AU718072B2 - Improvements in fire collars - Google Patents

Description

S.

45649 AWT:KP P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: FYREGUARD PTY. LTD.R- roooJ re,,or. SEC Name of inventor: 11 JON WEXLER r S" Address for Service: COLLISON CO., 117 King William Street, Adelaide, S.A. 5000 Invention Title: IMPROVEMENTS IN FIRE COLLARS S. Details of Associated Provisional Applications: PN7193 dated 18th December 1995 The following statement is a full description of this invention, including the best method of performing it known to us: FIELD OF INVENTION This invention is of an improved form of fire collar for sealing of plastic pipe penetrations through walls and floors of buildings.

BACKGROUND TO THE INVENTION In the event of fire in a building where walls or floors are penetrated by pipes of PVC, Polyethylene, Polypropylene, CPVC, ABS, or other thermoplastic material, to prevent passage of fire through the penetrated element it is necessary to provide a device which can provide an appropriate sealing function.

Such devices are commonly known as fire collars. They are commonly but not exclusively of a toroidal shape which surrounds the pipe and consists essentially of a heat activated, chemically intumescent packing contained within an outer metal shell. The shell constrains thermal expansion of the intumescent packing so as to direct it radially inwards to occupy the space vacated by the plastic pipe as it softens and decomposes in a fire.

Less commonly the fire collar shell can be of transverse rectangular periphery, with circular holes in opposing ends for the pipe to pass through and containing rectangular shaped packs of intumescent which expand under fire conditions to squash the pipe flat instead of crushing it inwards in a mainly 20 radial direction.

Fire collars of toroidal shape commonly have cylindrical lengths from 50% to 100% of pipe diameter, inside diameters a close fit around the pipe, and outside diameters varying from perhaps 120% to 150% of pipe diameter.

These size variations depend the type and effectiveness of chemically intumescent packing utilised, and the configuration in which the fire collar is to be mounted with respect to the wall or floor surface involved.

One typical configuration is retrofitting when the pipe has been built into a wall or floor, after which it is then required to fit a collar around the pipe and attach it to the wall or floor surface. In the event of fire the entire collar body is in 30 contact with the heating medium and heats up relatively quickly, activating the intumescent packing at an early stage to achieve an effective closure.

When the fire collar is built within the thickness of a wall this avoids protrusion into the space in which fire may occur. In this case heating of the collar can only occur through the much smaller area at its exposed end, and closure takes place more slowly. With certain types and/or larger sizes of pipe this rate of closure can be so slow, that after the fire exposed end of the pipe has melted or burned away, hot fire gases can pass through the pipe in sufficient quantity and length of time to cause collapse and falling away of pipe at the unexposed side of the wall. This then leaves an unclosed opening through which the fire can pass.

1 0 Other circumstances in which fire collars are found to react insufficiently quickly include protection of very large diameter pipes, pipes locally thickened with the occurrence of joiner or fitting sockets, or configurations where the collar material is set back from the exposed face of a wall or floor so that it receives correspondingly slower heating.

1 5 It is known to improve the speed of operation of chemically intumescent fire collars by incorporation of supplementary mechanical means, for example in collars of rectangular cross section by having pivoted metal flaps in front of the intumescent packing which are driven inwards to accelerate occlusion of the opening as intumescence initiates. Such collars tend to be of expensive and heavy construction when configured as retrofits, because their geometry does not inherently provide the hoop strength under fire conditions comparable to that of a circular perimeter.

With collars of cylindrical shape and size limitations described the geometry is less conducive to operation of simply pivoted flaps or the like; sliding 25 mechanisms such as iris diaphragms are feasible but difficult to incorporate or ***engineer reliably. One effective enhancement device has been the spring choker, consisting of a preliminary wrap of refractory cloth around the pipe underneath the collar and projecting outwardly by a diameter or so, over which a stretched spring in hoop tension is applied and set in place. When the 3 0 pipe softens at the onset of fire the spring contracts and pulls in the refractory *cloth to choke down the opening, and is retained from falling away by the continuation of refractory cloth trapped between the collar and the pipe. This rapid choking action substantially diminishes early hot gas flow through the opening and avoids the overheating and consequent failure described above.

