BY JAMES M. FOLEY
The fire service today needs members who challenge the future. New technology, building materials, and construction methods are making today’s fire responses markedly different from those in the past. Fire alarm systems summon firefighters to the scene faster. Firefighter protective clothing allows greater penetration into hostile immediately dangerous to life and health (IDLH) environments, and plastic and synthetic fuels burn hotter and faster than ever before. The challenges to today’s firefighters require a good education in the fire sciences as well as a firm understanding of the fire phenomena.
 1) Front of test apparatus, lower chamber. (Photos by M. Palcko.) |
In my chemistry for fire protection class at Camden County College in Blackwood, New Jersey, students are required to develop and conduct a fire research experiment involving the analysis of some aspect of the combustion process or its effect on the living environment. The project challenges the students to research a fire problem and develop a solution. They must design and construct the test apparatus and test method and evaluate the results to support or negate their hypotheses.
Student projects this year ranged from the effects of thermal transmission in ARFF boots to the examination of labeling and fire resistance of children’s sleepwear.
FLASHOVER PROJECT
One student project, however, stood out. Three fire service instructors from the Camden County Fire Academy-Peggy Palcko (Blackwood Fire Department) and Matt Skowronick and Keith Davis (Collingswood Fire Department)-built and developed a small-scale flashover simulator that they used to demonstrate the flashover phenomenon to nonfirefighting groups.
 (2) Rear chamber with wood panels. |
They identified flashover in terms of a transitional point in a fire condition where the fire rapidly changes from fuel dominant to compartment dominant. From the supporting literature, they identified this transition point to occur at temperatures greater than 1,125°F with a critical radiant flux of 22kw/m2. Radiant flux is the measurement of energy needed to continue self-sustained ignition of a material.
The students identified the conditions necessary to generate flashover based on the Consolidated Fire and Smoke Transport (CFAST) fire model and a flashover correlation model. The CFAST model is based on the size and height of the compartment and the ventilation opening and is considered a two-zone model. Using the information from the model and using a full-scale flashover simulator as a guide, the students proceeded to develop their small-scale test apparatus.
 (3) Crib fire and hay fuel load. |
The simulator is constructed out of 1⁄4-inch steel plates with an upper and lower compartment. The upper compartment has slide glides that accept 19- by 19-inch plywood panels. Boards are also on the ceiling and the back of the loading door. The lower compartment has two slots for inserting wire observation glass.
A crib fire, using 26 one-half-inch pieces of oak stripping, is ignited in the middle of the upper compartment; a handful of hay is also used to facilitate ignition. The lower compartment has a hinged vent and pulley system that allows air entrainment to the crib fire.
The students ignited the crib fire with a propane torch and recorded observations at specific intervals. In the numerous tests they conducted for this college experiment, flashover occurred in approximately 13 to 14 minutes (in this particular simulator).
 (4) Test fire ignition. |
Note: In the real-life fire environment, however, the time to flashover depends on many variables-among them, fuel moisture content, fuel configuration and mass, ventilation, and rate of heat transfer. These particular aspects of the science of flashover were not examined in this small-scale test. It is important that the audience viewing a demonstration in this simulator understand that the small-scale testing they are witnessing most likely will not mirror a flashover in a structural fire.
As a training aid, this simulator should be used in conjunction with training videos of large-scale, authentic structural flashovers.
 (5) Flashover, in 13 minutes. |
The value of this small-scale test vehicle is that it produces the thermal layers, rollover effect, and flashover phenomena effectively without exposing the novice or recruit firefighter to actual flashover conditions. Instructors using this type of device are cautioned to reinforce the fact that a real flashover can occur in as little as two to five minutes, and with much greater destruction. A flashover in a structure fire is the turning point for occupant life safety as the fire transforms from fuel dominant to compartment dominant.
Teaching fire protection chemistry to firefighters is a formidable task at the least; however, having the students involved in some aspect of combustion science challenges them and makes the learning more memorable. This project will assist the Camden County Fire Academy in explaining the flashover phenomenon to nonfirefighting personnel and public officials. ■
■ JAMES M. FOLEY, a 34-year veteran of the fire service, is deputy chief fire official in the Atlantic City (NJ) Fire Department, a leader of the New Jersey Task Force 1 urban search and rescue team, and a certified Fire Instructor II. He teaches in the fire code programs at Rutgers University and Camden County College. He has a bachelor of science degree in fire protection technology and fire administration from the University of Maryland and a bachelor of arts degree in biological science and chemistry from Rowan University.
