Coast Guard Conducts Tests on Engine Room Fires—Part II

Coast Guard Conducts Tests on Engine Room Fires—Part II

Carbon Dioxide and Fog Employed in Instructive Series of Demonstrations; New Theories on Fire Extinguishment Indicated

THIS is the second installment of an article describing fire extinguishing tests made on the Liberty Ship “Caspar de Portola” at For McHenry, Md., by the Coast Guard under direction of Commander Lloyd Layman.

The first installment, which appeared in the February issue, reviewed the scope and purpose of the tests, and outlined the procedure followed; it also included reports of the first four tests. The article resumes the review of individual tests.

Test No. 5

1. TIME—

23 October, 1944.

1. PURPOSES—
1. To determine the effectiveness of the carbon dioxide extinguishing system under the following conditions:
2. During a major fire involving fuel oil under the floor plates.
3. With the ventilators and other air intake openings uncovered.
4. Release of the carbon dioxide within a predetermined period of time (ten minutes) after the temperature within the engine room had reached the degree of temperature that would be present under normal operating conditions.
5. A secondary purpose was to determine if a major fire involving fuel oil under the floor plates could be extinguished by the control of air flows and the use of water fog.
1. CONDITIONS BEFORE TEST—
2. The engineroom remained the same as reported after Test Fire No. 4 with the following exceptions:
1. Both boiler foundation spaces used in previous tests as fuel oil containers were covered.
2. Five thousand gallons of bunker “A” fuel oil were placed in the bilge of the engineroom. Because of a starboard list, it was necessary to add approximately ten thousand gallons of water to obtain maximum coverage without raising the oil above the floor plates. This provided an oil depth of approximately four and one-half inches and brought the oil level to within one inch of the floor plates on the starboard side. Full coverage of the bilge was obtained with the exception of about one hundred and fifty square feet at the farward port corner.
3. Two 2 1/2 inch hose lines were laid from a 500 gallon skid pump unit, located on the pier, to the main deck to supply the 1 1/2 inch hose lines equipped with all-purpose nozzles. Two 1 1/2 inch lines were placed down the forward escape hatch to the shaft tunnel. Two 1 1/2 inch lines were laid to the main engine room entrance. Two 1 1/2 inch lines were laid to the starboard passage door of the engine room on the main deck.
4. An electronic pyrometer for determining the degree of heat at various locations in the engine room had been installed in a cabin on the main deck. Eleven thermocouple terminals had been placed in the engine room so that the degree of heat, at levels from three teet above the floor plates up to one foot from the top of the stack and at all overheads inside the space, could be obtained. In the Test Record which follows, reference is made to the thermocouples at the following locations:

No. 1—Projecting downward one foot into engine room space from second deck port side passage, sixteen feet aft of forward engine room bulkhead and fourteen feet inboard from port side shell plating.

No. 5—Projecting downward one foot into engine room space from carbon dioxide compartment, port side second deck, four feet forward of storeroom and workshop bulkhead and six feet inboard from port side shell plating.

No. 6—Projecting downward one foot into engine room space from second deck, above electrical equipment platform, five feet forward of aft engine room bulkhead and seven feet inboard side shell plating.

No. 15—Three feet above floor plates and ten feet forward of shaft tunnel entrance.

1. IV.TEST RECORD-
2. At 1331, the oil in the engine room was ignited at six different locations. Gasoline was used to prime the oil. Smoke banked down quickly from the overhead. The two priming parties were forced to withdraw from the engine room immediately following the ignition of the oil.
3. From the topside, it was noted that almost immediately after ignition, black smoke started to come from the stack casing and open skylights. During the following five minutes, the smoke coming from these openings was very black and in large volume.
4. At 1338, the smoke was changing to dark gray and diminishing in volume. At this time, the average temperature at the overheads in the engine room was over 200° F. and near the floor place level under 100° F.

