EP2623159A1

EP2623159A1 - Fire suppression system and method for fire suppression in an airborne vehicle

Info

Publication number: EP2623159A1
Application number: EP12153704.7A
Authority: EP
Inventors: Paul Rohrbach; Rainer Beuermann; Jens Taberski; Oliver Family
Original assignee: Airbus Operations GmbH; Airbus Operations Ltd
Current assignee: Airbus Operations GmbH; Airbus Operations Ltd
Priority date: 2012-02-02
Filing date: 2012-02-02
Publication date: 2013-08-07
Anticipated expiration: 2032-02-02
Also published as: EP2623159B1

Abstract

The present invention pertains to a fire suppression system and a method for fire suppression in an airborne vehicle, particularly in cargo bays of aircraft. The fire suppression system comprises a fuel tank inerting system including at least two on-board inert gas generating systems, a halon-based fire suppression subsystem configured to release halon as a first fire suppression agent, a monitoring module, which is coupled to the at least two on-board inert gas generating systems, and which is configured to monitor the operability of the at least two on-board inert gas generating systems and to output a monitoring signal indicating the state of operability of the at least two on-board inert gas generating systems, and a control module, which is coupled to the monitoring module, the at least two on-board inert gas generating systems and the halon-based fire suppression subsystem, and which is configured to select one of the at least two on-board inert gas generating systems depending on the monitoring signal and to control the selected on-board inert gas generating system to release an inert gas as a second fire suppression agent.

Description

Field of the invention

The present invention pertains to a fire suppression system and a method for fire suppression in an airborne vehicle, particularly in cargo bays of aircraft.

Background of the invention

Cargo compartments according to CS25.857(C) are usually equipped with a halon 1301 fire suppression system. Halon 1301 or bromotrifluoromethane is an organic halide, which is a gaseous substance used for fire quenching by inhibiting the radical reaction of the combustion.
Halon 1301 belongs to the group of chlorofluorocarbons (CFCs) which present a potential environmental hazard due to their destructive effects on the ozone layer of the stratosphere. Based on the Montreal protocol list and the EU regulation 744/2010, the use of halon 1301 is banned and only allowed in certain circumstances. Therefore, it is desirable to restrict the use of halon 1301 and search for alternative fire quenching agents.
Cargo bay fire suppression may be done in two stages. First, a rapid discharge of a first quenching agent may be triggered. Simultaneously, a second quenching agent may be released slowly, so that after the concentration of the first quenching agent in the area where fire is to be quenched diminishes below a certain threshold, the concentration of the second quenching agent or at least the combination of both agents is high enough to guarantee subsequent fire suppression.
The document Cavage, W.: "Cargo Bay Fire Protection with a Fuel Tank Inerting System", International Systems Fire Protection Working Group, Atlantic City, New Jersey, 2005 discloses the use of an on-board inert gas generator (OBIGGS) of a fuel tank inerting system to supply nitrogen enriched air (NEA) as a second quenching agent instead of halon 1301 for cargo compartment fire suppression systems.
The document Reynolds, T.L.; Bailey, D.B.; Lewinski, D.F.; Roseburg, C.M.: "Onboard Inert Gas Generation System/Onboard Oxygen Gas Generation System (OBIGGS/OBOGS) Study - Part I: Aircraft System Requirements", NASA Technical Report 2001-210903, 2001, chapter 4 discloses a hybrid system using a non-nitrogen fire suppression agent in conjunction with an OBIGGS.
The document US 6,997,970 B2 discloses an on-board inert gas generating system for an aircraft which is configured to generate inert gas for either inerting a fuel tank or a cargo bay of the aircraft.
The document EP 1 306 801 A1 discloses a conventional fire detection system that initially detects the existence of a fire and initiates a fire alarm, upon which, either automatically or by crew action, Halon is released in a short interval as a first extinguishant. A second extinguishant in the form of nitrogen-rich air is supplied to ensure longer-term fire suppression.
The document Reinhardt, J.: " The Synergistic Effect When Combining Nitrogen and Halon 1301 During the MPS Aerosol Can Simulation Explosion", The Fifth Triennial International Aircraft Fire and Cabin Safety Research Conference, 2007, discloses the occurrence of a synergistic effect occurs when Halon 1301 and nitrogen of an OBIGGS system of an aircraft are combined to protect an aircraft compartment against a propane explosion.

