AU2021309129A1

AU2021309129A1 - An improved fire collar

Info

Publication number: AU2021309129A1
Application number: AU2021309129A
Authority: AU
Inventors: David DENOVAN
Original assignee: IG6 Pty Ltd
Current assignee: IG6 Pty Ltd
Priority date: 2020-07-14
Filing date: 2021-07-14
Publication date: 2023-03-09
Also published as: WO2022011419A1

Abstract

This invention relates to a fire collar (10) that can be located in a circular, or generally circular shaped, penetration in a concrete wall. The fire collar (10) includes a metal housing (11) having an open ended bore that includes a first opening (17) and a second opening (23) that is spaced from said first opening. The bore is adapted to receive a conduit that extends through both the first and second openings and from one side of the wall to the other side of the wall. The fire collar (10) includes one or more mountings (25) that extend outwardly away from one end of the housing, adjacent the first opening, for supporting said housing in the penetration. The fire collar (10) also includes a layer or a segment of intumescent material (60) located within the bore and connected to the housing and actuating means (34) operatively connected to said housing and located within the bore for movement from a non-operating mode proximal to said intumescent material to an operating mode in which said actuating means shall move at least a portion of said intumescent material generally towards the conduit.

Description

AN IMPROVED FIRE COLLAR

This invention relates to fire collars.

This invention has particular, but not exclusive application, to drop in fire collars and wherein reference will be made to same. However, it will be appreciated that at least some aspects of this invention are applicable to other types of fire collars, including cast-in fire collars.

Fire collars are typically used for preventing fire spreading from one side of a wall or floor to the other side via a penetration through which pipes, ducts or other service carriers pass.

Possibly one of the more important uses of fire collars is with conduits, particularly pipes and ducts, which are formed from plastics materials, such as, PVC and HDPE, but they are also used with rubber based materials, deformable metals and various composite materials.

Drop in fire collars are typically used to prevent the spread of fire through a penetration in concrete walls where it is not possible to use a cast-in fire collar, such as thin concrete floors and trapezoidal steel tray concrete floors having an underside which includes a plurality of ribs that are separated from one another by a respective valley.

Because drop in fire collars will not be embedded in concrete, they are typically made of metal, such as stainless steel. One known type of drop in fire collar comprises a metal, generally cylindrically shaped, housing having an open ended passage that resembles a bore, that is adapted to be dropped into an opening that has been created in a wall, said bore being adapted to receive a conduit that in use shall extend through the opening in the floor.

The housing further includes a plurality of equi- angularly spaced mounting tabs that each extend outwardly from an upper end portion of the housing and which in use shall engage a lip that surrounds the opening. Further, the mounting tabs typically include a mounting aperture through which a threaded fastener, that is used to secure the fire collar to the lip, may extend.

The bore typically includes a liner consisting of a layer of an intumescent material which is secured to a side wall of the bore and whereby, in the event of a fire on one side of the wall, the intumescent material expands when the temperature of the air in the vicinity of the opening reaches a predetermined level. As the intumescent material expends, it comes into contact with the conduit and either forces the conduit to collapse or pinches it off, thereby inhibiting the spread of the fire.

One problem with drop in fire collars of the type described above is that the time taken for the intumescent material to seal off the void left by a melted conduit can be too long in rapidly advancing fires which may result in fire or poisonous gases penetrating the wall.

1 It has also been observed that the intumescent material used in the construction of fire collars is not a good conductor of heat. Further, it has also been observed, where there is a high volume of smoke, the intumescent material tends to be slow to expand.

It is therefore an object of the present invention to provide a fire collar which will alleviate at least some of the disadvantages of the prior art.

With the foregoing and other objects in view, this invention relates to a fire collar that can be located in a circular, or generally circular, shaped penetration in a concrete wall, said fire collar including: a metal housing having an open ended bore that includes a first opening and a second opening that is spaced from said first opening, said bore being adapted to receive a conduit that extends through both said first and second openings and from one side of the wall to the other side of the wall; one or more mountings that extend outwardly away from one end of said housing, adjacent said first opening, for supporting said housing in the penetration; a layer or a segment of intumescent material located within said bore and connected to said housing in a manner whereby it does not prevent the location of the conduit in said bore, and actuating means operatively connected to said housing and located within said bore for movement from a non-operating mode proximal to said layer of intumescent material to an operating mode in which said actuating means shall move at least a portion of said layer of intumescent material generally towards the conduit.

