NO343232B1

NO343232B1 - Air transfer and water draining firestop device

Info

Publication number: NO343232B1
Application number: NO20170434A
Authority: NO
Inventors: Geir Jensen
Original assignee: Scuti As
Priority date: 2017-03-20
Filing date: 2017-03-20
Publication date: 2018-12-10
Also published as: NO20170434A1; WO2018174720A1

Abstract

The invention provides an air transfer and water draining firestop device in a ventilated cavity or air gap, comprising a flame quenching gap element, wherein said quenching gap element is at least one malleable and non-combustible mesh made of a number of strands or threads which are braided, knitted or otherwise interconnected to each other in a linear fashion, and wherein the threads of the 10 malleable mesh can slide freely against each other without any fixed or rigid connection in order to fill irregularities of the ventilated cavity or air gap. The air transfer and water draining firestop device may comprise an intumescent material, which upon exposure to heat expands and seals the ventilated cavity or air 15 gap. The malleable mesh is preferably reshapeable as the strands or threads of the mesh can move in any directions away from the original produced form by compression or tensile strain.20 The grid size of the malleable mesh, being the size of openings between the strands or threads, is less or equal to a quenching gap of the combustible gas or gas mixture. The malleable mesh is preferably reshapeable as the strands or threads of the mesh can move in any directions away from the original produced form by compression or tensile strain. The grid size of the malleable mesh, being the size of openings between the strands or threads, is less or equal to a quenching gap of the combustible gas or gas mixture. The malleable mesh is preferably made out of knitted steel with low friction surface threads which slide against each other when under stress, such as tempered high-carbon steel giving a spring steel effect. The malleable mesh can be structured in multiple ways, such as rolled into a tube 30 structure which is compressible to be formed in an oval structure. The intumescent material is preferably placed within or at least partially within the tube structure.The invention provides an air transfer and water draining firestop device in a ventilated cavity or air gap, comprising a flame quenching gap element, wherein said quenching gap element is at least one malleable and non-combustible mesh made of a number of strands or threads which are braided, knitted or otherwise interconnected to each other in a linear fashion, and wherein the threads of the 10 malleable mesh can slide freely against each other without any fixed or rigid connection in order to fill irregularities of the ventilated cavity or air gap. The air transfer and water draining firestop device may comprise an intumescent material, which upon exposure to heat expands and seals the ventilated cavity or air 15 gap. The malleable mesh is preferably reshapeable as the strands or threads of the mesh can move in any directions away from the original produced form by compression or tensile strain.20 The grid size of the malleable mesh, being the size of openings between the strands or threads , is less or equal to a quenching gap of the combustible gas or gas mixture. The malleable mesh is preferably reshapeable as the strands or threads of the mesh can move in any direction away from the original produced form by compression or tensile strain. The grid size of the malleable mesh, being the size of openings between the strands or threads, is less or equal to a quenching gap of the combustible gas or gas mixture. The malleable mesh is preferably made out of knitted steel with low friction surface threads which slide against each other when under stress, such as tempered high-carbon steel giving a spring steel effect. The malleable mesh can be structured in multiple ways, such as rolled into a tube 30 structure which is compressible to be formed in an oval structure. The intumescent material is preferably placed within or at least partially within the tube structure.

Description

Field of the invention

The present invention relates to a firestop device within a ventilated cavity or air gap in a building construction, comprising a flame quenching gap element.

Background of the invention

Unprotected ventilation openings in the exterior of buildings are critical when exposed to fire. Fires that spread underneath the facade cladding represent a major challenge for the fire brigade; both since is it difficult to identify where it actually is burning, and also since it often is difficult to get access to the fire. Both statistics and real fire situations point at increased safety benefits by preventing fire from spreading through gaps and cavities in the construction.

