Static structures (e.g. – buildings) – Irreversibly reactive component
Reexamination Certificate
2001-11-02
2004-11-23
Friedman, Carl D. (Department: 3635)
Static structures (e.g., buildings)
Irreversibly reactive component
C052S741300, C052S745210, C428S040100, C428S195100, C156S062000, C156S250000
Reexamination Certificate
active
06820382
ABSTRACT:
Partitions in general, including walls, floors and ceilings in buildings, may have holes in them for passage of items such as vent pipes, drain pipes, plumbing pipes, gas pipes, electrical wiring, conduits to contain electrical telephone and computer wiring, optical fibre, air conditioning ducts, heating ducts and the like. One hole may accommodate one or several such items. Annular spaces between the hole and the item passing through the hole create passages through which heat and fire can spread, especially if a pipe collapses or burns under the influence of heat. It is therefore desired to provide means for filling or blocking these spaces to prevent the spread of heat and fire through the holes. There are devices and materials known for this purpose. These have the disadvantages as they are cumbersome to apply, require tools and skills for their installation, and may require use of metal frames and screws or grout or caulking for their permanent installation. They may require that a seal to prevent passage of heat and fire is formed at the moment of installation. Such devices and materials make reentry to repair or to retro-fit piping and cabling systems difficult. Furthermore, in many cases subsequent visual inspection does not readily reveal whether the device or material has been properly installed or not.
It is an object of the present invention to alleviate some or all of the above-mentioned disadvantages.
SUMMARY OF THE INVENTION
The present invention provides a device that comprises a material that intumesces on exposure to heat, a patch of an adhesive connected to one surface of the intumescent material and a liner that covers the adhesive and is readily detachable from the adhesive by means of a pull, to expose the adhesive.
In another aspect the invention provides a method of providing a fire stop in a space between a hole in a partition and an item passing through the hole, which method comprises wrapping around the item a device as defined above, sliding the device along the item into the hole and pulling on the pull tab to expose adhesive and anchor the device permanently on the item by means of the adhesive.
DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
In the description of preferred embodiments that follows, for purposes of illustration reference is made to a pipe passing through a hole. It should be appreciated that the pipe is merely representative of items that may pass through a hole, and examples of such items are mentioned above.
When the device is in place in a hole and heat from fire is encountered, the intumescent material swells markedly, thereby blocking the hole and preventing passage of heat, flame, smoke and the like. Suitable intumescent materials include flexible fire barrier felts that are disclosed in U.S. Pat. No. 5,830,319, the disclosure of which is incorporated by reference. The felt comprises an organic polymeric binder, organic fibres having pendant hydroxyl groups, for example cellulosic fibres, a heat absorbing compound that is suitably an intumescent compound, for example intercalated graphite, mica, perlite, vermiculite, hydrated sodium silicate, and a phosphorus compound.
One such intumescent material that is suitable for use in the present invention is a flexible fire barrier felt that is available from 3M under the trade-mark Interam Ultra GS. It is available in strips about 2 inches wide and about_inch thick in any length. When exposed to temperatures of at least 300° F. (149° C.) it intumesces rapidly, expanding up to approximately 25 times its original volume. It turns into a hard char that impedes or prevents passage of heat, fire, smoke and gases. The material exerts substantial pressures on items in the hole so that it compresses piping and wiring materials, thus further effecting a seal of the hole against fire, heat, smoke and the like. It also releases chemically bound water that helps to slow temperature rise.
In one simple embodiment of the invention, suitable for use with small holes and small pipes, the patch of adhesive is present directly on a surface of a strip of an intumescent fire barrier felt. The liner is removed from the patch of adhesive, the felt is flexed to permit it to be pushed into the hole and the adhesive attaches either to the exterior surface of the pipe or the interior surface of the hole, where it is held permanently in place. In another simple embodiment the intumescent felt strip is contained in a coating of, for example, a plastic sheet, woven fabric or, preferably, aluminum foil and the adhesive patch is on the coating. The intumescent felt material and the adhesive are operatively connected to each other via the coating, although not in direct physical contact. The coating contains the intumescent material when it first encounters heat and intumesces, so that the expanded material remains contained in the hole and blocks the hole, rather than perhaps being blown around by a fire draught and leaving the hole unblocked. These embodiments are more suited for use with small pipes, up to about 1 inch nominal diameter, and small holes, up to about
1½ inch nominal diameter.
For use with pipes larger than 1 inch and holes larger than
1½ inch it is preferred to enclose the intumescent material in a container.
The container surrounding the intumescent material is preferably flexible and has a certain degree of strength. Suitable materials for the flexible container include plastics materials and mention is made of polyolefins, particularly polyethylene, which heat will melt and may assist in sealing. Another flexible container material that can be used is a metal foil, such as aluminum foil. Yet another material is a fabric, for instance woven fibres of polyamide, polyester, polyolefin, polyacrylate, glass or ceramic or the like. A preferred container, particularly for more stringent conditions, is composed of a thin aluminum sheet or foil attached to a fabric or fiber reinforcing material made of, for instance, polyamide, polyester, glass, ceramic or the like. Suitable materials include fabric net reinforced aluminum foils with polyethylene heat seal layer available from Alpha Associates, Inc., of Woodbridge, N.J., U.S.A particularly the foil available under the designation Alpha) Style 4413-VLS™.
To make a device for use with pipes sizes of about 1½ a inch nominal and greater, the flexible container, when laid flat, is normally elongate and in use is folded to bring one end into contact with the other to form an annulus. In a preferred embodiment the two ends are held in contact by some means. The particular means for holding the ends is not critical. Persons skilled in the art will be able to suggest many possible means for this purpose, for instance a clip or clamp, or tape, or Velcro. Preferred is an adhesive covered with a detachable liner, so that the annulus can be readily made simply by detaching the detachable liner and pressing the two ends of the container together to be held by the adhesive. The demands on this adhesive are not particularly stringent, and suitable adhesives are available from 3M under the designation Scotch™ 467 HiPerformance Adhesive and 468 HiPerformance Adhesive.
A device of the invention can be made by taking a sheet of the flexible material that will form the container. The sheet should be of the approximate length required for the maximum length of the container when flat, plus, if necessary, an allowance for sealing at each end to enclose the intumescent material. It should be of a width sufficient to encompass both the width and the height of the unexpanded intumescent material, plus again, if necessary, an allowance for sealing along one edge. The material can then be folded over the unexpanded intumescent material and sealed along one side and both ends, to form the required enclosure. One suitable way of doing this is by heat sealing, although it is again clear that this could be done by many other means, for instance use of adhesive or even stitching. The flexible container should not be a tight fit over the intumescent ma
Chambers David C.
Whitty Laurence M.
3M Innovative Properties Company
Friedman Carl D.
Nguyen Chi Q.
Patchett David B.
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