4
The suppressants used in the single agent system tests were
dry chemical, wet chemical, CO2, or water mist. The dual
agent system tests had 2 suppression nozzles on each side,
one for dry chemical and one for wet chemical suppression
agents, also shown in figure 3b. The suppressants used in
the dual system were wet chemical and dry chemical, and
they were released simultaneously, running through the
pipes down to the nozzles.
EXPERIMENTS
The diesel engine block sat at a distance of 12 feet
(3.66 meters) from the fan, positioned at the center of the
Fire Suppression Facility. Before commencing the test, the
fan was adjusted to achieve the desired airflow to remove
the smoke from test area, approximately 145 feet per min-
ute (0.74 meters per second) at the exit section. Airflow
in front of the diesel engine was measured using a vane
anemometer via a traverse method. Once the fan was set,
no further adjustments are made. Data acquisition began
30 seconds before each test to capture baseline param-
eters. After recording baseline data, the fuel spray system
was activated, igniting the fuel with a propane burner as
it sprayed from the nozzle. The PJ20 spray fire nozzle [2],
situated 3 inches (0.08 meters) in front of the diesel engine
and 14 inches (0.36 meters) above the floor, atomized the
fuel. This process was replicated for motor and hydraulic
oils, with the addition of a heating strip wrapped around
the cylinder to decrease viscosity so that adequate atomiza-
tion and stable spray fire could be achieved.
The spray fire was allowed to burn until the concen-
trations of CO and CO2 gases stabilized typically within
60 seconds, before activating the fire suppression system.
Suppression nozzles were positioned at one of the six con-
figurations. In one instance, a wet chemical fire suppressant
agent was employed with the nozzle configuration A. The
activation of the wet chemical suppressant agent was man-
ually initiated from outside the Fire Suppression Facility.
Once the fire suppression agent was fully discharged from
the cylinder, typically within 45 seconds, and if the fire was
successfully suppressed, the fuel continued to spray for an
additional 20 seconds to test for potential reignition. If no
reignition occurred, the fuel spray system was deactivated,
marking the completion of a suppression test. However, if
the fire suppression system failed to suppress the fire, the
diesel fuel dispersal system was shut down, indicating a
non-suppression test outcome.
At the exit section of the modified shipping container,
a 6-point gas monitoring array was installed to measure the
gas components generated from the fire. The two arrays
consisted of ½-inch diameter PVC pipes positioned at
the facility’s center. Each pipe featured six 1/8-inch holes
drilled along its vertical section to sample gases. These sam-
pling points were vertically positioned at 53 inches (134.6
cm), 72 inches (182.9 cm), and 94 inches (238.8 cm) from
the floor. A ½-inch tube connected these PVC pipes to
the control room, leading to a set of infrared gas analyzers
where the mixed gas was analyzed. The gas analyzers moni-
tor CO, CO2, and O2 gas concentrations, collecting data
every 0.1 seconds. The raw data underwent further analysis
to accurately determine gas concentrations. A 6-point ther-
mocouple array was positioned at the exit section to mea-
sure gas temperatures. These thermocouples were affixed to
two vertical ½-inch diameter PVC pipes running from the
floor to the roof, spaced at the same location as the gas
sensors. Gas temperature data was recorded in the control
room via the data acquisition system.
RESULTS AND DISCUSSION
Heat Release Rate (HRR) of a fire is a good indicator of
the fire size and intensity, and in most cases, can be used to
identify the stage of a fire, for example, the growth stage or
decay stage, etc.
The method for calculating the HRR is based on the
CO2 and CO generation rates. With this method, the
HRR is calculated from measured gas concentrations of
CO, CO2, and measured gas velocity [3]. The calculation is
expressed as equation 1:
QA k
HC
m [k
H kCO HCO
mCO
CO2
CO
CO
C
2
=+
-o F (1)
where QA is the HRR, kW HC is the total heat of com-
bustion of the fuel, kJ/g, and can be determined from the
proximate analysis of the fuel HCO is the heat of combus-
tion of CO, 10.1 kJ/g kCO
2
is the stoichiometric mass of
CO2 produced per unit mass of the fuel kCO is the stoi-
chiometric mass of CO produced per unit mass of the fuel
mCO
2
is the production rate of CO2 from the fire, g/s and
mCO is the production rate of CO from the fire, g/s kCO
2 and kCO are the fuel-dependent constants and can be cal-
culated based on the experimental results from Egan [4] for
different fuels.
For combustion of a fuel, the CO and CO2 generation
rates can be determined from their bulk-average concentra-
tions downstream of the fire by the expressions:
m VAr CO 1.97 10 VACO
CO CO 2 2
2 2
#==-3 o (2)
m VArCOCO 1.25 10 VACO
CO #==-3 o (3)
where V is the exit average air velocity, m/s A is the entry
cross-section area, m2 rCO2 is the density of CO2, which
The suppressants used in the single agent system tests were
dry chemical, wet chemical, CO2, or water mist. The dual
agent system tests had 2 suppression nozzles on each side,
one for dry chemical and one for wet chemical suppression
agents, also shown in figure 3b. The suppressants used in
the dual system were wet chemical and dry chemical, and
they were released simultaneously, running through the
pipes down to the nozzles.
