FIRE RESISTING SYSTEM AND METHOD FOR PROVIDING SUCH SYSTEM

The invention is related to a transit system for incorporation in a construction element that divides two compartments, comprising a conduit through which at least one pipe extends from one of the two compartments to the other of the two compartments and into which heat can be conducted.

Such a transit system is known from ships and other off-shore applications such as oil rigs. These transit systems are seen as unwelcome necessities in such a construction. After all, pipes for, for instance, water distribution and water waste systems, air conditioning systems, hydraulic and pneumatic control, sprinkler etc . need to be extending throughout such a construction, even though this entails introducing "weak spots" in the separation of the compartments. Such weak spots do not manifest themselves in the mechanical strength of the construction but much more in the undesired transport of physical phenomena throughout the structure. One of these physical phenomena is the occasion of a fire which needs to be confined to only one area as long as possible, not only to allow for control and extinguishing the fire, but also to provide time for people present in compartments near to the fire for reaching a safe distance from the fire before the fire expands. To prevent smoke and/or fire to pass through the transit from one compartment to another, the transit is usually provided with material that closes the transit, at least for some time, when the transit is exposed to heat due to a fire. Such transit systems are often referred to as "pipe penetrations".

EP 0 534 563 Bl discloses a conduit in which a fire resistant and heat expandable rubber sheet is wrapped around the pipe. A wire may be tied around the sheet which is wrapped around the pipe, to ensure that the wrapped sheet remains its tight position around the pipe. A remaining part of the conduit may be filled with fire resistant and heat expandable rubber sleeves. The rubber sleeves and sheets together and as installed are often referred to as a sealing system. NL 1019909 describes that the heat expandable rubber sheet may also in a helical fashion be wrapped around the pipe. This system has in many aspects proved to be superior in comparison with alternative sealing systems such as for instance formed by casting into the transit a compound that solidifies or sealing systems composed of rubber blocks. With the former, shrinkage and/or corrosion may occur; the latter needs tightening and causes therefore many engineering problems . It must be borne in mind that these problems relate to relaxation of the rubber that may occur over time, loosening the sealing. A tight fitting also means radial pressure on the pipe which causes in the long run a reduction of the pipe's diameter when the pipe is made of plastic and therefore subject to creep-related phenomena. Both relaxation and creep require continuous monitoring of the sealing integrity as, even after renewed tightening, the phenomena continue to take place.

Installation of the sealing system disclosed in

EP 0 534 563 Bl can still be too time consuming and too laborious . The number of sheets wrapped around the pipe, the thickness of these sheets, the number of wrappings and the interspacing left between the pipes covered by wrapped sheets is very specific and time consuming. Flexibility on the construction site is

limited and there is a probability that mistakes are made.

The sizes of the conduits, and the number and sizes of pipes extending through these conduits may differ enormously for a number of pipe penetrations . To allow for these differences, large stocks of both sheets and sleeves are required. Missing sheets or sleeves, could lead to a delay in the installation or an incomplete installation and therefore these stocks need to be carefully monitored when installation of these sealing systems progresses during the building of a construction such as a ship or an oil rig.

Pipes extending through such a conduit sleeve may be used for transport of water, gas or may be used for guiding for instance electrical or optical cables, from one compartment to another. Conventionally, these pipes are made of metal. However, nowadays also plastic pipes comprising glass-fibre reinforced materials are more commonly used. In general it applies that the material of which the (service) pipes are made allow for conduction of heat.

When one side of the transit system is exposed to heat due to a fire, the pipe extending into the conduit at that side will supply heat to the inner space of the conduit. As heat expandable rubber sheets are wrapped around the pipe, these heat expandable rubber sheets are efficiently heated. When heated, these wrapped sheets start expanding in a radial direction as well as into a direction from which the heat is supplied. The heat expandable rubber sleeves will also become hot and will also expand. A solid rubber mass will form within the conduit sleeve at the side exposed to the heat. The conduit sleeve will consequently be closed off by the

rubber mass to avoid spread of fire and smoke. This mass will expand towards the direction from which the heat is supplied.