Official U. S. Coast Guard Photo

1. During the following ten minutes, the emitting smoke continued to diminish in volume and changed from dark to light gray.
2. At 1348, the carbon dioxide was’released. At this time, the temperature in the engine room ranged from 255° F. near the floor plates to 1065° F. at the port side overhead. The average temperature was 530° F.
3. At 1351, three minutes following the release of carbon dioxide, the highest temperature was 785° F. at thermocouple No. 5. The average temperature was 461 degrees, a decrease of 69 degrees. During these three minutes, dense white vapors in large volume were emitting from the stack casing. During the next few minutes, the emitting vapors decreased in volume and changed to light gray.
4. At 1355, seven minutes after the carbon dioxide was released, the temperature at thermocouple No. 5 was 1070°F. The average temperature was 550° F., an increase of 20 degrees over that present when the carbon dioxide was released.
5. At 1401, thirty minutes after start of test, covering of air intake openings was started. The skylight housing and the aft port ventilator were cooled with water fog to permit covering operations. At 1415, the covering of air intake openings was completed.
6. At 1418, forty-seven minutes after start of test, the main door to the engine room was opened and high velocity water fog was applied from two 1 1/2 inch all-purpose nozzles. At 1417, the highest temperature at thermocouple No. 5, 1325° F. The average temperature was 774 degrees. At 1447, the starboard passage door on the main deck was opened and high-velocity water fog was applied from one 1 1/2 inch all-purpose nozzle.
7. At 1505, the cover was removed from the skylight. At this time, fortyseven minutes after the application of water fog was started, the average temperature had decreased from 774 to 271 degrees.
8. At 1514, water fog application was discontinued and the removal of covers from main ventilators was started. From 1505, when the cover was removed from the skylight until 1513 the average temperature increased from 271 to 344 degrees. At 1519, all main ventilators had been uncovered.
9. At 1515, two fire-fighting parties, each consisting of two men, entered the engine room from the shaft tunnel. Each fire-fighting party was provided with a 1 1/2 inch hose line equipped with an allpurpose nozzle. They attempted to extinguish the fire using high velocity fog. Due to the volume of air entering through the open ventilators, it was impossible to extinguish the fire under the floor plates. The circulation of air was sufficient to allow almost complete combustion. At 1529, fourteen minutes after entering the engine room, the fire fighting parties withdrew and closed the door from the shaft tunnel to the engine room. At this time, the average temperature was 659° F.
10. At 1529, covering of air intake openings was started. It was found that the canvas used to cover the grilled opening between the second deck port passage and the Engineer’s Storeroom had ignited and burned. This may, in part, account for the higher temperature developed in the port side overhead. The temperature at thermocouple No. 5 reached 1493° F. at 1524. This opening was again covered with canvas. Later this piece of canvas ignited and burned. At 1541, the covering of all air intake openings was completed. It was necessary to use water fog to cool some of the ventilators before covers could be placed.
11. At 1544, high velocity water fog was applied from two 1 1/2-inch all-purpose nozzles at the main engine room entrance and also from one 1 1/2-inch allpurpose nozzle at the starboard passage door on the main deck. An immediate decrease in temperature was obtained at all locations. The smoke emitting decreased in volume with considerable steam apparent. At 1604, an additional l 1/2-inch all-purpose nozzle was employed at the starboard passage door.
12. At 1543, one minute before the application of water fog, the average temperature was 578° F. A decrease of 81 degrees had occurred from 1529 when covering of air intake openings was started. During the twenty-seven minutes that water fog was applied, 1544 to 1611, the average temperature decreased from 578° to 240° F. The highest tem.perature was 407° F. at thermocouple No. 6.
13. At 1611, two-fire fighting parties equipped with 1 1/2-inch all-purpose nozzles again entered the engine room from the shaft tunnel. It took ten minutes for the fire-fighting parties to extinguish the burning oil using high velocity water fog. Application of water fog, from the main deck openings, was continued during this period. At 1621, the average temperature was 171° F. The highest temperature was 270° F. at thermocouple No. 1.
14. At 1622, the application of water fog was discontinued at the main deck openings. At 1626, all air intake openings had been uncovered. At 1628, the only remaining fire within the engine room had been extinguished. This was wooden shelving in the Engineer’s Storeroom.
15. The fire fighting parties operated without respiratory protection.
16. At 1400, the following day, burning was discovered in No. 3 hold. Although the odor of wood smoke had been detected from time to time during this period, it was impossible to locate the source. Wooden planks, three by ten inches, used to retain a two inch thickness of insulation, which provides a protective bulkhead for the port fuel oil settling tank, were involved. The planks involved were located about one foot from the top of the settling tank and about three feet from the port shell plating. This fire was extinguished with a small amount of water.
17. The volume of water employed to control and extinguish the fire is estimated as follows:

