Flashover simulation for firefighter training

A system and method is disclosed for providing a simulation of a flashover condition that can occur during the course of suppression of a live fire. The flashover simulation is implemented by selectively supplying and igniting fuel to an auxiliary or flashover fuel burner assembly positioned adjacent the ceiling of the burn room of a firefighter trainer. Preferably, the flashover simulation is implementable only upon attainment of a threshold value of one or more pre-selected trainer operational parameters that are monitored throughout the course of a training scenario. Preferred trainer operational parameters for such monitoring include flame height at a main burner assembly and air temperature adjacent to or near a ceiling portion of the burn room.

BACKGROUND OF THE INVENTION: 
1. Field of the Invention 
The subject invention relates generally to fire simulation systems for 
training municipal, military, and other firefighter trainees as to the 
preferred procedures for suppressing and ultimately extinguishing fires. 
More particularly, the invention relates to a firefighter training system 
which is operable to produce an indication of a flashover as a consequence 
of improper fire extinguishing procedures on the part of the trainees. 
2. Description of the Related Art 
Conventional firefighter training practices typically provide for the 
combustion of flammable materials, such as wood, straw, and other organic 
and inorganic materials, which are to be extinguished by the trainee upon 
the application thereon of sufficient quantities of an appropriate 
extinguishing agent. The extinguishing agent that is most commonly 
utilized is water, due principally to its availability, cost and 
widespread usage as a fire extinguishing material. However, these 
conventional training practices have come under scrunity in recent years 
as a result of the relatively high injury rate, adverse environmental 
impact, and limited training effectiveness and trainee throughput that is 
associated with such practices. For example, the National Fire Protection 
Association (NFPA) reports that in the United States alone, nearly 6,000 
training-related injuries were sustained by firefighters in 1988. 
Nevertheless, live fire training is a crucial and necessary component of 
firefighter training, for it most closely represents the overall 
environment a firefighter is likely to encounter during a genuine fire 
emergency. Unfortunately, conventional live fires that are set for the 
purpose of firefighter trainee education suffer from many of the very same 
hazards that are associated with genuine fire 
emergencies--unpredictability of fire propagation and its response to 
trainee action. As a consequence of these characteristics, it is 
oftentimes necessary for the trainee supervisors to themselves suppress 
the live fire prior to rendering perhaps life-saving assistance to a 
fallen trainee. Furthermore, because the very nature of a conventional 
live fire is unpredictability, it is not possible to accurately and 
readily reproduce a desired fire condition for a succession of firefighter 
trainees. 
In an effort to address the foregoing deficiencies in firefighter training, 
live fire simulator systems have been implemented since the early 1970's 
which provide for, among other features, the substitution of various 
controllable arrangements of propane and natural gas-operable burners 
located within dedicated "burn rooms" for the prior practice of igniting 
various flammable props (i.e., wood or straw bundles) or even buildings to 
be razed. Illustrative of the newer generation of live firefighter 
training simulators is that disclosed in U.S. Pat. No. 4,303,396 and 
assigned to the United States of America as represented by the Secretary 
of the Navy. The simulator disclosed in this referenced patent, which is 
hereby incorporated by reference, provides a plurality of chambers, each 
of which can be provided with a fire from a fuel burner that is 
representative of a variety of different types of fires. This simulator is 
useful in educating firefighter trainees as to some general principles of 
fire extinguishment, such as spray nozzle control and various 
extinguishing agent application techniques. However, it does not simulate 
certain "real life" fire situations, such as flashover, that a firefighter 
may encounter during the course of combating of a genuine fire emergency 
of the type that can be present in a generally enclosed space. As used 
herein, the term "flashover" refers to the spontaneous combustion and/or 
explosion of heated gases which collect adjacent the ceiling of a room as 
a consequence of the various gases emitted from burning material having 
attained their flash point temperatures. Flashover manifests itself in the 
form of a fireball which explodes downwardly from the ceiling to the 
floor. As the fireball can attain temperatures in excess of 1,000.degree. 
F. (538.degree. C.), which is far greater than the temperature at which 
conventional firefighter survival suits are rated, the occurrence of a 
flashover is oftentimes fatal to all personnel in the vicinity of the 
fireball. Additionally, the concussive effect of the downward explosion of 
the fireball can disable personnel not in the immediate vicinity of the 
flashover. 
