EP0536331A1

EP0536331A1 - Device for sealing a plastic pipe extending through a partition

Info

Publication number: EP0536331A1
Application number: EP91915230A
Authority: EP
Inventors: Juergen Goebell; Koos Luitwieler; Marvin H. Christmann
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1990-06-01
Filing date: 1991-05-31
Publication date: 1993-04-14
Also published as: AU651132B2; BR9106522A; CA2082828A1; WO1991019127A3; AU6310294A; ZA914047B; DE4017656A1; WO1991019127A2; JPH05506494A; AU8416191A

Abstract

L'invention se rapporte à un dispositif qui sert à sceller un tuyau en plastique (22) pour le protéger en cas d'incendie et qui comprend à cet effet, de préférence, un manchon (12) contenant un ressort (34) et une matière intumescente (26). Le ressort (34) et la matière intumescente (26) sont disposés dans le manchon (12) de sorte que, après fermeture du tuyau en plastique (22) par le ressort (34), une partie (17) du tuyau (22) reste ouverte pour communiquer avec le feu ou la source de chaleur. La partie ouverte (17) permet à la chaleur d'atteindre plus rapidement la matière intumescente (26) afin de produire sa dilatation. Le ressort (34) est protégé de la source de chaleur jusqu'à la dilatation de la matière intumescente (26) par une enveloppe (30) en matière thermo-isolante, déformable et ignifuge.The invention relates to a device which serves to seal a plastic pipe (22) to protect it in the event of fire and which preferably comprises for this purpose a sleeve (12) containing a spring (34) and a intumescent material (26). The spring (34) and the intumescent material (26) are arranged in the sleeve (12) so that, after closing the plastic pipe (22) by the spring (34), a part (17) of the pipe (22) remains open to communicate with fire or heat source. The open portion (17) allows heat to reach the intumescent material (26) more quickly to cause it to expand. The spring (34) is protected from the heat source until the expansion of the intumescent material (26) by a casing (30) of heat-insulating, deformable and flame-retardant material.

Description

DEVICE FOR SEALING A PLASTIC PIPE EXTENDING THROUGH A PARTITION

TECHNICAL FIELD

This invention pertains to a device for sealing a plastic pipe extending through an opening in a partition in the event of a fire.

BACKGROUND OF THE INVENTION

In buildings, plastic pipes are progressively being used in lieu of metallic pipes. Plastic pipes, however, unlike metallic pipes, pose fire containment problems. In a fire, the plastic pipes will melt or burn leaving openings in the partitions (e.g. walls, ceilings, floors) which permit expansion of the fire. Devices have been made to combat this kind of fire expansion.

Germany Utility Model 89 07,017 published October 5, 1989 discloses a plastic pipe sealing device having a collar that includes a radially outwardly extending fastening portion at one end for attaching the device to a wall or a ceiling. The device also has a tubular portion extending away from the wall OL the ceiling adapted to accommodate a lining of intumescent material. An annular portion of the collar extends radially between the plastic pipe and the tubular portion retaining the lining of intumescent material within the collar. In the event of a fire, which causes the plastic pipe to collapse or burn, the intumescent material expands to fill the opening through which the collapsed or burned plastic pipe passed. A fire-resistant barrier is thereby formed which prevents an expansion of fire and passage of smoke from one room to another. The front annular portion of the collar prevents the intumescent material from being axially expanded beyond the collar. ith plastic pipes of υp to medium diameters (e.g. on the order of about 30 to 100 mm), the device disclosed in German Utility Model 89 07,017 works satisfactorily. If the pipe diameter is relatively large (e.g. greater than about 100 mm), however, the intumescent material cannot sufficiently seal the pipe in a timely manner because the intumescent material typically needs a few minutes to chemically convert and expand. Within this time, flames, gases, and smoke may pass through the opening.

From the prospectus of bio BRANDSCHUTZ system CRASH-FOAM, it is known to enclose a pipe in a collar that has spring-biased closing parts. When the plastic pipe melts in a fire, the spring-biased closing parts will seal the pipe. Such fire-protection collars are relatively expensive to manufacture and have costly material inventory. They require a lot of space and have a poor appearance.

