TECHNICAL FIELD

The present invention relates to fire sealing a lead-through for a conduit through a building member such as a cast concrete wall, roof or floor, or cast section thereof. The building member can also consist of a relatively thin wall, for example, in a fireproof material such as steel, e.g. a vessel bulkhead. By the term "conduit" is intended, for example, electric cable, piping, ventilation, ducting or the like, and the term is also intended to include a group of such elements.

The lead-through, i.e. the hole in a wall or floor enabling the passage of electric cables, piping, ventilation, ducting or other installation components from one room to another always constitute a large risk in connection with fire. These leads-through constitute obvious propagation paths for both smoke and flames. It is therefore often of decisive importance for fire safety that such a lead-through is sealed in a mode effectively preventing the propagation of both smoke and fire. The lead-through is usually prov-ided by leaving a recess in a wall or the like on casting concrete or laying the courses of a wall. Alternatively a passage can be cut in the ready-cast or laid wall. At a later building stage conduits are then taken through these leads-through, which a re subsequently sealed against fire, i.e. the free space between the conduits and the wall of the lead-through is filled out with a fire resistant filling material.

BACKGROUND ART

It is known to mount a frame in a lead-through, said frame being filled with a plurality of parallelepipedic blocks. At least some of these blocks are parted and have mutually opposing semicircular recesses for a cable. The cylindrical space between these block halves is filled with a cylindrical sealing body which can thus be removed to make room for a cable. By tightening or clamping, the clamping frame affords the desired tight engagement between the blocks and the cables. The drawback of such a clamping frame is however that the blocks supplied only afford sealing for certain cable dimensions and a certain number of cables. In turn, this has resulted in that during the supplementary laying of cable through such a clamping frame, a whole block is quite simply removed so that the seal between the cable

blocks is lost. Further, it has often been observed that blocks have been lost during handling and have not been replaced, the lead-through thus having through openings which nullify the fire protecting function of the device.

It is further already known to utilize rubber bushings to seal a cable le through (of British Patent Specification 953 869), a tubular rubber gromm being pressed into a lead-through, subsequent to which a cable group is forced through the hole in the grommit. Such a technique is not particula usable for fire sealing purposes, however, since the cables must usually pulled a long way through the grommit, as well as a new lead-through havi to be arranged and a new grommit provided if a further cable group is to laid through the wall.

A plastics moulding, technique has therefore been taken up, which signifie that the cables or conduits are laid in the lead-through,-the lead-throug then being temporarily sealed with shuttering, and a fire resistant silic is foamed in situ in the lead-through. This technique is offered by Studs Energiteknik AB under the name "Brandtatningssystem (Fire Sealing System FC-225", where a silicon foam is utilized, which is commercially available under the name "Dow Corning 3-6548 RTV". If it is desired to lay a condui after afterwards, e.g. through a wall, a further Lead-through should be m for it, and the lead-through should be sealed with the FC-225 technique. is troublesome, especially if the wall is con-crete, and expensive, not th least with the thought that wall claddings such as panels and wallpaper a often damaged thereby, and must be replaced.

Alternatively, a hole can be bored through a fire seal in an existing lea through and after laying the cable, the annular gap between hole and cabl can be subsequently sealed.

DISCLOSURE OF INVENTION

The present invention relates to a special means for fire sealing a lead- for a conduit through a buildning member such as a cast wall, roof or flo or cast section thereof e.g. lightweight concrete blocks or wall modules structural flooring from precast concrete pr lightweight concrete units, whereby the above-mentioned disadvantages are considerably reduced ξfoR

eliminated by the invention, and furthermore particular advantages are gained with regard to simplicity and economy in production, economic stock- keeping and simple and reliable application. The invention furthermore enables a reliable fire seal during buildning also.

The means in accordance with the invention includes a prefabricated body with a tubular casing and an elastomeric fire retardant foamed material adapted in the casing, this material being compressed by the casing transverse the longitudinal axis of said casing, whereby the conduit is sealingly clamped in the foamed material by compression of the latter. What is characterizing for the invention is that the casing has an exterior helical thread.