Because flashover can have such a profound impact on the health, safety and 
performance of firefighters, it is desirable to properly educate 
firefighters as to the fire extinguishing techniques which are successful 
in preventing flashover from occurring in the first instance. One commonly 
used method for inhibiting the occurrence of flashover is to periodically 
spray with water the ceiling of the room in which the fire is present, 
thereby cooling the gases located adjacent to the ceiling. 
Efforts to incorporate flashover precursor simulation in prior live fire 
simulators have not been entirely successful and can present unduly 
hazardous conditions for trainees. For example, an attempt has been made 
to provide flashover prevention training by monitoring generally the 
manner in which water is applied to the fire. In instances where improper 
watering techniques are used, the fire is made to expand and rollover 
conditions are caused to develop three to five feet (1-1.5 m) across the 
ceiling. Unfortunately, this can give rise to hazardous conditions in the 
event that the trainees are in undesirably close proximity to the burners. 
In view of the foregoing limitations of the prior art, it is an object of 
the subject invention to provide a flashover simulation for firefighter 
training which is operable in a highly controllable manner and to provide 
a visual, aural and thermal indication of flashover once predetermined 
conditions have been met. 
A further object of the subject invention is to simulate flashover arising 
from a variety of different fire types and occurring when a variety of 
different extinguishing agents, such as water, foam, CO.sub.2 and other 
agents, are in use. 
Yet another object of the subject invention is to provide flashover 
simulation for firefighter training which is responsive to a range of 
variable user-selectable parameters. 
These and other objects and advantages will become apparent from a reading 
of the following detailed description of the preferred embodiment. 
SUMMARY OF THE INVENTION 
A system and method is provided for simulating flashover during a live 
firefighting training exercise. The education of firefighter trainees as 
to the precursor conditions which give rise to flashover and the fire 
suppressing practices that can be implemented on the part of firefighters 
to avoid flashover is of considerable importance, as flashover, once it 
occurs, is oftentimes harmful, and even fatal, to the personnel in the 
vicinity of the event. 
In one aspect of the invention, a flashover simulation system is provided 
for use with a firefighter trainer having a main burner that is mounted 
within a generally enclosed burn room. The flashover simulation system 
includes at least one auxiliary or flashover burner that is positioned 
adjacent to a ceiling portion of the burn room. The auxiliary burner is 
operable to burn fuel that is supplied to it from a fuel reservoir to 
provide the flashover simulation. A fuel ignitor is positioned adjacent 
the auxiliary burner and is operable to generate, preferably in a 
continuous manner, fuel ignition output to the auxiliary burner. A control 
system is operable to effect fuel delivery to the auxiliary burner, 
preferably for a prescribed interval of time, independently of fuel 
delivery to the main burner. The control system can include, for example, 
a valve assembly such as a motorized linear valve, for providing a 
variable control of fuel delivery to each of the main and auxiliary 
burners independent of one another. 
A preferred aspect of the flashover simulation system provides for the 
monitoring of at least one firefighter trainer operational parameter and 
the generation from the control system of a flashover enablement signal 
after the monitored operational parameter has attained or exceeded a 
pre-selected threshold value. The preferred operational parameters are 
main burner flame height and the temperature of air adjacent or near the 
burn room ceiling. Preferably, both operational parameters are monitored 
and the flashover enablement signal is generated only after the respective 
pre-selected threshold values have been substantially simultaneously 
attained. Optimally, at least one of the respective threshold values is 
operator selectable from a prescribed range of such values and can be 
applied as an input to the control system. 
Because the combustion of fuel is inherently dangerous, it is desirable to 
transmit the flashover enablement signal to a flashover actuation switch 
which is selectively operable by supervisory personnel that are preferably 
on-site at the burn room. In this fashion, supervisory discretion can be 
exercised in determining the appropriateness of the flashover simulation 
under the totality of circumstances existing in the burn room during the 
training scenario. Such circumstances can include, for example, trainee 
experience and composure during the training scenario, as well as their 
proximity to the main and auxiliary burners. However, the flashover 
simulation system can also be configured to provide for automatic (i.e., 
non-discretionary) flashover simulation implementation, particularly when 
the monitored operational parameters are within acceptable ranges of 
operation. 