1 Preferably the periphery of the housing, or a substantial portion of the periphery of the housing, is capable of forming a close fit with the penetration whereby in use little, if any, hot gases or flames may pass therebetween.

Preferably the actuation means is actuated by the surrounding temperature having reached a predetermined level.

The housing may be substantially cylindrical in shape and includes a generally cylindrically shaped bore. Further, preferably the first and second openings are coaxial.

The housing may include a first portion and a second portion and wherein the external diameter of the first portion may be greater than the external diameter of the second portion and wherein the periphery of the first portion in use shall form a close fit with the penetration. Further, the second portion may be provided with one or more recesses formed in a side wall thereof and wherein a each recess shall be used to house a respective actuation means. Further, it is preferred that the external diameter of the side wall of the recess is the same or smaller than the external diameter of the first portion.

The mountings may be integral with the housing or attached thereto, and each may include a mounting aperture through which the shank of a threaded fastener, used to secure the fire collar to a lip surrounding the penetration, may extend.

1 Preferably the actuation means includes a contactor which is adapted to move in a plane extending longitudinally through the bore relative to the conduit and to engage (directly or indirectly) an outer face of the layer or segment of intumescent material, being the face of the material that is adjacent the side wall. It is also preferred that the contactor move in a plane containing the longitudinal axis of the conduit or a plane close to that plane.

The contactor may be elongate and may make contact with the intumescent material over a substantial longitudinal distance relative to the conduit thus being positioned to force a substantial portion of the intumescent material into an obstructing position within the bore.

Alternatively, the contractor may be configured such that it will make contact with the intumescent material over a broad area.

Alternatively, the contactor may be broad and may make contact with the intumescent material over a broad area relative to the conduit thus being positioned to force a substantial portion of the intumescent material into an obstructing position within the bore.

Alternatively, the contactor may be both elongate and broad.

Preferably the actuating means is a torsion spring having a body, consisting of a plurality of helical coils, and two legs that extend outwardly away from opposite ends of the

1 body. Preferably, one leg of the torsion spring is the contactor, or is connected to the contactor.

Preferably the torsion spring is mounted within the bore. For example, the housing may include a recess formed in a side wall that is adapted to receive the torsion spring as previously described above.

The leg of the torsion spring that is required to move from a non-operational position to an operational position may be retained in its non-operational position by a sacrificial component, such as a fusible link connecting the leg to the other leg of the torsion spring, and whereby destruction of the sacrificial component will allow the leg to move in the direction of the intumescent material and thereby force it across the bore. In one such form, the axis of the body of the torsion spring is parallel to a tangent to the outer surface of the conduit extending through the bore in the case of a cylindrically shaped conduit and parallel to a side wall of the conduit in the case of a polygonal conduit.

Typically, the fusible link is formed from a plastics material which softens to a fusible state upon the ambient temperature reaching a predetermined temperature at which the spring forces that are urging the legs to splay apart shall cause it to break. In such form, the fusible link holds the leg of the spring in the "loaded" position, that is in a position with the spring wound sufficiently to apply a suitable force to the intumescent material.

Preferably the fire collar includes a plurality of actuation means and wherein the actuation means may be equi- angularly spaced around the bore of the fire collar.

1 Preferably, a layer of protective material extends about the layer or segment of intumescent material to protect it from damage by the actuation means as it softens pursuant to an increase in temperature. Thus, reference to engagement of the intumescent material by the actuating means is to be understood as encompassing engagement with a layer of the other material which might be interposed between the actuation means and the intumescent material, for example a layer of stainless steel gauze or fibreglass cloth.

Preferably, the layer of intumescent material is generally cylindrical in form and arranged so as to closely fit around the conduit which is to pass therethrough. In such form, it is preferred that the collar also include retaining means for retaining the cylindrical layer of intumescent material at one end in position or alternatively that it be secured to the mounting and be free at the other end whereby the actuating means can force the layer to collapse over the bore from the free end. Further, if desired, the layer of intumescent material may be constituted by a plurality of layers or segments.

Preferably, the actuation means is supported within the bore by the mounting means and wherein the mounting means may further include retaining means for retaining the layer of intumescent material in a preferred position within the bore.

