IE49283B1 - A method and means for fire-sealing a penetration for a conduit - Google Patents

Description

The invention relates to a method of fire-sealing a penetration for a conduit such as an electric cable, through a building part comprising a cast building member, an plastic fire resistant foam material being arranged in the penetration. The invention also relates to a means for carrying out the method.

Penetrations, that is the holes in walls or floors enabling the passage of electric cables, pipes, ventilation ducts oi’ other building elements from one room to another, arc always a great hazard in connection with fire, since they constitute obvious propagation paths for both smoke and flames. It is therefore of decisive importance for fire safety that the penetrations arc sealed in a way which effectively prevents the spread of both smoke and fire. The penetration is usually provided by arranging a recess in a wall or the like during pouring or bricklaying etc. Alternatively, a penetration can be cut out in the ready-cast or built-up wall. At a later building stage, conduits are taken through these penetrations and the 48283 penetration is fire-sealed, i.e. the free space between the conduits and the wall of the penetration is filled with a fireproof filler. it is known to fix a clamping frame in tlie penetration. 5 This frame is filled witli a plurality of parallelepipedic blocks. At least some of these blocks are parted and have semicircular cavities facing towards each other for accommodating a conduit. The cylindrical space between these block halves is filled out with a cylindrical sealing body which can also be removed to make room for a conduit. By clamping, the frame affords the desired tight engagement between the blocks and the conduits. The disadvantage with such a clamping frame is, however, that the blocks provided. only afford a seal for certain cable or conduit dimen15 sions and for a certain number of cables. In turn, this has resulted in that when supplementary cables are laid through such a frame, a complete block is removed so that the seal between the cable and the adjacent blocks is no longer effective. Furthermore, it has often been observed in conjunction with handling that blocks have been lost and have not been replaced, the firesealed penetration thus having through openings which nullify the fire resisting function of the device.

It is also known to utilize rubber grommets to seal a cable penetration (cf. British Patent 953,869), a tubular rubber stopper being pressed into the penetration, and a group of cables then being forced through the hole in the stopper. Such a technique is not particularly usable for fire-sealing purposes, since the cables must usually 48283 be pulled a long distance through the stopper, and a new penetration must be arranged and a new stopper provided if a further cable group is lo he taken through the wall.

An in situ moulding technique has therefore been :> adopted, which involves placing the cables or conduits in lhe penetration and temporarily sealing the penetration by shuttering, subsequent to which a fireresistant silicon rubber is foamed on site in the penetration. This technique is accounted for by Studsvik linergiteknik ΛΒ under the designation Fire-scaling system FC-225, utilizing a silicon foam which is commercially available under the designation Dow Corning 3-6548 RTV. However, if it is subsequently desired to lay a conduit through a wall, for example, a further penetration for it should be made, e.g. in aa existing wall and a sealing of the penetration using the IC-225-techniquc. This is difficult, especially if the wall is concrete, and expensive, not in the least with regard to wall coverings such as panelling and wallpaper, which are often damaged and must be replaced.

Alternatively, a hole can he drilled in a fire seal in an existing penetration, the annular gap between the hole and cable being sealed after laying the cable.

One object of the invention is therefore to provide a new technique for fire-scaling penetrations, where the above-mentioned disadvantages have been considerably reduced or eliminated.

In accordance with the invention, this object is achieved by a method of fire-scaling a penetration for a conduit in a building part including a cast building member, a resilient fire-resistant foam material being disposed in the penetration, wherein when casting the building member a pre-fabricated body is cast in place in the member, said body comprising a tubular jacket which is filled with the foam material and keeps the latter compressed transverse to the axial direction of the jacket, and wherein when casting-in the body the jacket is disposed with its longitudinal axis approximately perpendicular to the opposing penetration surfaces of the building member, so that the conduit can be passed through the foam material of the cast-in body.

