GB2573884A

GB2573884A - Improvements in and relating to ventilated fire barriers

Info

Publication number: GB2573884A
Application number: GB1905125.9A
Authority: GB
Inventors: Coggon Rupert; Thompson Christopher
Original assignee: Tenmat Ltd
Current assignee: Tenmat Ltd
Priority date: 2018-04-11
Filing date: 2019-04-11
Publication date: 2019-11-20
Anticipated expiration: 2039-04-11
Also published as: GB201905125D0; GB201805975D0; GB2573884B

Abstract

The ventilated fire barrier (VFB) 10 comprises first 12 and second 14 intumescent layers either side of a carrier body 16. The second intumescent layer may be located within the body and may be aligned with the first layer. The layers and body may be enclosed by a shell, which may be openable. The layers may have different dimensions. The second intumescent layer may comprise a plurality of segments displaced from one another. The intumescent layers may be comprised of a thermally-reactive material and the carrier body may comprise a thermally-stable material such as glass or mineral wool. The layers may comprise a uni-directional intumescent material and a mounting means for affixing the barrier to a wall. Also claimed are a cavity and a cavity wall comprising the VFB, and methods of construction of the cavity and cavity wall.

Description

IMPROVEMENTS IN AND RELATING TO VENTILATED FIRE BARRIERS

Field of the Invention [01] The present disclosure relates to ventilated fire barriers.

Background of the Invention [02] A Ventilated Fire Barrier (VFB), otherwise known as an Open State Fire Barrier, is designed to allow ventilation of a cladding/fagade cavity during normal use. However, in the event the event of a fire within the cladding/fagade cavity, a VFB is designed to expand rapidly to create an insulating barrier to fire, smoke and heat.

[03] The performance of a fire barrier is defined by its ability to withstand the passage of flame (known as integrity) and withstand the passage of heat (known as insulation) when exposed to particular thermal and pressure curves, i.e. a fire.

[04] Existing fire barriers are composed of an intumescent (thermally reactive) material combined with a carrier body made from a thermally stable material. That is, the intumescent material has a greater reaction to a heat source, e.g. by expanding, than the thermally stable carrier body.

[05] In the initial stages of a fire the intumescent material expands quickly to create a seal in the cavity by applying pressure to the cavity and carrier body. As a fire continues however the VFB will begin to break down due to prolonged heat exposure.

[06] In particular, one of the major reasons for failure of a VFB is due to the shrinkage of the carrier. As shrinkage occurs the pressure on the barrier within the cavity is lost. This is because the intumescent rapidly loses its ability to react to heat in the later stages of the fire, and therefore any shrinkage in the carrier cannot be compensated for. Thus hot gases are allowed to pass at joints or perimeters of the barrier which accelerates breakdown of the VFB which can lead to pre-mature failure.

[07] Therefore, a ventilated fire barrier which compensates for the shrinkage and loss of pressure during a fire is highly desirable.

[08] The following example embodiments have been provided with a view to addressing at least some of the difficulties that are encountered with current ventilated fire barriers, whether those difficulties have been specifically mentioned above or will otherwise be appreciated from the discussion herein.

Summary of the Invention [09] It is an object of the present invention to overcome at least one of the above or other disadvantages. According to the present disclosure there is provided a multi-layered ventilated fire barrier as in claim 1, a cavity as in claim 12, a cavity wall as in claim 16, and methods of construction as in claims 14 & 19. Additional features will be apparent from the dependent claims and the discussion herein.

[10] Accordingly there is provided a multi-layered ventilated fire barrier comprising a first intumescent layer; a second intumescent layer; and a carrier body between the first intumescent layer and the second intumescent layer.

[11] The first intumescent layer may be in contact with a surface of the carrier body. The second intumescent layer may be in contact with a surface of the carrier body. In combination, the first intumescent layer may be in contact with a first surface of the carrier body and the second intumescent layer may be in contact with a second surface of the carrier body.

[12] The second intumescent may be located within the carrier body. The second intumescent may also be located between a first carrier body and a second carrier body.

[13] The first intumescent layer and the second intumescent layer may be substantially aligned with each other.

[14] The carrier body may comprise a thermally stable material which may be comprised of mineral fibres. The mineral fibres may be mineral wool, glass wool, or a combination thereof.

[15] The first intumescent layer and second intumescent layer may be comprised of a thermally reactive material. The first intumescent layer and second intumescent layer may be comprised of the same thermally reactive material or different thermally reactive material.

[16] Further, there is provided a cavity comprising the aforementioned ventilated fire barrier.