Today, this problem is solved by using different types of ventilating fire barriers. These are characterized by that they allow air to vent cavities and prevent fire from penetrating after they are sealed. Some prevent flames from propagating into the cavities for a brief period. Commonly, strips of intumescent are used to protect ventilated or ventilating cavities. When exposed to fire the intumescent material is activated by the heat and expands so that it fills the gap completely, hence preventing flames and hot gases to enter the cavity. The weakness with this solution is that flames can enter the cavity in the early stage of a fire, in seconds or minutes before the intumescent has completely sealed the gap. Fire barriers such as perforated metal sheets or metal sheet labyrinths, stop embers and flames in early stages. However, these solutions will not be efficient for longer fire durations.

The applicant has previously invented ventilating solutions that blocks flames instantly and prevent fire spread throughout the entire fire rating period, all based on a fully reactive and ablative vent design, i.e. it contains no moving parts, no detector activating system and no cabling.

The known vents are described in the inventor's earlier patents WO2004/004837 and WO2010/140893, and comprise a fire resistant mesh and intumescent.

Other fire barriers are known from GB2107183A, US2279791, US5811713, and WO9422536A1.

US2013/0255893A1 relates to a fire and smoke protection system for limiting the spread of fire and smoke through an opening, including those in building structures.

The fire and smoke protection system comprises a flexible protection member and a winding shaft about and onto which the flexible protection member is fully-wound (and, hence, fully-retracted) when the system is configured in the storage configuration so as not to occlude an opening. Conversely, the flexible element is fully-unwound from the winding shaft when the system is configured in the fullydeployed configuration so that the flexible protection member fully occludes the opening.

The quenching effect is well known in the art of chemical explosion suppression in pipes. The openings of a quenching net must be designed to block flaming by particular mixtures of combustible gas. The opening distances are referred to as quenching diameter or quenching gap and are listed in millimetres for each type of gas or gas mixtures.

During normal use of the known vents and during initial flame exposure, a gap between the vent and the surrounding surfaces must not be more than the quenching gap size, as flames will pass such openings, and thereby penetrate the vent to the unexposed side. Such gaps must be protected, for instance by battens or mastic, and this complicates correct mounting of the vents or the expected effect may not be achieved. This is particularly challenging in a gap or opening where the surrounding surfaces are irregular or change in size.

All known vents offer a limited ability to provide instant fire block and to fully fill irregularities in gaps and cavities, both during normal use in open state, and during the initial phase of a fire or in sealed state of the vent. The gaps may arise or enlarge during fire or by unfavourable handing and mounting of the vents. This particularly is a problem in voids and cavities behind the facade cladding.

A major problem is delamination of facade elements by impact of fire, which cause them to deflect away from air gaps and increase them. Most cavity fire barriers cannot cope with large expansion and flame or fire are known to bypass them and having caused large damage.

Some type of firestop devices or cavity fire barriers tends to trap condensed water or rain droplets for extended time against surfaces of air gaps, which eventually damage construction. The purpose of ventilated cavities is to keep construction dry.

Objects of the present invention

The object of the invention is to provide a new vent in the form of an air transfer and water draining firestop device, which solves the above problems related to the known vents.

Further, it is an object that the new air transfer and water draining firestop device according to the invention shall be easy and quick to install correctly.

It is also an object that the air transfer and water draining firestop device according to the invention is malleable to fill irregularities of a ventilated cavity or air gap.

Summary of the invention

Said objects are achieved with a firestop device according to the characterizing part of the independent patent claim. Further advantageous features are stated in the dependent claims.

The invention provides a firestop device within a ventilated cavity or air gap in a building construction, comprising a flame quenching gap element, wherein said quenching gap element is at least one malleable and non-combustible mesh made of a number of strands or threads which are braided, knitted or otherwise interconnected to each other in a linear fashion, and wherein the threads of the malleable mesh can slide freely against each other without any fixed or rigid connection in order to fill irregularities of the ventilated cavity or air gap.

The firestop device may comprise an intumescent material, which upon exposure to heat expands and seals the ventilated cavity or air gap.

The malleable mesh is preferably reshapeable as the strands or threads of the mesh can move in any directions away from the original produced form by compression or tensile strain.

The grid size of the malleable mesh, being the size of openings between the strands or threads, is less or equal to a quenching gap of the combustible gas or gas mixture.

