GB2216220A - Fire damper sleeves - Google Patents

Abstract

A fire damper 10, 16 for sealing, in the event of fire, a penetration 12, 18 in a fire-resistant wall 14 for the passage of a service 11, 17 e.g. pipe or cable comprises a number of segments 19,32 each consisting of strips 20, 36 of intumescent material contained in a sheath 22, 34 of extruded PVC. Each segment 19 is adhered to an outer foil 24 and inner foil 26, and each segment 32 to an outer foil 38. End plates are secured to the wall 14 by expansion bolts. Many alternative forms of intumescent material, segments, sheaths and attachment means are described. <IMAGE>

Description

FIRE DAMPER SLEEVES This invention relates to fire dampers for sealing in the event of fire a service penetration in a fireresistant structure such as a wall or floor, and which may be constructed also to perform a pipe closing function.

Where an electrical or mechanical service penetrates a fire-resistant structure there is a need for the penetration to be fire-protected or sealed in the event of a fire, and fire damper/pipe closure devices have been available on the market for some time to fulfil this need: examples are the subject of our UK Patents No. 2 077 382B and 2 111 624B. In general these devices incorporate intumescent material within a metal canister which provides mechanical and possibly chemical protection to the intumescent core, and in the event of a fire directs the expansion and pressure (depending on whether a pressure or non-pressure developing intumescent material is used), inwardly towards the service to be sealed.Plastic inner liners, silicone rubber or epoxy resin have been applied to the intumescent material to protect it from chemical attack, mainly by water and atmospheric carbon ~ dioxide, and also to provide a degree of mechanical protection to the inner face of the device. One manufacturer also coats the outside of the canister with an intumescent paint which will expand outwardly in the event of fire to seal any small gaps which may occur between the canister and the penetration and which thus present a weakness.

The intumescent coating is vulnerable to mechanical and chemical damage which is likely to occur on a building site, prior to installation of the device in a fireresistant structure.

There is also known an array of parallel intumescent strips which are taped together side-by-side and enclosed in a polyethylene bag. In use the wrapped strips are wound round the pipe to the desired thickness, secured by adhesive tape and then slid along the pipe to lie within the penetration. This system of sealing has the disadvantage that the ends of the strips are not sealed, that the strips and protective bag do not afford adequate protection against mechanical damage; and that, as there is no inherent structural control, the system is therefore very subject to operator error.

It is an aim of the present invention to provide a construction of fire damper in which the intumescent material is adequately protected against mechanical damage; allows the material to be protected, if necessary, from moisture and atmospheric carbon dioxide; and can be simply and easily installed in a precise manner.

According to the present invention there is provided fire damper for sealing in the event of fire a penetration formed in a fire-resistant structure to allow the passage of a service, the damper comprising a number of segments, each comprising a core of intumescent material and a protective sheath, and attachment means for forming the segments into a sleeve surrounding the service. Preferably the fire damper also comprises end plates which overlie the surface of the structure around the penetration and cover the ends of the sleeve.

According to the present invention there is further provided a kit of the foregoing components for assembly into a sleeve around a service to form a fire damper.

The conventional dampers which include a canister require back filling with concrete or mortar to seal the gap between the canister and the structure, which is a labourintensive operation and often not done satisfactorily.

Where the canister is coated with intumescent material the amount of intumescent material is enough to seal a gap of 1-2 mm only which is usually inadequate.

The damper of the present invention may be constructed so that the intumescent material may expand not only inwardly but also outwardly so that it is capable of both sealing large gaps around the outside of the sleeve and sealing around a service as in the case of metal pipes or crushing the service (providing a pressuregenerating intumescent material is used, as in the case of plastics pipes or ductwork. This means that a damper according to the present invention can be applied around a service in a hole considerably larger in diameter (in practice up to 5 mm more or even more) than the damper.

The amount of intumescent material incorporated must of course be sufficient also to seal the void on the outside of the sleeve and thus more intumescent material is required than in a conventional damper in which expansion is directed only inwardly.

The advantage. of the above-described type of damper according to the present invention is that installation can be carried out in a fraction of the time required by conventional back-filling techniques and using unskilled or semi-skilled labour.

