzak and Dan Madrzykowski

By Brian Kazmierzak and Dan Madrzykowski

Firefighters have always been taught that basement fires are dangerous fires to fight. They have been trained to operate above the fire and make their way down the throat of the fire, to attack the fire on its own level. Previous research has shown that the floor systems we walk or crawl on fail quickly and without warning. Exposed wood flooring systems do not maintain their structural integrity for long under fire conditions, unless they are protected by drywall or a sprinkler system. Since the double line-of-duty deaths (LODDs) on Cherry Road in Washington, D.C. in 1999, we have also been aware of the “flow path” and its impact on firefighting, particularly in basement fires. The flow path didn’t just come about in 1999; we became more aware of it because of the National Institute of Standards and Technology (NIST) research, which enabled us to re-create it and distribute simulations for the fire service to study. This article provides an overview of the International Society of Fire Service Instructors’ (ISFSI) Understanding and Fighting Basement Fires Project, including a brief history of previous research, LODD basement fires, the research questions, and the tactical considerations developed as part of this research.

Basement Fires

In 2016, the ISFSI was awarded its most recent Assistance to Firefighters Fire Prevention and Safety Research Grant. The Understanding and Fighting Basement Fires study was funded to research basement fire attack tools and tactics to determine the most effective methods. As the first step of the study, ISFSI developed a technical panel to guide the research to ensure that the end results would be of use to the fire service. The panel included representatives from several sections of the International Association of Fire Chiefs (IAFC), the North American Fire Training Directors, the National Institute for Occupational Safety and Health, and representatives from several fire departments that had suffered LODDs because of basement fires. The ISFSI partnered with the Underwriters Laboratories Firefighter Safety Research Institute (UL FSRI) and the Delaware County (PA) Emergency Services Training Center to conduct the research.

In the next step, we examined the previous research and fireground experience to understand the gaps in understanding basement fires. During the past 10 years, several floor collapse studies have been conducted. In 2008, UL FSRI published its research findings on the structural stability of engineered lumber exposed to fire conditions [1]. The experiments were conducted on a floor furnace. The research demonstrated that “modern” engineered wood floor assemblies failed faster than wood floor assemblies with “legacy” designs. This study also pointed out that modern tools like thermal imagers (Tis) had limited use in determining the condition of the floor assembly or the fire conditions under the floor. Further, the study questioned the use of the time-honored means of “sounding the floor” to determine if operating on the floor was safe.      

Flooring Systems

In 2012, UL FSRI and NIST released a study that examined four types of flooring systems in a townhouse type arrangement, with a 720-sq ft (67 sq m) floor area and a 20-ft (6.1 m) span. These experiments examined the time to collapse for residential floor systems constructed with dimensional lumber, wood I-joists, parallel chord wood trusses, and lightweight steel C-channel. The results from this study proved that any of the unprotected floor assemblies could collapse within the operational time frame of the fire department. This report also showed that the current fireground practices of entering on the floor above the fire and working down to the fire in the basement would not provide the firefighter with the appropriate information to make decisions to enable a safe operating environment [2].     

As a follow-up to UL’s floor furnace experiments, NIST conducted experiments in two-level wood structures with a 16-ft (4.8 m) span that supported the findings of the UL study on the value of gypsum board to protect the floor assembly and the challenges for the TIs. Three firefighting TIs, each with a different type of sensor, were used to view and record the thermal conditions of the top of the floor assembly from the open doorway in the upper compartment. The times to collapse of each floor were also noted. Given the insulating effects of the oriented strand board (OSB) and the floor coverings, the temperature increase or thermal signatures viewed by the TIs were small, given the fact that the ceiling temperatures below the OSB were in excess of 1,110°F (600°C).

These experiments further demonstrated that TIs alone cannot be relied on to determine the structural integrity of a wood floor system. Therefore, it is critical for the fire service to review the practice of size-up and other fireground tactics needed to enable finding the fire prior to conducting fire operations inside a building. This study also highlighted that increased ventilation to the fire in the lower level resulted in a larger fire, which led to the failure of the floor assemblies [3].

