GB2215204A

GB2215204A - Fire protection system for passenger carriers

Info

Publication number: GB2215204A
Application number: GB8804284A
Authority: GB
Inventors: James Steel
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-02-24
Filing date: 1988-02-24
Publication date: 1989-09-20
Anticipated expiration: 2008-02-24
Also published as: GB2215204B; GB8804284D0

Abstract

A fire protection system (12) for a passenger carriage (11) which includes a plurality of water spray nozzles (16) spaced along a plurality of longitudinal conduits (17) all cross-connected by a plurality of transverse conduits (18) with "choking" type flow restrictors spaced between groups of spray nozzles (16) to limit flow following conduit rupture. The conduits (17, 18) are connected to the on-board water supply system (13) via a pump and a non-return valve in series and, additionally or alternatively, a plurality of externally mounted selff-sealing couplings (25) are interconnected to the conduits (17, 18). The couplings (25) should be accessible to fire-fighting personnel for fire tender hose hookup. <IMAGE>

Description

FIRE PROTECTION SYSTEM FOR PASSENGER CARRIERS The present invention relates to systems for the prevention of fires aboard road going, or railway passenger carriers, for example coaches and railway carriages including such carriages which have crashed.

Fires may be caused within a carriage or alternatively, may result from outside influences, possibly following a crash. When the carriage is in open country the dangers of fire is present but the consequences may not be disastrous. However, when a carriage is in a tunnel, the consequences of a fire may be catastrophic.

A carriage fire will involve combustion of the fabric and furnishings inside the carriage and the emission of toxic fumes. Hand-held fire extinguishers are of some use in such fires, but would be quite ineffective in the major fires which can follow crashes or brake block fires or terrorist activities.

In particularly long tunnels, such as the planned English Channel tunnel between England and France, it has been proposed to include water supply lines for fire fighting purposes. However, the deployment of this water to fight a fire inside a carriage is likely to take some minutes. In this brief period, a large number of passengers may have died from the effects of toxic fumes given off by the burning furnishings, external fumes ducted through the carriage by the chimney effect, flash-over fires in the furnishings, and high temperatures in the carriage.

It is therefore an object of the present invention to provide a system which suppresses a carriage fire at least until it is possible to deploy a supply of water or the like from an external source.

More generally, it is an object of the invention to provide an on-board carriage fire protection, suppression or extinguishing system, which is capable of operating effectively, using a minimum amount of water.

According to the invention, there is provided a passenger carriage fire protection system including a plurality of spray nozzles dispersed throughout the carriage interior, a plurality of distribution conduits interconnecting the spray nozzles, and a fire extinguishirtg fluid supply system arranged to supply extinguishing fluid to the conduits.

Preferably the extinguishing fluid supply system comprises an on board water system. Additionally or alternatively, the fluid supply may comprise at least at least one self-sealing coupling mounted on the external surface of the carriage and connected to the conduits, whereby an external pressurised source of extinguishing fluid, e.g. water, can be connected to the conduits via the coupling.

Preferably, the distribution conduits include: a plurality of longitudinal conduits running along the longitudinal axis of the carriage, at least one of the longitudinal conduits being located on each side of the carriage, the spray nozzles being spaced along the longitudinal conduits; and at least one crossover conduit extending generally transverse to, and interconnecting, the longitudinal conduits.

Preferably, the crossover conduits are spaced along the longitudinal axis of the carriage. The conduits may be configured to supply each of the plurality of spray nozzles along at least two flow paths whereby a redundancy is achieved.

The apparatus may include means for limiting the flow of fluid in the distribution conduits in the event of a rupture in one of the plurality of distribution conduits upstream of one or more of the spray nozzles.

Preferably, the flow restrictors are spaced along the longitudinal conduits between groups of the spray nozzles. Each flow restrictor may be configured to restrict the maximum flow rate of the fluid to a value approximately equal to that of the combined capacity of the downstream spray nozzles. Such a system may be effective in extinguishing or suppressing a fire with a water flow rate from the on-board system of as little as about ....... gallons per minute.