Previously, heat only entered the conduit sleeve via the pipe or pipes which extended from the side exposed to fire into the conduit. Entrance of heat through material of which the conduit is made, was often inhibited by a thermally insulating lining provided against the outer wall of the conduit and the construction in which the conduit is incorporated. Most often this entails a steel construction. However, nowadays, thermally insulating lining is not always applied around the conduit and consequently heat can be conducted through conduit material from an outside to an inside of the conduit sleeve. It follows that heat can be supplied via at least two routes to the inner space of the conduit. The first route is the supply via the pipes extending into the conduit and a second route is the supply of heat to the inner space of the conduit via the thermally conductive material out of which the conduit is made. As heat may be supplied via two routes, heat may be supplied very rapidly to the inner space of the conduit sleeve. These conditions are often found in off-shore constructions and vessels, where construction materials are made of metal, i.e. a heat conducting material. In constructions other than offshore constructions and vessels, like for instance onshore constructions, entrance of heat via the second route, is often much less taking place, if occurring at all.

A sealing system known from the prior art as described in EP 0 534 563 Bl, comprising sheets wrapped around the pipes and sleeves inserted in the remaining part of the conduit sleeve, is not optimised for a situation in

which heat is supplied via the two routes as outlined above. A result is that the heat expandable material expand to such an extent that material expands outwardly of the conduit, becomes unsupported by the conduit and may fall out of the conduit, causing for instance a risk of igniting other material .

It is an object of the present invention to reduce at least one of the problems mentioned above while remaining the functional requirements of the transit system.

This object is reached with a transit system that is according to the invention characterized in that a substantially endless inner wall of the conduit defines an inner cross-sectional volume which is composed of a pipe-free part that is unoccupied by the at least one pipe and a pipe-occupied part that is occupied by the at least one pipe, the transit system further comprising a plurality of similar fire resistant and heat expandable rubber members with which that pipe- free part of the inner cross-sectional volume is filled up, wherein each of the heat expandable rubber members is made of a heat expandable rubber and wherein at least one of the pipes extending through the conduit is free from being coaxially surrounded by a single one of the rubber members. As the fire resistant and heat expandable rubber members used for filling up the pipe- free part of the inner cross-sectional volume, are similar, stockage of these heat expandable rubber members is much less dependant on a difference between a number of transit systems in which these fire resistant and heat expandable rubber members need to be used.

As the fire resistant and heat expandable rubber members are freely insertable in the conduit, the installation of these members in the conduit sleeve is much less time consuming, and much less laborious. The rubber members are substantially evenly distributed. After all, there is no cross-sectional part, such as a ring-shaped cross-sectional part around each pipe, that is to be supplied with these rubber members in a much higher density than elsewhere in the cross-sectional volume.

Also, mistakes are less likely to occur, given the straightforward and simple installation of the rubber members .

Surprisingly, it has turned out that also with this even distribution of fire resistant and heat expandable rubber members, a solid rubber mass can be formed, when the rubber members are subjected to heat, in that situation fully closing off the conduit sleeve.

As indicated above, as the pipe-free part is being filled up with rubber members and as at least one of the pipes, and preferably each of the pipes, is free from being coaxialIy surrounded by a single one of the rubber members, the rubber members are substantially evenly distributed over that part.

This even distribution is much more appropriate for a heat supply to the inner space of the conduit sleeve via at least two different routes . As two routes are available for heat supply, the rubber members are still efficiently heated up in case of fire, closing off rapidly enough the conduit sleeve. A transit system according to the invention has passed fire safety tests according to international regulations and has been certified.