Near Misses

Chief Gary Morris, representing the IAFC Safety Health Survival Section and Pine-Strawberry Fire District, shared a study that he conducted for the IAFC on basement fires [4].  He reviewed 21 incidents involving basement fires that resulted in 30 LODDs. In addition, he reviewed 400 near-miss reports related to basement fires that had been submitted to The National Near Miss Reporting System.

The National Near-Miss Reporting System data showed the largest category for the near-miss reports related to basement fires involved collapse of the first floor or firefighters falling through holes in the floor. The second largest category of near-miss events involved disorientation, separation, or entrapment of a firefighter operating in a basement. This information aligns with data from Chief Don Abbott’s Project Mayday that showed the second most common cause of a Mayday is a firefighter falling into a basement. 

Then, the technical panel reviewed basement LODD case studies. There are plenty--from Joe Samec in Burr Ridge, IL; to Joyce Craig in Philadelphia, PA; to Richard T. Sclafani in New York City; to Robin Broxterman and Brian Schria in Colerain Twp., OH; to Patrick Wolterman in Hamilton, OH, just to name a few. We know from the NIOSH LODD reports that there are two common causes of these deaths: a collapse or the firefighters caught in the flow path.

2017 Research

The ISFSI and the UL FSRI technical panel used the knowledge from previous LODDs along with previous research to develop its research questions for the 2017 research. The Technical Panel came up with the following research questions for the Understanding and Fighting Basement Fires research:

·                  What if the interior stairs are the only firefighter access?

·                  What if there are no basement windows to the exterior?

·                  Can door control be applied to basement fires?

·                  Are alternative fire suppression techniques effective?

·                  What if the basement was larger than those in previous studies?

The ISFSI basement fires study took place at the Delaware County (PA) Fire and Emergency Services Academy. A ranch-style house with a full basement was built for this project. The floor area of the upper level was approximately 1,150 sq. ft. (106 sq. m.), and the basement floor area was approximately 1,050 sq. ft. (97 sq. m.).  Floor plans of the upper level and the basement are shown below.

Figure 1. Floor Plan of the Upper Level

Figure 2. Floor Plan of the Basement

The house was instrumented with sensors to measure temperature, pressure, gas velocity, and gas concentrations. These sensors provided information on the hazard conditions in different sections of the house to examine what occupants or firefighters would be exposed to at any given time in the fire. In addition, the data allowed us to see if a given tactic or tool was working to decrease the hazard from the fire. 

Three types of basement access were considered. No exterior access and no exterior vents. In other words, the only access was by  an interior stair. The second type was no exterior access but exterior vents that could be used to apply water into the basement. The third type had exterior access at the basement level, which allowed firefighter entry.

Several firefighting nozzles and appliances were used during the experiments. Basic nozzles such as a smooth bore and a combination nozzle were used along with a cellar nozzle, a Bresnan distributor, and piercing nozzles. The nozzles were applied in favorable and less than favorable circumstances to see how well they controlled or extinguished the fire conditions and to examine the thermal conditions along the flow path and throughout the house.

The fires were started in one of four sofas located in the basement. In addition, five wood pallets were arranged as a “desk” adjacent to each sofa. The exposed floor assembly was composed of wood I-joists on 16-inch centers and an OSB subfloor. 

A full description of the experiments and the results are contained in the research report developed by UL FSRI [4]

In addition to the graphs of all the data recorded, pictographs were developed to show the impact of a given tactic on the fire conditions. An example of one of the pictographs is shown in Figure 3. In the example below, a 150-gallon-per-minute (gpm) straight stream was flowed into the small basement window remote from the fire and was unable to hit the seat of the fire directly because of shielding from the stairway and a utility room. Even so, peak temperatures in the basement were reduced from over 1,000°F to 320°F, and temperatures along the flow path were also reduced, making entry to the basement easy. An added benefit was that oxygen levels improved in remote areas of the house where victims may have been trapped. 