Summary of the invention

It is a technical problem of the present invention to provide for a fire suppression system and a method for fire suppression in the cargo compartment of an airborne vehicle which reduces the amount of chlorofluorocarbons (CFCs) needed, minimizes the additional weight of the airborne vehicle and complies with the safety, reliability and availability requirements that are mandatory for a cargo compartment fire suppression system.
This problem is solved by a fire suppression system with the technical features of claim 1, a method for fire suppression with the technical features of claim 7 and an airborne vehicle having the technical features of claim 6.
According to an aspect of the present invention, a fire suppression system comprises a fuel tank inerting system including at least two on-board inert gas generating systems, a halon-based fire suppression subsystem configured to release halon as a first fire suppression agent, a monitoring module, which is coupled to the at least two on-board inert gas generating systems, and which is configured to monitor the operability of the at least two on-board inert gas generating systems and to output a monitoring signal indicating the state of operability of the at least two on-board inert gas generating systems, anda control module, which is coupled to the monitoring module, the at least two on-board inert gas generating systems and the halon-based fire suppression subsystem, and which is configured to select one of the at least two on-board inert gas generating systems depending on the monitoring signal and to control the selected on-board inert gas generating system to release an inert gas as a second fire suppression agent, for example into a cargo compartment of an airborne vehicle in order to start a fire suppression atmosphere in combination with the first fire suppression agent.
According to a further aspect of the present invention, a method for fire suppression in an airborne vehicle having a fuel tank inerting system including at least two on-board inert gas generating systems and a halon-based fire suppression subsystem configured to release halon as a first fire suppression agent, the method comprising the steps of monitoring the operability of the at least two on-board inert gas generating systems, outputting a monitoring signal indicating the state of operability of the at least two on-board inert gas generating systems, selecting one of the at least two on-board inert gas generating systems depending on the monitoring signal, controlling the halon-based fire suppression subsystem to release halon as a first fire suppression agent, and controlling the selected on-board inert gas generating system to release an inert gas as a second fire suppression agent, for example into a cargo compartment of an airborne vehicle in order to start a fire suppression atmosphere in combination with the first fire suppression agent.
According to yet another aspect of the present invention, an airborne vehicle comprises at least two cargo compartments, and a fire suppression system according to an embodiment of the invention, which is configured to suppress a fire in at least one of the cargo compartments by releasing the first fire suppression agent and subsequently the second fire suppression agent, for example a combination of Halon 1301 and nitrogen enriched air.

Embodiments of the invention

One main idea of the present invention is to make use of the on-board inert gas generation systems (OBIGGS) of the fuel tank inerting system (FTIS) of an airborne vehicle by selecting one of the two OBIGGS to supply an inert gas as second quenching agent for assisting a halon-based fire suppression system.
The dependent claims provide additional technical features of advantageous embodiments and further improvements of the invention.
According to an embodiment, the fire suppression system further comprises an agent conduit pipe configured to pipe the first fire suppression agent from the halon-based fire suppression subsystem, a first inert gas conduit pipe configured to pipe inert gas from a first one of the on-board inert gas generating systems and coupled to the agent conduit pipe by a first valve, and a second inert gas conduit pipe configured to pipe inert gas from a second one of the on-board inert gas generating systems and coupled to the agent conduit pipe by a second valve, wherein the control module is configured to open the first or the second valve in case of fire in a compartment of an airborne vehicle, depending on the monitoring signal.
According to a further embodiment of the fire suppression system, the compartments of the airborne vehicle are cargo bays. The fire suppression system is particularly suited for cargo bays of airborne vehicle, since the capability of one of the on-board inert gas generating systems is sufficient to fulfil the fire suppression requirements for a cargo bay.
According to yet another embodiment of the fire suppression system, the inert gas is one of the group of nitrogen, nitrogen enriched air and oxygen depleted air.
According to yet another embodiment of the fire suppression system, the first fire suppression agent is halon 1301.
The invention will be explained in greater detail with reference to exemplary embodiments depicted in the drawings as appended.

