GB2150828A

GB2150828A - Fire protection systems with fillable liquid containers

Info

Publication number: GB2150828A
Application number: GB08318664A
Authority: GB
Inventors: Eric William Crew
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-07-11
Filing date: 1983-07-11
Publication date: 1985-07-10
Also published as: GB8318664D0; GB2150828B

Abstract

A fire protection system comprises a layer of thermally insulating material 5 beside a plurality of containers 4 for thermally absorbing liquid. The containers are provided with filling ports (not shown) connected to a liquid supply conduit so that any liquid lost through evaporation or leakage can be replaced. A further layer 8 of thermally insulating material may be provided on the side of the containers the opposite to layer 5. The containers may also be provided with vents to allow vapour generated to escape and also with outlet ports so as to allow flow of liquid through the containers even in the absence of leaks. The containers can be rigid or flexible and may be arranged in an integral structure comprising a plurality of such containers. <IMAGE>

Description

SPECIFICATION Fire Protection Systems with Fillable Liquid Containers This invention relates to the provision of protection against the effects of fire or excessive heat.

The protection consists of layers of thermal insulating and thermal absorbing materials with supporting structural members in an assembly which shields or encloses items to protect them from the effects of fire or excessive heat external to the protection.

The protection combines the use of thermal insulating material, as is generally used for fire protection, with heat absorbing material and, when required, the provision of a supply of additional heat absorbing material from one or more distribution points.

The heat absorbing material is a non-flammable evaporative cooling liquid enclosed in a number of rigid or flexible containers. Provision is made for filling or refilling the containers in the event of a loss of liquid. The preferred liquid is water, with any suitable additives such as dyes, sterilizing chemicals or anti-freeze agents.

The rate of flow of heat from an external fire or heat source is reduced by the thermal insulating material. Heat passing through the outer wall of the fire protection system and the thermal insulating material enters the thermal absorbing liquid causing its temperature to rise slowly. When the temperature of the liquid reaches boiling point its rise is halted by absorption of latent heat as the liquid evaporates. When all or most of the liquid in one or more containers has been evaporated the temperature of the protected items then rises further unless more liquid is supplied to the container or containers.

A further reduction of the temperature rise of the protected items can be obtained by providing an additional layer of thermal insulating material on the inner surface of the protection system. The inner surface of the protection is that closest to the items being protected.

This fire protection system is an improved form of "An improved cable support system" covered by Patent Specification Serial No. 2027155B (Crew, Harvey and Fry) in which the heat absorbing material is contained in sealed sachets or other containers.

In the fire protection system with fillable liquid containers there are one or more groups of containers. The containers in each group are linked together by a means of supplying liquid from one or more filling points, comprising a tube or tubes. The filling points may also serve as a vent for air or vapour but it is preferred to provide separate vents.

The filling point may be an open tube or a tank which is filled manually or automatically. The liquid inlet and vent outlet may have a seal to prevent evaporation in the normal non-emergency use of the protection system which opens at a set pressure to act as a safety release under fire withstand conditions.

The or each relief device may take any convenient form. Suitable relief devices include an aperture closed by a press fit plug which will be ejected when the pressure of the liquid in the container group rises to a particular value. Another relief device consists of a plug or plugs of fusible metal or thermoplastic material which melts or yields at or near the boiling point temperature of the heat absorbing liquid. Another relief device consists of an aperture closed by a diaphragm which is designed to rupture as the pressure in the container group rises.

Thefillable liquid container fire protection systems may be arranged so that liquid from an external source flows continuously through the containers when cooling of the protected items is required, either in normal use, as for example when power cables are protected, or in an emergency condition when there is an external fire or excessive heating. Sensing devices may be fitted to regulate the flow of cooling liquid.

The or each container may be separately formed with respect to the supporting structure of the fire protection system or it may be formed in part by the wall, cover or floor of the supporting structure. The thermal insulating material may be applied to the outer surface of the wall, cover or floor of the supporting structure or on the inner surface.

In all cases, where there is more than one sachet or other container lining a part of the protective system structure, the sachets or other containers may be separately formed with respect to one another or they may be integral with or connected to one another additionally to the connection by the liquid supply tubing or cavities.