Japanese Utility Model Laid Open Application 64-57479 published April 10, 1989 illustrates a device for sealing a plastic pipe in the event of a fire. The device has two springs, one on each side of a wall through which the pipe passes. The springs encircle the pipe under tension to close the pipe when the pipe becomes soft from heat generated in a fire.

U.S. Patent 4,559,745 to Wexler discloses a device for "shutting-off" plastic pipes in the event of a fire. The device includes a collar having an intumescent material packed therein, a refractory fabric, and a tension spring. The collar and intumescent material are embedded in a wall or floor of a building. The refractory fabric encircles the outside of the plastic pipe inside and outside of the wall or floor. The tension spring is located outside of the wall and is placed circumferentially around the refractory fabric and plastic pipe .

The device of U.S. Patent 4,559,745 has at least two deficiencies. Firstly, the tension spring is located in a position that hinders activation of the intumescent material. When the tension spring constricts about the pipe, hot gasses are restricted from passing through the pipe to the intumescent material. The intumescent material therefore would not be activated as quickly. Secondly, the spring is not protected from being damaged by heat from a fire. Heat from a fire can damage the tensile properties of the spring, injuring the spring's ability to constrict and seal the plastic pipe.

WO 87/00761 published February 12, 1987 discloses a composite fire stop device having two tension springs, each located on opposite sides of an opening of an annulus of intumescent material. A sheath of refractory fabric is located between the outer surface of the pipe and the intumescent material. Fingers of the refractory fabric are placed around the tension springs to hold the springs to a support sleeve. The device disclosed in this patent possesses the same problems discussed above for U.S. Patent 4,559,745: (i) the springs and intumescent material are not positioned in the. device in such a manner that, upon softening of the plastic pipe and closure of the spring(s), heat from the fire can still pass unrestricted through the pipe from the heat source to the intumescent material; (ii) and the spring is not fully protected from heat generated in a fire because there are open spaces between the fingers of refractory fabric.

SUMMARY OF THE INVENTION

The above-noted problems in the art are overcome by the new and improved plastic pipe sealing device of this invention. This new plastic pipe sealing device has a collar with an opening for a plastic pipe to pass therethrough. The collar contains a first and second means for sealing the plastic pipe. The first sealing means seals the plastic pipe when heat from the fire causes that pipe to become soft. This occurs before the second sealing means acts to seal the plastic pipe. The second sealing means acts to seal the plastic pipe after being exposed to a sufficient amount of heat. The first and second sealing means are arranged in the collar so that when the device is mounted in or on a partition the first sealing means is located closer to the center of the partition than at least a portion of the second sealing means. Upon closure of the plastic pipe by the first sealing means, the plastic pipe still has a portion of the pipe open in communication with the fire or heat source. This open portion permits heat to more readily reach at least a portion of the second sealing means to induce its closure of the opening.

A preferred first sealing means of the invention includes a radially compressive means such as a helical spring. The radially compressive means can be protected from heat damage by being completely enclosed in a means for protecting the radially compressive means. Such a protecting means can include a layer of a fire-resistant, deformable, heat-insulating material. This kind of material protects the tensile properties of the radially compressive means from damage caused by heat, and it also assists in sealing the plastic pipe.

Thus an object of the invention is to provide a device for sealing a plastic pipe in the event of a fire, which can seal the plastic pipe without restricting the flow of heat to a heat-activatable sealing means such as an intumescent material.

Another object of the present invention is to provide a device for sealing a plastic pipe which insulates a radially compressive means such as a spring from heat generated by a fire so as to preserve the spring's function.

The above objects and other novel features of the invention are more fully described and illustrated in the following detailed description and accompanying drawings, where like reference numerals are used to designate similar parts. It is to be expressly understood, however, that the description and drawings are for the purposes of illustrating the invention and are not to be read in a manner that would unduly limit the scope of this invention.

As used herein, the term "plastic pipe" means any conduit composed of a substance(ε) that permits the conduit to soften or melt after being exposed to heat from a fire.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a device for sealing a plastic pipe in the event of a fire in accordance with the present invention.

FIG. 2 is a partial cross-sectional view taken along lines 2-2 of FIG. 1 illustrating a device for sealing a plastic pipe in the event of a fire in accordance with the present invention.

FIG. 3 is a perspective view of a helical spring for use in the devices depicted in FIGs. 1, 2, 4, and 5.

