Another Newly Developed Foam System
Employs Two Ejectors and Uses Two Powders— Two Solutions so Formed Meet at Desired Point to Produce Foam
AFTER many months of experimental work the National Fire Protection Company of Philadelphia, Pennsylvnia, have developed and placed on the market a new foam generating system. Before starting with the development of their chemical ejectors, the company first investigated the question of foam and have been able to produce a very satisfactory product both from the standpoints of expansion and consistency, and almost a pure white in color.
After having settled the foam question attention was turned toward developing the mixing apparatus, Bearing in mind that for years the chemicals used in foam systems have been dissolved before bringing together for mixing, in hand foam extinguishers, hand foam engine, and in stationary foam systems, the company worked along this line to produce apparatus which would give the benefits of the old system together with the facility of the foam “generator” idea.
Feeling that the chemical when stored in a dry-mixed condition deteriorated, due to the fact that it required only moisture to produce reaction, every effort was made toward perfecting a system whereby chemicals could be kept separate until they are brought into solution and just prior to the time when the two solutions are brought together to produce foam. Ffence the company divided the single stream into streams—each independent and each flowing through a separate ejector of special design. These ejectors may, if desired, be permanently attached to each other, or they may be separated as much as desired. Into one ejector is introduced in powder form chemical A and into the other, chemical “B”. Each goes into solution with the water, but no chemical reaction takes place. These chemical streams “A” and “B” may be run independently through any length of hose desired. Then Injoining the lines in a standpipe, deluge set, or another length of fire hose foam is obtained at the point of mixing. In speaking of their system the company representative says: “To begin with out ‘A’ and ‘If chemicals are stored and used separately. They will last as long as the strong cans that contain them. There is no need to add an inert substance to keep them from deteriorating, which does not form foam. Being introduced separately the water has a chance to thoroughly dissolve the chemicals before any chemical action takes place.
“In the National Foam System the foam is not generated at the machine, hut at a jxiint determined by the operator. The distance from the fire is not predetermined by the distance foam will travel through hose or pipe before breaking down.”
In order to determine the capabilities of the National method of lifting foam, the Atlantic Refining Company at Philadelphia conducted extensive tests and from which the following data is taken:
Tests by Atlantic Refining Company
Tanks diameter 100 feet.
Area to be covered 7,854 square feet.
Foam required to cover area 6 in. thick 3,927. cu. feet.
Apparatus Used in Test
A 30′ dia. hole was provided in ground about 3 ft. deep and a 5′ steel tank ring 30′ in dia. was installed therein. One side of this ring was built up, forming a tank shell about 24 ft. high. A 6″ riser was installed from ground up to the side of the tank and an A. R. Co. distributing chamber was installed at the top so that foam was directed at inside shell of tank, falling along same until liquid level in tank was reached. Two (2) 2/” pipe lines each 60 ft. long were attached to a common connection at bottom of the riser, entering same at right angles to each other. Fifty (50) ft. of 2/” hose was connected to the ends of each of the 2/” pipes and run to the outlet end of the Ejector. Two (2) separate lengths (50′) .of 2)4” hose led front the Ejector inlet to a fire hydrant. A separate meter to measure the water was installed on the inlet side of the Ejector. The tank was filled with 17″ of water and 1200 gals, of oil poured on same, making approximately 3)4″ of oil, consisting of 850 gals, of fuel oil, 250 gals, of Cross (ias Naptha, and 100 gals of Gasoline.
The oil was ignited and left burning approximately 45 seconds at which time the entire tank was enveloped, and the fire had reached its fullest possible height. The foam was then started, the powders being poured by hand from cans, each can containing about 30 lbs. of powder. Water was played on shell of tank, adjacent to riser to keep shell cool.
Thirty (30) seconds were required for foam to reach tank after water was turned on. Fire was completely out in 2)4 minutes after foam began pouring down shell of tank, making a total time of 2)4 minutes from time the water and chemicals were started.
Quantity of Powder Used
250 lbs. of “A” Chemical.
250 lbs. of “B” Chemical.
Foam Produced (Effective)
Foam averaged 2″ thick over tank area or approximately 118 cu. ft.
Summary of Results Obtained
Total quantity of combined powders used—500 lbs. or 9 cu. ft.
Total quantity of water used—310 gals, or 41.4 cu. ft.
Effective Foam produced—118 cu. ft.
Ratio of Expansion—(Effective Foam produced to Liquid Chemicals) 2.4 to 1.
Ratio of Expansion—(Effective Foam produced to Total Powders Used) 13 to 1.
1 lb. of combined powders produced .236 cu. ft. of effective foam.
1 cu. ft .of combined powders produced 13 cu. ft. of effective foam.
1.61 lbs. of combined powders used per gal. of water.
Time required to produce 118 cu. ft. of effective foam—2)4 minutes or 165 seconds.
Foam produced per second, .71 cu. ft.
Velocity of liquid chemicals thru 2)4″ lines, 5 ft. per second. (Approximately.)
The National Chemical Ejector weighs 25)4 pounds and has an overall length of 13)4 inches. The gauge is on the intake side of the quick operating valve, enabling the operator to read the water pressure whether or not the valve is open. Density of the foam can be controlled by the operation of the water valve, and the flow of the chemical is governed by a small handle on the top of the ejector.
Tenth Term for Milford, Conn., Fire Official—The reelection of William M. O’Hara as president of the Milford, Conn., Board of Fire Commissioners, brings the tenth term to this official. President O’Hara has served continuously since the Fire Board was established at Milford in 1917.
Chief Heitman Receives Raise in Salary—Through an act of the 1927 Connecticut State Legislature which took effect on July 1, the salary of Chief Henry H. Heitman of the Waterbury, Connecticut, fire department is increased to §6,000 per annum. This raise in salary for the head of the Waterbury fire department, gives Chief Heitman the honor of being the second highest paid fire official in the New England states; the salary of Chief Daniel F. Sennott of Boston being the only one larger than that of Chief Heitman.