In another aspect of the invention, a method is provided for simulating 
flashover in a firefighter trainer of the type having a main burner 
mounted within a generally enclosed burn room. The novel method provides 
for selectively enabling a flow of combustible fuel to an auxiliary or 
flashover burner while a fuel ignitor positioned adjacent to the burner is 
in operation to direct a flame near the ceiling of the burn room. 
Preferably, the fuel flow is enabled only after a predetermined threshold 
value for at least one monitored operational parameter for the firefighter 
trainer has been attained. Preferred operational parameters for monitoring 
include main burner flame height and the temperature of air adjacent to a 
portion of the ceiling of the burn room. Ceiling temperature is preferably 
sensed by a thermocouple which provides an output signal indicative of 
sensed temperature to a control unit such as an automatic processing unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With reference to the drawings, wherein like reference characters represent 
corresponding parts throughout the various views, and with particular 
reference to FIG. 1, there is depicted a multi-compartmented firefighter 
trainer in accordance with the principles of the subject invention, 
designated generally by reference character 10. The trainer is comprised 
generally of a plurality of compartments or chambers 12, 14 16 and 18, 
each of which is independently operable and controllable in the manner 
described below by a master processing unit 20 which may comprise a 
personal computer, workstation, or the like. However, it is to be 
understood that the principles of the subject invention are equally 
applicable to firefighter trainers having only a single compartment or 
"burn room". As shown in the drawing, the master processing unit 20 
comprises a central unit 22 which includes a central processing unit (CPU) 
and at least one disk drive, a display screen 24 such as a CRT, and a 
suitable data input device 26 such as a keyboard and/or manual input 
device (e.g., "mouse"). The master processing unit 20 can be positioned 
remote from the compartments 12, 14, 16 and 18 and is operable to 
communicate in a "master/slave" relationship in the manner described 
below, as indicated by control line 30, with a local automated processing 
unit 28 that is preferably associated with one or more of the compartments 
in which a fire simulation is to be conducted. The local processing unit 
28 provides control signal inputs to the various devices such as fuel 
inlet valves, smoke generators and emergency fire suppression and 
ventilation apparatus described below. Data regarding the operability 
and/or performance of the apparatus controlled by the local processing 
unit 28 is conveyed to the master processing unit 20 along the control 
line 30. Additionally, data sensed by various sensors, such as compartment 
ceiling temperature sensors 32, is communicated to the local processing 
unit 28 along sensor data line 34 for processing after which the processed 
sensor data can be communicated to the master processor 20 for display to 
the operator. Fuel such as propane or natural gas is housed within a 
suitable storage tank 36 and is supplied to main gas burner units 38 
within the compartments through fuel supply lines 40. Signal inputs are 
received at the local processing units 28 for opening the appropriate fuel 
control valves associated with a given burner in the compartment 12, 14, 1 
or 18 in which a training exercise is to be conducted. Fuel can also be 
supplied to the overhead flashover burner unit 41 in a similar manner upon 
the occurrence of pre-established criteria applied as inputs through the 
data input device 26, as described in detail below. The flashover burner 
unit preferably comprises two elongated, cylindrical burners 41a and 41b, 
positioned in spaced-apart relation with one another so as to produce, 
upon burner ignition, a flame spread generally parallel to the ceiling. As 
indicated in the drawing, the preferred embodiment of the subject 
invention permits a firefighter crew, indicated in the drawing generally 
by reference character 42, preferably under the watchful eye of one or 
more supervisory personnel positioned behind an observation or fire wall 
44, to advance through the trainer 10 to a specific one or more of the 
trainer compartments, such as compartment 12, to combat a live fire 
therein generated by the main burner assembly 38 in a manner well known in 
the art. 