In still yet another embodiment, this invention relates to a fire collar that can be located in a circular, or generally circular shaped, penetration in a concrete wall, said fire collar including:

1 a metal housing having an open ended bore that includes a first opening and a second opening that is spaced from said first opening by at least one side wall, said bore being adapted to receive a conduit that extends through both said first and second openings and from one side of the wall to the other side of the wall; one or more mountings that extend outwardly away from one end of said housing, adjacent said first opening, for supporting said housing in the penetration; a layer or a segment of intumescent material contained within said bore, adjacent said second opening, and supported in said bore by retaining means, said intumescent material having an inner face that faces the interior of said bore and an outer face that faces said side wall, said layer of intumescent material being spaced from said side wall by spacing means such that there is provided a gap between said side wall and said outer face, whereby in use hot gases created by a fire may enter said bore via said second opening and wherein some of those hot gases may circulate within said gap.

Preferably there exists at least one gap, or a plurality of gaps, between the side wall and the outer face of the intumescent material, whereby hot gases may pass over much, if not all, of the outer face of the layer of intumescent material.

Further, the gap may have a first end having an opening through which gases may enter the gap and a second end that is generally opposite the first end, and wherein the second end may be closed or, if it is open, the opening may be quite narrow so as to inhibit gases escaping therethrough.

1 The layer of intumescent material may include one or more discrete segments and wherein the segments may be secured within the bore so that they form a substantially continuous wall of intumescent material. Preferably, the fire collar includes a segment of intumescent material that is formed into a cylinder having an inner face and an opposing outer face.

The outer face of the intumescent material is preferably spaced from the side wall by spacing means, such as one or more protrusions that extend away from the side wall in the direction of the bore. For example, the spacing means may include ribs and wherein the ribs may extend partway between the first opening and the second opening. Similarly, the spacing means may include one or more raised wall portions, such as a plurality of knobs. Further, the spacing means may be formed integrally with the side wall.

However, in other embodiments, the spacing means may include the actuation means or a part thereof. Alternatively, the spacing means may include the retaining means.

The fire collar may also include actuating means operatively connected to said housing and located within said bore for movement from a non-operating mode proximal to said layer of intumescent material to an operating mode in which said actuating means shall move at least a portion of said layer of intumescent material generally towards the conduit.

Preferably the actuation means includes a contactor which is adapted to move in a plane extending longitudinally through the bore relative to the conduit and to engage

1 (directly or indirectly) the outer face of the layer or segment of intumescent material. It is also preferred that the contactor move in a plane containing the longitudinal axis of the conduit or a plane close to that plane.

Alternatively, the contactor may be both elongate and broad.

Preferably the actuating means is a torsion spring having a body, consisting of a plurality of helical coils, and two legs that extend outwardly away from opposite ends of the body. Preferably, one leg of the torsion spring is the contactor, or is connected to the contactor.

1 Preferably the torsion spring is mounted within the bore. For example, the housing may include a recess formed in a side wall that is adapted to receive the torsion spring.

The leg of the torsion spring that is required to move from a non-operational position to an operational position may be retained in its non-operational position by a sacrificial component, such as a fusible link connecting the leg to the other leg of the torsion spring, and whereby destruction of the sacrificial component will allow the leg to move in the direction of the intumescent material and thereby force it across the bore. In one such form, the axis of the torsion spring is parallel to a tangent to the outer surface of the conduit extending through the bore in the case of a cylindrically shaped conduit and parallel to a side wall of the conduit in the case of a polygonal conduit.

Typically, the fusible link is formed from a plastics material which softens to a fusible state upon the ambient temperature reaching a predetermined temperature at which the spring causes it to break. In such form, the fusible link holds the leg of the spring in the "loaded" position, that is in a position with the spring wound sufficiently to apply a suitable force to the intumescent material.

Preferably, the layer of intumescent material is retained in a preferred position, namely spaced from the side wall, at

1 its upper end by said retaining means and at its lower end by said fusible link.

The terms "upper", "lower", "side" and similar terms are used herein for the purpose of describing the invention in its normal in use position in a building floor unless the context clearly indicates another meaning and are not intended to limit the invention to use in any particular orientation and it is to be understood that the invention could be used in floors, walls, ceilings and other barriers of various types and orientations. It is also to be understood that the term "longitudinal" used herein refers to the direction of a conduit as it passes through a fire collar according to the invention unless the context clearly indicates another meaning.