First Operation— Gallons

Applied from main deck openings …………………. 7,866

Used by fire-fighting parties… 1,500

Second Operation— Gallons

Applied from main deck openings ………….. 7,178

Used by fire-fighting parties… 1,080

Total number of gallons…. 17,574

At completion of the test, the liquid level within the engine room had increased approximately nine inches on the starboard side. This had raised the oil level above the floor plates on the starboard side and extended inboard approximately seventeen feet. This rise of the liquid on the starboard side resulted in complete oil coverage of the hundred and fifty square feet, located at the forward port corner, which were not covered at the start of test. A part of this rise was due to several leaks, which developed during the fire, at blanked off pipe openings. This allowed some water from the forward tanks to enter the engine room. A considerable part of the water used to control and extinguish the fire was converted into steam which escaped from the engine room by way of the opening between the stack and stack casing.

Official U. S. Coast Guard Photo

1. The nature of the burning within the engine room was quite different from that which occurred during the preliminary test fires. The burning surface in the preliminary test fires did not exceed 346 square feet. With the oil released in the bilge, the burning surface was increased to approximately 1800 square feet. In the preliminary test fires, the oil was located in the boiler foundation spaces which formed tank like containers. Here, the air to support combustion had to enter from the sides and free burning did not extend to the center part of the surface. A considerable volume of black smoke was given off during the fires. With the oil located in the bilge, air is distributed over the entire surface and the burning at all points appeared to have had sufficient air to allow almost complete combustion. Except during the first few minutes of burning, no black smoke was emitted from the engineroom. At other times, the smoke was from dark to light brown or gray in color, and the volume was very limited. A much greater volume of heat was generated per gallon of oil consumed in this test than was generated during the preliminary test fires.

1. CONDITION AFTER TEST—
2. The ship was in practically the same condition as reported after test Fire No. 4, with the following changes:
1. There was considerable warping of the floor plates in the port side section.
2. There was considerable warping of the deck of the port and starboard passages of the second deck.
3. There was some warping of the shell plates, port side.
4. Wooden shelving in Engineer’s Storeroom was damaged by fire.
5. Additional warping of the forward bulkhead occurred.
6. Deck of carbon dioxide compartment extremely warped. Paint on deck and aft bulkhead blistered and charred.
7. The two small doors located in the forward bulkhead of the engine room were warped during the fire. This allowed air to enter the engine room from No. 3 hold. These doors were cut in the bulkhead to provide access to the engine room from No. 3 hold for the placement of oil and the removal of water. Since these opening are not provided in a standard ship, this allowed more burning near the forward bulkhead than would have occured under normal conditions.
3. Five thousand gallons of oil provided an oil depth of approximately four and one-half inches. Following the test, sufficient water was removed to bring the oil level to the same position as before the test. The measurement of the oil depth showed approximately three and one-half inches remained. It was estimated that not more than 1200 gallons of oil were consumed during the test.
4. VI. TENTATIVE CONCLUSIONS—

Some of the tentative conclusions set forth in the reports of previous test fires are not applicable, in their entirety, to a fire of this nature. They are: Tentative Conclusions No. 1-3-4-5, Report of Test Fire No. 1.

Tentative Conclusion No. 4, Report of Test Fire No. 2.

