WO1996029117A1

WO1996029117A1 - Device for waterfog extinguishing of especially a-fires

Info

Publication number: WO1996029117A1
Application number: PCT/NO1996/000066
Authority: WO
Inventors: Søren ØVRETVEIT; Ottar Braut
Original assignee: Fokus Bank Asa
Priority date: 1995-03-23
Filing date: 1996-03-25
Publication date: 1996-09-26
Also published as: EP0820327A1; AU5164796A; NO951105L; NO951105D0; NO302604B1

Abstract

A device for waterfog extinguishing of fires, especially for use in sensitive wooden buildings worth preserving. According to the invention, the room is internally equipped with nozzles for supply of waterfog both from ceiling and floor, the nozzles in the floor, preferably, being adapted to supply waterfog having larger drops than the nozzles in the ceiling of the room.

Description

DEVICE FOR WATERFOG EXTINGUISHING OF ESPECIALLY A-FIRES

The invention relates to a device for waterfog fire extinguishing of especially A-fires.

It has been found efficient to extinguish fires by means of waterfog, and installations for waterfog fire extinguishing replace little by little other known types of fire extinguishing installations as sprinkler and halon system. Waterfog fire extinguishing has been demonstrated in connection with relatively vigorous fires developing a large heat effect, such as hydrocarbon fires.

In waterfog fire extinguishing, relatively small amounts of water are supplied, and waterfog installations have been met with great interest in connection with sensitive wooden buildings such as stave churches and other old houses worth preserving. However, reliable extinguishing of fires of this type, socalled A-fires, has not been demonstrated with success, in spite of many attempts and many concepts of various kinds. High impulse supply of waterfog from a small number of fog nozzles by means of one or more fans has been met with interest, but satisfactory extinguishing results have failed to appear. Little by little, it has been generally accepted that it is possible to dampen and control an A-fire by means of waterfog, but that extinguishing requires other means. The object of the invention is to provide a device for waterfog extinguishing fires.

According to the invention, the object is achieved in that a building internally is equipped with nozzles for supplying waterfog both from ceiling and floor, and that the nozzles in the floor of the building are adapted to supply waterfog having a somewhat larger drops than the nozzles in the ceiling of the building.

Waterfog extinguishes fires in that the waterfog is converted into steam binding heat and, thus, acts cooling, and in that the steam displaces air and, thus, oxygen from the combustion zone. Waterfog is produced in that water under pressure is conducted through nozzles of a known type. There exist several types of nozzles for supplying waterfog. In the ceiling, fixed nozzles may be used. In the floor, for practical reasons, vertically movable nozzles of a known type are used, said nozzles being aligned with the floow surface when they are not in use, and raise from the floor, releasing nozzle openings when the water pressure has been put on in connection with extinguishing.

When waterfog is supplied from above, the room above the flame is gradually filled with water steam displacing air and reducing access of oxygen. With a small fire in a large room, it takes a long time to produce enough steam and, in practice, it has been found that such a fire may most probably be kept down, but it will not be extinguished. Experiments have shown that a small bonfire on a floor will not be notably influenced by fog supplied from above, relatively little steam being produced. When supplying fog from below towards a correspondingly small bonfire, experiments show that this is not sufficient either. Through a combination of fog supplied both from above and from below, the fire can be extinguished.

Claims

C l a i m

A device for waterfog extinguishing of fires in a room wherein the room internally is equipped with nozzles for supplying waterfog both from ceiling and floor, c h a r a c t e r i z e d i n that the nozzles in the floor of the room are adapted to supply waterfog having larger drops than the nozzles in the ceiling of the room, the nozzles in the floor of the room being adapted to supply waterfog in the lower portions of the room volume, the nozzles in the ceiling of the room being adapted to supply waterfog in the higher portions of the room volume.