In all cases, also, the or each sachet or other container may be preformed to any desired shape appropriate to the part of the structure which it is to line.

The liquid containers are secured to the fire protection system by suitable clamps or fixing devices to prevent movement after they have been installed. The tubes or cavities for distribution of liquid are located at a higher level than that of the containers they supply to ensure that liquid will run into the containers and in the event of a rupture or leak in one container no liquid or only a small amount of liquid will flow from adjacent or other containers into the rupture. For this reason containers used on horizontal sections of the protective system are sloped so that the container portion is at a lower level than the liquid feed-in portion.

The operation of the fire protection system is that when it is in an external fire the heat raises the temperature of the liquid and its pressure of evaporation rises. At a particular pressure the sealing device or devices will permit the vapour to escape and more liquid will flow into containers from the distribution system to replace that lost by evaporation. The evaporation at or slightly above normal atmospheric pressure will prevent the temperature of the liquid rising appreciably above its boiling point temperature and there would be an equivalent limitation of the maximum temperature of the items being protected during the period of evaporation.

In the event of a very severe fire causing damage to a container while it still contained liquid, the liquid would escape and any additional supplies of liquid flowing into the container from the distribution system would also escape. This would have a cooling effect on the fire at or near the point where the damage first appeared. Liquid would remain in other undamaged containers unless the fire continued until all the liquid had evaporated and refilling had stopped.

The provision for filling a container or group of containers with liquid consists of a pipe of plastic, metal or other suitable material which carries the liquid to the lowest level in the container assembly and a vent or another pipe is provided to allow displaced air to escape. These pipes may be located adjacent to each other or at separate locations or may comprise a concentric system to give improved mechanical protection. Pipes may be joined by through connections or/and linked to manifolds to enable filling and vent points to be situated at convenient locations. The filling or vent points may be arranged so that the liquid level can be readily checked.

Thefillable liquid containerfire protection systems have the following advantages compared with the system using individually sealed containers: 1. If there is any loss of liquid from containers by evaporation or diffusion during a long period of use of the fire protection system under normal conditions, the containers will be or can be maintained completely full of liquid by occasional topping up at the supply point, or from a tank supply, or by automatic means such as a liquid level operated valve. This is particularly important when the fire protection is installed in high ambient temperature conditions or to protect electric cables in power systems.

2. If there is a leak of liquid from a container during normal operation this would be revealed by an unusual fall of level of liquid at the supply point or by a continual leak from the fire protection system if the liquid is automatically supplied. A warning device could be fitted if required to show an excessive fall in level of liquid at the supply point, to give an indication of risk of a prolonged leakage.

3. If a container is ruptured in fire conditions, liquid fed into it would reach the hottest part of the fire which caused the container to rupture. Liquid would remain in the intact containers until evaporated.

4. If water is used as the heat absorbing liquid, its temperature would be stabilised at about 1 00 C, the boiling point at normal atmospheric pressure, for a long period during a fire, until all the water is evaporated.

5. The protective system can be dispatched from the factory or supplier and installed without liquid if preferred, and the liquid could be added after the installation of the fire protection system. This would reduce weight during transport and enable the fire protection system to be packed for transport in a compact and secure manner.

The fillable liquid containerfire protection systems have the following advantages compared with systems relying on water spray devices: 1.A quantity of heat absorbing liquid is availabie at all times, including that of the onset of a fire.

Protection is provided even if there is no supply of additional liquid to replenish that which escapes.

2. Flow of liquid released from fillable liquid containers by the action of a fire is adequate but not excessive, whereas the water spray system operates at a much higher water pressure without the restricting effect of thermal insulation so that the large volume of released water generally causes damage additional to the fire damage.

The invention is further illustrated by a description, by way of example, of a preferred form of fire protective system using flexible plastic containers of liquid and of the components of this system, by reference to the accompanying drawings, in which: Figure 1 is a diagrammatic transverse crosssectional view of a portion of the fire protection system for horizontal use.

Figure 2 is an end view of a shaped metal support component.

Figure 3 is a plan view of a shaped metal component.

Figure 4 is a plan view of a flexible container for liquid.

Figure 5 is a plan view of a portion of the fire protection system for horizontal use.

Figure 6 is a diagrammatic transverse crosssectional view of a portion of the fire protection system forvertical use.

