GB2118037A - Aircraft fire protection apparatus - Google Patents

Abstract

Means for employing utility water in a passenger aircraft to permit personnel egress from such an aircraft on fire on the ground, the means including forming a water curtain over the door to wet the outgoing person and the shute, and perhaps either or both of forming a water curtain over the windows to prevent them breaking away, and mixing with a suppressant foam former for ejection from the aircraft to form a traversable fire-free swathe. <IMAGE>

Description

SPECIFICATION Improvements in aircraft fire protection The present invention relates to fire protection in aircraft, and particularly to means for protecting personnel in and escaping from an aircraft fire on the ground.

According to the present invention an aircraft fire protection apparatus is characterised by a water reservoir in the aircraft and means for discharging water in the vicinity of an exit door from the aircraft.

According to a feature of the invention the means for discharging water may include a nozzle situated over the doorway and arranged for spraying a curtain of water downwards across the doorway. If the aircraft is one having an inflatable or other escape chute down which escaping personnel may slide the nozzle is preferably arranged to spray the water down onto the chute to protect it from fire as well as the personnel.

When an aircraft on the ground is surrounded by a fuel fire the fire often gains access to the cabin by heat shrinking the plastics window transparencies away from the frames thereof.

According to another feature of the invention fire protection apparatus may also include nozzles arranged to direct water over the window transparencies. The nozzles exit preferably outside the aircraft so that in addition to cooling the window the aircraft skin may be cooled and a pool of water formed beneath it to douse or dislodge a liquid fuel fire.

The general use of aircraft carried utility water in personnel fire protection, in particular utility water dispersed as a fog within the cabin, is described in the Special Report "Aircraft Fire Risks' Probe at BAFS '78 Seminar" published in the April 1 978 edition of Fire Protection Review, and some of the features of that apparatus may be employed in apparatus according to the present invention. For example, small bore light alloy or plastics piping may be used in conveying the water and the apparatus may include pump means, perhaps using a compressed inert gas such as nitrogen or carbon dioxide of alternatively comprising or employing a gas generating means, such as pyrotechnic means or means permitting two substances, e.g. aluminium sulphate and soda bicarbonate, to be mixed.Of course a battery driven pump may be employed, but in these circumstances it may be wiser not to have to rely on electrics. The apparatus may also include control means, preferably located at the or each doorway provided with a water nozzle, for initiating operation of the apparatus. The control means may be associated with an emergency crach handle, crash switch, undercarriage collapse sensor, emergency hatch release handle and/or slide inflation control.

It will be appreciated that water is particularly advantageous as a fire protection medium in the context of personnel escaping from aircraft because of its inertness. Moreover, it acts as a lubricant to the chute when sprayed thereon and, following absorption by a person's clothing provides protection from fire for a period after the person has left the aircraft.

Aircraft, such as the Lockheed TriStar 10-11, the Vickers VC 10 and the Boeing 747 carry 131, 1 50 and 232 Imperial gallons of utility water respectively, and are likely to have water for use in fire protection according to the present invention even at the end of a flight. Shorthaul aircraft, such as the Hawker Siddeley Trident, the Boeing 737 and the Boeing 727-100, with 30, 30 and 37 Imperial gallons of utility water respectively may require an additional quantity of water.

According to an alternative or additional feature of the invention the apparatus may include means for metering a fire suppressant foam forming substance into the water to form a fire suppression foam, and for ejecting the foam with sufficient force to form a fire free swathe extending to 1 0-1 5 metres from the aircraft. The means for ejecting the foam may comprise a nozzle stored adjacent an aircraft exit. Moreover pivotal mounting means may be provided whereby the nozzle can be directed by an operator while the back pressure therefrom is reacted by the aircraft.

The foam forming substance employed may be a fluoroprotein, in which case the apparatus is advantageously provided with means for inspiring air closer to the point at which the two gases are mixed then to the ejection nozzle. Preferably however, the foam forming substance is an aqueous film forming foam (AFFF) such as "light water", which is a trade mark of 3M company limited, because the fire extinguishant formed thereby with water is particularly resistant to reignition when walked upon.

The means for metering the substance into the water is preferably a jet pump rather than a motor, and may include a turbulence generator to ensure mixing of the substance into the water.