EXPERIMENTS
The diesel engine block sat at a distance of 12 feet
(3.66 meters) from the fan, positioned at the center of the
Fire Suppression Facility. Before commencing the test, the
fan was adjusted to achieve the desired airflow to remove
the smoke from test area, approximately 145 feet per min-
ute (0.74 meters per second) at the exit section. Airflow
in front of the diesel engine was measured using a vane
anemometer via a traverse method. Once the fan was set,
no further adjustments are made. Data acquisition began
30 seconds before each test to capture baseline param-
eters. After recording baseline data, the fuel spray system
was activated, igniting the fuel with a propane burner as
it sprayed from the nozzle. The PJ20 spray fire nozzle [2],
situated 3 inches (0.08 meters) in front of the diesel engine
and 14 inches (0.36 meters) above the floor, atomized the
fuel. This process was replicated for motor and hydraulic
oils, with the addition of a heating strip wrapped around
the cylinder to decrease viscosity so that adequate atomiza-
tion and stable spray fire could be achieved.
The spray fire was allowed to burn until the concen-
trations of CO and CO2 gases stabilized typically within
60 seconds, before activating the fire suppression system.
Suppression nozzles were positioned at one of the six con-
figurations. In one instance, a wet chemical fire suppressant
agent was employed with the nozzle configuration A. The
activation of the wet chemical suppressant agent was man-
ually initiated from outside the Fire Suppression Facility.
Once the fire suppression agent was fully discharged from
the cylinder, typically within 45 seconds, and if the fire was
successfully suppressed, the fuel continued to spray for an
additional 20 seconds to test for potential reignition. If no
reignition occurred, the fuel spray system was deactivated,
marking the completion of a suppression test. However, if
the fire suppression system failed to suppress the fire, the
diesel fuel dispersal system was shut down, indicating a
non-suppression test outcome.
At the exit section of the modified shipping container,
a 6-point gas monitoring array was installed to measure the
gas components generated from the fire. The two arrays
consisted of ½-inch diameter PVC pipes positioned at
the facility’s center. Each pipe featured six 1/8-inch holes
drilled along its vertical section to sample gases. These sam-
pling points were vertically positioned at 53 inches (134.6
cm), 72 inches (182.9 cm), and 94 inches (238.8 cm) from
the floor. A ½-inch tube connected these PVC pipes to
the control room, leading to a set of infrared gas analyzers
where the mixed gas was analyzed. The gas analyzers moni-
tor CO, CO2, and O2 gas concentrations, collecting data
every 0.1 seconds. The raw data underwent further analysis
to accurately determine gas concentrations. A 6-point ther-
mocouple array was positioned at the exit section to mea-
sure gas temperatures. These thermocouples were affixed to
two vertical ½-inch diameter PVC pipes running from the
floor to the roof, spaced at the same location as the gas
sensors. Gas temperature data was recorded in the control
room via the data acquisition system.
RESULTS AND DISCUSSION
Heat Release Rate (HRR) of a fire is a good indicator of
the fire size and intensity, and in most cases, can be used to
identify the stage of a fire, for example, the growth stage or
decay stage, etc.
The method for calculating the HRR is based on the
CO2 and CO generation rates. With this method, the
HRR is calculated from measured gas concentrations of
CO, CO2, and measured gas velocity [3]. The calculation is
expressed as equation 1:
QA k
HC
m [k
H kCO HCO
mCO
CO2
CO
CO
C
2
=+
-o F (1)
where QA is the HRR, kW HC is the total heat of com-
bustion of the fuel, kJ/g, and can be determined from the
proximate analysis of the fuel HCO is the heat of combus-
tion of CO, 10.1 kJ/g kCO
2
is the stoichiometric mass of
CO2 produced per unit mass of the fuel kCO is the stoi-
chiometric mass of CO produced per unit mass of the fuel
mCO
2
is the production rate of CO2 from the fire, g/s and
mCO is the production rate of CO from the fire, g/s kCO
2 and kCO are the fuel-dependent constants and can be cal-
culated based on the experimental results from Egan [4] for
different fuels.
For combustion of a fuel, the CO and CO2 generation
rates can be determined from their bulk-average concentra-
tions downstream of the fire by the expressions:
m VAr CO 1.97 10 VACO
CO CO 2 2
2 2
#==-3 o (2)
m VArCOCO 1.25 10 VACO
CO #==-3 o (3)
where V is the exit average air velocity, m/s A is the entry
cross-section area, m2 rCO2 is the density of CO2, which