*I~

The above form of spring choker, however, requires a relatively complicated installation procedure additional to that for application of the collar, as well as separate provision to the building site of expensive wrapper and spring elements.

Installation is even more difficult when access to a wall such as a shaft wall may only be from one side, but symmetrical fire performance from both sides is required. In such conditions the wrapper with front and back springs have to be pre-mounted on a plastic sleeve concentric to the pipe, and which with much inconvenience must be either fitted over the pipe end prior to completing the pipe run or else when the pipe is cut open and rejoined.

It is the object of this invention to provide a fire collar arrangement which will overcome the above disadvantages or at least provide the public with a useful alternative.

DISCLOSURE OF THE INVENTION In one form the invention is said to reside in a choker spring assembly adapted to be positioned around a plastics material pipe to contract in the event of melting or softening of the pipe to compress and assist in closing off the pipe, the choker spring assembly including a spring and a meltable former to hold it in a shape to surround the pipe such that on the application of heat the former is adapted to melt *to allow the spring to contract to compress the pipe, wherein the spring is a spiral form extension spring and the former is positioned within the spring.

The former may be adapted to be supported on a frame arrangement to hold the spring in an extended position so that a pipe can be inserted into the choker spring S* assembly.

In an alternative form the invention is said to reside in a fire collar comprising a housing adapted to surround a pipe in use, intumescent material in the housing and a choker spring assembly within at least one end of the housing, the choker spring assembly adapted to contract in the event of melting or softening of the pipe to compress the pipe to thereby close off the pipe, the choker spring assembly including a spring and a meltable former to hold it in a shape to surround the pipe such that on the application of heat the former is adapted to melt to allow the spring to contract to compress the pipe and means to support the former with respect to the housing or the intumescent material to hold the choker spring with respect to the housing, wherein the former is made from a thermoplastic resin or a high melting Spoint wax.

Preferably the means to support the former comprise attachment points being screws or similar which extend through the former and fasten into the housing or the intumescent material.

In this embodiment of the invention the housing comprises a cylindrical body with annular end caps, an aperture in each of the end caps being for the pipe to pass through in use.

The cylindrical body may have a longitudinally slit and the end caps each have a transversely split so that the housing may be opened on a longitudinal axis diametrically opposite to the longitudinal slit to enable the fire collar to be placed around a pipe.

There may be further included a line of weakness defining the longitudinal axis diametrically opposite to the longitudinal slit. The line of weakness may be defined by a partial longitudinal slit or by a longitudinal crease in the cylindrical body.

*"o ::The former may be joined to the body adjacent the longitudinal slit and end loops of the spring may be connected to the body adjacent the longitudinal slit.

There may be further included a third attachment point for the former diametrically opposite the longitudinal slit such that, when the collar is subjected to fire the former melts and then softens the penetrating pipe, the spring contacts to squash the pipe by spanning in two parallel strands across the diameter of the hole, and is retained in this configuration by the diametrically opposite attachment points within the collar assembly.

The third attachment point may be a screw or similar projecting piece fastened to S* the housing which extends an appropriate distance past the body of the spring to effect the above described diametral retention.

Preferably the former is made from a thermoplastic resin or a high melting point wax.

SLL.

A/V

In an alternative form the invention may be said to reside in a fire collar and choker spring assembly, the fire collar being of a type having a cylindrical body and a longitudinal split in the cylindrical body and having a longitudinal line of weakness diametrically opposite the longitudinal split such that the collar can be opened to be placed around a plastics material pipe, the choker spring assembly being retained in the fire collar such that when a pipe is inserted into the collar the choker spring assembly is extended to fit around the pipe.

The choker spring assembly may be retained in the collar at two points 1 0 respectively each side of the longitudinal slit such that when the collar is not surrounding a pipe the spring is in a relaxed state and when the collar is opened the spring is stretched and extends around the pipe when the pipe is inserted.