The construction according to the present invention not only provides adequate fire resistance but also allows fulfilment of the insulation requirement of the Building Regulations and of British Standards relating to the fire-resistance of elements of constructions that the temperature on the unexposed face of the element does not rise more than 1800C above ambient temperature. Meeting this insulation requirement is not possible when metal or other high heat transfer materials are incorporated in the design of a damper unit whereby the metal passes through the wall or floor structure from the exposed to the unexposed face.

Where the damper is to be used in a hole which has been accurately drilled through concrete by the use of a diamond drill; it is desired to back fill; the installation is in a hollow structure such as a hollow pot floor; or is another location without lateral restriction such as retrofitting underneath an existing floor, the damper preferably comprises an outer container. Preferably the container is formed of two shells which can be secured by a hinge and toggle catch or by straps.

The sleeve may take a variety of forms and be, for example, annular, oblongate or square in cross-section, and need not correspond to the cross-section of the service: an oblongate or square cross-section sleeve may be used to fit around a cylindrical pipe and an annular cross-section around a rectangular duct. The number of segments is desirably kept as small as possible but is generally more than the theoretical minimum of two.

An annular sleeve is usually constituted by a number of segments each of which is a sector of the annulus and thus has two plane lateral faces: the inner and outer surface may be curved or plane (trapezoidal crosssection). A rectangular sleeve is generally formed of rectangular cross-section segments.

Although the sleeve is normally formed of juxtaposed segments there may be discontinuities: for example a rectangular cross-section sleeve may have a pair of opposed sides formed of panels connecting opposed pairs of segments.

The following considerations arise in selecting a material for the sheath:1. Cost effectiveness 2. Ease of production 3. Construction of the damper 4. Handleability and durability of the product on site 5. Service life of the product 6. Heat conductivity of the material 7. Insulative properties of the material 8. Properties of the intumescent materials to be used 9. The need to provide mechanical and/or chemical protection to the intumescent material Whilst a number of different materials may be used for forming the sheath, thermoplastics materials generally offer the greatest advantages and can be combined with metal where added support or improved heat transfer is required.

Thermoplastics sheaths may be formed by extrusion, whereby the tubular sheath produced is open at both ends.

Besides the cross-sections mentioned above the extrusion may be of generally H-section; have the lateral walls formed as bellows; or have common walls so that one extrusion carries a number of cores. The sheaths may also be produced by injection moulding, in which case the sheath will have an end closure moulded in. It is also possible to fabricate by vacuum-forming segments in two or more parts and welding or bonding the parts together, and this technique may also be used for extruded sections.

Again, the sheath may be produced by wrapping and forming the plastics around a mandrel.

From a production point of view, extrusion offers the easiest proposition since the segments can then be cut to any length required. This procedure would not be possible by injection moulding without having an infinite number of (very expensive) moulds.

If thermoplastics extrusion is chosen as the best means of manufacturing the segment sheaths, then unplasticised rigid PVC is the most suitable material to choose, since it is well established in the building construction industry. Moreover, it has a good fire performance and excellent chemical resistance; and - is especially suitable since it has a low gas permeability, particularly to carbon dioxide. Mechanically, it has the advantages of being of good dynamic stiffness, and being selectable to have medium to high impact strength to withstand site handling during installation. Other suitable materials are nylon, polypropylene and poly ethyleneterephthalate: on the other hand metal may be chosen for particular applications especially for an H-section or bellows-type extrusion which allows expansion of the intumescent material.

Whether the ends of the extruded sections have to be sealed or not depends on the intumescent material selected. If water-sensitive or carbon dioxide-sensitive intumescent material, such as that based on hydrated sodium silicate (Palusol from BASF AG) is used then the ends of the sheath should be sealed. Sealing can be effected in the following ways:a) By fitting plastic or metal end caps, either individual caps or common end caps covering a number of segments.

b) By inserting silicone rubber or polysulphide sealant into the ends of the sheaths (or other suitable fire resistant sealant).

If the intumescent material is water- and chemical-resistant, such as that based on vermicular graphite (Intumex L from Chemie Linz AG) then there is no need to seal the ends of the core, but the intumescent inserts must then be bonded or fixed in position to prevent them from falling out prior to installation in the wall or floor structure.

