Field of the invention

This invention relates to fire collars.

The invention has particular application to fire collars of the type which are "cast-in", that is, fire collars which are placed in concrete walls or floors during construction. However, the invention may have application to other types of fire collars.

Background of the invention

Typically, cast-in fire collars have a housing constructed of a plastics material, for example, pvc or HOPS, which forms a sleeve or passage through which a duct, pipe, cable or other building service passes. Generally, an intumescent material is mounted in the housing and arranged to close off the duct or pipe in the event of fire so as to prevent the egress of smoke and heat to an adjoining room or floor. During construction of a concrete floor, the housing acts as a "former" about which the concrete floor can be poured (and similarly for concrete walls) . Such cast-in fire collars typically have a flange at one end which is adapted to rest on or against the formwork and be secured thereto before the concrete is poured- For that purpose, the flange generally has holes formed therein through which screws or nails can be driven into the formwork. In some such fire collars, the screw holes are formed in frangible portions which are adapted to break away from the housing and remain with the formwork when it is taken off the concrete after curing. However, sometimes the frangible portion does not break away as desired and in consequence the screws pull out of the formwork and remains protruding from the flange of the fire collar with _. its head embedded in the concrete on the other side of the flange. Such protruding screws can impinge on space required for pipes and other services and can also be dangerous to construction workers on the site. Consequently, generally they must be cut off, usually by an angle grinder or other suitable equipment. Another problem faced by constructions workers placing known cast-in fire collars is that they are not as easy to accurately locate in a desired position on the formwork as desired because the locations are usually defined only by a centre line mark which cannot be accurately used without a template or similar device.

The present invention is aimed at providing a fire collar which overcomes or at least ameliorates at least one of the aforementioned problems. To that end, the inventor has found that a fire collar can be secured to the formwork by a single large screw passing through the centre of the housing through which the conduit or pipe about which the collar is to be mounted passes and that the fire collar can be more easily centred at its design location by such an arrangement and that the screw head remains accessible after pouring of the concrete and thereby be easily removed after the concrete has cured.

Summary of the invention

With the foregoing in view, the present invention resides broadly in a fire collar including:

a housing having an outer wall defining a passage having an upper end and a lower end;

heat reactive blocking means in said housing and arranged to expand and substantially block said passage upon reaching a predetermined temperature; and

securement means in said passage, said securement means being operatively connected to said outer wall so as to substantially inhibit undesired lateral movement of said outer wall relative thereto and said securement means being adapted to receive therethrough a fastening screw coaxial with said passage and extending therethrough for fastening the fire collar in a predetermined position to formwork on or against which the fire collar is placed.

Preferably, said securement means has a centre hole or bore therein for receiving the fastening screw and preferably at least a portion of said securement means is between said upper end and said lower end. In a preferred form, said securement means is a top cap portion with a centre shank or stem having a bore therein for receiving the screw with the shank or stem being braced by a plurality of fins or ribs extending therefrom to the outer wall and integrally formed therewith. Suitably, in such form, said top cap portion closes the passage to prevent ingress of wet concrete during pouring of the floor in which it is to be cast in and can be removed after curing of the concrete. Further, the shank or stem and the screw to extend therethrough are designed to hold the housing within an acceptable tolerance of the design position during pouring of the concrete.

In another aspect, the invention resides broadly in a fire collar including:

a housing defining a passage having an upper end and a lower end;

heat reactive blocking means in said housing and arranged to expand and substantially block said passage upon reaching a predetermined temperature; and

locating means in said passage, said locating means being connected to or operatively engaged with said housing and arranged so as to prevent or substantially inhibit lateral movement of said housing relative to said locating means when said locating means is secured to formwork on which the fire collar is to be placed.

Preferably, said locating means is provided at or towards said lower end and arranged to resist movement of the lower end portion of the housing under the pressure of wet concrete poured thereabout.

Preferably, said locating means includes a centre bore or hole adapted to receive therethrough a screw for fastening the fire collar to formwork centred on a desired point aligned with the axis of the passage.