Apparatus in accordance with the present invention will now be described by way of example with reference to the accompanying drawings, of which: Figure 1 is a block diagram of a first embodiment of the invention.

Figure 2 is a view of the apparatus shown in Figure 1 in operation at an aircraft exit, and Figure 3 is a block diagram of a second embodiment of the invention.

In the embodiment shown in figures 1 and 2 an aircraft has a water reservoir 10 connected via a pump 11 to a sprinkler tube 12. The tube 1 2 is led over aircraft cabin windows 13 and, via a cock 14, over an exit doorway 1 5. The pump 11 is electrically powered, as initiated by a crash switch 1 6. The cock 14 is associated with an emergency hatch release handle 1 7.

The tube 1 2 has sprinkler orifices above the windows 1 3 outside the aircraft, which are arranged to cover the windows with water in operation, while over the doorway 1 5 the tube 1 2 has sprinkler orifices arranged to divert water downwards and slightly outwards in operation, so that if there is an escape chute 20, as shown in Figure 2, the water is diverted onto the floor thereof.

In the embodiment shown in figure 3 an aircraft has a water reservoir 30 connected via a cock 31 and a jet pump 32 to a nozzle apparatus adjacent an aircraft door 33. The pressurising gas generator 34 is ducted via a cock 35 to the top of the water tank 30, while an aqueous film forming foam (AFFF) container 36 is ducted via a cock 37 to the jet pump 32. The nozzle apparatus comprises a swivel mount 38 and an ejector nozzle 39 pivotally mounted thereon, the nozzle 39 having a control cock 40 thereon for controlling output and an indicator not shown, to indicate that a working pressure has been achieved. The swivel mount includes switch means so associated with the switches 37, 31 and 35 as to open them when manipulated into an operative configuration.

The store 36 and nozzle apparatus are normally stowed behind access panels. In the event of a fire, the nozzle is brought out of the storage, thus opening the switches 31, 35, 37, and permitting gas pressure to urge water out of the tank 30 and towards the nozzle 39. When a sufficient working pressure is indicated by the nozzle indicator a door 33 is opened and the cock 40 also. The flow of water through the jet pump 32 entrains AFFF thereinto, and suppressant foam is ejected from the nozzle 39 onto the ground outside the aircraft.

Swivelling upwards of the nozzle then permits a blanket of foam to be laid forming a pathway from the door.

In an alternative embodiment to that described with reference to figure 3, the nozzle apparatus is located in the vicinity of the door in such a way as to be capable of being brought into operation, that is to spread foam outside the aircraft, while the door is still closed, in order that heat, flames and fumes will not enter the aircraft via the door before the foam takes effect.

In a specific embodiment of the invention of the types described with respect to figure 3, the volume proportion of foaming substance to water is between 1 and 7%, while the energy stored in the gas generator 34 is of the order of 50,000 ft Ib.

Claims (11)

1. Aircraft fire protection apparatus characterised by a water reservoir in the aircraft and means for discharging water in the vicinity of an exit door from the aircraft.

2. Apparatus as claimed in claim 1 and wherein the means for discharging water includes a nozzle situated over the doorway and arranged for spraying a curtain of water downwards across the doorway.

3. Apparatus as claimed in claim 2 and wherein the nozzle is arranged to spray the water down onto an escape chute.

4. Apparatus as claimed in any one of claims 1 to 3 and including window nozzles arranged to direct water over window transparencies.

5. Apparatus as claimed in claim 4 and wherein the window nozzles are outside the aircraft.

6. Apparatus as claimed in any one of the preceding claims and wherein the means for discharging water includes a pump in the form of a gas generator.

7. Apparatus as claimed in any one of the preceding claims and including means for metering a fire suppressant foam forming substance into the water to form a fire suppression foam, and for ejecting the foam with sufficient force to form a fire free swathe extending to 10-1 5 metres from the aircraft.

8. Apparatus as claimed in claim 7 and wherein the foam forming substance is an aqueous film forming foam.

9. Apparatus as claimed in claim 7 or claim 8 and wherein means for metering the substance into the water is a jet pump.

10. Apparatus as claimed in any one of claims 7-9 and wherein the means for metering the substance into the water includes a turbulence generator.

11. Apparatus substantially as hereinbefore described with reference to the accompanying drawings.