The intumescent material forming the segment cores may be selected from one of the three essential categories of intumescent material, each based on different types of chemical compound, as follows: a) Free-foaming, multi-directionally expanding with high volumetric expansion but non-pressure deve loping; b) Uni-directionally expanding and developing a positive pressure; and, c) Multi-directionally expanding, and developing a high positive pressure with high volumetric expansion.

Although the intumescent material may be in paste, powder or granular form, strip form is generally preferred, a laminate built up of several strips beng particularly preferred. The orientation of the laminate may be important: although type (c) material may be used with the strips set radially or circumferentially, with a type (b) material they must be set circumferentially.

A combination of two or three types of intumescent material may be employed.

The construction of the damper will depend to some extent on the category of the intumescent material selected. With category (a) a container is required to direct the expansion of the product in the right direction.

To allow expansion inwards the sheaths in which the intumescent material is housed will require to be perforated, slotted or contain a mechanical weak point or points on the inner faces thereof so that the intumescent material can expand inwardly towards and around the service. Alternatively, the inner wall may be omitted, provided of course that some other protection is provided for the intumescent core. If the damper is required to expand externally, then the external walls of the segments must also be perforated, slotted or be formed with mechanically weak points through which the intumescent may expand to fill the external void.

Intumescent materials types (b) and (c) develop sufficient pressure to expand and stretch or burst the material from which the hollow profiles are manufactured if they are of low thermal stability such as thermoplastics or composite plastics materials, rubber, paper, cardboard, or composites of plastics material and paper, rubber or cardboard. If the sheaths are produced from a material such as a metal, alloy, ceramic, glass, reinforced cement, glass reinforced polyester or epoxy material, then there must be incorporated mechanically weak points or means to allow the inner, or inner and outer walls to expand to accommodate the expansion of the intumescent material.

The attachment means for attaching a segment to its neighbour may take a great variety of forms the most important of which are listed below: (a) Bonding the juxtaposed lateral faces with adhesive (b) Where the sheath is formed of suitable material, welding the juxtaposed faces using heat, solvent or sonic techniques (c) Interlocking profiles (d) A metal or plastics hinge (e) Flexible plastics connecting web formed by, for example, a hot-melt adhesive or extruded plastics web (f) A metal or plastics backing foil attached to the inner faces of each segment, to the outer faces or to both faces (g) End caps in which the respective ends of the segments are received (h) A combination of two or more of the above-listed forms of attachment means Generally a number of segments are attached together during manufacture and before being placed around the service to form a sleeve. Particularly when the lateral faces are bonded or hinged together the final fixing can be conveniently effected by the use of adhesive tape. However where the attachment means are constituted by interlocking profiles, hinges or common end caps, only the one form of attachment means is necessary and all inter-segmental attachment is performed on site.

The flange plates are usually of metal, for example steel or aluminium, but may equally well be of calcium silicate board, other-non-metallic fire-resistant material, and are fixed to the face of the structure on each side of the aperture to hold the damper in position. The flange plates should either be approximately 5O-lOOmm larger in diameter than the aperture size so that they may be secured by expansion bolts fixed into the structure; or the flange plates should just overlap the edges of the aperture and be securable in position by clips mounted on the back of the flange, which locate against the aperture wall.

In a fire situation on the underside of a floor slab, a damper could fall or drop out due to the thermoplastic nature of the intumescent material at low temperatures i.e. 40-1000C, and in addition due to the pressure developed during expansion. In such a location the metal flanges must hold the damper in position. Metal (mild steel) is the preferred material since it is thin, rigid and strong; can be plated to protect it from corrosion; has good thermal conductivity; and can be easily bolted or clipped in position.

Where the damper is required to be fitted into a hollow pot concrete floor construction, only the type in which outward expansion is restricted should be fitted.

The damper must incorporate a metal container on the outside of the segments or a steel plate immediately inside the outer wall of the sheath of each segment, all intumescent inserts being located on the inside of these steel inserts.

A steel banding strip must be used around the outside of the sleeve and the hole back-filled with concrete.

Steel flange plates must be fixed above and below the floor structure.