Further details of the flashover simulation apparatus of the subject 
invention are depicted in FIG. 2. With reference to the drawing, a 
firefighter crew 42 is shown applying an extinguishing agent such as 
water, foam, powder or CO.sub.2 gas to a fire at the main burner assembly 
38. In a manner well known in the art, the fire at the burner 38 can be 
optionally controlled to simulate various types of fires such as wood, 
chemical, electrical and grease fires. The extinguishing agent 46 can 
optionally be collected at a funnel 48 formed in the floor grating 50 for 
conveyance to, for example, one or more detectors 52 for analysis as to 
volume and/or composition. Results of the analysis can ultimately be 
reported to the trainees and supervisor for critiquing as to, for example, 
the quantity and/or appropriateness of the extinguishing agent applied to 
the fire. In this regard, it is well known that particular extinguishing 
agents are more appropriate than others for extinguishing certain types of 
fires. For example, water is generally regarded as an inappropriate 
extinguishing agent for application to grease fires and can, in fact, 
exacerbate such fires. Obscuration of the trainees' vision in a manner 
likely to be encountered in a genuine fire emergency can optionally be 
provided by suitable smoke generating apparatus (not shown), such as that 
described in co-pending patent application Ser. No. 07/707,868 filed on 
May 31, 1991 and assigned to the assignee of the subject invention, that 
are capable of producing simulated smoke through inlet vents 54. 
The flashover burners 41 are positioned adjacent to the compartment ceiling 
56, preferably at a height level of at least about 60% of the height of 
the room in the vicinity of the fire simulation. For example, placement of 
the flashover burners 41 at a height of from about 2 ft. (e.g., for crawl 
space-or drop ceiling-type simulators) to about 15 ft. above the 
compartment floor 50 is optimal. The burners can be suspended from the 
ceiling by suitable brackets 57, or can be arranged so as to extend from 
one of the compartment sidewalls 58, the burners being supported along 
their length by the above-referenced brackets. The flashover burners 41 
are preferably positioned above the portion of the floor 50 where 
firefighters are likely to take positions in combating a live fire 
emanating from the main burner assembly 38. Preferably, the flashover 
burners 41 are adapted to burn the same fuel as that supplied to the main 
burner assembly 38. The burners 41a and 41b are preferably arranged so as 
to provide a broad, substantially even flame distribution from the burner 
nozzles 60 thereof (upon burner enablement and ignition in the manner 
described below) along a path generally parallel to the ceiling. Flame 
distribution along the ceiling rather than downward toward the 
firefighters in the compartment 12 is preferred so as to ensure safety of 
the personnel within the compartment. A suitable burner can be obtained by 
providing a row of 1/8-inch apertures spaced about every 2 inches along a 
2-inch diameter pipe. As the principal purpose of the flashover simulation 
is to provide a graphic and memorable visual, aural and thermal indication 
of the occurrence of a flashover event, rather than an additional fire to 
be suppressed by the firefighters 42 assembled in the simulator 
compartment, the flashover burners are preferably operable for only a 
brief, preselected interval of time, such as from five to ten seconds. The 
flashover burners 41a and 41b are preferably ignitable by spark ignitors 
61 that are positioned preferably adjacent the fuel inlet end 64 of each 
burner. The ignitors 61 are operable, preferably continuously, throughout 
the live fire training exercise, to emit a spark as shown in the drawing 
toward the flashover burners so as to ignite fuel supplied thereto upon 
flashover enablement and implementation as described below. A suitable 
spark sensor 65, such as an ultraviolet (UV) sensor, is provided adjacent 
to the ignitors 61 to monitor spark emission from the ignitor. A similar 
arrangement of ignitors 62 and ignitor sensors 66 is provided at the main 
burner assembly 38. As is described in detail in the specification which 
follows, fuel is not to be supplied to the flashover burners 41 unless 
spark emissions from the ignitor 61 are detected by the detectors 65, thus 
ensuring that unignited flammable fuel is not emitted by the flashover 
burner to descend and possibly spontaneously ignite in the vicinity of the 
firefighters 42. The foregoing confirmation of spark emissions is 
especially important when propane is employed as a burner fuel, as propane 
is heavier than air and would therefore descend upon the firefighters 
assembled within the compartment and possibly ignite into a fireball, 
absent provision of the foregoing safeguard, following its emission from 
the burner nozzles 60. 