Figure 3. The Impact of Tactics on Fire Conditions

The following tactical recommendations were developed from the research:

1.                Recognize that basement fires are a challenge because of the high potential for floor collapse and positioning in the exhaust   portion of the flow path.

2.                As with any fire, size-up is key.

3.                If the fire is located in the basement, identify potential flow paths--interior stair, side windows, ground level door—and            coordinate ventilation with suppression tactics.

4.                Cool using piercing nozzles, cellar nozzles, hose streams through holes and windows at grade attack (fastest, effective   water).

5.                Extinguish after cooling, assess and enter if appropriate.

6.                Rescue--survival profiles, closed door, open door, gas concentrations.

7.                Continue to study relative to making/understanding your tactical choices. Know why you are using them.

8.                Support codes and standards that support firefighters in achieving their goal of saving lives from fire.

The ISFSI has been offering 50 Assistance to Firefighters Grant program funded, eight-hour Understanding and Fighting Basement fire courses throughout the United States in 2018. Additionally, they will produce a training video of a general overview of the course. Additional information is at or contact the ISFSI at 800-435-0005. 

This course is dedicated to the memory of Lieutenant Matt LeTourneau, Philadelphia Fire Department, who passed away on Saturday, January 6, 2018, from injuries suffered in a tragic LODD in a structural collapse while fighting a rowhouse fire. He was an essential part of the research team and a contributor to the Tech Panel of the ISFSI Basement Fire Research and Curriculum.


                    1. Izydorek, MS, Zeeveld, P0., Samuels, MD, Smyser, JP. Report on Structural Stability of Engineered Lumber in Fire Conditions. Underwriters Laboratories, Northbrook, Illinois, September 2008.

                    2. Kerber, S, Madrzykowski, D, Dalton, J, and Backstrom, R. Improving Fire Safety by Understanding the Fire Performance of Engineered Floor Systems and Providing the Fire Service with Information for Tactical Decision Making. Underwriters Laboratories, Northbrook, Illinois, March 2012.

                    3. Madrzykowski, D and Kent, J. Examination of the Thermal Conditions of a Wood Floor Assembly above a Compartment Fire,  National Institute of Standards and Technology, Gaithersburg, MD.,  NISTTN 1709, July 2011.   

                    4. Madrzykowski, D and Weinschenk, C. Understanding and Fighting Basement Fires: Report of Experiments, UL FSRI, Columbia, MD, January 2018.


Dan Madrzykowski, PhD, has a Master of Science degree in fire protection engineering from the University of Maryland and a PhD from the University of Canterbury in New Zealand. Throughout his career, he has performed research focused on fire suppression, large fire measurements, fire investigation, and firefighter safety. He has conducted fire investigation-related studies over a wide range of topics that include firefighter line-of-duty deaths and injuries; the post-earthquake fires in Kobe, Japan; oil field fires in Kuwait; the Station Night Club fire; and the Cook County Administration Building fire in Chicago. He is a dedicated fire service researcher as well as educator and was presented the Fire Engineering/ISFSI Instructor of the Year Award in 2009.

Brian P. Kazmierzak, EFO, CTO, a member of the fire service since 1991, is the chief of Training for the Penn Twp. Fire Department in Mishawaka, Indiana. He has a bachelor’s degree in fire service administration from Southern Illinois University and serves as the director of operations for and the Webmaster for He was the recipient of the 2006 F.O.O.L.S. International Dana Hannon Instructor of the Year Award, the 2008 Indiana Fire Chiefs Training Officer of the Year Award, and the 2011 ISFSI/FDIC George D. Post Fire Instructor of the Year. He completed the National Fire Academy’s Executive Fire Officer Program in 2006 and is a CPSE credentialed Chief Training Officer. He is the 1st vice president for the ISFSI and was on the UL FSRI PPV Research Study Panel and the ISFSI/UL FSRI Basement Fire Tactics Study Pa