In a retrofit situation where upgrading of a building is being carried out it is easier to suspend the intumescent fire damper from the underside of the floor slab or mount it on either side of the wall in which case the damper is constructed with a steel support flange of a diameter approximately 5Omm greater than the overall diameter of the body. This support flange contains holes towards the outside perimeter of the flange, through which steel expansion bolts are passed and secured into the floor slab wall. Steel plates are incorporated just inside the outer wall of the PVC segments. These steel inserts may have flanges at each end which are secured to the support flange and a flange at the other end of the sleeve, for example, by means of pop riveting.Alternatively the insert plates may be flat and the flanges secured together by bolts which pass down through the PVC segments and hold the damper in the longitudinal direction. One or more steel strapping bands are fitted around the unit to secure the sleeve together.

A further alternative is that two semi-cylindrical shells are hinged and fastened together by a toggle to form a canister having a supporting flange at one end and containing the segments forming the sleeve. Again, the body of the canister can be made using two inwardlyprojecting spun metal end half rings of L-section to which the semi-cylindrical shells are attached. The canister is constructed with an outwardly-projecting flange at one end containing holes through which expansion bolts secure it to the structure.

To install a damper according to the invention half shells formed of laterally attached segments are placed around the service and held together by selfadhesive tape of a length greater than the circumference of the sleeve so formed, which is then slid along the service into the penetration. If the segments have interlocking profiles, or hinged shells or straps are employed the sleeve-forming procedure is varied appropriately.

If smoke sealing of the penetration is required, this is achieved by ramming the gap with rockwool or similar fibrous inorganic material; stuffing the gap with a fire-resistant foam material; or sealing underneath the support flanges with silicone rubber or similar mastic, or by incorporating a flexible gasket underneath the support flanges and between the flange and the fireresistant structure.

Some embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which Fig. 1 is an isometric view, partly broken away, of a wall having two service penetrations fitted with typical forms of fire damper according to the present invention; Fig. 2. is a detail of Fig. 1, showing the arrangement of segments in the upper fire damper; Fig. 3 is a view corresponding to Fig. 1, but taken from the other end, showing the arrangement of segments in the lower fire damper; Figs. 4 to 9 are each an isometric view of part of an end of a sleeve in position around a pipe and showing different forms of segment; Figs. 10 to 14 are each an isometric end view of further forms of segments; Figs. 15 to 19 are each an isometric view of various forms of damper according to the present invention;; Figs. 20 and 21 are each an exploded isometric view of end portions of further forms of damper according to the invention; Fig. 22 is an isometric exploded view of a complete damper, being a modification of the type shown in Figs.

20 and 21; Fig. 23 is an isometric view, partly broken away, of a damper according to the invention retrofitted to the underside of a floor; Fig. 24 is an isometric view of a further form of damper of the type shown in Fig. 23; Fig. 25 is an exploded isometric view of a yet further embodiment of a damper according to the invention; and Fig. 26 shows a set of dampers of Fig. 25 laid out flat.

As shown in Fig. 1 an upper, cylindrical fire damper 10 according to a first embodiment of the invention is fitted around a pipe 11 passing through a penetration 12 in a wall 14, and a lower, square-section fire damper 16 is fitted around a duct 17 passing through a penetration 16 The damper 10 comprises a number of segments 19 each consisting of strips of intumescent material 20 contained in a sheath 22 of extruded PVC. The outer and inner surfaces of the sheaths 22 are adhered respectively to an outer plastics (or metal) foil 24 and a similar inner foil 26 as shown in more detail in Fig. 2. Alternatively the sheaths 22 may be adhered only to an outer foil or only to an inner foil. After the foil-mounted segments 19 have been placed around the pipe 11 the segments are secured by a tape 27 and slid into position.

Semi-annular end plates 28 are secured to the surface of the wall 14 by expansion bolts (not shown) and hide the ends of the segments 19 and the gap between the segments and the edge of the penetration 12.

The damper 16 is generally similar but the sleeve 30 is formed of oblong section segments 32 (shown without foils in Fig. 3) comprising an extruded PVC sheath 34 and intumescent strips 36, the sleeve being secured by a tape 30; end plates 40 are of correspondingly rectangular form.

Figure 4 shows segments 42 each extruded from PVC with a projection 44 on one lateral face and a groove 46 on the other lateral face. By interlocking the projection 44 and grooves 40 on adjacent segments 42, the segments may be joined together around a pipe 48 to form a sleeve 50. Figs. 5 and 6 show segments 52 and 54 respectively having modified interlocking profiles.