It has further been shown that with a transit system according to the invention the transit length does not need to be as long as the transit length used for transit systems known in the prior art. A reduction of the length of the transit implies a reduction of the length of the sleeve or coaming. This on its turn implies a significant reduction in weight of the transit of enormous interest to the shipbuilding industry. A conduit sleeve in a transit system according to the invention may have a length of 200 mm to meet the requirements achieved by a transit system known of the prior art and having a length of 250 mm. This example shows that a weight reduction of 20% may be feasible for one transit. This contributes for vessels to an enormous weight reduction, as each vessel is normally equipped with hundreds to thousands of transits.

The weight reduction and shorter length of the transit system allow thus also for a more economic operation of a vessel.

Not only the length of the conduit can be reduced in comparison to the length used for a conduit of the prior art, also the length of the rubber members can be reduced in an equal way and to an equal extent .

Often a pipe needs to extend in a direction that is different from the direction into which the pipe extends within a conduit . Pipes extend preferably closely along a wall, deck, ceiling or floor, as in that case the pipe does not inconveniently cross space of a compartment . A bend in a pipe is therefore preferably situated close to a construction element such as a wall, deck, ceiling or floor. Short transits, allow for relatively short bends where redirection of

the pipe is required. Thus short transits allow for a 90° bending of the pipe beyond the penetration close to the partition, resulting in saving space and ultimately material .

In an embodiment of a transit system according to the invention each of the rubber members extends substantially in a direction parallel to a longitudinal direction of the at least one pipe. This has the advantage that the rubber members can easily be applied in the conduit sleeve. Furthermore the members can be applied such that on either end of the conduit sleeve a sufficient and equal amount of heat expandable rubber is provided by installation from only one side. Finally, such members can easily be produced by for instance an extrusion process or a moulding process.

Preferably, each member has a rotational position obtainable by rotating that member around its axis which extends in a longitudinal direction of that member, the rotational position of each- member being independent of any of the neighbouring members of that member. During installation no time needs to be spent on assuring that the rotational positions of each member is in correspondence with a predetermined rotational position that may for instance be dependent on a rotational position of neighbouring members.

It is possible that in an embodiment in the inner cross-sectional volume a part of an outside of each of the at least one pipe is along a longitudinal direction free from contact with any of the rubber members . This has the advantage that there is a space along the pipe into which the heat expandable rubber can expand. In other words, a volume around the pipe is not too densely filled with heat expandable rubber, and

expansion is unlikely to lead to a situation in which high expansion forces force expanding rubber members for instance out of the conduit sleeve.

It may further apply that the rubber members are such that the rubber parts together are unable to form in an unexpanded condition a rubber sleeve that narrowly fits to any of the at least one pipe. This ensures that a ring-shaped volume around the pipe will not be too densely filled with heat expandable rubber and/or providing contact with the complete outside of the pipe.

It may apply that in the inner cross-sectional volume a part of the inner wall of the conduit is along a longitudinal direction free from contact with any of the rubber members. So, also close to the inner wall of the conduit sleeve is enough space available for the expanding rubber to expand into.

It is possible that the rubber members are such that the rubber members together are unable to form in an unexpanded condition a rubber lining that closely covers in the inner cross-sectional volume the endless inner wall of the conduit. In such an embodiment it is therefore not possible that accidentally space close to the inner wall of the conduit sleeve is ^• completely- occupied by rubber before expansion occurs.

Preferably at least one of the rubber members has a tubular shape . This has the advantage that at least one rubber member has inherently space into which the rubber can expand when heated. This space is namely available within the tube.

It is preferable that at least one of the rubber members has a cylindrical shape. Such a shape has the

advantage that it is symmetrical with respect to its axis . In other words there is no need to spend time on getting the rotational position right when installing these rubber members. Furthermore, rubber members having a cylindrical shape will, when stacked together or bundled together in a conduit, inherently allow for space between them. Also when such members are aligned against an inner wall of the conduit or against an outer part of a pipe, a part along a longitudinal direction of the inner wall and a part along a longitudinal direction of that outer part are inherently free from contact with rubber parts . Installation in the preferred way, allowing for an even distribution and for space into which the rubber can expand when heated, will thus occur naturally.