The malleable mesh is preferably made out of knitted steel with low friction surface threads, which slide against each other when under stress, such as tempered highcarbon steel giving a spring steel effect.

The malleable mesh can be structured in multiple ways, such as rolled into a tube structure, which is compressible to be formed in an oval structure.

The intumescent material is preferably placed within or at least partially within the tube structure.

A core of intumescent material can be placed within the tube structure. Further, a core of intumescent material can be placed or embedded in or on a periphery of the tube structure.

The malleable mesh can be arched shaped, and a core of said intumescent material can be placed within the arched shaped structure.

The core of intumescent material can be spherical or rectangular or other. Further, the intumescent material is preferable made of a reactive and endothermic substance. The intumescent material can be made of graphite or sodium silicates.

The quenching gap element is preferably made of memory metal, which when under exposure to heat expands to increase contact area with ventilating opening surfaces of the ventilated cavity or air gap. The malleable form of the quenching gap element can be adapted to reset itself to original form when not under stress.

A lower part of the malleable mesh, when placed between surfaces in the ventilated cavity or air gap, may function as a liquid drip-off part of the malleable mesh.

The malleable mesh of the quenching gap element may be rolled into a circular or oval tube form, and comprise an internal, helical support spring, which in a nonstretched condition has a larger external diameter than an internal diameter of the tube. The spring can be arranged to expand or keep the malleable mesh expanded.

Upon exposure to heat, the intumescent will expand at the least until it covers the gap in the exposed area or, in the case of 3D embodiment, until a longitudinal cross section of the surrounding mesh tube is filled. When the intumescent expands to fill the gap, air is prevented to transfer the vent and hence both heat and flames are prevented from transferring through the cavity.

Reshaping of the malleable firestop device may be done by hand in all directions to fill larger gaps in some parts, and smaller gaps in other parts. In this way, the vent in the form of the firestop device will fit into uneven ventilation gaps with crevices, cracks, indents or sloping surfaces wherein it should be installed. The vent area may be changed on site, and therefore one achieves optimal size to fully fill in linear gaps at any point such that the above-mentioned gaps between the vent and the surrounding surfaces are avoided. This is especially advantageous when the opening or cavity wherein the firestop device is to be fitted is long and the gap size irregular.

For a malleable vent shaped into a tube surrounding intumescent, an important feature is the encapsulation ability to be slightly pressed into a narrow gap to form a “flat oval”. This means that when sealed a much thicker layer of intumescent can provide a barrier of insulation against fire than previous designs with encapsulations that are circular after installation.

If the opening is longer than the length of the vent, the ends of devices with all treads or strands meet up against each other for instance by compressing or feeding into another, and thereby creating a splice without dedicated seals.

The vent in the form of the firestop device shall be able to stretch and compress in order to fill the space between opposing surfaces of the gap wherein it shall be fitted. This avoids the need to cut lengths precisely prior to fitting.

The vent may be described as a ventilating dry linear seal which can be formed by hand using no tool or adhesives to fit into uneven ventilating gaps witch incorporates crevices, cracks, indents, irregularities or sloping surfaces. At the same time by hand one may straighten out by hand any bends or indents of the device itself caused by former impact of handling. The device properties that allow forming by hand on site resemble that of putty beads, mastic gun or clay by being 3D elastic, although it still transfers air and drains water without being sticky and without requiring tools.

A firestop device according to the present invention provides a reversible or provisional fire protection. It can be removed at any time, hardly leaving any marks. Further, as the vent comprises a mesh, it may also provide draining of water at the same time as it prevents rodents from penetrating into cavities.

Instead of trapping water against porous surfaces of cavity the firestop device preferably offer its lower point as a part of metal mesh between the surfaces, which allows drip-off to ground, and faster natural air-drying.

The firestop device thus provides robust fire resistance by integrity, insulation, blocking of direct flame impingement and of embers. The firestop device provides said fire resistance in open state as well as sealed state.