[17] The first intumescent layer may be positioned proximate to a first surface of the cavity, and the second intumescent layer may be positioned proximate to a second surface of the cavity. The first intumescent may be positioned between the second intumescent and the first surface of the cavity. Correspondingly the second intumescent may be positioned between the first intumescent and the second surface of the cavity.

[18] The first intumescent layer may be arranged to expand first in response to a heat source and the second intumescent layer may be arranged to expand second in response to the same heat source.

[19] Accordingly, there is provided a method of construction of a cavity comprising the multi-layered ventilated fire barrier.

[20] Further, there is provided a cavity wall comprising the aforementioned multi-layered ventilated fire barrier.

[21] Accordingly, there is provided a method of construction of a cavity wall comprising the aforementioned multi-layered ventilated fire barrier.

[22] It will be appreciated that, advantageously, aspects of the present disclosure solve the problem of shrinkage and pressure loss that may occur in a fire barrier exposed to a heat source.

Brief Description of the Drawings [23] For a better understanding of the present disclosure reference will now be made to the accompanying drawings, in which:

[24] Fig. 1 shows a perspective cross-sectional view an example of a multi-layered ventilated fire barrier;

[25] Fig. 2 shows a cavity comprising an example multi-layered fire barrier;

[26] Fig. 3 shows another example multi-layered fire barrier in a cavity;

[27] Fig. 4 shows an example of a multi-layered ventilated fire barrier according to another embodiment of the present disclosure;

[28] Fig. 5 shows yet another example of a multi-layered ventilated fire barrier;

[29] Fig. 6 shows yet another example of a multi-layered ventilated fire barrier;

[30] Figs. 7A and 7B are an example of a further multi-layered ventilated fire barrier in a passive (no fire) and an active (fire) configuration, respectively.

Detailed Description of the Present Embodiments [31] The following examples of the present disclosure provide an improved ventilated fire barrier (VFB). The examples provide for a ventilated fire barrier which is less likely to experience early breakdown. Many other advantages and improvements will be discussed in more detail herein.

[32] Figure 1 shows an example multi-layered VFB according to the present disclosure. A multi-layered VFB 10 comprises a first intumescent layer 12, a second intumescent layer 14, and a carrier body 16 between the first intumescent layer 12 and second intumescent layer 14.

[33] In the example of Figure 1 the first intumescent layer 12 and second intumescent layer 14 are positioned in contact with the carrier body 16. Put another way, the first intumescent layer 12 may be positioned in contact with a first surface of the carrier body 16 and the second intumescent layer 14 may be positioned in contact with a second surface of the carrier body 16.

[34] The first intumescent layer 12 and second intumescent layer 14 may be aligned with each other. In the example of Figure 1, the first and second intumescent layers 12, 14 are aligned to be parallel to one another. In other examples, not shown, the first and second intumescent layers 12, 14 may be substantially aligned in the same direction but at an angle.

[35] Further, in the example of Figure 1 both the first and second intumescent layers 12, 14 have the same dimensions. It will be appreciated however that alternative configurations, whereby the first and second intumescent layers 12, 14 have different dimensions, are also consistent with the present disclosure.

[36] Figure 2 shows a cavity comprising the example of the multi-layered VFB of Figure 1. The cavity may be, for example, the cavity of a cavity wall.

[37] As shown in Figure 2, the first intumescent layer 12 is positioned proximate to a first surface of the cavity 18. That is, the first intumescent layer 12 is positioned between the carrier body 16 and the first surface of the cavity 18. Put another way, the first intumescent layer 12 is positioned closer to the first surface 18 of the cavity than the carrier body 16 and the second intumescent layer 14.

[38] The second intumescent layer 14 is positioned proximate to a second surface 20 of the cavity. That is, the second intumescent layer 14 is positioned between the carrier body 16 and the second surface of the cavity 20. Put another way, the second intumescent layer 14 is positioned closer to the second surface 20 of the cavity than the carrier body 16 and the first intumescent layer 12.

[39] In the example of Figure 2, the first intumescent layer 12 is separated from the first surface of the cavity 18. This separation is to allow ventilation in the cavity during normal use. The second intumescent layer 14 is positioned in contact with the second surface 20 of the cavity.

[40] In an alternative arrangement, not shown, the first intumescent layer 12 may be in contact with the first surface 18 of the cavity while the second intumescent layer 14 may be separated from the second surface 20 of the cavity.