FIG. 4 is a partial cross-sectional view of a further embodiment of the present invention illustrating a radially compressive means inside a collar adjacent to a partition. FIG. 5 is a cross-sectional view of a further embodiment of the present invention illustrating a radially compressive means located centrally in a collar.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In describing the preferred embodiments of the present invention, specific terminology will be used for the sake of clarity. The invention, however, is not intended to be limited to the specific terms so selected, and it is to be understood that each term so selected includes all the technical equivalents that operate similarly. Looking first to FIGs. 1 and 2, a collar 12 is illustrated that contains a first and second means 13 and 15, respectively, for sealing a plastic pipe 22. First pipe sealing means 13 can include a radially compressive means such as the spring identified by the numeral 34. Spring 34 is shown encircling plastic pipe 22 under tension adjacent collar 12. In a fire, tension from spring 34 causes a progressive strangling of plastic pipe 22 as the pipe softens and becomes ductile from heat generated by the fire. Tension spring 34 is shown to be contained within an enclosure 30 that will contract in conjunction with spring 34 to seal pipe 22 in the event of a fire. Enclosure 30 is comprised of a fire-resistant, deformable, heat-insulating sheet material that insulates spring 34 from heat so that it can maintain its function for a longer duration while being exposed to high temperatures generated in a fire. This kind of protection is maintained at least until the commencement of the effect of the second sealing means 15. Second sealing means 15 can include a heat-activatable intumescent material identified by numeral 26.

Tension spring 34 can be attached to an inner side of enclosure 30 by suitable fastening means, for example, by sewing. In the embodiment of FIGs. 1 and 2, a layer of the fire-resistant, deformable, heat-insulating material is folded at 32 with the spring being located in the looped end between superimposed layers. Upon contraction of spring 34, enclosure 30 contemporaneously closes therewith to assist in sealing the plastic pipe to prevent passage of flames, smoke, gases, and the like. Preferably, two layers of folded material 30 extend into collar 12 radially inward of intumescent material 26. Enclosure 30 can be made of a flat blank of sheet material that is wrapped around plastic pipe 22. The flat blank of sheet material has a first portion that is located radially inward of an opening of an annulus of intumescent material 26, a second portion that is folded at 32 about spring 34, and a third portion that is located radially inward of an opening of an annulus of intumescent material 26. Alternatively, enclosure 30 can be a double-layered hose. In this event, enclosure 30 will be slid over plastic pipe 22 prior to its assembly. It is preferred that the layer of fire-resistant, deformable, heating insulating material be wrapped around the plastic pipe for a distance of at least one half the diameter of the plastic pipe.

Enclosure 30 preferably consists essentially of a deformable textile fabric that is fire-resistant and heat-insulating, preferably made from high temperature resistant inorganic filaments such as ceramic filaments, for example, alumina-silica-boria fibers. Two examples of alumina-silica-boria fibers are indicated as follows:

62% Al₂0₃ 24% Si0₂

14% B₂0₃ or

70% Al₂0₃ 28% Si0₂ 2% B₂0₃

Fabrics made from these filaments are available from 3M under the trademarks NEXTEL 312 and NEXTEL 440.

The fabric of enclosure 30 preferably . is relatively smooth so that no parts or filaments of the enclosure extend between the turns of spring 34, which could prevent the spring from being completely contracted. The fabric preferably has a relatively small mesh to restrict flames, gases, smoke, and contaminates from passing therethrough.

In the event of a fire, a typical plastic pipe will soften when it reaches a temperature of about 80 to 140 °C. Upon a softening or melting of pipe 22, spring 34 under tension contracts and takes along the associated part of enclosure 30, forming a barrier that prevents penetration of flames, smoke, gases, and other corrosive, aggressive or toxic gases. Enclosure 30 protects spring 34 so that it will not be rendered useless by the influence of heat. The above-mentioned examples of fabric for the enclosure may resist temperatures of up to 1200 °C to effectively protect the spring for at least about 15 to 20 minutes. The device works with smoldering fires and high intensive fires, for example, fires with oil, gas, solvents, etc. Enclosure 30 together with spring 34 thereby forms a temporary sealing of the opening duct until the intumescent material 26 has had sufficient time to react and to expand.