Description of the diagrams

Embodiments of the present invention will now be described, by way of example only, with reference to the following diagrams wherein:

Figure 1 – 5 show an air transfer and water draining firestop device according to the invention, in ventilated cavities or air gaps of different configurations.

Figure 6 – 9 show different configurations of the air transfer and water draining firestop device according to the invention, in a ventilated cavity or air gap.

Figure 10 show the air transfer and water draining firestop device according to the invention in a long and irregular ventilated cavity or air gap.

Figure 11 – 19 show different configurations of the air transfer and water draining firestop device according to the invention, in a ventilated cavity or air gap, and including intumescent material.

Description of preferred embodiments of the invention

As shown in the drawings, an air transfer and water draining firestop device according to the invention comprises a quenching gap element 10 placed in a ventilated cavity or air gap 12. Optionally, an intumescent material 14 can be used together with the quenching gap element 10.

A vent in the form of the air transfer and water draining firestop device according to the invention offers a malleable form of non-combustible mesh and possible intumescent. The malleable form is preferably made of a number of strands or threads 10a, which are braided, knitted or otherwise, held into each other in a linear fashion. The threads 10a of the mesh should not be welded or glued to each other. Such malleable form shall be alterable by hand. The form may thus be reshaped as the strands or threads 10a of the mesh can move in all directions away from the original produced form by compression or tensile strain at any point. The grid size of the mesh, being the size of the opening between threads 10a or the openings between the firestop device and adjoining surfaces, must be less or equal to the maximum size of the quenching gap of the application as determined by the gas mixture. The distance a and b, as shown in figure 1, is thus less than the quenching gap in mm of the gas or mix of gases for the specific flame blocking application.

In the drawings, c denotes linear height of surface contact between the quenching gap element 10 and the inner surface of the ventilated cavity or air gap 12, which serves as heat sink for absorbing and storing heat only.

Figure 1-9 show different embodiment suitable for ember and flame blocking, normally short duration flame blocking.

Figure 1 shows the quenching gap element 10 placed in a linear even gap 12, with the mesh in a normal tube form, i.e. not stretched nor compressed or bent.

Figure 2 shows the quenching gap element 10 placed in a nor-linear gap 12, in where the gap width linearly increases or decreases, and the openings of the mesh are compressed in the wide sections and stretched in the narrow sections.

Figure 3 shows the quenching gap element 10 placed in an uneven gap 12, in where the gap width randomly increases or decreases, and the openings of the mesh are compressed in the wide sections and stretched in the narrow sections.

Figure 4 shows similar the quenching gap element 10 placed in an uneven gap 12, in where the gap width randomly increases or decreases and the openings of the mesh are compressed in the wide sections and stretched in the narrow sections.

Figure 5 shows the quenching gap element 10 placed in a somewhat linear gap 12, but where sharp edges occasionally leave voids larger than the quenching gap. Said voids may require to be filled with fire resistant mastic or not depending on the edge. The mesh of the quenching gap element 10 may suitable be pushed into the voids.

Figure 6 shows a cross section of the quenching gap element 10 placed in an even gap 12 with good linear height, and with the mesh in a compressed oval form.

Figure 7 shows a cross section of the quenching gap element 10 placed in a gap 12 with irregular gap height, showing that the mesh has the flexibility of adapting to the gap 12.

Figure 8 shows the quenching gap element 10 placed in an even gap 12, with the mesh in a sheet form fixed to make a quenching element of four layers with good heat sink performance. The mesh of the quenching gap element 10 thus displays an S or arched form.

Figure 9 shows the quenching gap element 10 placed in an even gap 12, and comprises a circular or oval mesh incorporating a smaller second circular mesh within, to achieve four layers of quenching and heat sink performance.

Figure 10 shows the quenching gap element 10 placed in an extremely rugged gap 12, for instance between mortar surfaces. The mesh can be compressed or stretched to fill most of the gap 12, and in addition a fire resistant linear seal 16, such as by mastic gun, can be applied to fill irregularities larger than the quenching gap. An intumescent material 14 can be used together with the quenching gap element 10, as explained in connection with the other drawings.