In order that the invention may be more easily understood and put into practical effect, reference will now be made to the accompanying drawings wherein:

Fig. 1 is a pictorial view of a fire collar constructed in accordance with the present invention;

Fig. 2 is a plan view of the fire collar illustrated in Fig 1;

Fig. 3 is a cross-sectional side view of the fire collar illustrated in Fig. 1 along line Q-Q, and Fig. 4 is a pictorial view of mounting means, actuation means and retaining means of the fire collar illustrated in Fig. 1.

1 The fire collar 10, illustrated in Figs 1 to 4, includes a generally cylindrically shaped housing 11 constructed from a sheet of pressed metal, such as stainless steel.

The housing 11 includes a cylindrically shaped upper portion 12 and a generally cylindrically shaped lower portion 13, and wherein the diameter of the upper portion is larger than that of the lower portion, and wherein the upper portion is connected to the lower portion by a plurality of eqi- angularly spaced, inwardly extending, ledges 14.

The upper portion 12 includes a continuous side wall 15 and wherein an upper portion 16 of the side wall 12 defines an upper or first opening 17.

The lower portion 13 includes a curved side wall 18 punctuated by four equi-angularly spaced recess 19, each comprising two outwardly extending, opposed, side walls 20 that are connected by an intermediate rear wall 21 that is flush with side wall 15.

A lower portion 22 of the side wall 18 generally defines a lower or second, substantially circular shaped, opening 23, and wherein the side walls 15 and 18 in combination define a bore 24 extending between openings 17 and 23.

The fire collar 10 also includes mounting means for mounting the fire collar relative to a penetration in a wall, including four mounts 25, (see Fig. 4), each manufactured from a sheet of pressed metal, such as stainless steel. The mounts 25 each include a substantially straight, generally rectangularly shaped, mounting portion 26, having an upper end

1 portion 27 and a lower end portion 28, and a mounting face 29 on one side thereof.

Each mount 25 also includes a flange 30 that extends outwardly away from the upper portion 27 of the mounting portion 26, and on the same side of the mounting as the mounting face 29, said flange 30 being generally orthogonal to a plane containing the mounting face 29. Each flange is provided with an elongate mounting aperture 31.

Each mount 25 also includes a ledge 32, which extends outwardly from the lower end portion 28 of the mounting portion 26, and on an opposite side of the mounting portion to the mounting face 29. Further, the ledge 32 is generally parallel to the flange 30.

Each mount 25 further includes support means 33 for supporting a respective actuation means 34. The support means 33 includes a curved wall 35 that is connected to, and which extends tangentially away from, the ledge 32 in a generally downward direction. The curved wall 35 has a generally semi circular shaped transverse cross-section and includes a generally rectangularly shaped tab 36, which during manufacture has been punched out of the curved wall 35. The tab 36, which extends tangentially from the curved wall 35 in a generally downward direction, is substantially parallel to the mounting portion 26, and includes a free or distal end portion 37. Further, the curved wall 35 is not as wide as the ledge 32, as can be seen in Figs 1 and 4.

The actuation means 34 includes a torsion spring 38 having a body 39 consisting of a plurality of helically wound

1 coils 40 and two opposing legs 41 and 42, each having a curved connecting portion 43 and 44 respectively, that extends downwardly and away from the last coil at respective ends of the body 39, and whereby in use the connecting portions 43 and 44 are located on opposite sides of a substantially vertical plane containing a longitudinal axis of the body.

The first leg 41 includes a first bend 45, located at an end of the connecting portion 43 and generally adjacent one end 39a of the body 39, and a second bend 46, and wherein the bends are connected by an intermediate portion 47 that extends generally away from the end 39a and terminating approximately in line with the middle of the body 39. Further, the obtuse angles of both bends are substantially the same such that a contact portion 48 of the first leg 41, consisting of a substantially straight, generally elongate, portion thereof, extends away from the body in a direction that is generally orthogonal to the longitudinal axis of the body, and which is contained in the same plane as the intermediate portion and the two bends.