There may be a third mounting point for the choker spring assembly opposite 1 5 the split adjacent the hinge region of the collar so that in the unstressed condition the spring extends across the opening in which the pipe is placed in use.

Hence it will be seen that by this invention the above disadvantages are overcome by providing a pre-stretched circumferential choker spring which may be assembled within and attached within a toroidal fire collar assembly of conventional shape, said spring having end loops terminating adjacently but not interlocking at attachment points within the collar so that the collar can if desired by opened and closed to retrofit around a pre-installed pipe. The attachment points may be screws or similar which extend through the former and fasten into the housing or the intumescent material.

The simple cylindrical body is well adapted for insertion in an aperture in a wall or floor without protrusion into the space on either side of the wall or floor.

This generally describes the invention but to assist with understanding the invention is further explained by reference to FIG 3 of the attached drawings.

3 0 BRIEF DESCRIPTION OF THE DRAWINGS In the drawings FIG 1 shows one embodiment of a fire collar according to this invention; FIG 2 shows a cross sectional view of the fire collar according to the embodiment of FIG 1; FIG 3 shows an alternative embodiment of a fire collar according to this invention; FIG 4 shows a cross sectional side view of the fire collar of FIG 3; FIG 5 shows a transverse cross section of the fire collar of FIG 3; FIG 6 shows a further transverse cross section of the fire collar of FIG 3; FIG 7 shows a transverse cross section of a further embodiment of the 1 0 invention without a pipe in the collar; FIG 8 shows the embodiment of FIG 7 with the pipe installed.

FIG 9 shows a transverse cross section of a further embodiment of the invention without a pipe in the collar; and FIG 10 shows the embodiment of FIG 9 with the pipe installed; and 15 FIG 11 shows the embodiment of FIG 9 with the pipe compressed by the choker spring after heating.

BEST MODE FOR CARRYING OUT THE INVENTION The embodiment of fire collar and choker spring assembly shown in FIGS 1 and 2 of the drawings comprises a cylindrical metal tube 1 with annular end olO*caps 2 at each end. Within the end caps 2 and at each end of the tube 1 there is a toroidal helical form choker spring 3 at each of end of the tube which is O *held in place by means of a meltable former 4. The former has a split 5 in it to S* 25 enable it to be inserted into the choker spring. Also within the cylindrical housing 1 is an intumescent material 6.

In ucp 9 C In use, a plastics material pipe 7 is inserted through the fire collar. In the event of a fire from either end of the fire collar the meltable former 4 in the respective choker spring 3 melts releasing the spring 3 to compress the pipe 7 as the fire softens the pipe. As it also heats up the intumescent material 6 expands to close off the aperture into which the fire collar has been inserted.

In the embodiment shown in FIGS 3 to 6 a fire collar and choker spring assembly is shown.

The assembly comprises a rolled cylindrical sheet steel casing 10 which is unjoined along the meeting edges 11. The casing 10 can be bent open about a diametrically opposite longitudinal line 13. This diametrically opposite longitudinal line 13 may be a crease line or may be a region of weakening formed by a partial longitudinal slit 14. There are pressed metal or spun sheet metal split ends 15 fixed to the cylindrical sheet steel casing by spot welding or other means. Each metal end has a central aperture 16 to accommodate passage of the penetrating pipe (not shown). The ends 15 are radially split at 17 to allow their halves to move apart when the cylindrical casing 10 is bent open for mounting the fire collar around a pipe. A catch arrangement 18 is provided to hold the casing together with the meeting edges in the closed position.

Stretched tension springs 19 at each end of the cylindrical casing are held open by means of an internal former 20 which is locked axially by end plugs 21. The springs have end loops 22.