Apart from the above-mentioned disadvantages in previously known devices for fire sealing of a lead-through being substantially reduced or eliminated, there is also gained, by means of the invention _. , that bodies are utilized which can be prefabr cated in a factory under conditions which can be easily and well controlled with respect to the foaming conditions. With the exterior thread there is obtained the advantage of casting in the fire sealing body in the building element such that the body is restrained by its form with good sealing round the body since the grout (concrete) resides in the threads. The casing is preferably shaped for the formation of an internal thread further to the external thread, whereby there is also obtained that the foamed material expanded into the thread is retained by its shape and a good seal between the casing and foamed material obtained. The external thread also has the advantage that by means of it there is enabled a simple and positive anchorage of the fire sealing body when it is cast in, by screwing in one end of the casing into a fastening element fixed to one of the shuttering walls. By screwing in the casing a suitable length there is also enabled an adjustment to correct length in a simple way, in relation to the thickness of the cast building element. Positive attachment of the opposite end of the fire sealing body can be simply obtained in a preferred embodiment by the foamed material at this end projecting a small distance outside the casing and thereby being compressed into engagement with friction against the shuttering wall. In combination with projecting foamed material ⁽ possibly alternatively to projecting foamed material) retention can further be ensured by attaching a retaining means in engagement with the foamed material to the shuttering wall.

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In one embodiment of the invention the casing is filled with foamed mater along the whole, of its length. In an alternative embodiment, the casing i filled wit foamed material from one end up to a distance from the other end thereof, the length of the foamed material being adapted to correspon to safety requirements made on the fire seal in question, and said distan not filled with foamed material having a length for adjusting the whole length of the body to the thickness of the building element in question. means of this alternative embodiment there is obtained an advantageous limitation of the amount of foamed material. Desired adaption of the body length to current thicknes's of the building element can, if the length do not already agree, be simply obtained by cutting the casing of the portio of the body not filled with foamed material. This can be economically advantageous by the casing being made of a material which is cheap in comparison with the foamed material, and is preferably a thermoplastic material such as polyethylene. In this way the foamed material is not los After fitting the body, the casing ends can be furthermore utilized for simple screwing-in of some suitable detail e.g. a decoration flange suita from the point of view of appearance.

^• Preferred embodiments of the invention will now be described in detail in following while referring to the appended drawings.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is a section along the line I-I in Figure 2 of an embodiment .of fire sealing body.

Figure 2 is an endview of the body seen from the left in Figure 1. Figure 3 illustrates in side view and in an exploded sketch the fitting o fire sealing body between two shuttering walls.

Figure 4 is a section corresponding to the one in Figure 1 and showing th body in a fitted position between two shuttering walls and after the shut has been f i l l ed wi th conc rete.

Fi gure 5 i s a p lan vi ew to a la rger sca le of a fasteni ng ele-.ent sui tab ly formed for the fi re sea li ng body accordi ng to Fi gures 1 and 2, ^' for fi xin body during casti ng, e. g. casting as i l lust rated in Fi gure 4. Fi gure 6 i s a secti on a long the li ne VI-VI i n Fi gure 5. Fi gure 7 i s a secti on a long the li ne VII-VII i n Fi gure 5.

Figures 8-11 are sections corresponding to Figure 4, but after taking away the shuttering, and in different work operations illustrates putting a cable through the body with the aid of a tool specially constructed for thi purpose. Figure 12 is a perspective view and to a larger scale of the head of a handle incorporated in the tool.

Figures 13 and 14 are perspective views of two different examples of fixing a ire sealing body in a previously made hole in a cast wall or building element, for example. Figure 15 is a perspective view of the attachment of a fire sealing body in a thin wall of fireproof material such as steel.

BEST MODE FOR CARRYING OUT THE INVENTION

Figures 1 and 2 illustrate the principle construciton of a ire sealing bod generally denoted by the numeral 1. This consists of a casing 2, axially formed with a thread 3..In the illustrated embodiment the casing 2 is forme so that there is an external as well as an internal thread. The casing may consist of a thermoplastic such as polyethylene.