The second leg 42 includes a first bend 49 , located at an end of the connecting portion 44 and generally adjacent an end, (not shown), that is opposite to end 39a of the body 39, and a second bend 50, and wherein the bends are connected by an intermediate portion 51 that extends generally away from the end of the body 39 and terminating approximately in line with the middle of the body 39. Further, the obtuse angles of both bends are substantially the same such that an elongate lower portion of the leg 42 extends away from the body in a direction that is generally orthogonal to the longitudinal axis of the body, and which is contained in the same plane as

1 the intermediate portion and the two bends. Further, the lower portion 52 is parallel to the contact portion 48 of the first leg, and wherein the lower portion 52 and the contact portion 48 are contained in a plane that is substantially orthogonal to the longitudinal axis of the body 39.

The two legs 41 and 42, which have a tendency to splay apart, are retained in this "non-operative" position by a fusible link 53 that is connected to the two distal end portions 54 and 55 thereof and is retained in place by a small bend 56 in the distal end portion 54. Further, the link 53 includes an outwardly extending flange 57 and a, generally upwardly pointing, barb 58.

The mounting face 29 of each mount 25 is secured to an inner face of side wall 15, such as by welding, whereby the flange 30 extends outwardly away from the housing 11 and generally is orthogonal to the side wall 15 and whereby the support means 33 is located generally in front of a respective recess 19 and spaced away from the wall 15 by the ledge 32.

A torsion spring 38, in its "non-operational" position, is then located in each one of the recesses 19 and supported therein by the body 39 that rests on a curved wall 35.

Finally, a layer of intumescent material of known type, typically neoprene based or high density polypropylene, formed into a cylinder 60 and enclosed by an outer layer of stainless steel gauze, is fitted within the lower portion 13 of the housing 11 adjacent the inner face of the side wall 18. In this particular embodiment, the intumescent material and the surrounding gauze is retained in place by wedging the upper

1 edge portion 61a, of cutaways 66, between a distal end 37 of a respective tab 36 and a lower outer portion of an adjacent curved wall 35, while the lower edge 62 rests on a flange 57 of a respective fusible link 53 and by embedding a barb 58 into a lower edge portion of the intumescent material.

Thus, there is created a gap between the inner face 64, of side wall 13, and the outer face 65, of the intumescent material 60.

In use, the fire collar 10 may be located within a penetration in a wall, such as a floor or a ceiling, and wherein the collar 10 may be supported in the penetration by the mounts 25 resting on a portion of the wall that surrounds the penetration. Further, the collar 10 may be secured to the wall using one or more threaded fasteners that extend through a respective mounting aperture 31.

Preferably the penetration is circular, or generally circular in shape, and wherein the cylindrically shaped upper portion 12 and the penetration form a close fit.

A conduit, not shown, may then be positioned such that it extends through the bore 24 of the collar 10, and wherein a suitable mortar may be used to fill the annualar gap that exists between the external wall of the conduit and say the interior face of the side wall 12, in the vicinity of the opening 17.

In the event of a fire in close proximity to the fire collar 10, the ambient air increases in temperature and causes the fusible link 53 to soften, and then break, under the

1 spring force of the torsion spring 38 (or alternatively it melts) whereupon the spring is released and the elongate portion 52 of the second leg 42 bears against the rear wall 21 while the contact portion 48 of the first leg 41 bears against the gauze and through the gauze the intumescent material 60, thereby forcing the gauze and the intumescent material encased thereby inwards towards the longitudinal axis of the passage 24.

Further, it will be appreciated that the intumescent material 60 will both soften and expand quickly due to a rise in the temperature of the material caused at least in part by hot gases passing over both the inner and outer faces of the intumescent material. In this regard, it is believed that some of the hot gasses entering the opening 23 will pass over the inner face 66 of the intumescent material, being gases that are permitted to circulate within the lower part of the collar 10, in particular, between the conduit and the inner face 66, (as generally indicated by arrows 67), while other hot gases will pass over the outer face of the intumescent material, being gases that are circulating in the gap that exists between the side wall 18 and the outer face 65 of the intumescent material, (as generally indicated by arrows 68).

Depending on the depth of the penetration and the height or axial length of the fire collar, it is envisaged that in some instances some hot gasses may become trapped between a side wall of the penetration and side wall 18 and that heat from these hot gases may be transferred to the interior of the fire collar and in turn may also assist in speeding up the softening of the intumescent material.

1 It will also be appreciated that the conduit will have softened coincidentally and may have even burned to an extent allowing the legs 41 in combination to crush it inwards while forcing the intumescent material into the passage or at least into engagement with the crushed pipe. It will be appreciated that as the intumescent material increases in temperature, it will expend and fully close the passage 24 thereby preventing the egress of smoke and poisonous gases from the site of the fire.