V The former 20 is conveniently of rod or tube section and made from a thermoplastic resin or other flexible relatively low melting and softening point material. End plugs 21 are conveniently short lengths of rod threaded to mate i.

o 25 internally with the spring diameter and pitch but can take alternative forms such as washers or shaped plates secured by screws or ties. The springs 19 are of a length suited to encircle the internal apertures 16 of the casing when sufficiently extended and of a diameter to fit snugly inside a groove or step 23 provided at either end of a toroidally shaped intumescent packing 24 which 30 fits within the casing 10 and end caps Three spring anchors 25 and 26 are arranged to project through each end .piece 15 from outside and are conveniently in the form of self-tapping screws with heads being down against the end surfaces. The twin screws adjacent to the meeting end have their shanks passing directly through the spring end loops 22 and then some distance into the intumescent material 24 behind. The single screw 26 at the opposite diameter has its shank projecting close to the body of the spring which it passes inside of the spring's circular aperture and again penetrates a short distance into the intumescent packing 24 behind the spring.

The arrangement according to the embodiment of this invention allows for the collar to be retro-fitted around an existing pipe by release of the catch 18, spreading open of the casing 10 containing its flexibly mounted intumescent packing 24 and springs 19 by hinging or bending about the longitudinal line 13 diametrically opposite to the opening 12, encircling the pipe and then reclosing the assembly about the pipe and re-activating the catch 18. In its simplest form the catch 18 is a hook attached to one meeting edge which releasably engages with a loop or matching hook attached to the opposite edge. The catch elements may be rigidly fixed at the meeting edges or engaged and disengaged by axially stretching the collar body or the catch elements may be pivotably mounted to engage and disengage by articulation at their pivots.

The casing ends 15 are optionally perforated as shown at 27 to allow faster heat transfer to the internal intumescent packing 24 from an external fire source.

n the event of commencement of fire conditions, heat is first transmitted through one or the other of the collar ends 15 to reach the thermoplastic spring former 20 which softens and subsequently melts. This allows the stretched spring to contract its length and reduce its internal circular diameter to that of the penetrating pipe running through the centre of the collar. Then as heat progressively affects the plastic pipe it to will soften and deform under further contraction of the spring. The spring is retained inside the collar at its anchor points 15 and 16 so that as it contracts it pulls into two parallel diametral lines across the aperture tending to squash the softening decomposing pipe flat in between the spring lines. This closing action of the i spring traps the carbonised pipe remanent within the aperture providing an immediate partial blockage to limit the volume flow of fire gases through the aperture and pipe continuation on the unexposed side of the fire separation.

35 The internal passage of heat through the penetration is thereby maintained in a limited condition until a full seal eventually results from expansion of the intumescent packing when it becomes sufficiently activated.

The embodiment of fire collar and choker spring assembly shown in FIGS 7 and 8 does not use a meltable former within the spring.

In this embodiment the choker spring 30 is mounted at its respective ends to a split end cap 31 fitted into the body of a housing 32. The length of the spring is such that when the fire collar is opened by bending around the crease point 33 and a pipe 34 is inserted into the collar the spring is extended as shown in FIG 8. The collar can then be locked by means of a clip arrangement In the embodiment of fire collar and choker spring assembly shown in FIGS 9, and 11 the choker spring 40 is retained at its end by pins 41 either side of the opening side of the body 42. A further pin 43 is diametrically opposite the opening portion near the crease point 44.

Once again when a pipe 45 is inserted into the collar when it is opened the spring 40 is expanded to extend around the pipe. When a fire occurs and the pipe 45 is able to be compressed after softening, the spring tends to form the shape as shown in FIG 11 with the fire softened pipe 45 compressed between two substantially parallel lengths of spring 40 extending between the pins 41 and pin 43 on opposite sides of the housing.

*i The invention described functions as an improved plastic pipe or other thermally collapsible service element penetration fire stopping means in situations where prior art devices have been found ineffective due to insufficiently rapidity in effecting closure of an opening after initial de-cost composition of the penetrating service.