1. The carbon dioxide system is not effective in an engine room of this type of ship under the following conditions:
1. To extinguish and prevent reignition of a major fire involving fuel oil in the bilge.
2. With ventilators and other air intake opening uncovered.
3. When the carbon dioxide system is released after the fire has been permitted to burn for a period of time sufficient to heat the steel, in the vicinity of the burning oil, to a temperature greater than the ignition temperature of the oil. A burning time of seventeen minutes, starting with a cold engine room (average temperature of 61° F.) is more than sufficient to heat the steel.
2. To control and extinguish a fire of this nature, in an engine room of this type of ship, it is necessary to close the air intake openings.
3. The use of canvas to close the opening to the Engineer’s Storeroom is not effective in this type of fire.
4. To reduce the temperature to a degree which will permit fire-fighting parties to operate at the floor plate level; it is necessary to apply sufficient volume of water, in the form of water fog, from the upper level of the engine room.
5. The extinguishment of the fire can be completed by firefighting parties, entering the engine room from the shaft tunnel, using water fog.

Photo by U. S. Coast Guard

Remarks: It is believed that a safer and more practical method can be developed than relying solely on water fog. Water fog will be used to extinguish open surface burning and to cool the floor plates; followed immediately by the application of mechanical foam to cover the oil surface under the floor plates. This should protect against the hazard of a reflash occurring.

1. There is sufficient heat transmitted through the forward engineroom bulkhead, in a fire of this nature and duration, to endanger cargo stowed in No. 3 hold.

Test No. 6

1. TIME—

On 13 November, 1944.

1. PURPOSES—
2. To determine if a major fire involving fuel oil under the floor plates could be extinguished by the control of air flows and the use of low velocity water fog applied from the upper level.

1. CONDITIONS BEFORE TEST—
2. The engine room remained the same as reported after Test Fire No. 5 with the following exceptions:

1. Twelve hundred gallons of Navy Special fuel oil were added to the thirty-eight hundred gallons of bunker “A” fuel oil which were not consumed in Test Fire No. 5. Due to the starboard list, approximately ten thousand gallons of water were allowed to remain in the bilge in order to obtain maximum oil coverage without raising the oil above the floor plates. This brought the oil level to within two inches of the floor plates on the starboard side. Oil coverage of the bilge was obtained with the exception of about one hundred and fifty square feet at the forward port corner. This volume of oil provided an oil depth of approximately four and one-half inches.
2. The grilled opening from the second deck, port side, passage to the Engineer’s Storeroom was closed with asbestos board previous to the start of test. This board was bolted to the grill and packed with asbestos packing to effect a positive air seal. The asbestos board was used because the asbestos cloth curtain was not available.
3. The two small openings located in the forward bulkhead of the engine room were sealed with bolted steel plates and asbestos gaskets. These openings were cut in the bulkhead to provide access to the engine room from No. 3 hold for the placement of oil and the removal of water.

1. Two 2 1/2 inch hose lines were laid from a 500 gallon skid pump unit, located on the pier, to the main deck to supply the 2 1/2 inch and 1 1/2 inch working lines. One 2-1/2–inch line with all-purpose nozzle and 12 foot applicator with low velocity head was laid to the main engine room door. A line similarly equipped was laid to the starboard passage door on the main deck. Two 1 1/2 inch hose lines equipped with allpurpose nozzles were placed down the forward escape hatch to the shaft tunnel. One 1 1/2 inch line equipped with a 1 1/2 inch straight applicator and a 2 1/2 inch low velocity fog head was laid to the skylight house on the boat deck. Additional 1 1/2 inch lines equipped with allpurpose nozzles were located at various strategic points on the bridge and top decks for use in cooling the exterior of the ventilators, if necessary, before covering. From another 500 gallon skid pump unit, located on the pier, a 2 1/2 inch line was laid to a twin twenty-five gallon mechanical foam pressure proportioner also located on the pier. From the proportioner a 2 1/2 inch line was laid to the main deck to supply two 1 1/2 inch hose lines equipped with mechanical foam nozzles.
2. An electronic pyrometer was used to determine the degree of heat at levels from three feet above the floor plates up to one foot down from the top of the stack and at all overheads within the space. Reference is made under Test Record to the thermocouple terminals at the locations given below. In the average temperatures given, however, thermocouple No. 15 has been omitted because the abnormal temperature obtained at this location is believed to be due to contact with flame.