Figure 7 is a side view of a portion of the fire protection system for vertical use.

The following drawings illustrate a fire protection system using fillable liquid containers which are made of rigid or semi-rigid materials, preferably of clear plastic to enable liquid contents to be inspected.

Figure 8 is an isometric view of a basic rigid or semi-rigid container of liquid for horizontal use.

Figure 9 is a side view of a fire protection assembly for horizontal use.

Figure 10 is an isometric view of a basic rigid or semi-rigid container of liquid for horizontal use.

Figure 11 is a side view of a fire protection assembly for vertical use.

Figure 12 is a plan view of a fire protection assembly for vertical use.

Referring to Figure 1, the sheet metal base 1 of the fire protection system has a number of electrically welded pins 2 fixed in particular positions to suit the shaped metal supports 3 for the flexible containers of liquid 4 to allow them to be secured by placing them over the pins 2. The metal supports are shaped so that the side of the liquid container 4 from which liquid is supplied to the individual containers is at a higher level than the opposite side when it is secured in position on a horizontal enclosure. A part of the lower surface of the shaped metal supports 3 is then horizontal so that it provides an adequate area of contact with the thermal insulation 5. The protection system is assembled by pushing a layer of thermal insulating material 5 through the pins 2 so that it rests on the inside surface of the sheet metal base 1.Thermal insulating sleeves 6 are inserted on the pins 2 if necessary to act as a shield against heat conducted from the metal base 1 into the area surrounding the hole in the liquid container 4. The liquid container assembly is then placed in the shaped metal supports 3 and these are then placed to rest on the thermal insulation 5 at a position where they are located by the pins 2.

Locking washers 7 are then pushed on the pins 2 until they touch the shaped metal supports 3. The locking washers also serve to conduct heat from the pins 2 into the shaped metal supports 3 which are in contact with and keEcool by the heat absorbing liquid container assembly 4. Clearance holes are provided for pins 2 and insulating sleeves 6 in the shaped metal supports 3 and for insulating sleeves 6 in the liquid containers 4 to allow them to be secured by the pins 2 and locking washers 7. The metal supports 3 are shaped to ensure that the liquid supply side of the containers 4 is at a higher level than the rest of the container. A part of the lower surface of the shaped metal supports 3 is horizontal to provide adequate area of contact with the thermal insulation 5.The container assemblies 4 are subsequently filled with liquid and the filling pipes and vents are sealed as described. An optional additional layer of thermal insulation 8 may be added to further reduce the internal temperature of the protected system during a fire.

Referring to Figures 2 and 3, of the shaped metal support 3, holes 8 provide a clearance fit for pins 2 and holes 9 provide a clearance fit for insulating sleeves 6.

Referring to Figure 4, of the flexible container of liquid 4, the type shown comprises plastic sheet heat or radiation welded to form a number of similar sized compartments for containing liquid, with a continuous channel for the liquid supply and air venting requirements. Clearance holes 10 are provided for insulating sleeves 6. One or both ends are extended to provide accommodation for pipes for liquid supply 11 and air venting 12, sealed at the point of entry to the container assembly. In an alternative arrangement the extended portion is of sufficient length to reach the filling point and it can then act as a vent in which the sealing requirements are less stringent.

Referring to Figure 5, this shows the location of the pins 2 on the base plate 1 in relation to the components of the fire protection assembly for horizontal surfaces. it is not necessary to provide pins at every point where a hole is provided in the flexible container of liquid 4.

Referring to Figure 6, of fire protection assembly for vertical (or non-horizontal) applications, the construction is similar to the horizontal assembly except that the shaped metal support components 13 need not be the same as those for the horizontal arrangement 3. A more compact shape 13, is shown.

As in the horizontal arrangement, an additional layer of thermal insulation can be installed if required to reduce the temperature of the protected equipment.

Referring to Figure 7, this is a side view of a fire protection assembly for vertical or near-vertical application showing the positions of the securing pins and washers. Part of the wire mesh 14 is also shown in this drawing.