As noted previously, flashover occurs when gases collecting adjacent to the 
ceiling of an enclosure attain their flash points. The flash point will 
vary in accordance with the chemical composition of the gases in the 
ambient air and those emitted from the material (wood, chemicals, and so 
on) that has been consumed by the fire. Typically, the flash point can be 
expected to range from about 900.degree. F. to about 1200.degree. F. In 
the flashover simulation of the subject invention, the temperature of the 
gases which have collected adjacent to the ceiling of the simulator 
compartment 12 is detected by a suitable ceiling temperature sensor 32. 
The preferred form of ceiling temperature sensor is a thermocouple 33 
which preferably provides an operational range that encompasses at least a 
portion of the range genuine ceiling temperatures that are typically 
encountered in the simulator. A suitable thermocouple for use in the 
flashover simulation of the subject invention is the model K23096G-10A-06 
manufactured by Pyromotion, Inc. of Fort Wayne, Ind. The thermocouple 33 
is positioned at the end of a support rod 67 that preferably extends from 
a sidewall 58 to the ceiling area where heated gases are likely to collect 
during operation of the firefighter trainer compartment at a height of 
from about 2 ft. to about 15 ft. above the compartment floor 50 in 
accordance with the nature and size of the simulator compartment (e.g., 
drop-ceiling/crawl space or full room-size simulator). Suitable support 
brackets 69 extending from the ceiling are provided to maintain placement 
of the thermocouple 33 in the desired position. Temperature data obtained 
from the thermocouple is conveyed along appropriate data lines 34 (FIG. 1) 
and converted by appropriate analog-to-digital (A/D) converter circuitry 
prior to delivery to the local processing unit 28 for processing in the 
manner set forth below and communication to the master processing unit 20. 
Once the pre-established flashover parameters have been attained, a 
flashover enablement signal is transmitted from the master processing unit 
20 (through local processor 28) to an activation switch 68 at an on-site 
control panel 70 located behind the firewall 44. With reference to FIGS. 2 
and 3, the activation switch 68, as well as the various other control 
switches (such as emergency off 72, pause on/off 74 and smoke on/off 76), 
are preferably provided with unique coloring and/or backlighting to 
facilitate their visualization throughout operation of the fire simulation 
exercises. A viewing port or window 78 is preferably provided in the 
firewall 44 to permit the supervisory personnel stationed behind the 
firewall an unobstructed view of the progress of the firefighter training 
scenario. Supervisory personnel are preferably present at the control 
panel 70 throughout the training exercise to oversee all activities within 
the compartment 12 and to exercise supervisory control over the conduct 
and progress of the training exercise. If, in the discretion of the 
supervisory personnel, flashover (once enabled) can be safely and 
effectively implemented, the flashover activation switch 68 can be engaged 
by one of the supervisory personnel, thereby effecting the supply of fuel 
from the reservoir 36 to the flashover burners 41 for ignition by the 
associated ignitors 61 and propagation of the ensuing flame in the manner 
described above. As noted previously, the conditions which give rise to 
flashover enablement can be inhibited, and even prevented altogether, by 
periodically spraying the ceiling of the compartment 12 with the 
extinguishing agent 46, thereby cooling the gases which have collected 
near the room ceiling. An insulative liner 80 (FIG. 3) is preferably 
provided adjacent to the respective portions of the compartment ceiling 
and sidewall which are likely to receive extinguishing agent so as to 
protect the compartment ceiling and sidewalls from the deleterious affects 
of repeated, sudden and extreme temperature changes. The liner can be 
formed from mild steel or "Corten" steel, manufactured by USX Corp. of 
Pittsburgh, Pa., and is removably mounted to the ceiling and sidewalls by 
conventional brackets 82. Smoke and heat can be exhausted from the 
compartment by one or more exhaust fans 79, which are operable to draw 
these trainer byproducts through a corresponding aperture 81 formed in a 
sidewall of the compartment. 