No. 7—Projecting aft one foot into engine room at the mid-point of the second deck athwartships passage at the deck level.

No. 13—One foot down and one foot aft of top forward edge of stack casing on the topside.

No. 14—Six inches below ridge and five feet aft of forward bulkhead of the skylight house.

1. TEST RECORD-
2. At 1337, the oil in the engineroom was ignited at six different locations after priming with gasoline. Smoke banked down quickly from the overhead forcing the priming parties to withdraw from the engineroom by way of the shaft tunnel immediately following ignition of the oil.
3. From the topside, it was noted that almost immediately after ignition, black smoke started to come from the stack casing, the open skylights, and the forward port main ventilator. During the following ten minutes, the smoke coming from these openings was very black and in large volume.
4. At 1349, and during the following twelve minutes, the smoke coming from the stack casing changed to dense, dark gray in color, with some dark brown smoke also present. At 1349, the average temperature within the engine room was 264° F.
5. At 1403, twenty-six minutes after start of test, covering of air intake openings was started. At this time the average temperature within the engine room was 401_____ F. Note: A hatch tarpaulin was used to cover the entire skylight housing including the two small ventilators. Specially designed canvas covers were used to cover the six main ventilators. These were the same as were used during Test Fire No. 1. Squares of canvas, six by six feet, provided with securing lines were used to cover the main ventilators during Test Fires No. 3, 4, and 5.
6. At 1410, thirty-three minutes after start of test, the average temperature within the engine room was 437° F. This average was the highest reached during the test.
7. At 1415, thirty-eight minutes after start of test, the covering of all air intakes was completed. At this time the average temperature was 419° F. During the covering operation, the emitting smoke constantly diminished in volume and changed to light gray and light blown in color.
8. At 1420, forty-three minutes after start of test, the average temperature within the engine room was 410° F. A very small amount of light gray and light brown smoke was emitting from the stack casing.
9. At 1425, forty-eight minutes after start of test, a 1 1/2 inch hose line equipped with a straight applicator and a inch low velocity fog head was inserted under the canvas hatch cover, used to cover the skylight house, into an open skylight on the port side. The hose line was lowered approximately 15 feet and low velocity fog applied at this point. At this time the average temperature within the engineroom was 382° F. The highest temperature was 493° F. at thermocouple No. 7.
10. At 1430, five minutes after start of the application of water fog at the skylight, the average temperature within the engineroom was 339_____ F. The highest temperature was 420° F. at thermocouple No. 7. A very small amount of smoke with considerable steam apparent was emitting from the stack casing.
11. At 1435, ten minutes after start ot the application of water fog at the skylight, the average temperature within the engine room was 291° F. The highest temperature was 353° F. at thermocouple No. 7.
12. At 1446, one hour and nine minutes after start of test, water fog was applied at the main engine room door and at the starboard passage door from two 2 1/2 inch all-purpose nozzles equipped with 12 foot applicators and low velocity heads. At this time, the average temperature within the engineroom was 250° F. The highest temperature was 265° F. at thermocouple No. 7. During the twenty-one minutes that water fog was applied from the skylight house only, 1425 to 1446, the average temperature decreased from 382° to 250° F.
13. At 1455, the application of watcr fog was stopped at the main engine room entrance. At this time an extremely small amount of light vapors were emitting from the stack casing.
14. At 1501, entry to the engine room was made by way of the door from the shaft tunnel. It was found that the fire had been completely extinguished. The application of water fog at the starboard passage door was stopped. The lowest temperature was 80° F. at thermocouple No. 13 and the highest temperature was 175° F. at thermocouple No. 14. The average temperature was 136° F., a decrease of 246 degrees in the average temperature since the time (1425) when the application of water fog was begun.
15. At 1502, the application of water fog through the skylight opening was stopped.
16. At 1503, and during the following two minutes the covers were removed from the skylight and all main ventilators. As soon as the covers were removed, an inspection party entered the engine room by the main door and proceeded down the ladders to the engine room floor. The inspection party experienced no more discomfort than they would have experienced in an engine room under normal operating conditions.
17. Heat indicating lacquer showed that the following temperatures were reached:
1. On the aft bulkhead of No. 3 hold, a temperature of at least 175° F. was reached at all locations and a temperature of 500° F. was reached at some locations. None of the spots painted on the forward surface (15 inches from, bulkhead) of a vertical “1” beam bulkhead stiffener reached 175° F.
2. In the No. 3 ‘tween deck section, spots painted on the deck one inch from the aft bulkhead and on the bulkhead at points one inch above the deck and five feet above the deckreached 175° F. only at the mid-point.
3. In the No. 4 ’tween deck section, spots painted on the deck one inch from the forward bulkhead reached 250° F. and spots painted on the bulkhead at points one inch above the deck and five feet above the deck reached 250° F. at some locations.
18. The volume of water employed to control and extinguish the fire was estimated at approximately 6,954 gallons. At the completion of the test, the liquid level within the engine room had increased approximately two and one-half inches. This had raised the oil level onehalf inch above the floor plates on the starboard side and extended the exposed surface inboard approximately tw-o feet. The rise of liquid resulted in complete oil coverage of the hundred and fifty square feet located at the forward port corner which were not covered at the start of test. A part of this rise was due to a leak, which developed during the fire, at a flange connection on a pipe from the fresh water tanks. The increase of water in the bilge at the completion of the test amounted to approximately 2,500 gallons. The major part of the 6,954 gallons of water used to control and extinguish the fire was converted into steam which escaDed from the engine room by way of the opening between the stack and the stack casing.