It is possible that the plurality of similar rubber members comprise two types of rubber members . Even though the types are similar, little differences between the rubber members may be possible, allowing for combining rubber members having, for instance, mutually exclusive properties. The differences are such that for installation in a conduit sleeve no predetermined ratio is required for the number of members of one type and the number of members of another type. In other words, members of one type can without major problems replace one or more members of another type.

It is possible that the two types differ in dimensions. Remaining unoccupied space in the inner cross-sectional volume may, especially when a large part of that cross- sectional volume has already been filled with rubber members, not have a dimension into which a type like the type of the already placed members would fit. In such a situation it may be advantageous that the

remaining space is filled up with a rubber member having different dimensions. It is still possible, and possibly preferable, that the members of each types have similar dimensions in longitudinal direction.

In an embodiment of a transit system according to the invention it is possible that at at least one free end of the conduit an end cross-sectional volume is substantially completely surrounded by the inner wall of the conduit sleeve and is filled up with a fire resistant sealant. This ensures that after filling the inner cross-sectional volume with rubber members as outlined above, the remaining spaces into which the rubber can expand when heated, is protected against the entrance of moisture, reducing the chance of corrosion within the transit. By applying the, sealant a smoke tight barrier is already available before the expandable rubber members expand. Such a fire resistance sealant can easily be applied. a fire resistant sealant may be like a heat resisting and/or liquid repellent material as disclosed in EP 0 534 563 Bl.

In an embodiment of a transit system according to the invention it is possible that at at least one free end of the conduit an end cross-sectional volume is substantially surrounded by the inner wall of the conduit and is filled up with a watertight sealant. This is especially advantageous when the division between the two compartments have to be watertight and/or gastight. When such a sealant is applied in both end cross-sectional volumes of the conduit, moisture cannot enter the inner cross-section volume and corrosion can be prevented. Note that the sealant can be applied such that a strong adhesive strength is obtained between the sealant and the pipes and between

the sealant and the inner wall of the conduit. In practise there is no need to open up the transit to inspect for possible corrosion. Such monitoring may normally be required to check whether gas leakage out of the pipe due to for instance corrosion of the pipe has occurred. So far, such monitoring has been needed. After all, if such corrosion and leakage were to occur in a transit, a gastight transit may become explosive. A gas and watertight sealant applied on both ends of the conduit can now make such time-consuming opening up of the transit unnecessary. Also the application of a fire resistant sealant on one end and a water and gastight sealant on the other end, has proved to provide full fire safety and integrity, when the fire- resistant sealant is also a water and gastight sealant. As a result neither maintenance work, nor monitoring work needs to be focussed on pipe-segments in transits.

It is also possible that one end cross-sectional volume of the conduit is filled up with a watertight sealant while another end cross-sectional volume of the conduit is filled up with a fire resistant sealant. This may be of use in LNG-tankers in which both leakage of gas and propagation of fire should be prevented by a transit system according to the invention.

It is further possible in an embodiment of a transit system according to the invention that between the end cross-sectional volume and between the inner cross- sectional volume an intermediate cross-sectional volume is filled up with an electrically conductive rubber product. In such an embodiment an effective short-cut may be provided between the metal substantially plate shaped construction element and the ducted pipe, if the thermally conductive conduit sleeve is also electrically conductive, which is usually the case.

Hence, propagation of electromagnetic signals along the pipe, is effectively attenuated. When the metal plate shaped construction element is part of a Faraday cage surrounding a compartment, the pipe entering such a shielded space cannot perforate the protective screen provided, if this embodiment of a transit system according to the invention is applied. The conductivity of the electrically conducting rubber situated between the pipe and the conduit sleeve, ensures that the pipe becomes part of the Faraday cage.