[41] In the example of Figure 2, the multi-layered VFB is longer in an X direction than in a Y and Z direction. In this example, X, Y, and Z are orthogonal axes that may be defined by either the fire barrier itself, or by its position within the cavity. For example, where the cavity is a cavity wall, the multi-layered ventilated fire barrier may be thought to be extended along the length of the wall (X, e.g. horizontally), while being shorter in depth (Y) and height (Z) inside the cavity.

[42] In other examples, not shown, the multi-layered VFB may be positioned in other orientations. For example, the fire barrier may be longer in the Z direction than in the X or Y directions. The fire barrier may be positioned vertically within a cavity or at a diagonal. In yet further examples, the multi-layered VFB may cover an entire surface of a cavity.

[43] Figure 3 shows an example of the multi-layer VFB comprising a shell 24. The shell 24 may be considered to comprise a plurality of shell walls which enclose the first intumescent 12, second intumescent 14, and carrier body 16. One shell wall 26 may comprise a door or shutter mechanism such that the shell wall 26 is openable.

[44] In the example of Figure 3A, the first intumescent layer 12 is positioned proximate to the openable shell wall 26. The shell wall 26 is configured to open in response to expansion of the first intumescent layer 12. In an alternative example, not shown, there may be no shell wall 26, such that the first intumescent layer is exposed.

[45] Using a shell 24, or more generally a container, it may also be possible to position the layers of the multi-layer VFB such that they are not in contact with each other. For example, only one of the first or second intumescent layers 12, 14 may be in contact with the carrier body 16, while the other layer 14, 12 may positioned such that there is a gap between the intumescent layer and the carrier body. Alternatively, both the first and second intumescent layers 12, 14 may be positioned such that there is a gap between carrier body and the intumescent layers.

[46] The first and second intumescent layers 12, 14 are comprised of a thermally reactive material. Thus the first and second intumescent layers are responsive to heat and will, for example, expand when exposed to a heat source. The first intumescent layer 12 and second intumescent layer 12 may be comprised of the same thermally reactive material or different thermally reactive materials. Example intumescent materials may comprise intercalated graphite, mono-ammonium phosphates, or sodium silicate, [47] The carrier body 16 is comprised of a thermally stable material such as a mineral fibre material. Examples of mineral fibres include mineral wool and glass wool.

[48] In operation, the first intumescent layer 12 is arranged to react first in response to a heat source. The second intumescent layer 14 is arranged to react second in response to the same heat source.

[49] Using the examples of Figures 1, 2 & 3, when the multi-layered VFB 10 is exposed to heat, the first intumescent layer 12 will react first by expanding into the gap between the first intumescent layer 12 and the first surface 18 of the cavity.

[50] In the example of Figures 3A & B, the expanding first intumescent layer opens the shell wall 26 in order to expand into the gap between the first intumescent layer 12 and the first surface 18 of the cavity. The remaining shell walls and the carrier body 16 prevent expansion in directions other than towards the shell wall 26. Conveniently a double door mechanism, such as that shown in Figure 3B, may be used to prevent expansion of the first intumescent in directions other than toward the first surface 18 of the cavity. Put another way, a double door mechanism may guide the expansion of the first intumescent 12 toward the first surface 18 of the cavity.

[51] Thus an initial seal against further heat flow will be created inside the cavity. The second intumescent layer 14 however is shielded from the initial heat flow due to its position between the carrier body 16 and the second surface of the cavity 20. The shell 24 may also have an insulating effect to shield the second intumescent 14 from the heat flow.

[52] As the temperature and pressure increase inside the cavity, the first intumescent layer 12 will reach the limit of its expansion, whilst the carrier body 16 will start to shrink. Thus there is the potential for a breakdown of the fire barrier due to an inability to maintain a seal in the cavity.

[53] The second intumescent layer 14 however will now start to also react to the heat source by expanding. This expansion maintains the pressure of the seal created inside the cavity as the second intumescent layer 14 continues to expand long after the first intumescent layer 12 has stopped, thereby compensating for the shrinkage of the carrier body 16.

[54] Thus, because the second intumescent layer 14 is not exposed to the initial heat within the cavity, the second intumescent layer 14 will only expand as the heat within the cavity, and therefore heat transferred to the second intumescent layer, gets to a certain level over the duration of the fire, thereby allowing a longer duration of both integrity and insulation to be maintained.

[55] Figure 4 shows a further example multi-layer VFB consistent with the present disclosure. In this example, the second intumescent layer 14 is located within the carrier body 16. That is, the second intumescent layer 14 is located between a first layer of the carrier body 16a and a second layer of the carrier body 16b. Alternatively, the first carrier body 16a and second carrier body 16b may be considered to be two separate carrier bodies, such that the second intumescent layer is positioned between a first carrier body 16a and a second carrier body 16b.