Fig. 7 shows segments 56 joined by hinges 58 extruded from thermoplastics material and secured to marginal edge portions of the outer surfaces of the segments 56: Fig. 8 shows a similar arrangement with the hinges secured to the inner surfaces of the segments 56.

In Fig. 9 the segments 56 are shown joined in a manner similar to that of Fig. 7 by a web 60 of hot melt adhesive.

Fig. 10 shows a segment 62 having a sheath 64 formed of plastics or metal and having the lateral walls 66 of concertina form so as to constitute bellows which will allow expansion of the strip-form intumescent material 68 on the outbreak of fire.

Fig. 11 shows a segment 70 having a sheath 72 formed of an inner PVC or metal channel 74 received in a similar, cooperating outer chamber 76. Fig. 12 shows a generally similar arrangement in which the inner channel 78 and outer channel 80 are of rectangular section.

Fig. 13 shows a segment sheath 82 extruded from metal or PVC and having a generally H-shaped crosssection. The upper and lower surfaces of intumescent core material 84 may be coved if desired with continuous or perforated plastics or metal foil, or with a mesh.

Fig. 14 shows a similar segment 82 in which the inner and outer surfaces of the intumescent core material (not shown) are protected by an inner cap 86 and an outer cap 88.

Fig. 15 shows segments 90 (similar to the segments 19 of Fig. 1) having adjacent lateral faces adhered together to form an annular sleeve 92.

A rectangular sleeve 94 as shown in Fig. 16 is formed of oblongate section segments 96 and 98 secured by a foil 100 adhered to their outer surfaces.

As shown in Fig. 17 a circular pipe 102 is received within a square or rectangular section sleeve 104 formed by two opposed pairs of segments 106 secured together by a heavy gauge foil sheet or laminate 108 which is extended to form an upper panel 110 and a lower panel 112.

Fig. 18 illustrates a generally similar arrangement to that of Fig. 17, but utilizing both square section segments 114 and oblongate section segments 116 to form an oblongate sleeve 118.

Fig. 19 shows a sleeve 150 in which a loose set of segments 152 are held together and have their ends protected by flanged, semi-annular end caps 154.

A damper 156 as shown in Fig. 20 comprises a sleeve formed of a set of annular segments 158 mounted within two semi-cylindrical steel shells 160 secured by straps 162. The assembly is completed by semi-annular end plates 164 identical to those now to be described in relation to Fig. 21.

A damper 120 as shown in Fig. 21 comprises segments 122 containing strips 124 of intumescent material and an outermost strip 126 of steel. The segments 122 are mounted on a foil sheet 128 and clamped by steel straps 130. The sleeve 132 thus formed is covered at each end by semi-annular steel end plates 134 which overlie the surrounding wall (not shown) to which they are secured by expansion bolts (not shown).

A damper 136, generally similar to the damper 120, as shown in Fig. 22 differs therefrom in being formed with steel plates 126 being incorporated in each PVC segment 122 between the outer PVC sheath 127 and the intumescent inserts 124. The segments 122 are mounted on a foil (not shown) although this is not absolutely essential. The damper 13 is designed to be fixed to one surface of the structure only and to be secured together by bolts 138 and barrel screws 140. The dampers 50, 120 and 136 are designed to prevent radially outward expansion of the intumescent material 124 and are thus suitable for use in hollow structures such as hollow pot flooring slabs.

A damper 166 as shown in Fig. 23 is intended for retrofitting to a concrete floor 168 having a penetration through which passes a PVC pipe 170. The damper 166 comprises a sleeve formed of segments 172 constituted by intumescent strips protected by a PVC sheath, and contained in a hinged steel canister 174 having inwardlyprojecting upper flanges 178, to the upper surface of which are riveted end plates 180. The whole structure is secured to the underside of the floor 168 by expansion bolts 182 with the interposition of a layer of mastic (not shown). The canister 174 is closed by a toggle catch (not shown).

Fig. 24 depicts a damper 184 which is an alternative to the damper 166 and has an L-section end flange 186 riveted to each end of each semi-cylindrical steel shells 188, the end plates 180 being riveted to the flanges 186 at one end (the left-hand end as shown in the drawing).

The steel shells 188 are held together by steel bands 190 fitted with a toggle catch 192 or alternatively by using a hinge and toggle catch.

