1. Field of the Invention
The present invention relates generally to the field of fire safety devices, and more specifically to fire barrier assembly for preventing fire and smoke from spreading from room to room through openings in building partitions for plastic pipes, the assembly including a metal tube having an outer diameter sized to fit snugly through the partition opening and an inner diameter larger than the outer diameter of the pipe so that there is an annular space between the pipe and the metal tube, a flange plate tack welded to a lip extending radially outward from one end of the metal tube to abut the partition around the opening, fastener ports in the flange plate through which fasteners are inserted into the plywood concrete form for the building partition to anchor the assembly in place, an annular gasket fit snugly into the tube and against the flange plate for snugly receiving the plastic pipe to act as a smoke barrier around the pipe, and strips of intumescent material within the annular space between the tube and the pipe extending from the tube toward the pipe but spaced apart from the pipe to permit some lateral variation in pipe location relative to tube location, the intumescent material being provided to act as a fire barrier by expanding to close the partition opening and block the passage of fire when the fire melts the plastic pipe and smoke barrier gasket.
2. Description of the Prior Art
In partitions such as floors, walls and ceilings made of poured concrete it is necessary to have openings for admitting pipes conducting liquids such as water and liquid wastes and the like. In order to prevent fire from spreading from one side of a partition to the other side, such openings must contain fire resistant materials in order to meet existing fire protection codes.
In recent years it has become the practice to use pipes made of plastic, such as polyvinyl chloride instead of steel, cast iron and copper as used in earlier times.
Since plastic pipes become soft, melt and burn at elevated temperatures that normally would not affect metal pipes, it has become necessary to introduce a fire barrier that obturates not only the space around the pipes, but also the empty space remaining after a plastic pipe has melted or burned away.
Several patents have disclosed devices for solving this problem. U.S. Pat. No. 4,796,401, for example, shows a composite fire stop device including a collar that can slide over a plastic pipe and fill the space between the poured concrete and the pipe. The collar includes an intumescent material packed around the collar, and circular tension springs that constrict the pipe as it becomes soft from the heat of the fire, while the intumescent material expands and obturates the void created by the melting pipe. U.S. Pat. No. 4,538,389 shows a fire-break device which includes a two-part collar of substantially incombustible material mounted around the pipe, and a slidable flange filling a space between the pipe and the collar. U.S. Pat. No. 4,221,092 shows a fire barrier including a packing of intumescent material packed into the space between a pipe and the poured concrete.
These prior fire barrier devices have, however, certain disadvantages in that they do not show a self-contained single assembly that can be readily installed on a construction site, and become an integral part of the pipe system. These prior systems also generally restrict the pipe to an exact location relative to the barrier device, needlessly burdening the builder with a requirement for precision installation. Applicants' invention overcomes these problems by providing a self-contained, one piece assembly that is an integral part of a pipe system for fluid-filled and air-vented PVC pipe systems, which has the further advantages of including a metallic casing that allows the firestop material to be replaced if needed, and has no external parts to activate or control intumescent action. Furthermore, it avoids the need for drilling holes in concrete partitions and it avoids unnecessary cutting and splicing of PVC pipe. Finally, there is a space between the pipe and the intumescent material to permit some lateral play in the pipe location relative to the apparatus, to accommodate common construction inaccuracies.
More recently, there is the Fire Barrier Device of the present applicant MacMillan, U.S. Pat. No. 5,105,592, issued on Apr. 21, 1992. This device overcomes many of the problems presented by the existing art, but still has more parts and greater complexity than is necessary to accomplish the intended function.
It is thus an object of the present invention to provide a very simple fire barrier assembly, having a minimal number of parts, which is very inexpensive to manufacture.
It is another object of the present invention to provide such an assembly which may be embodied in a pipe box beneath a bath tub to receive the drain and vent pipes where these pipes converge into a single pipe, to provide a fire barrier in the floor opening for the single pipe.
It is still another object of the present invention to provide such an assembly which accommodates various lateral pipe positions relative to the apparatus to permit minor construction, adjustment and maintenance inaccuracies in apparatus or pipe location.
It is still another object of the present invention to provide such an assembly which is reliable and durable.
It is finally an object of the present invention to provide such an assembly which is easy and inexpensive to install.