In an embodiment the at least one pipe comprises a plurality of pipes. It is for instance possible that the plurality of pipes comprises at least one metal pipe and at least one plastic pipe. The rubber members will, when heated, expand and crush the plastic pipe. Any opening created by a plastic pipe that is softened by the heat will be filled up by the expanding rubber members. A transit system according to the invention may thus be used for "multiple pipe penetrations". Especially when a transit system can be used for pipes of plastic and at the same time for pipes of metal and/or pipes with different diameters, major advantages for the construction can be achieved. Such a situation is often referred to as "mixed multiple pipe penetrations". It should also be borne in mind that a system according to the invention is capable of coping with different thermal expansions of the different pipes. The rubber members can easily be placed such that one or some of the rubber members act as an element that separates the pipes so that galvanic corrosion as a consequence of contact between pipes of different metals can be prevented. Linear and/or axial vibrations can easily be absorbed by a system according to the invention. One transit for different types of pipes saves much space, installation time and welding

costs, in comparison with a situation wherein for each type of pipe a separate transit system is required. Another major advantage of a transit system according to this embodiment of the invention is the reduction of the necessary numbers of conduit sleeves, allowing for much lighter constructions.

The invention is .also related to a method for providing in a transit system, across a metal substantially plate shaped construction element that is situated between two compartments and comprises a conduit sleeve through which at least one pipe extends from one of the two compartments to the other of the two compartments, a system that acts as a barrier resisting propagation of fire and possibly smoke, gasses and water through the transit system.

The invention is further described with reference to the drawings . In the drawings :

Fig. 1 shows schematically a cross-section of a first embodiment of a transit system according to the invention;

Fig. 2 shows schematically a cross-section of a second embodiment of transit system according to the invention;

Fig. 3 shows a frontal view of a cross-section of a third embodiment of transit system according to the invention;

Fig. 4 shows schematically a cross-section of a fourth embodiment of a transit system according to the invention.

In the drawing, like parts have like references.

Fig. 1 shows schematically an example of a cross- section of a transit system TS according to the invention. The transit system TS is incorporated in a metal substantially plate shaped construction element P. This plate shaped construction element P is situated between the two compartments CI, CII and divides as such these two compartments I, II. The plate shaped construction element may for instance be part of a bulkhead, a wall or a deck in or on a ship or another construction that substantially is constructed of metal such as steel. The transition system comprises a conduit, in this example a conduit sleeve CS, made of a material which is in this example thermally conductive so that heat can be conducted through sleeve material between an inside and an outside of the sleeve. The conduit sleeve CS may be made of metal and may be welded into an opening of the plate P.

Although in this example shown, the conduit is incorporated in a metal substantially plate shaped construction element, it is ^' also possible to incorporate the conduit in for instance a concrete wall or a separation made of any other material .

It is further conceivable that the conduit is made of a material that is not a good heat conductor, such as a ceramic material .

If heat will enter the conduit via only one of the routes outlined above, for instance only via pipes which extend through the conduit, the response of the heat expandable rubber members is still such that the conduit is satisfactorily closed off.

Although the example shows a simple and straightforward shape of the conduit, namely a sleeve, any shape of the

conduit is possible. Instead of a sleeve the conduit may for instance be a coaming.

The transit system further comprises a pipe PP which extends through the conduit sleeve CS from one of the two compartments CI, CII to the other of the two compartments CI, CII. An endless inner wall IW of the conduit sleeve CS defines an inner cross-sectional volume IV. The term "endless" refers to the feature that the inner wall is closed in itself between end parts of the conduit, like a cylindrical wall. The inner cross-sectional volume IV is composed of a pipe- free part UP which is unoccupied by the pipe PP and a pipe-occupied part that is occupied by the pipe PP. The pipe may be a metal pipe, a pipe made of a glass-fibre- reinforced material or any other material conducting heat. The pipe may also be of a plastic. In that case it is preferable that either another pipe also extends through the conduit and that this pipe is of a material that conducts heat, and/or that the conduit itself is made of a material that conducts heat. The transit system TS further comprises a plurality of similar fire resistant and heat expandable rubber members RM with which that part UP of the inner cross-sectional volume IV is filled up. As can be seen in the figures, it applies that at least one of the pipes extending through the conduit is free from being coaxially surrounded by a single one of the rubber members. Preferably, each of the pipes extending through the conduit is free from being coaxially surrounded by a single one of the rubber members. The rubber members RM are substantially evenly distributed over that part UP. It may apply that the substantially even distribution relates to a manner of positioning the rubber members in the unoccupied part such that the positioning is unrelated to a predetermined pattern. In other words,

the rubber members may be applied randomly while filling up the unoccupied part with the rubber members RM.