The interior of the casing from one end along a portion 3 thereof is filled with an elastic f re retardant foamed material 4, which is foamed in situ i the casing so that the cured foam is kept compressed by the casing. The foamed material suitably comprises a silicon foam which is commercially available under the designation "Dow Corning 3-6548 RTV", this scum suitabl being produced in situ in the casing 2. Since the material expands ^' as it is produced, when it assumes a consistency like that of foam rubber, the interior threads of the casing are also filled, which, apart from the casin holding the foamed material compressed transverse the axial direction of th casing, contributes to the retention of the foamed material and furthermore gives a decidedly better seal than if the inside of the casing were smooth. Although not shown, one or more reinforcing nets can be set into the foamed material, partly to prevent the material from being broken off during subsequent cable laying (see Figures 8-11), and partly for enabling a sealing arrangement of a plurality of cables through the fire sealing body without breaking up the material and forming cracks in it. The length 3a,

filled with foamed material, is adapted to the stipulations applicable fo the fire seal in question, which have the form of a fire classification signifying a given minimum length, and electrical safety stipulations signifying given maximum length.

The fire sea-ling body 1 is produced with an unfilled portion ^" 5 suitably having a length enabling the use of the fire sealing body for different current wall thicknesses. The portion 5 can be easily cut, suitably with saw, to the correct length, e.g. as illustrated in Figure 1, along the ch dotted line 6. Figures 3 and 4 illustrate how a fire sealing body is cast between two shuttering walls 7 and 8, the body having the principle embod illustrated in Figures 1 and 2.

Figure 3 illustrates how a fastening frame generally denoted by the numer 10 is attached by means of nails 9 to one shuttering wall 7, said frame h an embodiment such as is more closely described below with reference to Figures.5-7, i.e. it has, inter alia, an internal thread adapted to the thread 3 of the casing 2. After cutting the body 1 to at least the approx length, the body is fixed relative the shuttering wall 7 by being screwed the attachment frame Ϊ0. By screwing-in to different depths, there is off a possibility of adjustment with relation to wall thickness. The shutteri wall 8 is subsequently erected and the shuttering pulled together, whereb the fire sealing body is clamped firmly between the shuttering walls. Adjustment within a given tolerance for the length of the body is also obtained- by the elasticity the body has longitudinally, due to its thread form. As will be seen from Figure 3 (and also Figure 1) the foamed materi thrusts out a small distance (some millimeters) outside the casing 2. Thi projecting portion is denoted by the numeral 11. There is thus obtained b friction between the foamed material and the shuttering wall a retention this end of the fire sealing body against the shuttering wall. Further su for retaining this end can be obtained by nailing a suitably relatively flat reaπs (not shown) against the shuttering wall 8 this mear.s being provided with inwardly thrusting means, e.g. in the form of concentric ri which come into engagement with the foamed material after erecting the shuttering wall. In this case, as an alternative, the project ⁱ ng foamed material 11 could be avoided. By using a fastening frame, there is no lon the recj rement for cutting off the body perfectly with relat ^" cn to the

flatness of the cut as well as perpendicularity to the longitudinal axis of the body.

Figure 4 illustrates the fire sealing body 1 with the fastening frame 10 after filling concrete 12 between the shuttering walls 7 and 8. By the external threads also being filled with concrete, a retention of the fire sealing body by means of its shape is obtained in the concrete. The body forms a gas-, fire-, watei— and sound-proof lead-through during the whole of the building time, both before and after cable laying through it.

An advantageous embodiment of the fastening frame 10 illustrated in Figure 3 will now be described with reference .to Figures 5-7. This frame comprises an annulary shaped wall 13, along the inside of which a thread is formed. The latter comprises, in the illustrated embodiment, two straight and practically semi-circular ridges 14 and 15, the free ends of which do not meet, seen in plan view. On the outside of the wall 13 there are arranged four diametrically opposing nail holes 16 for nailing the frame to the shuttering wall (wall 7 in Figures 3 and 4). The nail holes 16 flare out in a direction towards the edge side of the frame wall 13 which is to engage against the shuttering wall. When the wall 8 is taken down, the nails accompany it, but the frame remains in the concrete. On the opposite endge side of the frame wall 13, four diametrically opposing corner portions 17 and 18 project out at right angles to the wall. The corner portions 17 are hereby formed with outwardly open slots 19 and the corner portions 18 are provided with buttons 20 which can be snapped into the slots 19 in an adjacent frame to form a desired number of frames 10 snapped together in a row- To ensure a positive such snapping together of adjacent frames, each frame is provided with- locking means comprising a dovetail tongue 21, projecting from the surface of the fastening frame wall and situated between the buttons 20 and a complementally shaped, diametrically opposite slot 22.