Details of the electromechanical control apparatus for the flashover 
simulation of the subject invention are illustrated in FIG. 4. With 
reference to the drawing, the master data processing unit 20 is in the 
form of a personale computer or workstation. Operation of the processing 
unit 20 is controlled by a central processing unit (CPU) 84, such as the 
model SB286SC marketed by Industrial Computer Source, Inc. of San Diego, 
Calif. A random access memory (RAM) 86 is electrically connected to the 
CPU and stores OSS software and provides working memory for the CPU. A 
read-only memory (ROM) 88 is also provided which stores various programs 
that are needed for input/output, power-up, self-test diagnostics, and 
booting procedures for the CPU 84. One or more disk drives 90 can be 
provided to interface with the CPU 84. The above-referenced video monitor 
24 (FIG. 1) and data input apparatus, such as the keyboard and/or mouse 
26, are provided to permit human operator interaction with the CPU 84. A 
printer 92 can optionally be connected to the CPU 84 to provide a hard 
copy of the data related to the flashover simulation, such as graphics 
and/or tabular data relating thermocouple temperature, quantity of 
extinguishing agent applied during the training exercise, and flame height 
at the main burner assembly 38 as a function of time. Alternatively, such 
data can be stored in RAM 86 for subsequent recall and display to the 
trainee(s) at one or more console monitors 24. 
The master processing unit 20 is coupled to the local processing unit 28 at 
the facility (also known as a "burn building") which houses the one or 
more trainer compartments by way of a bidirectional data, address and 
control bus 94. Preferably, a single, dedicated local processing unit 28 
having all of the features specified below is provided adjacent to one or 
more of the plurality of trainer compartments, a data bus extending 
between the processors of the respective processing units. More 
particularly, the CPU 84 of the main processing unit 20 is coupled to the 
CPU 96 of the local processing unit 28. As is the case with the master 
processing unit 20, the local processing unit 28 includes suitable 
programming and hardware interfaces for communicating with and controlling 
various hardware devices. These devices include the fuel burner control 
valves 98 and smoke generator 100 that are associated with the firefighter 
training simulator of the subject invention, as well as A/D converter 
apparatus that allows the processor to receive and interpret signal inputs 
received from the thermocouple 33. Preferably, outputs from the ignitors 
61 and 62, and UV sensors 65 and 66 are in the form of digital data for 
direct transmission to the CPU 96. 
The CPU 96 of the local processor unit is connected to the various sensor 
and hardware devices associated with each simulator compartment, such as 
compartment 12 illustrated in FIG. 4. For example, the CPU 96 receives 
temperature sensor input (following processing by appropriate A/D 
converter apparatus, not shown) from the thermocouple 33 along data line 
106. Data from the main burner and flashover UV sensors 65 and 66 relating 
respectively to operation of the main burner and flashover ignitors 61 and 
62 is transmitted to the CPU 96 along data lines 108 and 110, 
respectively, whereas ignition signal input to the corresponding ignitors 
are transmitted along communication lines 112 and 114. Fuel is conveyed 
under pressure from tank 36 to the main burner unit 38 and optionally the 
flashover burner unit 41, upon receipt by the burner control valve system 
98 of appropriate signal commands transmitted along communication line 
116. The valve control system includes a valve assembly, such as the 
series 1800-MLV motorized linear valve manufactured by Ben Metzger, Inc. 
of Perry, Ohio, that is mounted in an independently controllable manner 
within the fuel flow path to each of the respective flashover and main 
burner units. Upon receipt of appropriate signal input from the CPU 96, 
the valve control system 98 is operable to bias the fuel control valves 
between a closed position and an open position so as to allow for precise 
metering of fuel under pressure from the tank 36 (through conduit 118) and 
into a corresponding one of the burner fuel supply lines 120 and 122 for 
delivery to the burners 38 and 41, respectively. A suitable connector, 
such as a "T" or "Y" connector (not shown), is provided along the 
flashover burner supply line 122 to split the flow of fuel substantially 
evenly to the two flashover burners 41a and 41b. Flashover enablement and 
other local control panel 70 control input (i.e., for emergency stop, 
pause on/off, smoke on/off, and so on) is communicated between the CPU 96 
and local control panel along communication line 124. CPU 96 control of 
the smoke generator 100 is implemented along communication line 126. Upon 
receipt of an activation signal input from the CPU 96, smoke, which is 
preferably of the simulated, non-toxic variety such as that produced by 
the smoke generator disclosed in commonly-assigned U.S. patent application 
Ser. No. 07/707,868 entitled Method and Apparatus for Controllably 
Generating Simulating Smoke filed on May 31, 1991, the disclosure of which 
is expressly incorporated by reference, is conveyed along conduit 128 to 
the main burner assembly 38 or any other suitable outlet within the 
trainer compartment for the purpose of further enhancing the realism of 
the simulation. The CPU 96 can be operated in a manner well known to 
persons of ordinary skill in the art to control any of a variety of other 
simulator components, such as compartment ventilation, lighting, and other 
hardware. Signal data relating generally to the enablement, status and 
control of the foregoing hardware components discussed above is exchanged 
between the local and main processing systems along the data bus 94, 
thereby minimizing the complexity of communication and control exchanged 
between these two processing systems. The foregoing communication and 
control hierarchy is further advantageous in situations where the master 
processing unit 20, for any of a variety of reasons, is not located 
on-site at the burn building. 