It will be seen that in one form the invention essentially comprises a toroidally shaped fire collar for insertion at a fire separation wall or floor having outer sheet material cylindrical container or canister having a thermally intumescent packing which is optionally longitudinally split to open, encircle and be reclosed about a penetrating thermoplastic pipe or service and provided with tension springs which may be held on an internal thermoplastic former. The spring is longitudinally curved to a circular shape with internal diameter 11 slightly large than that of the penetrating service and fixed within the body of the collar. The spring may be optionally fixed at its two end loops and a point or points diametrically opposite to allow it to open and close with the collar and under fire conditions to contract to form parallel diameter lines across the penetration aperture. The invention is not so limited to the particular examples described but can also be in the form of an unsplit toroidal shape collar with pre-stretched thermoplastically releasable springs within or immediately without the fire collar body. The springs have end loops optionally joined or anchored apart or together.

1 0 The fire collar can also be in the form of a collar of rectangular or other polygonal cross-section with the stretch spring retained to conform with the polygonal periphery.

Throughout this specification unless the context requires otherwise, the words comprise and include and variations such as comprising and including will be 1 5 understood to imply the inclusion of a stated integer or a group of integers but not the exclusion of any other integer or group of integers.

@0 0 *0 *oo co•

Claims (32)

1. A choker spring assembly adapted to be positioned around a plastics material pipe to contract in the event of melting or softening of the pipe to compress and assist in closing off the pipe, the choker spring assembly including a spring and a meltable former to hold the spring in a shape to surround the pipe whereby on the application of heat the former is adapted to melt to allow the spring to contract to compress the pipe, wherein the spring is a spiral form extension spring and the former is positioned within coils of the spring.

2. A choker spring assembly as in Claim 1 wherein the former is adapted to be supported on a frame arrangement to hold the spring in an extended position so that a pipe can be inserted into the choker spring assembly.

3. A choker spring assembly as in Claim 1 or Claim 2 wherein the former is made from a thermoplastic resin or a high melting point wax.

4. A fire collar comprising a housing adapted to surround a plastics material pipe in use, intumescent material in the housing and a choker spring assembly within at least one end of the housing, the choker spring assembly adapted to contract in the event of melting or softening of the pipe to compress the pipe to •thereby close off the pipe, the choker spring assembly including a spring and a meltable former positioned within coils of the spring, to hold the spring in a shape i:, F to surround the pipe whereby on the application of heat the former is adapted to melt to allow the spring to contract to compress the pipe and means to support the former with respect to the housing or the intumescent material to hold the choker S.spring with respect to the housing, wherein the spring is a spiral form extension spring.

5. A fire collar as in Claim 4 wherein the means to support the former include attachment points being screws or similar which extend through the former and fasten into the housing or the intumescent material.

6. A fire collar as in Claim 4 wherein the housing includes a cylindrical body with annular end caps, an aperture in each of the end caps being for the pipe to pass through in use. 13

7. A fire collar as Claim 6 wherein the or each end cap is perforated so as to allow access of heat to the former and the intumescent material.

8. A fire collar as in Claim 6 wherein the cylindrical body has a longitudinally slit and the end caps each have a transversely split so that the housing may be opened on a longitudinal axis diametrically opposite to the longitudinal slit to enable the fire collar to be placed around a pipe.

9. A fire collar as in Claim 8 further including a line of weakness defining the longitudinal axis diametrically opposite to the longitudinal slit.

A fire collar as in Claim 9 wherein the line of weakness is defined by a partial longitudinal slit.

11. A fire collar as in Claim 9 wherein the line of weakness is defined by a longitudinal crease in the cylindrical body. a oo.

12. A fire collar as in any one of claims 4 to 11 wherein the former is joined to :the body adjacent the longitudinal slit and respective end loops of the spring are connected to the body adjacent the longitudinal slit on either side thereof.

13. A fire collar as in claim 12 further including a third attachment point for the former diametrically opposite the longitudinal slit such that, when the collar is subjected to fire the former melts and then softens the penetrating pipe, the spring contacts to squash the pipe by spanning in two substantially parallel strands across the diameter of the hole, and is retained in this configuration by the diametrically l opposite attachment points within the fire collar.