Short summary of the drawings

The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments of the present invention and together with the description serve to explain the principles of the invention. Other embodiments of the present invention and many of the intended advantages of the present invention will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts.

Fig. 1: shows a fire suppression system according to an embodiment of the invention.
Fig. 2: shows an airborne vehicle including a fire suppression system according to another embodiment of the invention.
Fig. 3: shows a method for fire suppression according to yet another embodiment of the invention.

Detailed description of the embodiments

Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. Generally, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.
Fig. 1 shows a fire suppression system 10, particularly a fire suppression system 10 for use in an airborne vehicle. The fire suppression system 10 may be used for fire suppression in a cargo compartment or cargo bay of an airborne vehicle, such as an aircraft. Fig. 2 exemplarily shows such an airborne vehicle 20 having at least two cargo compartments 21, and a fire suppression system, which is configured to suppress a fire in at least one of the cargo compartment 21. The fire suppression system in Fig. 2 may be a fire suppression system 10 as explained in conjunction with Fig. 1.
Returning to Fig. 1, the fire suppression system 10 may comprise a fuel tank inerting system 1, a halon-based fire suppression subsystem 2, a monitoring module 3 coupled to the fuel tank inerting system 1, and a control module 4 coupled to the monitoring module 3.
The fuel tank inerting system 1 may include at least two on-board inert gas generating systems (OBIGGS) 5. The number of the OBIGGS 5 in Fig. 1 is exemplarily shown as two, but more than two OBIGGS 5 may be provided as well. The OBIGGS 5 may receive air from respective air conditioning systems 6 which may for example include heat exchangers and/or filter systems in order to condition bleed air that may be extracted from gas turbine engines of an airborne vehicle. The conditioned air may be input to the OBIGGS 5 which are configured to generate an inert gas, such as nitrogen, nitrogen enriched air (NEA) or oxygen depleted air (ODA) as output gas. The inert gas generated by the OBIGGS 5 may then be used to inert the ullage in fuel tanks 7a, 7b, 7c of the airborne vehicle. For example, the fuel tanks may comprise a left wing fuel tank 7a, a right wing fuel tank 7c and a centre wing fuel tank 7b.
Fuel tank inerting systems 1 are mandatory for aircraft having a centre wing fuel tank 7b in order to prevent explosions of the centre wing fuel tank 7b, especially when the centre wing fuel tank 7b is only filled to a low level, for example during short distance flights. The number of fuel tanks is exemplarily shown as three, however, any other number of fuel tanks may be provided in an airborne vehicle as well.
The inert gas generated by the OBIGGS 5 may be led through a conduit pipe system. The conduit pipe system may comprise a valve 8a and 8b for each of the OBIGGS 5, which controllably couple the conduit pipe system with an agent conduit pipe 9 configured to pipe a first fire suppression agent from the halon-based fire suppression subsystem 2.
Coupled to the first valve 8a is a first inert gas conduit pipe 9a configured to pipe inert gas from the first OBIGGS 5 to the agent conduit pipe 9. Similarly, coupled to the second valve 8b is a second inert gas conduit pipe 9b configured to pipe inert gas from the second OBIGGS 5 to the agent conduit pipe 9.
The halon-based fire suppression subsystem 2 may be configured to release halon as a first fire suppression agent, in particular halon 1301 or bromotrifluoromethane. Other organic halides may be used as a first fire suppression agent as well, for example trifluoroiodomethane. The halon-based fire suppression subsystem 2 is coupled via the agent conduit pipe 9 with cargo compartment valves 21a and 21b of cargo compartments of an airborne vehicle, for example a fore fuselage cargo bay and an aft fuselage cargo bay. The halon-based fire suppression subsystem 2 may release a predetermined amount of halon in case of a fire in one of the cargo compartments into the agent conduit pipe 9 and through the valves 21a and 21b in order to quench the fire in the respective cargo compartment for at least a first amount of time, for example several minutes up to an hour. It is officially assumed that a potential fire will not occur in both cargo compartments 21 at the same time during the same flight, thus, in case of a fire in one of the cargo compartments 21, the fire suppression agents will be released into the respective compartment 21 via the according valves 21a or 21b.