Details of the program control for the flashover simulation of the subject 
invention are set forth in the flow diagram of FIG. 5. Prior to the 
implementation of the training exercise, the CPU 84 commands the CPU 96 to 
initiate a test of the fuel pressure and fuel control valves 98 in order 
to confirm their operability, as indicated by block 130. This test is 
accomplished by CPU 84 accessing of appropriate program data stored in RAM 
86, as described above, resulting in generation of an appropriate input 
signal to the CPU 96 of the local processing unit 28 on-site at the 
trainer compartment at which the firefighter training exercise is to be 
undertaken. The test is implemented upon accessing by the CPU 96 of 
test-related program data stored in RAM 102 in a manner known in the 
computer art, which effects signal output from the CPU 96 along 
communication line 116 to command the hardware at the control valve 
assembly 98 to undergo a prescribed regimen of openings, closings and 
system pressure checks. This pre-implementation test can further encompass 
test-firing of the respective burner ignitors 62 and 61 and the monitoring 
thereof by the UV sensors 66 and 65 associated with the respective 
ignitors by means of signals exchanged with the CPU 96 along the 
respective communication lines 112 & 114 and 108 & 110. Upon satisfactory 
completion of the pre-implementation test procedures, the main processing 
unit 20 prompts the console operator, as indicated by blocks 132 through 
138, for entry of the appropriate fire simulation parameters for the 
training exercise. An illustrative example of the operator console prompt 
is illustrated in FIG. 6. Once the various desired simulation parameters 
have been entered (through the keyboard and/or mouse input 26), the 
training scenario can proceed. In the preferred embodiment, the operator 
console generates prompts for flashover trigger temperature (block 136), 
main burner height flashover trigger (block 138) and burn duration 
selection (block 140) only in the instance where the flashover simulation 
has been selected. However, for the sake of illustration, options for the 
selection of these respective parameters have been included in the 
operator console screen representation depicted in FIG. 6. The flashover 
prompts indicated by blocks 136 and 138 are preferably not generated at 
the console in instances where flashover simulation has not been elected. 
Following entry of the respective training scenario parameters, the 
training scenario is initiated, as shown at block 142. In instances where 
the flashover simulation has been selected (see block 144), the 
operability of the flashover ignitors 61 is confirmed (block 146) by the 
local processing unit 28 in the manner described above (i.e., by 
monitoring signal output from UV sensors 65). Upon confirmation of ignitor 
operability at the local processor 28 and transmission of this data along 
bus 94 to the main processing unit 20, the flame height at the main 
burners 38 is monitored (block 148) in a conventional manner, as can be 
accomplished by monitoring the valve position (i.e., percentage of valve 
aperture opening as transmitted by the referenced valve) or, 
alternatively, by monitoring the quantity of gas flow to the burners by 
means of a conventional in-line fuel flow gauge. In either case, a 
determination is made as to whether the main burner flames have met or 
exceeded the pre-selected flashover triggering height. Main burner flame 
height is preferably continuously monitored, as an underlying assumption 
for the flashover simulation is that flashover ordinarily does not occur 
in fire emergencies unless the flames have attained a certain minimum 
height necessary for the fire to generate sufficient thermal energy to 
elevate the temperature of gases which collect adjacent to the ceiling to 
the collective gas flash point. With reference to FIG. 6, the main burner 
flashover trigger height that has been selected for the illustrative 
scenario is 3 ft., although any of the other height values provided in the 
prompt can be substituted therefor in accordance with such varied factors 
as the proficiency and experience of the trainee(s) and the type of fire 
to be simulated (wood, chemical, grease, and so on). 
