NOVEL CRASH FIRE FIGHTING UNIT PROTECTS NEW YORK AIRPORT
Provides Fog, Fog-Foam, Foam, Carbon Dioxide and Water; “Nurse” Truck Augments Effectiveness
WHEN the Port of New York Authority assumed responsibility for operation of the New York City and Newark Airports, one of the problems was to provide adequate rescue forces and equipment to combat airplane crash fires. The trend toward larger planes, with more passengers, made that problem increasingly important and difficult.
War experience had demonstrated that a foam blanket made by a mixture of foam compound and water was an effective agent for fighting aircraft gasoline fires and for controlling them to effect rescue of personnel. Therefore it was considered essential that these airports have fire fighting equipment carrying large quantities of foam and be able to reach any section of the airport in a minimum of time.
The history of the use of and experiments with Army type trucks such as the Model 155 water fog; 150 low pressure CO2 and Navy type FFN5 foam truck indicated that a new type of foam apparatus was required and that each airport should have one. In the course of training emergency crews on different equipment, various modifications of the specifications were made to meet the particular needs. The new truck is designed to be operated with minimum personnel and has the capacity to control and extinguish a relatively large gasoline fire in and around a crashed aircraft and to provide and maintain access to the aircraft for the rescue of entrapped personnel.
The new unit has a sturdy four-wheel drive chassis, carrying a 1,000 gal. water tank; a 90 gal. foam liquid tank; a gasoline engine driven pumping system; foam delivery devices, including the turret nozzles, ground sweep and three hand lines, and a high pressure carbon dioxide system of 800 pounds capacity.
In operation, the truck will be followed by a ‘nurse’ truck, consisting of a similar chassis, carrying 2,500 gals, water and 250 gals, of foam liquid. The ‘nurse’ truck will be provided with hose lines for coupling to the foam truck and through its own pumping system will supply additional foam compound and water properly proportioned. With the two trucks operated as a team, there will be available 3,500 gals, of Water, which with the foam compound, will provide approximately 30,000 gals of foam blanket as the primary fire fighting agent.
The functional design of the foam truck was furnished by the Department of Operations, Port of N. Y. Authority. The manufacture was done by the Maxim Motor Co., Middleboro, Mass.
Major specifications of the new crash unit are as follows:
CHASSIS: heavy duty 4×4 truck, one front and one rear axle; positive drive to all 4 wheels. Truck is powered with a 240 H.P. engine; 6 speeds forward and 2 reverse; gear ratio will provide a road speed of 45 M.P.H. at governed engine speed with full load. Acceleration to speed of 45 M.P.H. can be obtained from rest in approximately 50 seconds.
TIRES: single 16.00 x 24, 16 ply, front and rear, inflated to 40 lbs. air pressure. Four-wheel drive and tire size were selected after tests with similar truck and loading had demonstrated its ability to travel successfully through loose sand present at N. Y. International Airport and over muddy roads and, when at rest in either type terrain, to pull free at a progressive rate. The truck is equipped with power steering; 4-wheel brakes; enclosed cab and auxiliary floodlights for on the scene illumination. Positive drive to all 4 wheels is provided by a differential system with patented automatic lock.
FOAM PUMPING SYSTEM: Tests indicated that the most satisfactory performance was obtained by a pressure of 300 P.S.I. and this choice was concurred in by the manufacturers of foam liquid.
The foam pumping system consists of 2 gasoline-engine-driven pumps connected in series with piping and valves, so arranged that either unit may be operated independently if required. Each unit has at 140 H.P. gasoline engine direct connected to a centrifugal pump with rated capacity of 600 G.P.M. at a normal operating pressure of 150 lbs. P.S.I. The 2 pumps when operated in series deliver 600 G.P.M. at an operating pressure of 300 P.S.I. at the discharge side of the second pump. Pumping units are located at rear of truck, one on each side parallel to the center line and are skid mounted and removable as a unit for repairs or replacement. Controls and instruments for pumping units are located in truck cab.
STORAGE TANKS: Water storage tank capacity 1,000 gals.; foam compound tank 90 gals, with an expansion chamber. Foam and water tanks are of same height and proportional in cross-section so that in using solution of 9% foam compound and 91% water, similar head pressures are maintained. Filler hose couplings for each tank are provided at both sides of truck, and foam compound tank has an additional fill opening at top.
WATER AND FOAM COMPOUND PROPORTIONER: Careful proportioning of foam compound to water is essential if foam blanket of proper consistency is to be maintained. The proportioner selected consists of metered orifices installed in the water and foam compound feed lines on suction side of pumps. As installed. they provide for a solution of 9% foam compound and 91% water. Orifices are easily removable to permit installation of other orifices giving other proportions.
FOAM DISCHARGE DEVICES: Foam discharge devices include a front ground sweep, 2 turret nozzles, 3 hand lines with nozzles, and an undertruck nozzle.
Ground sweep has 3 foam nozzles, located in fixed position under front bumper of truck, with sufficient ground clearance to prevent damage when truck is moving. Center nozzle has capacity of 40 G.P.M.; other 2 Outer nozzles each have capacity of 25 G.P.M. at 300 P.S.I. operating pressure. Foam discharge is controlled by valve mechanically operated from cab or a ground position. The foam streams from nozzles merge to form a continuous fan-shaped pattern: projection approximately 40 ft.; spread approximately 20 ft. at full pressure.
Two foam discharge turrets are mounted on platform over truck cah, one at each side, at the front. Each turret has a nozzle, movable through a complete arc of 360 deg. and with total turret vertical movement of about 80 deg. Each is provided with weighted handles for movement and direction by one ODerator. Each turret is equipped with one Rockwood fog, foam and fogfoam nozzle, with removable diffuser head and foam shaper, and with capacity of 200 G.P.M. at 300 P.S.I. operating pressure. Control of foam discharge is by manually operated valve at nozzle. Turret nozzle has effective projection of 75 ft. of fog-foam with screen adapter and approximately 125 ft. of straight foam with foam shaper in place.
In normal operation, the procedure is to use fog-foam from the nozzles because greater water content of fog-foam provides greater cooling effect.
There are three foam hand lines, mounted on electrically rewinding reels located at the sides of truck. Each line has 100 ft. of rubber fire hose, equipped with combination fog and foam nozzle, with capacity of 30 G.P.M. at 300 P.S.I. operating pressure.
A foam nozzle with capacity of 15 G.P.M. at 300 P.S.I. is located underneath the truck to protect truck itself from a creeping ground fire caused by gasoline spill. This can be operated from cab or the ground.
CARBON DIOXIDE SYSTEM: An auxiliary medium of extinguishment is provided to supplement the foam. This consists of a carbon dioxide system complete with tanks, manifold and discharge hose. The CO2 is contained in eight 100 lb. high pressure cylinders, in a cradle at the rear of the truck cab. Cylinders are connected to a discharge manifold in groups of 4 and are easily removable for refilling. A discharge nozzle and 100 ft. of discharge hose mounted on an electrically rewinding reel is provided at the side of truck.
RADIO: Telephone radio transmitting and receiving equipment for communicating with the airport control tower is installed in cab of truck. Both transmitter and receiver operate on frequency of 121.9 kc. and have ample power to maintain contact within radius of 5 miles.
AUXILIARY EQUIPMENT: The truck is equipped with the necessary forcible entry and rescue tools, including 1-16 ft. and 1-24-ft. ext. ladders (metal) and portable hand extinguishers.