When the concentration of the first fire suppression agent has dropped below a predetermined threshold value due to leakage, the first fire suppression agent cannot guarantee an effective quenching of the fire anymore. The time until the concentration of the first fire suppression agent has dropped below a predetermined threshold value may correspond to the first amount of time.
In case of a fire in the cargo compartment or to prevent fires in the cargo compartment, inert gas generated by one or both of the OBIGGS 5 may be used to sustain a predetermined concentration of inert gas in the cargo compartment in order to guarantee a quenching of the fire by the inert gas as second fire suppression agent. Usually, the inert gas produced by one of the OBIGGS 5 is sufficient to fulfil the fire suppression requirements for a cargo compartment.
The monitoring module 3 may be configured to monitor the operability of the OBIGGS 5 and to output a monitoring signal indicating the state of operability of the OBIGGS 5. Since the OBIGGS 5 are part of the fuel tank inerting system 1 which is a Master Minimum Equipment List (MMEL) B system, their operating time is ten days in an inoperable state, i.e. an aircraft with an inoperable OBIGGS 5 may be operated regularly for ten days before the OBIGGS 5 will have to be repaired again. Therefore, it may be possible that one of the OBIGGS 5 is found to be inoperable by the monitoring module 3. The monitoring signal output by the monitoring module 3 may in such a case indicate that one of the OBIGGS 5 is inoperable.
The control module 4 may be configured to receive the monitoring signal of the monitoring unit 3. Depending on the monitoring signal, the control module 4 may then be configured to select one of the OBIGGS 5 that may subsequently be used as the supplying system for the second fire suppression agent. In case of a fire or in order to prevent fires in a cargo compartment, the control module 4 may be configured to control the selected OBIGGS 5 to release an inert gas as a second fire suppression agent, for example nitrogen, NEA or ODA. This may be done by configuring the control module 4 to open the first valve 8a or the second valve 8b in case of fire in a compartment of an airborne vehicle, depending on the monitoring signal.
Fig. 3 shows a method 30 for fire suppression in an airborne vehicle. The airborne vehicle may for example be an aircraft 20 having a fuel tank inerting system including at least two on-board inert gas generating systems and a halon-based fire suppression subsystem configured to release halon as a first fire suppression agent, as depicted in Fig. 2. The method 30 may be used to operate a fire suppression system 10 as depicted in Fig. 1.
The method comprises as a first step 31 monitoring the operability of the at least two on-board inert gas generating systems. In a second step 32, outputting a monitoring signal indicating the state of operability of the at least two on-board inert gas generating systems is performed. As a third step 33, the method 30 comprises selecting one of the at least two on-board inert gas generating systems depending on the monitoring signal. In a fourth step 34, the halon-based fire suppression subsystem is controlled to release halon as a first fire suppression agent. In a fifth step 35, the selected on-board inert gas generating system is controlled to release an inert gas as a second fire suppression agent.
In the foregoing detailed description, various features are grouped together in one or more examples or examples for the purpose of streamlining the disclosure. It is to be understood that the above description is intended to be illustrative, and not restrictive. It is intended to cover all alternatives, modifications and equivalents. Many other examples will be apparent to one skilled in the art upon reviewing the above specification.
The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. In the appended claims and throughout the specification, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein," respectively. Moreover, the terms "first," "second," and "third," etc., are used merely as labels, and are not intended to impose numerical requirements on or to establish a certain ranking of importance of their objects.