Figures 8, 9, 10, 11 and 12 show a form of fire protection system in which rigid or semi-rigid fillable containers of liquid are used. The containers are grouped in an assembly by fixing them in channel-shaped components by adhesives or other sealing methods involving heat or radiation. The arrangement for filling with liquid and venting makes use of these components together with pipes as used for liquid containers constructed with flexible materials.

Figure 8 shows a container 15 for use in horizontal fire protection assemblies. The open top is sealed when the container is fixed in the assembly, except for small apertures 16 provided for liquid filling and air venting. The apertures may also be formed by making opposite sides of the container slightly lower than the two other sides.

Figure 9 shows a diagrammatic end view of an assembly of containers 15 for horizontal use. These are secured together to cover the required area, or portion of the area, to be protected from fire, using channel components 24 for two opposite sides and cover plate 17 with channel components for the other two sides (not shown on the drawing). Gaps 18 are provided for the distribution of liquid and venting of air. Pipes 19 are connected to the liquid supply tank or topping-up location and to the vent outlet location. Liquid flowing into the assembly through one of these pipes 19 will fill containers 15 in succession and the displaced air is vented from the other pipe 19. This form of fire protection system can be modified to suit surfaces inclined at small angles to the horizontal by providing deeper containers or arranging the containers in step formation in the assembly.For vertical or nearvertical surfaces the system described below is applicable.

Figure 10 shows a container 20 for use in vertical or near-vertical fire protection assemblies. The open top is sealed when the container is fixed in the assembly except for small apertures 21 for liquid filling and air venting. The apertures are formed by making the narrow sides of the container slightly lower than the two other sides, but other methods such as cutting V-notches or semi-circles are acceptable. The assembly is secured inside the protected enclosure next to a sheet of thermal insulation material, as described for the assembly shown in Figure 1 for horizontal use. As in this case, an additional layer of thermal insulation can be secured to the inside face of the assembly to obtain lower internal temperatures during a fire.

Figure 11 shows a diagrammatic side view of a portion of an assembly of rigid or semi-rigid containers 20 for use in vertical or near-vertical fire protection assemblies. A group of containers to cover the required area are secured together by means of channels 22. On the drawing these are shown separated by small gaps for clarity, but they would be fixed in close contact to prevent the escape of liquid. The sides of the channels at the vertical edges are of increased size to form a channel 23 for liquid supplied to the containers. The ends of these channels are sealed and a pipe 23 is connected at the top of the two side channels. One of these pipes supplies liquid to the containers and the other is for the air vent connection. The arrows show the direction of flow of liquid when the containers are being filled from the pipe shown on the drawing. The liquid container assembly is fixed in position in the fire protection system by means of suitably shaped brackets, clips, or pins and washers, either at positions along the sides of the complete assembly or by providing specially made holes in the assembly, with sealing to prevent loss of liquid.

Figure 12 shows a plan view of the assembly of rigid or semi-rigid containers of liquid shown in side view in Figure 11.

Claims

1. A fire protection system comprising a layer of thermally insulating material, thermally absorbing liquid contained in a plurality of containers, each having a filling port, and filling means for filling the containers with the thermally absorbing liquid.

2. A system as claimed in claim 1 comprising a vent for each container.

3. A system as claimed in claim 2 comprising seal means for the vents andlor filling ports, said seal means being openable when the pressure inside the container reaches a predetermined value.

4. A system as claimed in any one of claims 1 to 3 wherein said containers are flexible.

5. A system as claimed in claim 4 wherein said containers are arranged side by side in an integral structure.

6. A system as claimed in any one of claims 1 to 5 wherein said containers are arranged in groups, each group being provided with a said filling means to supply all the containers of that group.

7. A system as claimed in any one of claims 1--6 wherein said containers comprise an outlet port for said liquid so that said liquid can flow through said containers from the filling port to the outlet port.

8. A system as claimed in any one of claims 1 to 7 comprising a layer of thermaliy insulating material on opposite sides of said containers.

9. A system as claimed in any one of claims 1 to 8 wherein said liquid is water.

10. A system as claimed in claim 9 wherein said water contains an additive such as a dye, a sterilizing chemical or an anti-freeze agent.

11. A system as claimed in any one of claims 1 to 10 wherein the containers overlap.

12. A fire protection system substantially as according to any of the embodiments hereinbefore described with reference to and as illustrated in the accompanying drawings.