The conduit may be passed through the foam material of the cast-in body e.g. by driving a substantially tubular mandrel, with its drive-in end provided with a conical drive-in tip, through the body, exposing the central cavity of the mandrel, e.g. by removing the driving tip, threading the conduit through the mandrel and withdrawing the mandrel from the body so that the foam material resiliently comes into sealing engagement against the conduit, the tubular wall of the mandrel then being opened to allow the tool to be removed from around the conduit by movement transversely with respect to the conduit. A tool for passing the conduit through the body thus conprises, for example, a substantially tubular, axially slit mandrel with a conical driving tip removably fitted to the driving end of the means· Xn the inventive method it is thus possible to utilise bodies which can be produced in a factory in circumstances where the foaming conditions can be controlled easily and well. The bodies can be produced in lengths corresponding to the thickness of the building members in which they are to be cast, e.g. aerated concrete blocks, such as Siporex'blocks, or wall modules, or so-called flooring planks made from concrete or aerated concrete. Alternatively, the bodies can be manufactured and supplied in continuous lengths, so that such a length can be sawn on site to a suitable length for placing in a wall or a floor which is cast in concrete on site.

The inventive means for carrying out the method includes a prefabricated body comprising a tubular jacket filled with an elastic fire-resistant foam material, known per se, and which keeps the foam material compressed transverse the longitudinal axis of the jacket, said body being intended for casting into the member. A conduit can be passed through the foam material of the cast-in body, e.g. with the help of the tool described above.

The jacket of the body is suitably shaped for being retained automatically in the cast building member in which it is cast-in. For example, the jacket wall can be corrugated in the longitudinal direction of the jacket. The jacket can consist of a material with low heat conductivity, such as a plastics material.

By the inventive method, and with the aid of the inventive firesealing body, building parts can be prepared for simplified conduit laying through the building part.

According to a first aspect of the invention, the body can be cast into a building member such as an aerated concrete block. When a wall is to be built up from such blocks, the wall can be provided at selected places with blocks provided with the inventive bodies. According to a second aspect of the invention, as previously mentioned, the body can be placed in a concrete wall before it is conventionally cast in situ.

By means of the technique discussed, the erected building parts will have satisfactory fire resistance (no open penetrations) directly after being finished. The fireresistant foam materials useful for the bodies have high density and a high proportion of closed pores, thereby providing satisfactory sound insulatiai for the penetrations. The cast-in bodies can be easily penetrated, as required, with the aid of the tool described above, so that a further conduit can easily be laid through the penetration in such a way that it will be immediately sealed against fire in the penetration.

In the following, the invention will be described in the form of an example with reference to the accompanying drawing.

Fig. 1 is an end view of a fire-scaling body in accordance with the invention.

I:ig. 2 is a section along tho line Jl-II in l;ig. 1.

Fig. 3 illustrates a building part in the form of a wall which has been built up with the help of building members including a fire-sealing body in accordance with r the invention.

Fig. 4 is an axial section through the inventive body, as cast-in in a building member or a building part, the material surrounding the body forming a penetration for a conduit.

Figs. 5-8 are sections corresponding to that in Fig. 4, and illustrate the sequence of work operations, - 49283 using a penetrating tool for laying a conduit through the foain materia] of the body cast into the building member.

Pigs. 1 and 2 show an axially corrugated jacket 28 made from a thermoplastics such as polyethylene, for example The interior of the jacket 28 is filled with a fire-resist ant silicon foam material, roamed in situ in the jacket so that the cured foam 8 is pre-compressed by the jacket 28.

In the factory production of building member 7 (see 10 Fig. 3) such as aerated concrete, the body defined by the jacket 28 and foam 8 can be cast into such a member. Building members 7 provided with such cast-in bodies 8,28 van be utilized together with ordinary building members 7' for construetiny a building part 27, such as a separating IS wall in a building. Λ building member 7 with bodies 8, 28 can thus be laid in positions where there is reason to believe that fireproof penetrations for cables will be needed in the future.

As indicated in I'ig. 4, a body 8, 28, in accordance with the invention, can also be cast-in in building parts cast on site, such as concrete walls, the peripheral portions of the body S, 28 in the building part 27 defining a penetration 17. The foam 8 is suitably produced by a silicon foam commercially available under the dcsignat25 ion Dow Corning 3-6548 RTV, this foam suitably being foamed on site in the jacket 28 while complying with the instructions in the Dow Corning publication PC-225.