Although the sleeves are shown to be symmetrically positioned within the conduit, this is in either direction (axially of radially) not necessarily the case.

Fig. 2 is almost identical to Fig. 1. In Fig. 2 and end of the conduit sleeve CS is connected to the substantially plate shaped construction element P whereas in Fig. 1 a position in the middle of the conduit sleeve CS is connected to the substantially plate shaped construction element P.

Such a conduit may be asymmetrically positioned with respect to the wall or deck and may be bolted or welded to the wall or deck.

Each of the rubber members RM extend substantially in a direction parallel to a longitudinal direction of the pipe PP. The longitudinal direction is indicated by arrow A.

Fig. 3 shows a cross-section of a third embodiment of a transit system TS according to the invention. The cross-section is of a different transit system then the transit system shown in Fig. 1 and in Fig. 2. Although the transit systems of Fig. 1 and Fig. 2 are not identical to the transit system shown in Fig. 3, Fig. 1 and Fig. 2 show as indicated by line 0-0 a likely position of a cross-section of which a frontal view is shown in Fig. 3. Fig. 3 shows a frontal view as seen when viewing along a direction into which the pipe PP extends .

In Fig. 3, a conduit sleeve is shown through which two pipes PPl and PP2 extend. The inner cross-sectional volume IV is defined by the endless inner wall IW of ^■ the conduit sleeve CS. As shown the inner cross- sectional volume IV is composed of a pipe-free part UP which is unoccupied by the pipe Pl, PP2 and a pipe- occupied part which is occupied by pipes PPl and PP2. As shown, the unoccupied part UP is filled up with a plurality of similar fire resistant heat expandable rubber members . Each of these rubber members is made of a heat expandable rubber. Each of the pipes extending through the conduit is free from being coaxially surrounded by a single one of the rubber members. As a result these rubber members RM are evenly distributed over the part UP that is unoccupied by the pipes. The members extend in a longitudinal direction that coincides in Fig. 3 with a direction that is normal to the plane in which the drawing is presented.

Each rubber member RM has a rotational position obtainable by rotating that member around its axis which extends in the longitudinal direction of that member. The rotational position of each member is independent of any of the neighbouring members of that member. This is clearly shown in Fig. 3. In the inner cross-sectional volume, a part of an outside OS of each of the pipes PPl, PP2 is in a longitudinal direction free from contact with any of the rubber members RM. The rubber members RM are such that the rubber members RM together are unable to form in an unexpanded condition a rubber sleeve that narrowly fits to any of the pipes PPl , PP2. In other words , each of the rubber members has a form that excludes formation of a rubber sleeve that narrowly fits coaxially around any of the pipes, on the basis of a number of these members, when the rubber members are in an unexpanded condition. In

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be used as a stockage of interconnected tubular, preferably cylindrical, rubber members from which single rubber members can be separated by for instance cutting through the connection between the members . The rubber may be based on an Ethyl-vinyl acetate copolymer .

It should be understood that a transit system according to the invention often has the advantage that in a relatively easy way an extra pipe can be added. The sealant can easily locally be pierced through and the cross-sectional volume comprises enough pipe-free and rubber-free space for insertion of a new pipe.

Finally, it is pointed out that the word "pipe" also encompasses a pipe-like cable. So, a cable with a stiff outer layer which is often made of a plastic is within the context of this specification also considered to be a pipe.

Also these embodiments and methods are understood to fall within a framework of the invention as defined by the. appended claims.