Preferably, the system includes at least one pair of self-sealing couplings mounted on the outside of the carriage, on opposite sides, and connected to a transverse conduit. The couplings are preferably so arranged to be easily accessible to fire fighting personnel outside the carriage for connection to a source of fluid such as water.

The present invention may make it possible therefore to operate a spray system without the need to carry very large quantities of water or other fluid in the carriage since the system would be effective using a very small quantity of water. This may be achieved by the use of an on-board water supply to cope with fires during the immediate period following the onset of the hazard and then by pumping water from the ordinary hoses of fire tenders or an external water supple into special connectors mounted on the outside of the carriage one of which is certain to be accessible to the firemen. An on-board reservoir of only about 40 gallons would extinguish and supress a fire for several minutes to enable the external source to be coupled.

Each of these two capabilities individually and especially in combination will provide the time necessary for safe evacuation. A system having the capabilities in combination would be expected to increase dramatically the chances for survival compared to a carriage without such protection.

Preferably, two or more longitudinal conduits are installed within the carriage. Sited at intervals along these pipes are spray nozzles, so disposed to provide complete coverage of the carriage interior with finely dispersed droplets of water. The longitudinal conduits are supplied with water from an on-board source and/or from feed inlets on the outside of the carriage. Thus, there are self-sealing couplings on the outside of the carriage each able to be supplied from hose pipes, these being fitted with matching selfsealing couplings. Feeder pipes extend from the couplings to the interior sprinkler system.

The longitudinal conduits and transverse conduits may be of titanium to save weight or may be of any other suitable material.

The self-sealing couplings are disposed so that some of the couplings will be accessible, regardless of the attitude of the carriage. They may be supplied with water at a normal pressure of 9 bar (IlOpsi), however, the sprinkler system should be effective provided the pressure is no less than 2.3 bar (35psi).

Should an accident cause a fracture of the conduits within the carriage, it should still be possible to achieve drenching of the carriage interior via the separate system parts. The sprinkler nozzles may be arranged in groups along the longitudinal conduits with flow restrictors between those groups.

The flow restrictors may then "choke", limiting the quantity of water which can spill from the fractured conduit ends to that quantity which would normally have been supplied to the sprayers on the broken-off section. This will ensure that all the spray nozzles supplied with water will function as intended. The flow restrictors may be of a design which enables them to restrict to two different flow values, depending upon the direction of water flow. Thus, it is possible to ensure successful drenching no matter where along the conduit length a fracture occurs.

The invention may be carried into practice in various ways and one embodiment will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is an overall schematic view of one embodiment of a carriage with a fire control system in accordance with the present invention; and Figure 2 is a schematic diagram showing the major features of the fire control system.

Figure 1 shows a railway carriage 11 incorporating a fire protection system 12 constructed in accordance with the present invention The carriage shown is of the type having an on-board "domestic" water supply system 13. As best seen in Figure 2, the domestic water supply system 13 includes a clean water reservoir 14 and a used water reservoir 15.

The fire protection system includes a series of sprinkler heads or nozzles 16 arranged along the carriage 11 and directed to provide coverage to all occupied parts. The individual nozzles 16 can be directed from below and from the side as well as from above passenger seating positions (as shown). The sprinkler heads are operable at least over the range of water supply pressures of about 10 psi to 110 psi through the preferred operating range would be about 15psi to 35psi.

The fire protection system further includes a distribution system for distributing water to the spray nozzles 16. The distribution system includes a number of longitudinal conduits 17 running the length of the carriage 11 with at least one longitudinal conduit 17 on each side of the carriage axis. Preferably, two or more longitudinal conduits 17 are used on each side, although Figure 1 shows one per side for the purposes of clarity. The longitudinal conduits 17 should be strong but relatively lightweight, and titanium conduits are preferred. These can be run out of sight between the carriage inner and outer walls with only the spray nozzles 16 penetrating the interior portion.

At least one transverse conduit 18 is employed interconnecting the longitudinal conduits 17.