Figs. 25 and 26 show a slightly modified method of mounting segments 194 on foil 196, bandolier-fashion, with projecting foil flap 196a to form a shell 198 constituting one half of a sleeve. The flap 196a is covered with adhesive and protected by a peel off strip (not shown).

In use the projecting flap 196a of one shell 198 is secured to the other sheel 198 thus dispensing with the need for adhesive tape.

The ends of each shell 198 are protected by caps 200 which also serve to maintain the shape of the shell.

Claims (33)

CLAIMS:

1. A fire damper for sealing in the event of fire a penetration formed in a fire-resistant structure to allow the passage of a service, the damper comprising a number of segments, each comprising a core of intumescent material and a protective sheathr and attachment means for forming the segments into a sleeve surrounding the service.

2. A damper as claimed in claim 1 and arranged to allow, in the event of fire, outward expansion of the intumescent material.

3. A damper as claimed in claim 1, and additionally comprising an outer tubular container.

4. A damper as claimed in claim 3, in which the outer container is formed of two shells and means for securing the shells together.

5. A damper as claimed in claim 3, in which the outer container comprises. an insert within the outer wall of each segment.

6. A damper as claimed in claim 3, 4 or 5, in which the container comprises an inwardly projecting flange at each end thereof.

7. A damper as claimed in any preceding claim and additionally comprising two end plates at at least one end thereof which, in use, overlie the surface of the structure and cover the ends of the sleeve.

8. A damper as claimed in claim 7 as an appendant to any one of claims 3 to 6, in which the end plates are secured to the outer container.

9. A damper as claimed . in any preceding claim, in which the sleeve is of annular form.

10. A damper as claimed in claim 9, in which each segment has a cross-section constituting a sector of the annulus.

11. A damper as claimed in any one of claims 1 to 8, in which the sleeve is rectangular in cross-section.

12. A damper as claimed in claim 11, in which each segment is of rectangular cross-section.

13. A damper as claimed in any preceding claim, in which the sheaths are of generally H-section.

14. A damper as claimed in any preceding claim, in which each sheath has its lateral walls formed as bellows.

15. A damper as claimed in any preceding claim, in which each sheath is formed of at least two interengaging lengths, at least one of which is of channel section.

16. A damper as claimed in any preceding claim, in which the sheaths are formed at least partly of thermoplastics material.

17. A damper as claimed in any preceding claim, in which the ends of the sheaths are sealed.

18. A damper as claimed in claim 17, in which sealing is effected by means of end caps each covering the ends of one or more segments.

19. A damper as claimed in claim 17 or 18, in which sealing is effected by means of a sealant.

20. A damper as claimed in any preceding claim, in which the intumescent material is in strip form.

21. A damper as claimed in any preceding claim, in which the attachment means comprise an adhesive or welded bond between juxtaposed lateral faces of the segments.

22. A damper as claimed in any preceding claim, in which the attachment means comprise interlocking profiles provided on adjacent segments.

23. A damper as claimed in any preceding claim, in which the attachment means comprise hinges provided between adjacent segments.

24. A damper as claimed in any preceding claim, in which the attachment means comprise end caps in which the respective ends of the segments are received.

25. A damper as claimed in any preceding claim in which the attachment means comprise a flexible plastics connecting web formed on to the segments.

26. A damper as claimed in any preceding claim, in which the attachment means comprise a backing foil attached to one or both of the inner and outer faces of each segment.

27. A damper as claimed in claim 26, in which the foil comprises an adhesive lateral extension for securing one end segment of a set of segments to the other end segment of the set, or to an end segment of another set of segments, to form a sleeve.

28. A damper as claimed in claim 26 or 27, in which the foil comprises a lateral extension in the form of a panel bridging a discontinuity between segments.

29. A damper as claimed in claim 1 and substantially as herein described.

30. A fire damper substantially as herein described with reference to Figs. 1 and 2, Figs. 1 and 3, any one of Figs. 4 to 25 or Figs. 25 and 26 of the accompanying drawings.

31. A kit of parts for forming a fire damper as claimed in any preceding claim.

32. A method of forming a fire damper around a service at or adjacent to its passage through a penetration in a fire-resistant structure, comprising assembling around the service a kit of parts as claimed in claim 31.

33. The features as herein disclosed, or their equivalents, in any novel patentable selection.