4
wet chemical suppressant agent is manually initiated from
outside the Fire Suppression Facility to see if it will suppress
the fire. After the fire suppression agent is emptied out from
the cylinder, in about 45 seconds, if the fire is suppressed
the fuel will continue to spray for another 20 seconds to
see if the fire will reignite. If the fire does not ignite, then
the fuel spray system is turned off. This will be a positive
test due to the fire being suppressed. If the fire suppression
system does not extinguish the fire, the diesel fuel disper-
sal system will be turned off, and this will be considered a
negative test. The Fire Suppression Facility’s water sprinkler
suppression system is turned on until the fire is out.
The Fire Suppression Facility is equipped with a 6-point
gas monitoring array at the exit section to measure the gas
components produced from the fuel fire. The array is made
of ½-in diameter PVC pipe positioned at the center of the
Fire Suppression Facility. A total of six 1/8-in holes are
drilled into the vertical section of the PVC pipe to sample
the gases. The sample holes are spaced vertically from the
floor at 53 inches (134.6 cm), 72 inches (182.9 cm), and
94 inches (238.8 cm). A ½-inch tube is connected to the
two PVC pipes that lead back to the control room to a set
of infrared gas analyzers where the mixed gas is analyzed.
The gas analyzer measures CO, CO2, and O2 gas concen-
trations. The gas data is collected every 2 seconds and is
recorded by a computer-based data acquisition system. The
raw data is further analyzed to calculate gas concentrations.
A 6-point thermocouple array is also located at the exit
section of the Fire Suppression Facility to measure the gas
temperature at the six monitoring points three on the left
and three on the right side. The thermocouples are attached
to two ½-inch diameter PVC pipes, vertically oriented from
the floor to the roof, at 53 inches (134.6 cm), 72 inches
(182.9 cm), and 94 inches (238.8 cm) above floor level.
The gas data temperature is recorded in the control room
onto the data acquisition system. All the gas concentrations
and temperature data are processed and stored in an Excel
file for further analysis.
The method for calculating the Heat Release Rate
(HRR) is based on the CO2 and CO generation rates from
the spray combustion. With this method, the HRR is cal-
culated from measured data of gas concentrations of CO
and CO2 and measured gas velocity [3].
The HRR calculation using the CO and CO2 genera-
tion rates measured at the exit section of the shipping con-
tainer is expressed as:
Q k
H
k
H k H
A
CO
C
CO2
CO
C CO CO
CO2
2
=+
-
d d nm nm
where QA is the actual HRR, kW HC is the total heat of
combustion of the fuel, kJ/g, and can be determined from
the approximate analysis of the fuel HCO is the heat of
combustion of CO, 10.1 kJ/g kCO2 is the stoichiometric
mass of CO2 produced per unit mass of the fuel kCO is the
stoichiometric mass of CO produced per unit mass of the
fuel m
CO is the production rate of CO2 from the fire, g/s
and m
CO is the production rate of CO from the fire, g/s
kCO2 and kCO are the fuel-dependent constants and can be
calculated based on the experimental results from Egan [4]
for diesel fuel:
For combustion of a fuel within a mine entry, the CO
and CO2 generation rates can be determined from their
bulk-average concentrations downstream of the fire by the
expressions:
m VA CO
2 CO CO2
2
=o
m VA CO
CO CO
=o
where V is the exit average air velocity, m/s A is the entry
cross-section area, m2 rCO2 is the density of CO2 rCO is
the density of CO DCO2 is CO2 produced in the fire,
ppm and DCO is CO produced in the fire, ppm. Using
the CO2 density of 1.97 kg/m3 and CO density of 1.25 kg/
m3, the expressions become:
Spray nozzle
Suppression
nozzle
Diesel engine
Figure 3. Locations of fuel spray nozzle and suppression
nozzle
wet chemical suppressant agent is manually initiated from
outside the Fire Suppression Facility to see if it will suppress
the fire. After the fire suppression agent is emptied out from
the cylinder, in about 45 seconds, if the fire is suppressed
the fuel will continue to spray for another 20 seconds to
see if the fire will reignite. If the fire does not ignite, then
the fuel spray system is turned off. This will be a positive
test due to the fire being suppressed. If the fire suppression
system does not extinguish the fire, the diesel fuel disper-
sal system will be turned off, and this will be considered a
negative test. The Fire Suppression Facility’s water sprinkler
suppression system is turned on until the fire is out.
The Fire Suppression Facility is equipped with a 6-point
gas monitoring array at the exit section to measure the gas
components produced from the fuel fire. The array is made
of ½-in diameter PVC pipe positioned at the center of the
Fire Suppression Facility. A total of six 1/8-in holes are
drilled into the vertical section of the PVC pipe to sample
the gases. The sample holes are spaced vertically from the
floor at 53 inches (134.6 cm), 72 inches (182.9 cm), and
94 inches (238.8 cm). A ½-inch tube is connected to the
two PVC pipes that lead back to the control room to a set
of infrared gas analyzers where the mixed gas is analyzed.
The gas analyzer measures CO, CO2, and O2 gas concen-
trations. The gas data is collected every 2 seconds and is
recorded by a computer-based data acquisition system. The
raw data is further analyzed to calculate gas concentrations.
A 6-point thermocouple array is also located at the exit
section of the Fire Suppression Facility to measure the gas
temperature at the six monitoring points three on the left
and three on the right side. The thermocouples are attached
to two ½-inch diameter PVC pipes, vertically oriented from
the floor to the roof, at 53 inches (134.6 cm), 72 inches
(182.9 cm), and 94 inches (238.8 cm) above floor level.
The gas data temperature is recorded in the control room
onto the data acquisition system. All the gas concentrations
and temperature data are processed and stored in an Excel
file for further analysis.
The method for calculating the Heat Release Rate
(HRR) is based on the CO2 and CO generation rates from
the spray combustion. With this method, the HRR is cal-
culated from measured data of gas concentrations of CO
and CO2 and measured gas velocity [3].
The HRR calculation using the CO and CO2 genera-
tion rates measured at the exit section of the shipping con-
tainer is expressed as:
Q k
H
k
H k H
A
CO
C
CO2
CO
C CO CO
CO2
2
=+
-
d d nm nm
where QA is the actual HRR, kW HC is the total heat of
combustion of the fuel, kJ/g, and can be determined from
the approximate analysis of the fuel HCO is the heat of
combustion of CO, 10.1 kJ/g kCO2 is the stoichiometric
mass of CO2 produced per unit mass of the fuel kCO is the
stoichiometric mass of CO produced per unit mass of the
fuel m
CO is the production rate of CO2 from the fire, g/s
and m
CO is the production rate of CO from the fire, g/s
kCO2 and kCO are the fuel-dependent constants and can be
calculated based on the experimental results from Egan [4]
for diesel fuel:
For combustion of a fuel within a mine entry, the CO
and CO2 generation rates can be determined from their
bulk-average concentrations downstream of the fire by the
expressions:
m VA CO
2 CO CO2
2
=o
m VA CO
CO CO
=o
where V is the exit average air velocity, m/s A is the entry
cross-section area, m2 rCO2 is the density of CO2 rCO is
the density of CO DCO2 is CO2 produced in the fire,
ppm and DCO is CO produced in the fire, ppm. Using
the CO2 density of 1.97 kg/m3 and CO density of 1.25 kg/
m3, the expressions become:
Spray nozzle
Suppression
nozzle
Diesel engine
Figure 3. Locations of fuel spray nozzle and suppression
nozzle