Figures 8-11 illustrate different work operations in pulling a conduit through a fire sealing body after the shuttering has been taken down. The body illustrated in exemplification corresponds to the body according to Figure 4 and is illustrated cast into the concrete wall 23. To obtain a sealed passage of the conduit a special lead-through tool is used. It comprises three parts, a conical tip 24, a sleeve 25 and a handle 26 with a

head 27, whi'ch coact in a mode apparent from the following description.

As shown in Figure 8, it is suitable to push the tip 24 by itself into th foamed material 4, or if several conduits are to be pulled through, a tip is inserted for each conduit, the placing of the different conduits can thereby be planned with the aid of the tips. The forward end 28 of the sleeve is inserted in the tip and with the aid of the handle. Tip and sle are pressed through the foamed material, and when the tip has passed ther through it falls away of its own accord. For this penetration, the handl can press against the back end 29 of the sleeve with the handle in a position as shown in Figure 8, there being in the head 27 of the handle a annularlyformed bottomm ^' ng groove (see Figure 12) in which the sleeve end inserted during penetration. As an alternative, by special forming of the head 27 (shown in more detail in Figure 12) with recesses 30 for hooking onto two of four heels or abutments 31, evenly distributed around the circ ference of the sleeve 25 in the vicinity of the back end of the sleeve, through penetration of the tip 24 and sleeve 25 can take place, after suc a hooking-on, and in an attitude which is angular relative to the sleeve the handle 26, which can be valuable for more inaccessible places.

Figure 9 illustrates a position of the sleeve 25 after it has been presse through the f re sealing body, and a conduit 32 has been pulled through th sleeve. Since the hole provided through the body is lines by the sleeve an thereby protected by it, the conduit can be pulled through the body withou damaging the latter. As is shown, the sleeve is slit up at the ends 28, 29 form tunnel-shaped openings, thus preventing the conduit from being jammed as it is being pulled.

Figure 10 illustrates the withdrawal of the sleeve 25 from the foamed material after pulling the conduit is completed. Especially for this with¬ drawal, the sleeve is provided with said abutments 31 and the head portion 27 of the handle with said recesses 30. By means of the four abutments 31, arranged around the circumference of the sleeve, there is permitted an all round engagement between two abutments and the recesses, for good accessi¬ bility. Turning the sleeve to the., most comfortable position is thus also permitted. Furthermore, the recesses 30 are flared outwards so that the abutments 31 are also guided into the bottoms of the recesses for an angle

within a relatively large angular range between the central axis of the handle and that of the sleeve, whereby there is also allowed a similarly large angular range between the handle and sleeve during withdrawal. After withdrawal, the sleeve must be removed from the conduit. For easily providing 5 this, the sleeve is formed with perforation or other weakened stretch (not shown ⁾ extending between two opposing bottoms of the slit-up ends 28, 29. After cutting up this perforation, the sleeve can be opened out and removed from the cable. The head 27 of the handle is specially adapted for use during this cutting. On the back of the head 27, relative to the recesses 30, the

10 head is provided with slitting-up portions (see Figure 12) each comprising a cutting edge 33, situated inside an outwardly rounded-off slide knob 34. A positive engagement of the slitting-up portion of the head 27 is obtained in the slits at the sleeve ends 28, 29, between which the perforation extends, the slitting-up portion also being formed so that the handle can be kept

15 within a large angular range relative the sleeve, e.g. 15-55°, for comfortable accessib lity. The accessibility furthermore increases by the head 27 being formed with two slitting-up portions, one behind each recess 30, which thus also increases the life of the handle. The rounded-off slide knob 34 is adapted for preventing the cutting edge 33 damaging the conduit 32 during

20 slitting-up.

Figure 11 illustrates the conduit 32 inserted in the lead-through after sleeve 25 is removed. Since no foamed material has been taken away, and the material has only been compressed, the foamed material 4 springs back elastically and a sealing closure of foamed material is obtained round the- conduit.

