GB2032773A

GB2032773A - Fire control method and system

Info

Publication number: GB2032773A
Application number: GB7838767A
Authority: GB
Original assignee: FLAEKT Ltd
Current assignee: FLAEKT Ltd
Priority date: 1978-09-29
Filing date: 1978-09-29
Publication date: 1980-05-14
Also published as: FR2437221A1; SE438417B; SE7907787L; NO793067L; DE2939151C2; NO150104C; DE2939151A1; NO150104B; GB2032773B; FR2437221B1

Abstract

The invention relates to a method of fire control, comprising the steps of supplying a nozzle which normally distributes ventilation air in a space to be ventilated by induction of an air jet into the space, supplying a source of flowable fire dampening and/or extinguishing medium, the nozzle and source being connected by a normally closed path, detecting a temperature rise, opening the closed path and passing the fire dampening and/or extinguishing medium along the path to the nozzle and distributing it to hinder or prevent fire. Preferably Halon may be used as the fire control medium.

Description

SPECIFICATION Fire control method and system The invention relates to a method of and system for fire control in a space.

A space such as a factory, office or ship's engine room or hold often has two separate systems, one being a ventilation system for ventilating the space, and the other being a fire control system in the form of a water sprinkling system. Alternatively, a gaseous extinguishing agent is often used.

The systems have the disadvantage that expensive equipment is necessary, and with the sprinkler system objects in the space are often ruined by the water if not by fire. The gaseous system require heavy duty steel piping which is expensive and takes up valuable space.

It is accordingly an object of the invention to seek to mitigate these disadvantages of the prior art.

According to one aspect the invention provides a method of fire control, comprising the steps of supplying a nozzle which normally distributes ventilation air in a space to be ventilated by induction of an air jet into the space, supplying a source of flowable fire dampening and/or extinguishing medium, the nozzles and source being connected by a normally closed path, detecting atemperature rise, opening the closed path, and passing the fire dampening and/or extinguishing medium along the path to the nozzle and distributing it to hinder or prevent fire.

According to a second aspect, the invention provides a fire control system, comprising a nozzle, a source of flowable fire dampening and/or extinguishing medium, the source and the nozzle being connected by a normally closed path, and a fire detector, the arrangement being such that when a rise in temperature is detected the normally closed path is opened and the medium flows from the source out of the nozzle for distribution to hinder or prevent fire.

The invention makes it possible to provide a simple system which is either a ventilation or fire control system which can be selectively operable for preventing, hindering the spread of, or extinguishing fire in a space in which the system is installed.

The fire dampening and/or extinguishing medium may be a gas, for example that known as Halon, which is stored under pressure in the source.

A system embodying the invention is hereinafter described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a schematic layout of the system: and Figure 2 shows an enlarged detail of the part marked 'A' on Figure 1.

Referring to the drawings, a space 1 being ventilated has a primary source 2 of ventilation air of a relatively low velocity and high volume, and a plurality of nozzles 3 arranged in banks which provide relatively high vetocity/low volume jets of air for distributing the ventilating air throughout the space.

A fan 4 distributes airjetsthrough the nozzles and there is a non-return valve 5 in a pipe 6 connecting the fan 4 with the nozzle3. There is also a source 7 of fire extinguishing medium in the form of a reservoir of Halon, stored as a liquid under pressure. The source 7 is connected by pipe line 8 to the pipe 6. As shown in Figure 2, the pipe line 8 terminates in a nozzle 9 inside an enlarged part 10 of the pipe 6 downstream of the non-return valve 5.

There is also gas and/or fire detectors 11, for example, a temperature responsive device, in the space 1.

The fire control system operates as follows. Nor malls the space 1 is ventilated by primary air from the primary source 2, this air being distributed uniformlly through the space 1 by jets of air issuing from the nozzles 3. The throw length of air from each nozzle 3 is such that it reaches the next successive nozzle as considered in a direction away from the source 2 so that induction of the air takes place throughout the whole of the space. The throw length of the jets is shown by the dashed lines t2 in Figure 1.

If the fire and/or gas detectors 11 detect a potential hazard, they operate to close a damper 13 so that no primary air reaches the primary air source 2. Simultaneously the non-return valve 5 in the pipe 6 is closed, although the fan 4 keeps running, and the pipe line 8 is opened to flow of Halon from the source 7 to the pipe lines feeding the nozzles 3. The pressure of the Halon in the source 7 is relieved so that Halon gas flows rapidly to the nozzles 3 whence it is rapidly distributed into the space 1.

There is also distribution of Halon from further vents 14 adjacent the primary air source 2. Once all the Halon is discharged, the non-return valve is opened 5 to maintain uniform Halon in circulation in the space 1, otherwise the Halon, which is about five times heavier than air, would tend to sink to the floor and may not be entirely effective as a fire suppressor.

Once the fire danger is passed, the primary air source can be re-started.

Using such a system it is possible to distribute a 5% by volume quantity of Halon gas in ten seconds.

In a typical example, the Halon is stored as a liquid in the source under a pressure of 3000 to 6000 Ibs per square inch, to give the above mentioned distribution at an average duct velocity of 25 M/S.

It will be understood that the system above described can be modified. For example, the pipe 6 may not require an enlarged section 10 near the Halon inlet nozzle 9. Also the non-return valve 5, shown as an automatically closable positive-close off flap valve or damper in Figure 2, could comprise a piston-closable damper operated by the Talon pressure when the system is activated. Or the non-return valve could have positive closing under spraying pressure plus the pressure in the duct when the Halon is released, making for a positive closing of the pipe. Further, any suitable medium other than Halon could be used, for example, a powder brother gas.

In every system the closing of the various dampers can take only 2 to 4 seconds particularly when using electric controls.

Claims

1. A method of fire control, comprising the steps of supplying a nozzle which normally distributes ventilation air in a space to be ventilated by induction of an air jet into the space, supplying a source of flowable fire dampening and/or extinguishing medium, the nozzle and source being connected by a normally closed path, detecting a temperature rise, opening the closed path and passing the fire dampening and/or extinguishing medium along the path to the nozzle and distributing it to hinder or prevent fire.

2. A fire control system, comprising a nozzle, a source of flowable fire dampening and/or extinguishing medium, the source and the nozzle being connected by a normally closed path, and a fire detector, the arrangement being such that when a rise in temperature is detected the normally closed path is opened and the medium flows from the source out of the nozzle for distribution to hinder or prevent fire.

3. A method according to claim 1, substantially as hereinbefore described.

4. Afire control system, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.