[56] When positioned in a cavity equivalently to Figure 2, the multi-layered VFB 10 of Figure 4 would not have the second intumescent layer 14 in contact with the second surface 20 of the cavity. Rather, the layer 16b of the carrier body 16, or put another way the second carrier body 16b, would be in contact with the second surface 20.

[57] Placing the second intumescent layer 14 within the carrier body 16 provides more insulation between the second intumescent layer 14 and a heat source. Thus the second intumescent layer 14 may be delayed in responding to the heat source compared to the above example, and therefore provide a longer duration of both integrity and insulation to the fire barrier.

[58] In further examples consistent with Figure 4, a plurality of intumescent layers and a plurality of carrier body layers may be positioned in sequence. For example, a first intumescent followed by a first carrier body, followed by a second intumescent, followed by a second carrier body, followed by a third intumescent, followed by a third carrier body, and so on. It will of course be appreciated that such a sequence could be terminated at either a carrier body or an intumescent.

[59] Figure 5 shows yet another example multi-layer VFB consistent with the present disclosure, whereby the first and second intumescent layers 12, 14 are different sizes (or dimensions). In this example, the second intumescent layer 14 has smaller dimensions than the first intumescent layer 12, in addition to being located within the carrier body 16.

[60] In the example shown by Figure 5, at least part of the second intumescent layer 14 is exposed on the surface 22 furthest from the first intumescent layer 12. Thus, when located within a cavity, both part of the second intumescent layer 14 and the carrier body 16 may be in contact with the second surface 20 of the cavity.

[61] In alternative configurations, not shown, the second intumescent layer 14 may be completely enveloped by the carrier body 16. When positioned within a cavity, the carrier body 16 may be positioned in contact with the second surface 20 of the cavity. The second intumescent layer 14 would still be closer to the second surface 20 of the cavity than the first intumescent layer 12.

[62] The example of Figure 5 provides additional shielding to the second intumescent layer 14 through the insulation provided by the additional carrier body material. Therefore the intumescent layer 14 may be further delayed in responding to a heat source.

[63] Figure 6 shows a further arrangement of the multi-layered fire barrier, consistent with the present disclosure, whereby the second intumescent layer is comprised of a plurality of segments. In this example, the second intumescent layer 14 is split into two segments 14a, 14b, or may be considered two separate layers 14a, 14b. The two segments 14a, 14b are displaced, or separated, from one another by a distance ‘D’.

[64] In the example of Figure 6, the second intumescent layer 14 is equivalent in volume to the second intumescent layer 14 in Figure 4, but split into two equal portions 14a, 14b. The two segments 14a, 14b may be positioned within the carrier body 16, similar to the arrangement shown in Figure 4, such that the carrier body 16 may be considered to be formed of two layers 16a, 16b. In this example the two carrier body layers 16a, 16b would be in contact along the imaginary line defining the distance ‘D’, rather than completely separated by the second intumescent layer 14.

[65] When positioned within a cavity, the carrier body layer 16b would be in contact with, or proximate to, the second surface of the cavity 20. The segment 14a of the second intumescent layer may also be considered to be arranged above the segment 14b. In an alternative example, not shown, the segment 14b of the second intumescent layer may be at least partially in contact with the second surface of the cavity 20 in a similar arrangement to that shown in Figure 5.

[66] The example of Figure 6 may extend the integrity and insulation of the multi-layered fire barrier by further delaying the time before breakdown. This is because the segment 14b will react to a heat source, which is assumed to be below the fire barrier, before the segment 14a. Thus the first intumescent layer will react first to a fire, followed by the segment 14b of the second intumescent layer, followed by the segment 14a of the second intumescent layer, and therefore integrity will be maintained for longer.

[67] Referring to Figures 7A and 7B of the accompanying drawings, in Figure 7A a multilayered VFB 30 in a passive (no fire) configuration and Figure 7B shows the VFB 30 in an active (fire present) configuration when mounted in a cavity wall construction as shown.

[68] In Figure 7A, the VFB 30 comprises a first intumescent layer 31 and a second intumescent layer 34 with a carrier body layer 36 therebetween. The first and second intumescent layers 32, 34 are formed from a uni-directional intumescent material such as TENMAT FF102 or TENMAT FF107 both available from Tenmat Limited of Ashburton Road West, Trafford Park, Manchester M17 1RU, United Kingdom. The carrier body layer is comprised of a mineral wool. The VFB 30 is impaled by a mounting means in the form of an Lshaped spike bracket 38 which is secured to an external wall 40 of a building by screws or nails 42 with the VFB 30 spaced from an internal wall 44 providing an air gap 46 for ventilation.