25 As given above, the head 27 of the handle is more clearly shown in Figure 12, which illustrates the forming of recess 30., cutting edge 33 and slide knob 34. The annular groove is further shown in the Figure, the end 29 of the sleeve 25 being inserted in said groove during pressing the tip 24 and sleeve 25 through the foamed material 4 of the body 1. This groove is denoted by the numeral

30 35 in the Figure. A groove 36 is also shown, defined by the side of the slide knob 34 facing towards the recess 30 and a bottom wall, the lower edge shewn in the Figure forming the cutting edge 33. One of the slit-up edges is successively guided by this groove 36 during slitting-up of the sleeve 25.

With reference to Figures 1-12 there has been described above a fire sealing

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-body partially filled with foamed material and having a circular cross section and threaded casing. Many of the advantages set forth in this description as well as in the introduction under the title "DISCLOSURE OF THE INVENTION" can be obtained with a fire sealing body having a cross- sectional shape other than that which is circular, e.g. quadratic, rectangular or oval, whereby the casing for such a body can indeed have external threads or other corrugations or other projecting portions or be smooth and instead of being threaded into the fastening frame it can be attached in some other way, e.g. by snapping onto a suitably formed fastening frame. Another alternative is to use a fire sealing body completely filled with foamed material, with a circular cross section and threaded casing. Such a body has all the above-mentioned advantages, apart from those obtained by having the casing of the body only partially filled with foamed material.

Other examples of fire sealing bodies, wholly or partially filled with foamed material, are shown in Figures 13-15, in Figures 13 and 14 there being shown bodies for attaching to a previously made hole in a wall or building element, and in Figure 15 there is shown a fire proof sealing body in a hole in a comparatively thin wall of material, e.g. a vessel bulkhead.

In Figure 13 there is shown a part of a wall or a building element 37 with a hole 38. An exterior sleeve 39 of foamed material is moulded on a slit pipe 40, and further to the illustrated internal thread 41, this pipe can have an exterior thread, and suitably taper towards the edges of the slits. The pipe 40 with sleeve 39 are inserted in the hole 38. A casing for a lead-through body 43, wholly or partially filled with foamed material 4, provided with an exterior thread 42 and preferably also an internal thread, is threaded into the pipe 40. On threading in, the slit tube 40 is forced against the outer sleeve 39 by expansion, the latter in turn pressing against the walls of the hole 38.

In Figure 14 there is illustrated a wall or a building element 44 shewn in a section throuch a hole provided with thread 45. The thread 45 can be formed in a cast-in sleeve, or formed in the material itself with certain wall materials. A lead-through body comprises two halves 46 and 47, semi-circular in cross section, with a mantle having an exterior thread 48 and to advan¬ tage an internal thread also, as illustrated and with grooves 49, se'ii-

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circular in cross section. The halves 46 and 47, for example those illustra¬ ted, are filled for their entire length with foamed material 4, are pressed onto a conduit 50 and squeezed against each other, whereafter the assembled halves are threaded into the hole provided with thread 45. This embodiment of a fire sealing body is intended for a single conduit, specially of heavy dimensions, and is particularly utilizable for conduits which cannot be pulled through the foamed material of a fire sealing body because the conduit is provided with some projecting connection, for example. Alternatively, it is possible to cast in the f re sealing body in a conventional way, thereafter to screw it out to put it round the conduit and then screw it back into the threaded hole. This has the advantage that a sealed lead-through can be obtained during building as well. Another alternative is to have a slit-up lead-through body instead of two separate halves 46, 47.

Finally, in Figure 15 there is illustrated a lead-through body 51 with a casing provided with an exterior thread 52 and preferably an inner thread also, the casing enclosing a foamed material 4 in a customary manner. The lead-through body is threaded through fastening pieces 54 provided with internal threads 53, said fastening pieces being previously fastened on either side of a wall 55 with the collars or flanges 56 of the fastening pieces sealingly surrounding a hole 55 made through the wall.

If only one conduit is to be arranged through the lead-through body in the embodiments according to Figures 13 and 15, the body can be divided into halves or slit-up similar to what has been shown and described with reference to the embodiment according to Figure 14.