Official Navy Photo

(Continued on page 178)

(Continued from page 167)

1. The nature of the burning within the engine room was different from that which occurred during Test Fire No. 5. The difference was due to the control of the air flow at the grilled opening from the second deck passage into the Engineer’s Storeroom. This opening has a cross sectional area of 10.5 square feet and is the major air intake opening during a fire in the engine room. The total cross sectional area of the six main ventilators is 25.9 square feet. The grilled opening was closed previous to the start of test and remained closed during the entire test. This restricted the flow of air which was allowed to enter the space during the fire. As a result, the fire did not burn as freely as it did in Test Fire No. 5. It is apparent that the difference in the nature of burning, the degree of temperature attained, and the difficulty of controlling and extinguishing the fire during the previous test, was due to this one factor.
2. Ten hundred and forty-five temperature readings were recorded during this test.

1. CONDITIONS AFTER TEST—
2. The engineroom was in practically the same condition as reported after Test Fire No. 5 conducted 23 October, 1944 with the following changes:
1. a. All surfaces are coated with carbon except where washed clean by water fog.
2. Floor plates, near forward end of engine, are extremely warped.
3. It was estimated by measurement before and after test, that not more than 500 gallons of oil were consumed during the test.

1. TENTATIVE CONCLUSIONS—
2. A major fire involving fuel oil under the floor plates can be extinguished by the control of air flows and the use of low velocity waterfog applied from the upper level.

Remarks: The use of low velocity water fog to control and extinguish an oil fire within a confined space, with all intake openings closed, introduces a new theory in the employment of water fog. This method utilizes the convectional currents developed within the space to carry the water, which is in the form of mist, to the base of the fire. Extinguishment of the fire and the cooling of the heated metal throughout the space are effected without direct application or equal distribution of the water fog. If, by future tests, this theory can be definitely established as a practical method, it offers a simple and effective answer to the problem of controlling and extinguishing fires of this nature.

1. The specially designed covers used on the main ventilators provide a more positive control of air flows at these openings than the six by six foot squares of canvas used during previous tests.

EDITOR’S NOTE: See the April issue for third installment of Commander Layman’s tests.