Advantageously, the stainless steel gauze also assists the operation of the fire collar in directing expansion of the intumescent material inwards rather than outwards which in turn assists in forcing the collapse of the conduit or pipe therein.

The foregoing description has been given by way of illustrative example of the invention and many modifications and variations which will be apparent to persons skilled in the art may be made without departing from the spirit and scope of the invention as defined in the appended claims.

1

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A fire collar that can be located in a circular, or generally circular shaped, penetration in a concrete wall, said fire collar including: a metal housing having an open ended bore that includes a first opening and a second opening that is spaced from said first opening, said bore being adapted to receive a conduit that extends through both said first and second openings and from one side of the wall to the other side of the wall; one or more mountings that extend outwardly away from one end of said housing, adjacent said first opening, for supporting said housing in the penetration; a layer or a segment of intumescent material located within said bore and connected to said housing in a manner whereby it does not prevent the location of the conduit in said bore, and actuating means operatively connected to said housing and located within said bore for movement from a non-operating mode proximal to said intumescent material to an operating mode in which said actuating means shall move at least a portion of said intumescent material generally towards the conduit.

2. A fire collar as claimed in claim 1, wherein the periphery of said housing, or a substantial portion of the periphery of said housing, is capable of forming a close fit with the penetration whereby in use little, if any, hot gases or flames may pass therebetween.

3. A fire collar that can be located in a circular, or generally circular, shaped penetration in a concrete wall, said fire collar including: a metal housing having an open ended bore that includes a first opening and a second opening that is spaced from said first opening by at least one side wall, said bore being adapted to receive a conduit that extends through both said first and second openings and from one side of the wall to the other side of the wall; one or more mountings that extend outwardly away from one end of said housing, adjacent said first opening, for supporting said housing in the penetration; a layer or a segment of intumescent material contained within said bore, adjacent said second opening, and supported in said bore by retaining means, said intumescent material having an inner face that faces the interior of said bore and an outer face that faces said side wall, said layer of intumescent material being spaced from said side wall by spacing means such that there is provided a gap between said side wall and said outer face, whereby in use hot gases created by a fire may enter said bore via said second opening and wherein some of those hot gases may circulate within said gap.

4. A fire collar as claimed in claim 3, wherein the periphery of said housing, or a substantial portion of the periphery of said housing, is capable of forming a close fit with the penetration whereby in use little, if any, hot gases or flames may pass therebetween.

5. A fire collar as claimed in claim 3, wherein said fire collar further includes actuating means operatively connected to said housing and located within said bore for movement from a non-operating mode proximal to said intumescent material to an operating mode in which said actuating means shall move at least a portion of said intumescent material generally towards the conduit.

6. A fire collar as claimed in claim 1 or claim 5, wherein said actuation means includes a contactor which is adapted to move in a plane extending longitudinally through said bore and wherein the contactor shall engage said outer face of said intumescent material either directly or indirectly.

7. A fire collar as claimed in claim 6, wherein said contactor is elongate and, in use, shall make contact with said intumescent material over a substantial longitudinal distance and thereby force a substantial portion of said intumescent material into an obstructing position within said bore.

8. A fire collar as claimed in claim 6, wherein said contactor is broad and, in use, shall make contact with said intumescent material over a broad area and thereby force a substantial portion of said intumescent material into an obstructing position within said bore.

9. A fire collar as claimed in any one of claims 6 to 8, wherein said actuating means is a torsion spring having a body, consisting of a plurality of helical coils, and a first leg and a second leg that both extend outwardly away from opposite ends of said body.

10. A fire collar as claimed in claim 9, wherein said second leg is said contactor.

11. A fire collar as claimed in claim 9 or claim 10, wherein said torsion spring is retained within a recess of said housing.

12. A fire collar as claimed in claim 10, wherein said torsion spring is supported in said recess by one of said mountings.

13. A fire collar as claimed in claim 11, wherein said mounting means is employed to retain said intumescent material within said housing.

14. A fire collar as claimed in any one of claims 9 to 11, wherein said second leg, in use, is required to move from a non-operational position to an operational position and wherein said second leg is retained in its non-operational position by a fusible link connecting it to said first leg.