Figure 11-15 show different embodiment suitable for ember, flame, and sustained fire blocking, and also with an intumescent material 14. The intumescent material 14 can be of any form, but preferably of a rectangular or spherical shape, and is a reactive and endothermic substance with heat sink performance.

Figure 11 shows the quenching gap element 10, with the mesh in an oval sheet form, embedded into an intumescent material 14, i.e. reactive element, which is fixed to the surface of the ventilating gap 12. As the reactive and endothermic material expands and removes heat the firestop device prevent embers, flames and sustained fire exposure to penetrate for an extended time.

Figure 12 shows a similar solution as in figure 11, but with the reactive element, i.e. intumescent material 14, resting at the bottom of a circular firestop device of the invention, and heat sink areas c on both sides of the ventilation gap 12.

Figure 13 shows use of three circular quenching gap elements 10, as shown in figure 11, compressed to fill a gap 12 with good linear height, and that gives extended time fire resistance in wide gap applications. The mesh is embedded into the reactive elements 14.

Figure 14 shows a sheet form of the invention, with the quenching gap element 10 in an arched or u-form, and with a circular reactive element 14.

Figure 15 shows a combination with any of several existing devices marketed for sustained fire resistance and the invention. The firestop device according to the invention can be added to make existing products ember and direct flame resistant. Figure 16-17 show different embodiment suitable for ember, flame, sustained fire, and radiation blocking, and also with an intumescent material 14.

Figure 16 shows a combination of different embodiments, in where three quenching gap elements 10 are used. One or more of the quenching gap elements 10 can have or be embedded in the intumescent material 14. The firestop device according to the invention may thus provide sufficient attenuation of heat radiation to prevent ignition on the unexposed side prior to the device being sealed by expanding reactive material.

Figure 17 shows a circular or oval quenching gap element 10 with intumescent material 14 in upright position within the mesh and with overlapping radiation shields below element 10 in order to provide radiation blocking without blocking air transfer.

Figure 11-19 all show different embodiments in an even gap 12, but may be used in similar gaps as shown in figures 1-10.

Figure 18 shows bundled circular forms of the firestop device according to the invention, which gives a good heat sink area. Figure 19 shows a similar embodiment for wide gaps 12.

The mesh can be of 3D shape (e.g. tube) or of 2D shapes such as rectangular, circular or triangular sheets. A quenching mesh alone without intumescent will protect against ember and short duration flame attacks. The malleable mesh in combination with intumescent material are embodiments for ember, flame attack and sustained fire exposure.

The malleable mesh of the invention is made out of knitted steel with low friction surface threads, which slide against each other when under stress. For knitting pattern and machinery, one may apply such as designed for decorative products or for sieve products.

Such meshes to be used in the firestop device according to the invention should be a mesh type with a suitable thread size and mesh gap diameter of for instance 2 mm (for quenching gap). Furthermore, rolled into a tube form prove especially useful when pushed into gap where it is compressed to an oval form. Tubes of 20 mm, 40 mm and 45 mm are tested in fire. There seems to be no limit in tube size small or large as long as the knitting machine handle the combination of tread diameter, tube diameter, and mesh size. A key property of the thread material, and most important, is a minimum of spring steel effect, achieved by it being for instance tempered highcarbon steel.

The invention does not require any specific intumescent material. Designs that require large expansion may require 5-15 times expansion of normal state, while even 2 times expansion may be sufficient in other designs. Typical intumescent materials are basically endothermic materials containing water or forming water by chemical process once heated. The water subsequently transforms to steam upon heat exposure, such as sodium silicate or graphite used for providing high-pressure expansion, which compacts the resulting char.

The mass of intumescent is designed to fill up the expansion volume and add sufficient pressure for good seal and even to compensate for delamination and deflection movements of cavity surfaces that may increase the gap or void cross section during impact of fire.

To avoid trapping of liquid against porous surfaces of the cavity, the firestop device can use its lower part of the metal mesh between the surfaces to allow for drip-off of liquid, such as water, to ground and faster natural air-drying. The lower part of the malleable mesh, when placed between the surfaces in the ventilated cavity or air gap 12, will thus be a drip-off part of the malleable mesh.