Once the main burner flames have attained the predetermined threshold 
height, temperature data continuously received from the thermocouple 32 
along data line 124 is evaluated by CPU 96, as indicated by block 150, to 
ascertain whether the preselected flashover temperature has been attained. 
Ceiling temperature data is preferably continuously monitored throughout 
the training scenario until its completion. Once the preselected main 
burner flame height and ceiling temperature values have been attained, the 
flashover simulation can be implemented. However, because little or no 
training value is obtained by repetitively generating the flashover 
simulation during a single training scenario, it is desirable to confirm 
that flashover has not been produced up to that time in the scenario, as 
indicated by decision block 152. In instances where flashover simulation 
has previously occurred during the scenario, the scenario proceeds without 
flashover again occurring. In the event that flashover simulation has not 
yet occurred during the ongoing scenario, the local processsor 28 
generates an enablement signal to the flashover activation switch 68 at 
the local control panel 70, as denoted by block 154. Switch activation is 
preferably indicated at the local control panel by switch illumination, 
audible means, and/or a combination of these respective types of indicia. 
The preferred embodiment of the flashover simulation of the subject 
invention provides the fire training supervisor (who is preferably 
positioned adjacent to the control panel 70) with discretion as to whether 
or not a flashover simulation, following switch enablement, is to ensue. 
Such an arrangement (as opposed to fully automatic flashover simulation 
generation upon attainment of the preselected parameters referenced above) 
affords a degree of further safety to the conduct of the training 
scenario, as instances can arise where it is highly undesirable to proceed 
with flashover simulation, even when the pre-established flashover 
conditions have been fully satisfied. Examples of such situations include 
panic on the part of the trainees within the compartment, undesirable 
physical trainee proximity to the flashover burners, and failure of 
equipment such as firefighter protective gear. It is therefore preferred 
to include human supervisory input as an aspect of flashover simulation. 
However, it is to be appreciated and understood by persons skilled in the 
art that a fully automated (i.e., non-discretionary) flashover simulation 
process, in which flashover simulation proceeds automatically upon 
attainment of the foregoing flasher simulation parameters (see blocks 
136-140 above), is within the scope of the subject invention. 
The status of each of the local console selection switches, including the 
flashover activation switch, is continuously monitored by the local 
processor 28 throughout the scenario, as indicated by block 156. With 
reference to flashover simulation, once the flashover activation switch 68 
has been engaged by the trainee supervisor, the CPU 96 generates an 
appropriate command to the flashover burner control valves of the valve 
assembly 98 to open, thereby providing for the delivery of fuel into 
conduit 122 and the flashover burners 41a and 41b for ignition by the 
associated ignitors 61. Once flashover burner ignition has optimally been 
confirmed by appropriate signal data received by the CPU 96 from the UV 
detectors 65 (block 160), the flashover burner control valves are 
maintained open for the prescribed flashover burn duration, as indicated 
by block 162, after which the valves are commanded by the CPU 96 to close 
(block 164). Similarly, in the event that flashover burner ignition 
confirmation has not been received from the UV sensors 65, the CPU 96 is 
preferably operable to command the flashover valves to close so as to 
minimize the release of unignited fuel through the flashover burners. 
Minimization of such uncombusted gas release is especially important in 
instances where fuels such as propane, which is heavier than air and will 
therefore tend to descend toward ground level, are utilized, as the 
presence of an unburned aggregation of fuel within the compartment could 
pose an undue health and safety risk to the trainees, exposing them to 
envelopment by fire. Once the flashover burner control valves have been 
closed, the scenario proceeds to main burner fire extinguishment, 
interruption by supervisory personnel at the local control panel or 
operator console, or automatic system shut-down upon receipt by the local 
processing unit 28 of signal data from the foregoing sensors indicative of 
a system malfunction. 
While the subject invention has been described in conjunction with 
preferred embodiments, it is to be understood and appreciated that the 
protection to be afforded the invention is defined by the accompanying 
claims and functional equivalents thereof, rather than by the specific 
features of the foregoing detailed description and accompanying drawings.