:14. A fire collar as in claim 13 wherein the third attachment point is a screw or similar projecting piece fastened to the housing and which extends an appropriate distance past the body of the spring to effect the above described diametral retention.

A fire collar as in any one of claims 3 to 12 wherein the former is made from a thermoplastic resin or a high melting point wax.

16. A fire collar as in any one of claims 3 to 13 including a choker spring ssembly at each end of the housing. h i

17. A fire collar including a one piece hinged openable external housing of a hollow cylindrical shape and containing a packing of heat activated intumescent material, the housing and packing constructed to diametrally open and close to fit around a plastics material pipe, and a spirally wound spring at least one end of the housing, the spring extended and maintained in tension by means of an axially stiff radially flexible former located within coils of the spring, respective ends of the spring being attached to the housing adjacent to joint edges of the housing such that the spring in use extends around a pipe when received within the collar, wherein the former is adapted to melt upon the application of heat whereby the spring contracts and compresses the pipe.

18. A fire collar as in claim 15 wherein the former is made from a thermoplastic resin or a high melting point wax.

19. A fire collar as in claim 17 wherein the housing includes cylindrical body with annular end cap, an aperture in each of the end caps being for the pipe to pass through in use.

20. A fire collar as in claim 19 wherein the or each end cap is perforated so as to allow access of heat to the former and the inturnescent material. *o

21. A fire collar as in Claim 17 wherein the hinge of the hinged housing is deformed by a line of weakness.

22. A fire collar as in Claim 21 wherein the line of weakness is defined by a I partial longitudinal slit.

A fire collar as in Claim 21 wherein the line of weakness is defined by a longitudinal crease in the cylindrical body.

24. A fire collar as in claim 17 wherein the former is joined to the body adjacent the joint edges of the housing.

A fire collar as in claim 24 further including a third attachment point for the former diametrically opposite the joint edges such that, when the collar is subjected to fire the former melts and then softens the penetrating pipe, the spring contacts to squash the pipe by spanning in two substantially parallel strands across the diameter of the hole, and is retained in this configuration by the diametrically opposite attachment points within the fire collar.

26. A fire collar as in claim 25 wherein the third attachment point is a screw or similar projecting piece fastened to the housing and which extends an appropriate distance past the body of the spring to effect the above described diametral retention.

27. A fire collar and choker spring assembly, the fire collar being of a type having a cylindrical body and a longitudinal split in the cylindrical body and having a longitudinal line of weakness diametrically opposite the longitudinal split such that the collar can be opened to be placed around a plastics material pipe, the choker spring assembly being retained in the fire collar such that when a pipe is inserted i: into the collar the choker spring assembly is extended to fit around the pipe.

"28. A fire collar and choker spring assembly as in Claim 27 wherein the choker spring assembly is retained in the collar at two points respectively each side of the longitudinal split such that when the collar is not surrounding a pipe the spring is in a relaxed state and when the collar is opened the spring is stretched and extends around the pipe when the pipe is inserted into the fire collar. *see

29. A fire collar and choker spring assembly as in Claim 28 including a third mounting point for the choker spring assembly opposite the longitudinal split adjacent the longitudinal line of weakness of the collar so that in the unstressed condition the spring extends across the opening in which the pipe is placed in use.

A fire collar and choker spring assembly as in any one of claims 27 to 29 wherein the longitudinal line of weakness is a partial longitudinal slit or a longitudinal bend line pressed in the material of the cylindrical body.

31. A fire collar and choker spring assembly as in any one of claims 27 to wherein the cylindrical body is a housing adapted to surround a pipe in use and RA7 including intumescent material in the housing. 16

32. A fire collar and choker spring assembly as in any one of claims 27 to 31 wherein the choker spring assembly comprises a spirally wound spring. Dated this 3rd day of February 2000 PROMAT FYREGUARD PTY LTD By their Patent Attorneys COLLISON CO a a. a a a a a a a a. a a a a a. a a a a. a a a a. .a a a a a a a (17 -7-z o~