2
organic and inorganic salts in solution and were originally
designed for cooking-oil fires. These agents can develop a
temporary foam layer on the surface of a flammable liquid
that permits the liquid to cool below the ignition tempera-
ture and prevents air from coming in contact with the liq-
uid. Carbon-dioxide fire suppressing systems have been in
use for many years and are used for the extinguishment of
flammable liquids, gas fires, and fires involving electrically
energized equipment. They extinguish fire by taking away
oxygen but have a limited cooling effect. In this study, five
fire-suppressant agents were tested to suppress three differ-
ent types of fluid spray fires on diesel mobile equipment.
The primary goal was to evaluate fire suppression effective-
ness and they were not tested to evaluate environmental or
health impacts.
EXPERIMENTAL APPROACH
Evaluating the effectiveness of fire suppression systems
using a spray fire caused by different flammable liquids such
as diesel fuel, motor oil, and hydraulic oil on a diesel engine
requires a test facility to conduct the tests. A steel shipping
container was modified to be used as a fire suppression test
facility at the National Institute for Occupational Safety
and Health (NIOSH) research center located in Pittsburgh,
Pennsylvania. The dimensions of the shipping container,
shown in Figure 1, are 40 ft (12.2 m) in length, 8 ft (2.4 m)
in width, and 9.5 ft (2.9 m) in height. Steel plates were
placed over the top of the wood floor inside the shipping
container to prevent the floor from catching fire during a
test. To control the ventilation, a 1-hp 42-inch (1.07-m)
diameter variable speed fan was installed at one end of the
shipping container, while the other end of the container
was left open. The fan can be adjusted up to 500 ft/min
(2.54 m/sec).
To measure the gases produced during the diesel engine
fire tests, an infrared gas analyzer located in the control
room is used to measure the carbon monoxide (CO), rang-
ing from 0 to 5,000 ppm, carbon dioxide (CO2), rang-
ing from 0 to 1 percent, and oxygen (O2), ranging from
0 to 25 percent. The output voltage from the infrared gas
analyzer is converted using a software package to store the
data on a laptop and display it graphically in real-time.
Thermocouples are used to measure the gas temperatures at
the exit section of the container. A diesel engine block with
dimensions of 53-inch (1.35-m) length, 23-inch (0.58-m)
width, and 36-inch (0.91-m) height was mounted onto a
steel frame with casters on it to have the ability to roll it
into the correct location for the test.
Five different fire suppression systems were evaluated
with the following suppressants/agents: namely, dry chemi-
cal, wet chemical, dual agent (dry and wet chemicals), water
mist, and carbon dioxide. The dry chemical agent chemical
makeup is monoammonium phosphate and ammonium
sulfate used for Class A, B, and C fires. It displaces the oxy-
gen content of the air around the fire and absorbs heat.
The wet chemical agent is a unique blend of organic and
inorganic salts coupled with surface active ingredients to
provide cooling and oxygen displacement. The dual agent
is a combination of the two systems, dry and wet chemicals,
used independently at the same time. The water mist sup-
pressant uses high-pressure water to create mist, to provide
cooling and oxygen displacement. The carbon dioxide sup-
pressant is used for Class B and C fires by displacing oxygen
from the fire.
Liquid spray fires using diesel fuel, engine oil, and
hydraulic fluid were used in the suppression tests. The
delivery system for the diesel fuel, motor, and hydraulic oils
is set up by using a compressed air cylinder with a regu-
lator on it to control the pressure and is connected to a
1-gal (3.8-l) stainless-steel cylinder filled with any fuel type
delivered by ¼-inch stainless-steel tubing to the fuel nozzle.
The output of the stainless-steel cylinder is fitted with a
Figure 1. Steel shipping container (a) outside and (b) inside, modified to be used as a fire suppression test facility
(a) (b)
organic and inorganic salts in solution and were originally
designed for cooking-oil fires. These agents can develop a
temporary foam layer on the surface of a flammable liquid
that permits the liquid to cool below the ignition tempera-
ture and prevents air from coming in contact with the liq-
uid. Carbon-dioxide fire suppressing systems have been in
use for many years and are used for the extinguishment of
flammable liquids, gas fires, and fires involving electrically
energized equipment. They extinguish fire by taking away
oxygen but have a limited cooling effect. In this study, five
fire-suppressant agents were tested to suppress three differ-
ent types of fluid spray fires on diesel mobile equipment.
The primary goal was to evaluate fire suppression effective-
ness and they were not tested to evaluate environmental or
health impacts.
EXPERIMENTAL APPROACH
Evaluating the effectiveness of fire suppression systems
using a spray fire caused by different flammable liquids such
as diesel fuel, motor oil, and hydraulic oil on a diesel engine
requires a test facility to conduct the tests. A steel shipping
container was modified to be used as a fire suppression test
facility at the National Institute for Occupational Safety
and Health (NIOSH) research center located in Pittsburgh,
Pennsylvania. The dimensions of the shipping container,
shown in Figure 1, are 40 ft (12.2 m) in length, 8 ft (2.4 m)
in width, and 9.5 ft (2.9 m) in height. Steel plates were
placed over the top of the wood floor inside the shipping
container to prevent the floor from catching fire during a
test. To control the ventilation, a 1-hp 42-inch (1.07-m)
diameter variable speed fan was installed at one end of the
shipping container, while the other end of the container
was left open. The fan can be adjusted up to 500 ft/min
(2.54 m/sec).
To measure the gases produced during the diesel engine
fire tests, an infrared gas analyzer located in the control
room is used to measure the carbon monoxide (CO), rang-
ing from 0 to 5,000 ppm, carbon dioxide (CO2), rang-
ing from 0 to 1 percent, and oxygen (O2), ranging from
0 to 25 percent. The output voltage from the infrared gas
analyzer is converted using a software package to store the
data on a laptop and display it graphically in real-time.
Thermocouples are used to measure the gas temperatures at
the exit section of the container. A diesel engine block with
dimensions of 53-inch (1.35-m) length, 23-inch (0.58-m)
width, and 36-inch (0.91-m) height was mounted onto a
steel frame with casters on it to have the ability to roll it
into the correct location for the test.
Five different fire suppression systems were evaluated
with the following suppressants/agents: namely, dry chemi-
cal, wet chemical, dual agent (dry and wet chemicals), water
mist, and carbon dioxide. The dry chemical agent chemical
makeup is monoammonium phosphate and ammonium
sulfate used for Class A, B, and C fires. It displaces the oxy-
gen content of the air around the fire and absorbs heat.
The wet chemical agent is a unique blend of organic and
inorganic salts coupled with surface active ingredients to
provide cooling and oxygen displacement. The dual agent
is a combination of the two systems, dry and wet chemicals,
used independently at the same time. The water mist sup-
pressant uses high-pressure water to create mist, to provide
cooling and oxygen displacement. The carbon dioxide sup-
pressant is used for Class B and C fires by displacing oxygen
from the fire.
Liquid spray fires using diesel fuel, engine oil, and
hydraulic fluid were used in the suppression tests. The
delivery system for the diesel fuel, motor, and hydraulic oils
is set up by using a compressed air cylinder with a regu-
lator on it to control the pressure and is connected to a
1-gal (3.8-l) stainless-steel cylinder filled with any fuel type
delivered by ¼-inch stainless-steel tubing to the fuel nozzle.
The output of the stainless-steel cylinder is fitted with a
Figure 1. Steel shipping container (a) outside and (b) inside, modified to be used as a fire suppression test facility
(a) (b)