A nonwoven material made of inorganic fibers could also be used as an enclosure 30. The nonwoven material should be selected to provide properties similar to the above-mentioned fabric.

Turning to FIG. 3, a spring is illustrated that can be used in the present invention. The spring preferably is helical and preferably is made of stainless steel. The spring can be designed and dimensioned such that a ductile plastic pipe is compressed to a fraction of its diameter. As shown in the figure, spring 34 has a hook 36 at at least one end to retain the spring in an annular shape. Spring 34 is wound around plastic pipe 22 under tension. As illustrated, two layers of enclosure 30 may be wrapped about plastic pipe 22 radially inward of intumescent material 26 extending through opening 24 in partition 30. Enclosure 30 may extend beyond collar 12 to a greater or lesser extent, but preferably extends at least partially within an opening of an annulus of the intumescent material 26.

As shown in FIGs. 1, 2, and 4, collar 12 can have a means for fastening the device to a partition such as a wall. Such a means can be a radially fastening portion or flange 14 which can be attached to wall 10 by using means such as screwboltε 16. Collar 12 also comprises a tubular portion 18 extending from the inner end of radial flange 14 away from wall 10. An annular radially inwardly facing portion 20 is shown at the end of tubular portion 18, portion 20 extending proximately adjacent to the outer side of plastic pipe 22. Plastic pipe 22 extends through tubular portion 18 of collar 12 and an opening 24 of wall 10. Collar 12 can resemble, for example, the collar of the German Utility Model Application 89 07 017 in regard to structure. Collar 12 can be formed, for example, from two heat-resistant metallic semi-cups. A plurality of layers of an intumescent material

26 can be positioned in tubular portion 18. The intumescent material greatly expands in volume upon exposure to heat in the event of a fire. Intumescent fire protection material is commercially available as a deformable preproduct in the form of tapes, plates, strips or the like. In most cases, a resilient plastic material is used which expels steam during the intumescing process. A material distributed by 3M under the designation FS 195 AA is suitable. Intumescent materials are disclosed in U.S. Patents 4,234,639 and 4,273,879.

Turning to FIG. 4, a further preferred embodiment of the invention is illustrated. In this embodiment, the first and second means 13 and 15 for sealing plastic pipe 22 are contained in collar 12. First means 13 (such as a spring 34 and a layer of fire- resistant, deformable, heat-insulating material) is arranged in collar 12 so that when the device is mounted to partition 10, the first sealing means 13 is located closer to the center of partition 10 than the second sealing means 15. Upon closure of the first sealing means 13, plastic pipe 22 will still have a portion 17 open providing communication between the heat source and the second sealing means 15 (such as an intumescent material 26). Spring 34 is located in a portion of collar 12 that is adjacent to partition 10 when the device is mounted. The intumescent material 26 is located further away from partition 10, closer to annular end face portion 20. The plastic pipe 22 therefore can be sealed by the spring 34 without restricting the flow of heat from a fire to intumescent material 26, thereby providing for an earlier closure of the plastic pipe 22 by the intumescent material. Turning to FIG. 5, a further preferred embodiment of the invention is shown. In this embodiment, spring 34 is located centrally in collar 12'. Collar 12' has a tubular portion 18' and annular radially inwardly facing portions 20'. Intumescent material is located in collar 12' on opposite sides of spring 34 as indicated by numerals 25 and 27. This embodiment is particularly suitable for placement within a partition 10. As with the embodiment shown in FIG. 4, this embodiment also allows plastic pipe 22 to be sealed by spring 34 without obstructing heat flow to the intumescent material 26. This embodiment of the device possesses this advantage for fires originating on both sides of a partition 10.

In the embodiment of FIG. 5, the fire-resistant, deformable, heat-insulating material can protect spring 34 by, for example, placing one layer 29 of such material radially inward of first and second portions of intumescent material 25 and 27, respectively, and radially inward of spring 34. A second layer 31 of fire-resistant, deformable, heat-insulating material can be placed radially inward of first and second portions of intumescent material 25 and 27 and radially outward of spring 34 to completely surround spring 34. The layers can be joined at the spring 34, for example, by sewing the layers together.