In a further embodiment of the invention, the malleable mesh of the quenching gap element 10 is rolled into a circular or oval tube form, and comprises an internal, helical support spring (not shown in the drawings), which in a non-stretched condition has a larger external diameter than an internal diameter of the tube. The spring, which can be a steel spring, is arranged to expand and keep the malleable mesh expanded. The steel spring, with thicker or stronger treads than those of the mesh, will when placed inside the tube expanded to support the tube inherent form keeping or memory metal effect. The spring is stretched to feed it inside the tube. When relaxed it retracts until it puts force against the tube wall and supports the mesh. When for instance used in a ventilated cavity or air gap 12 as shown in any of figures 1-5 and 10, the spring will contribute to the expansion and support of the malleable mesh, and to the fire protection abilities of the present invention.

Claims

1. A firestop device within a ventilated cavity or air gap (12) in a building construction, comprising a flame quenching gap element (10), characterized in that said quenching gap element (10) is at least one malleable and non-combustible mesh made of a number of strands or threads (10a) which are braided, knitted or otherwise interconnected to each other in a linear fashion, and wherein the threads (10a) of the malleable mesh can slide freely against each other without any fixed or rigid connection in order to fill irregularities of the ventilated cavity or air gap (12).

2. Firestop device according to claim 1, characterized by comprising an intumescent material (14), which upon exposure to heat expands and seals the ventilated cavity or air gap.

3. Firestop device according to claim 1, characterized in that the malleable mesh is reshapeable as the strands or threads (10a) of the mesh can move in any directions away from the original produced form by compression or tensile strain.

4. Firestop device according to claim 1, characterized in that a grid size of the malleable mesh, being the size of openings (a,b) between the strands or threads (10a), is less or equal to a quenching gap of a specific combustible gas or gas mixture.

5. Firestop device according to claim 1, characterized in that the malleable mesh is made out of knitted steel with low friction surface threads (10a) which slide against each other when under stress, such as tempered high-carbon steel giving a spring steel effect.

6. Firestop device according to claim 1, characterized in that the malleable mesh is rolled into a tube structure, which is compressible to be formed in an oval structure.

7. Firestop device according to claim 6, characterized in that the intumescent material (14) is placed within or at least partially within the tube structure.

8. Firestop device according to claim 6, characterized in that a core of intumescent material (14) is placed within the tube structure.

9. Firestop device according to claim 6, characterized in that a core of intumescent material (14) is placed or embedded in or on a periphery of the tube structure.

10. Firestop device according to claim 1, characterized in that the malleable mesh is arched shaped, and a core of said intumescent material (14) is placed or embedded within the arched shaped structure.

11. Firestop device according to claim 8, 9 or 10, characterized in that the core of intumescent (14) material is spherical or rectangular.

12. Firestop device according to claim 1, characterized in that the intumescent material (14) is made of a reactive and endothermic substance.

13. Firestop device according to claim 1, characterized in that the intumescent material (14) is made of graphite or sodium silicates.

14. Firestop device according to claim 1, characterized in that the quenching gap element (10) is made of memory metal, which when under exposure to heat expands to increase contact area with ventilating opening surfaces of the ventilated cavity or air gap (12).

15. Firestop device according to claim 1, characterized in that the malleable form of the quenching gap element (10) is adapted to reset itself to original form when not under stress.

16. Firestop device according to claim 1, characterized in that a lower part of the malleable mesh, when placed between surfaces in the ventilated cavity or air gap (12), is a liquid drip-off part of the malleable mesh.

17. Firestop device according to claim 1, characterized in that the malleable mesh of the quenching gap element (10) is rolled into a circular or oval tube form, and comprises an internal, helical support spring, which in a non-stretched condition has a larger external diameter than an internal diameter of the tube.

18. Firestop device according to claim 17, characterized in that the spring is arranged to expand or keep the malleable mesh expanded.