List of Reference Signs

1: Fuel tank inerting system
2: Halon-based fire suppression subsystem
3: Monitoring module
4: Control module
5: On-board inert gas generating system
6: Air conditioning system
7a: Left wing fuel tank
7b: Centre wing fuel tank
7c: Right wing fuel tank
8a: First valve
8b: Second valve
9: Agent conduit pipe
9a: First inert gas conduit pipe
9b: Second inert gas conduit pipe
10: Fire suppression system
20: Airborne vehicle
21: Cargo compartment
21a: Cargo compartment valve
21b: Cargo compartment valve
30: Method
31: Method step
32: Method step
33: Method step
34: Method step
35: Method step

Claims

A fire suppression system (10), comprising:
a fuel tank inerting system (1) including at least two on-board inert gas generating systems (5);

a halon-based fire suppression subsystem (2) configured to release halon as a first fire suppression agent;

a monitoring module (3), which is coupled to the at least two on-board inert gas generating systems (5), and

which is configured to monitor the operability of the at least two on-board inert gas generating systems (5) and

to output a monitoring signal indicating the state of operability of the at least two on-board inert gas generating systems (5); and

a control module (4), which is coupled to the monitoring module (3), the at least two on-board inert gas generating systems (5) and the halon-based fire suppression subsystem (2), and which is configured to select one of the at least two on-board inert gas generating systems (5) depending on the monitoring signal and to control the selected on-board inert gas generating system (5) to release an inert gas as a second fire suppression agent.
The fire suppression system (10) of claim 1, further comprising:
an agent conduit pipe (9) configured to pipe the first fire suppression agent from the halon-based fire suppression subsystem (2);

a first inert gas conduit pipe (9a) configured to pipe inert gas from a first one of the on-board inert gas generating systems (5) and coupled to the agent conduit pipe (9) by a first valve (8a); and

a second inert gas conduit pipe (9b) configured to pipe inert gas from a second one of the on-board inert gas generating systems (5) and coupled to the agent conduit pipe (9) by a second valve (8b),
wherein the control module (4) is configured to open the first or the second valve (8a, 8b) in case of fire in a compartment (21) of an airborne vehicle (20), depending on the monitoring signal.
The fire suppression system (10) of claim 2, wherein the compartment (21) of the airborne vehicle (20) is a cargo bay.
The fire suppression system (10) of one of the claims 1 to 3, wherein
the inert gas is one of the group of nitrogen, nitrogen enriched air and oxygen depleted air.
The fire suppression system (10) of one of the claims 1 to 4, wherein
the first fire suppression agent is halon 1301.
An airborne vehicle (20), comprising:
at least one cargo compartment (21); and

a fire suppression system (10) of one of the claims 1 to 5, which is configured to suppress a fire in the at least one cargo compartment (21) by releasing the first fire suppression agent and subsequently the second fire suppression agent.
A method (30) for fire suppression in an airborne vehicle (20) having a fuel tank inerting system (1) including at least two on-board inert gas generating systems (5) and a halon-based fire suppression subsystem (2) configured to release halon as a first fire suppression agent, the method (30) comprising the steps of:
monitoring (31) the operability of the at least two on-board inert gas generating systems (5);

outputting (32) a monitoring signal indicating the state of operability of the at least two on-board inert gas generating systems (5);

selecting (33) one of the at least two on-board inert gas generating systems (5) depending on the monitoring signal;

controlling (34) the halon-based fire suppression subsystem (2) to release halon as a first fire suppression agent; and

controlling (35) the selected on-board inert gas generating system (5) to release an inert gas as a second fire suppression agent.