[69] The cavity wall contains insulation 48 on the external wall 40 other than where the VFB is located.

[70] Figure 7B shows the outcome of the effect of a fire on the VFB 30. As can be seen, the first intumescent layer 32 expands and compresses the carrier body layer 36. As a result, the carrier body layer 36 is pushed along the bracket 38, moving the second intumescent layer 34 towards the internal wall 44. The second intumescent layer 44 expands as a result of the heat from the fire and fills the gap 46 between the VFB 30 and the internal wall 44, thus providing a fire barrier.

[71] It will be appreciated that the VFB 30 can be configured according to other embodiments described herein.

[72] In summary, examples of a multi-layered VFB have been described. The described embodiments provide for an improved fire barrier by extending the time before a breakdown of the fire barrier occurs. In particular, the present disclosure addresses issues caused by shrinkage of a carrier body in a ventilated fire barrier.

[73] The multi-layered VFB may be manufactured industrially. An industrial application of the example embodiments will be clear from the discussion herein.

[74] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[75] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[76] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[77] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A multi-layered ventilated fire barrier, comprising:

a first intumescent layer;

a second intumescent layer; and a carrier body between the first intumescent layer and the second intumescent layer.

2. The ventilated fire barrier of claim 1, wherein first intumescent layer is in contact with a surface of the carrier body.

3. The ventilated fire barrier of claim 1 or claim 2, wherein the second intumescent layer is in contact with a surface of the carrier body.

4. The ventilated fire barrier of any preceding claim, wherein the second intumescent layer is located within the carrier body.

5. The ventilated fire barrier of any preceding claim, wherein the first intumescent layer and second intumescent layer are aligned with each other.

6. The ventilated fire barrier of any preceding claim further comprising a shell.

7. The ventilated fire barrier of claim 6, wherein the first intumescent layer, second intumescent layer and carrier body are enclosed by the shell.

8. The ventilated fire barrier of claim 7, wherein at least one wall of the shell is configured to be openable.

9. The ventilated fire barrier of any preceding claim, wherein the first and second intumescent layers have different dimensions.

10. The ventilated fire barrier of any preceding claim, wherein the second intumescent layer comprises a plurality of segments.

11. The ventilated fire barrier of claim 10, wherein the plurality of segments of the second intumescent layer are displaced from one another.

12. The ventilated fire barrier of any preceding claim, wherein the first intumescent layer and second intumescent layer are comprised of a thermally reactive material.

13. The ventilated fire barrier of claim 12, wherein the first intumescent layer and second intumescent layer are comprised of the same thermally reactive material.

14. The ventilated fire barrier of any preceding claim, in which the first intumescent layer and/or the second intumescent layer is or are comprised of a uni-directional intumescent material.

15. The ventilated fire barrier of any preceding claim, further comprising a mounting means for mounting the ventilated fire barrier to a wall.

16. The ventilated fire barrier of any preceding claim, wherein the carrier body comprises a thermally stable material.

17. The ventilated fire barrier of claim 16, wherein the thermally stable material is comprised of mineral fibres.

18. The ventilated fire barrier of claim 17, wherein the mineral fibres are comprised of mineral wool.

19. The ventilated fire barrier of claim 17, wherein the mineral fibres are comprised of glass wool.

20. A cavity comprising the multi-layered ventilated fire barrier of any preceding claim, wherein:

the first intumescent layer is positioned proximate to a first surface of the cavity, and the second intumescent layer is positioned proximate to a second surface of the cavity.

21. The cavity of claim 20, whereby the first intumescent layer is arranged to react first in response to a heat source, and the second intumescent layer is arranged to react second in response to the same heat source.

22. The cavity of claim 20 or claim 21, wherein the first intumescent layer is positioned such that there is a gap between the first intumescent layer and the first surface of the cavity.

23. A method of construction of a cavity according to any single one of claims 20, 21 or 22.

24. A cavity wall comprising the multi-layered ventilated fire barrier of any single one of claims 1 to 19, wherein:

the first intumescent layer is positioned proximate to a first surface of the cavity wall, and the second intumescent layer is positioned proximate to a second surface of the cavity wall.

25. A method of construction of a cavity wall according to claim 24.