Preferably, a plurality of transverse conduits 18 (three being shown in Figure 1), spaced along the axis are employed to achieve a redundancy in the water supply flow path to each spray nozzle 16. In this same vein, the transverse conduits 18, are closed rings which act as distribution plenums. In the event of a crash followed by the rupture of one of the longitudinal conduits 17 and/or transverse conduits 36 there would then exist an alternative flow to each spray nozzle 28, as can be appreciated from the configuration of the conduits 17, 18 in Figure 1.

To assist in achieving the flow path redundancy, flow restrictors are placed in the longitudinal conduits 17 between groups of spray nozzles 16 to limit or "choke" the flow that would leak out of the ruptured conduit downstream of the restrictor. Preferably, flow restrictors are sized to limit the rupture flow rate to approximately that of the combined downstream spray nozzle capacity, and it is further preferred that the flow restrictors be "two way" to accommodate the alternative redundant flow path design.

The fire protection system includes means for selectively connecting the distribution system to the on-board water supply system. A pipe 19 connects the domestic water supply system 13 with the centrally located transverse conduit 18. Other connection locations are, of course, possible e.g. with one of the longitudinal conduits 17. With reference now to Figure 2, a selective connection system 21 can include a water pump 22, a non-return valve 23 in series, and a change over valve 24 selectively connectable to the clean water reservoir 14 and the used water reservoir 15 either individually, or to both, simultaneously.

The fire protection system can also include means for optionally connecting the distribution system to a source of pressurised water from outside the carriage 11. For this purpose, a plurality of self-sealing couplings 25 are distributed about the external surface of the carriage on both sides. These are individually connected via feeder pipes 26 to the transverse conduits 18. This distribution should allow at least one of the self-sealing couplings 66 to be accessible to fire fighting personnel even following a crash.

Claims

1. A passenger carriage fire protection system including a plurality of spray nozzles dispersed throughout the carriage interior, a plurality of distribution conduits interconnecting the spray nozzles, and a fire extinguishing fluid supply system arranged to supply extinguishing fluid to the conduits.

2. A system as claimed in Claim 1 in which the extinguishing fluid supply system comprises an on board water system.

3. A system as claimed in Claim 1 or Claim 2 in which the extinguishing fluid supply system comprises at least one self-sealing coupling mounted on the external surface of the carriage and connected to the conduits, whereby an external pressurised source of extinguishing fluid, e.g. water, can be connected to the conduits via the coupling.

4. A system as claimed in any preceding claim in which the distribution conduits include: a plurality of longitudinal conduits running along the longitudinal axis of the carriage, at least one of the longitudinal conduits being located on each side of the carriage, the spray nozzles being spaced along the longitudinal conduits; and at least one crossover conduit extending generally transverse to, and interconnecting, the longitudinal conduits.

5. A system as claimed in Claim 4 in which the crossover conduit is a closed ring-type conduit encircling the carriage.

6. A system as claimed in Claim 5 in which the distribution conduits include a plurality of closed ring-type crossover conduits spaced along the longitudinal axis of the carriage.

7. A system as claimed in any preceding claim in which the distribution conduits are configured to supply each of the plurality of spray nozzles along at least two flow paths whereby a redundancy is achieved.

8. A system as claimed in any preceding claim including means for limiting the flow of fluid in the distribution conduits in the event of a rupture in one of the plurality of distribution conduits upstream of one or more of the spray nozzles.

9. A system as claimed in Claim 8 in which the flow limiting means comprises a plurality of flow restrictors spaced along the longitudinal conduits between groups of the spray nozzles.

10. A system as claimed in Claim 9 in which each flow restrictor is configured to restrict the maximum flow rate of the fluid to a value approximately equal to that of the combined capacity of the downstream spray nozzles.

11. A system as claimed in any of Claims 3 to 10 including at least one pair of self-sealing coupings mounted on the outside of the carriage, on opposite sides, and connected to a transverse conduit.

12. A fire protection system constructed and arranged substantially as herein specifically described with reference to and as shown in the accompnaying drawings.