Pig. S is a section corresponding to that in Fig. 4, but also shows a tool for laying a conduit through the foam material 8. The tool comprises a substantially tubular mandrel 1 having an axial slit 3. At the driving end of the mandrel 1 there is a removable conical driving tip 2 forming a part of the tool, and at its rear end the mandrel has radial flange elements 6 secured thereto. The tool is driven through the body 8 in the direction indicated by the arrow, until the tip 2 has come outside the foam material 8. A conduit 9 can thereafter be passed through the central cavity of the mandrel 1 as indicated in Fig. 6, the removable tip 2 being knocked from the end of the mandrel 1 by means of the conduit 9. The conduit 9 can thereafter be passed through for a desired length, the radial flange elements 6 preventing the mandrel 1 from being pulled through the foam body 8 by friction against the conduit 9.

The mandrel 1 is then withdrawn, as indicated in Fig.7, the foam material 8 resiliently returning to sealing engagement against the conduit 9. When the mandrel 1 is completely removed from the foam body 8, the axial slit 3 of the mandrel can be widened manually so that the mandrel can be removed from around the conduit by movement transversely of the conduit, as indicated in Fig. 8. The mandrel 1 preferably has a hinge 4 opposite the slit 3 to facilitate opening it.

By conduit is here intended an electric cable, a pipe, a ventilation duct or the like. The expression conduit can naturally also embrace a group of said members, e.g. a group of electric cables.

At least the mandrel 1 of the tool is suitably made from an electrically insulating material such as a plastics material and preferably one having low friction against the silicon foam body 8, polytetrafluoroethylene conceivably being suitable material for the mandrel 1 of the tool.

Hie inventive fire-sealing body can have substantially optiuii.il cross sectional shape. The cross section of the body is preferably circular, but square, rectangular or uv.il shapes .are also conceivable, iur example, by keeping tbe foam compressed in the jacket two advantages .arc won, namely that tbe foam expands and fills out tiie penetration, should the jacket bo destroyed by fire or should the penetration cross-section be enlarged due to e.g. heat expansion, and that the foam offers a good grip against the conduits, preventing easy pull-out of the conduits from the penetration.

Claims (10)

1. A method of fire-sealing a penetration for a conduit in a building part including a cast building member» a resilient fire-resistant foam material being disposed in the penetration» wherein when casting the building member a pre-fabricated body is cast in place in the member, said body conprising a tubular jacket which is filled with the foam material and keeps the latter compressed transverse to the axial direction of the jacket» aid herein when casting-in the body the jacket is disposed with its longitudinal axis approximately perpendicular to the opposing penetration surfaces of the building member» so that the conduit can be passed through the foam material of the east-in body.

2. A method as claimed in claim 1» wherein the body is cut off in a length corresponding to the thickness of the building member before it is cast into said member.

3. A method as claimed in claim 1 or claim 2» wherein the step of passing the conduit through the foam material of the cast-in body conprises penetrating the cast-in body with a tipped tool having a hollow interior through which the conduit can be introduced» whereafter the tool is removed to allow the resilient fire-resistant foam material to press on the conduit. 49383

4. A method according to claim 3» wherein the tip of the tool is removed before extraction of the tool and the tool is then removed in a direction opposite the direction in which the tool was inserted into the 5. Resilient fire-resistant foam material.

5. A means for fire-sealing a penetration for a conduit through a building part, comprising a cast building member; and a pre-fabricated body comprising a tubular jacket filled with a resilient, fire-resistant 10 foam material, said jacket keeping the foam material compressed transverse to the longitudinal axis of the jacket, said body being intended for placing in the member in conjunction with casting the latter, so that the conduit can be passed through the foam material of 15 the cast-in body.

6. A means as claimed in claim 5, wherein the jacket is designed for form-locked retention when cast-in in the member.

7. A means as claimed in claim 6, wherein 20 the jacket wall is corrugated in the longitudinal direction of the jacket. S. A means as claimed in claim 6 or 7, wherein the jacket consists of a material having low heat conductivity. 25 9. A means as claimed in any one of claims 5 to 8, wherein the body has a circular cross sectional shape

8. 10. A means as claimed in any one of claims 5 to 9« wherein the body has a rectangular cross sectional shape.

9. 11. A method of fire-sealing a penetration 5 for a conduit in a building part» such method being substantially as hereinbefore described with reference to the accompanying drawings.

10. 12. A means for fire-sealing a penetration for a conduit through a building part» substantially 10 as hereinbefore described with reference to» and as illustrated in» the accongjanying drawings.