Various modifications and alterations of the invention will be apparent to those skilled in the art. Accordingly, the present invention is to be defined by the limitations contained in the claims and equivalents thereof. It is to be understood that this invention may be suitably practiced in the absence of any element not specifically disclosed herein.

Claims

CLAIMS :

1. A device for sealing a plastic pipe mounted through an opening in a partition in the event of a fire, the device comprising: a collar having an opening for a plastic pipe to pass therethrough, the collar containing first and second means for sealing the plastic pipe, the first sealing means acting to seal the plastic pipe upon softening of the plastic pipe before the second sealing means acts to seal the plastic pipe, the second sealing means acting to seal the pipe after being exposed to a sufficient amount of heat, the first and second sealing means being arranged in the collar so that when the device is mounted in or on a partition the first sealing means is located closer to a center of the partition than at least a portion of the second sealing means, whereupon closure of the plastic pipe at the first sealing means the plastic pipe has a portion thereof open in communication with the fire or heat source to permit heat to more readily reach the at least a portion of the second sealing means.

2. The device of claim 1, wherein the collar includes a means for mounting the device to an outside surface of a partition, the first sealing means being located within the collar on a portion that would be closer to the partition when the device is mounted than the at least a portion of the second sealing means.

3. The device of claim 1, wherein the second sealing means has two portions, each located on opposite sides of the first sealing means.

4. The device of claim 3, wherein the first sealing means is a radially compressive means located centrally in the collar and the second sealing means comprises first and second portions of intumescent material, the first and second portions being located on opposite sides of the radially compressive means.

5. The device of claim 1, wherein the first sealing means includes a radially compressive means for closing the plastic pipe, the radially compressive means has an opening for the plastic pipe to pass therethrough and is under tension when the plastic pipe is located within the opening of the radially compressive means, and the radially compressive means is completely enclosed within a layer of fire-resistant, deformable, heat insulating material.

6. The device of claim 1, wherein the collar has a fastening portion adapted to be attached to a partition, a tubular portion extending axially away from the fastening portion, an annular end face portion being located at an end of the device away from the fasting portion and extending radially inwardly, and wherein the first sealing means includes at least one spring that is in tension when the device is placed about a plastic pipe, the second sealing means includes an intumescent material, the intumescent material being located within the collar closer to the annular end face portion that the at least one spring.

7. A device for sealing a plastic pipe in the event of a fire, which comprises:

(a) a radially compressive means for closing the plastic pipe in the event of a fire, the radially compressive means having an opening for the plastic pipe to pass therethrough and being under tension when the plastic pipe is located withing the opening; and

(b) a means for insulating the radially compressive means from heat in the event of a fire, the insulating means completely enclosing the radially compressive means.

8. The device of claim 7, further comprising a collar having an opening for a plastic pipe to pass therethrough, the collar containing an intumescent material that will expand and constrict the plastic pipe in the event of a fire, the insulating means providing heat insulation to the radially compressive means to prevent its failure until the intumescent material, begins to expand.

9. The device of claim 7, wherein the radially compressive means includes a spring encircled by a layer of fire-resistant, deformable, heat-insulating material.

10. The device of claim 9, wherein the fire- resistant, deformable, heat-insulating material can insulate the spring at temperatures up to 1200 °C for at least about 15 to 20 minutes.

11. The device of claim 9, wherein the layer of fire-resistant, deformable, heating insulating material comprises alumina-silica-boria filaments, and the spring is made of stainless steel.

12. A device for sealing a plastic pipe extending through an opening in a wall in case of fire, comprising a collar having a fastening portion adapted to be attached to the wall and a tubular portion extending axially away from the wall and accommodating the plastic pipe within an opening, an annular end face portion being located at an end of the tubular portion away from the wall and extending radially inwardly towards the plastic pipe, and a lining comprising an annulus of intumescent material positioned at a radially inward side of the tubular portion, a spring which encircles and engages the plastic pipe under tension when the device is located about the plastic pipe, and an enclosure of fire- resistant, deformable, heat-insulating material is disposed about the plastic pipe extending into the tubular portion of the collar between the plastic pipe and an opening of the annulus of intumescent material, the enclosure completely surrounding the tension spring.

13. The device of claim 12, wherein the spring is placed in the collar further away from the annular end face portion than at least some of the intumescent material .