Preferably, said locating means includes a bottom portion adapted to engage with the housing at or adjacent the lower end. In such form, it is preferred that the bottom portion be adapted to substantially close the passage at or near its lower end so as to prevent the ingress of concrete into the passage during pouring of the slab in which the fire collar is being cast. In such form, it is also preferred that the locating means include a top portion spaced from the bottom portion and adapted to engage with the housing between said upper end and said lower end. In one such form, the top portion and the bottom portion have aligned centre holes coaxial with the axis of the passage thereby facilitating the placement of a long screw through both holes whereby the fire collar can be secured to the formwork on or against which it is to be fitted.

Preferably, said housing includes a closure portion or top cap that initially closes the passage at or adjacent its upper end (to form a blind passage) so as to prevent concrete entering said passage during pouring of the floor in which the fire collar is being cast. Such closure portion may be integrally formed with an outer wall of said housing. In a preferred form, the closure portion or top cap includes a centre hole therein through which a screw may pass or through which a screw driver may pass for driving a screw through said locating means. In a particularly preferred form where the locating means includes a bottom portion and a top portion both engaging with the housing, the centre holes of said top cap and said bottom portion and said top portion are all coaxial with the axis of the passage thereby facilitating alignment of the screw though all holes and particularly the centre hole in the bottom portion of the location means.

In another aspect, the invention resides broadly in a housing for a fire collar, the housing including:

a side wall defining a passage having a .top end and a bottom end;

a top cap at or adjacent the top end of said passage and arranged to at least substantially close, said passage; a selectively removable bottom cap in said passage at or adjacent the bottom end, said bottom, cap being operatively engaged with said side wall so as to substantially inhibit relative · lateral movement therebetween.

In yet another aspect, the invention resides broadly in a locator for use with a fire collar having a housing defining a passage with an upper end and a lower end adapted to receive a conduit therethrough and heat reactive blocking means in said housing and arranged to substantially block said passage upon reaching a predetermined temperature, said locator including:

a top half and a bottom half, said top half having a top portion adapted to extend across the passage to engage the housing of the fire collar at least at a plurality of angularly spaced points and being adapted to receive a screw substantially centrally therethrough and a skirt depending from said top portion and terminating in a bottom end, said top half being adapted to slidably fit in the passage of the fire collar between its upper end and its lower end such that said skirt engages the housing of the fire collar at least at a plurality of angularly spaced points; and

said bottom half having guide means for guiding a screw therethrough substantially centrally thereof and top half engagement means spaced from said guide means and operatively connected thereto, and being adapted to engage said top half skirt at a plurality of angularly spaced places adjacent its bottom end.

In another aspect, the invention resides broadly in the combination of a fire collar and a locator therefor, the fire collar including a housing defining a passage having an upper end and a lower end, heat reactive blocking means in said housing and arranged to expand and substantially block said passage upon reaching a predetermined temperature, said locator including a top portion and a skirt depending from said top portion and defining a bottom opening spaced from said top portion, said locator being adapted to slidably fit in the passage of the fire collar between its upper end and its lower end and such that said skirt engages the housing of the fire collar to prevent or substantially inhibit lateral movement of said housing relative to said locating means when said fire collar is secured to formwork.

In yet another aspect, the invention resides broadly in a method of installing an in-cast fire collar in a concrete floor to be constructed, the fire collar having a housing defining a passage with an upper end and a lower end adapted to receive a conduit therethrough, a cap or closure portion extending across the passage at or near its upper end to at least substantially close the passage, and heat reactive blocking means in the housing arranged to substantially block the passage upon reaching a predetermined temperature, the method including:

placing the fire collar on formwork on which a concrete floor is to be poured with the housing arranged such that the lower end of the passage is at or adjacent the formwork; and

driving a screw through the cap or closure portion and the passage from the upper end thereof and into the formwork to secure the fire collar thereto.

In yet another aspect, the invention resides broadly in a method of installing an in-cast fire collar in a concrete floor to be constructed, the fire collar having a housing defining a passage with an upper end and a lower end adapted to receive a conduit therethrough, heat reactive blocking means in the housing arranged to substantially block the passage upon reaching a predetermined temperature, and locating means in the passage, the locating means being connected to or operatively engaged with the housing so as to prevent or at least substantially inhibit lateral movement of the housing relative to the locating means, the method including:

placing the fire collar on formwork on which a concrete floor is to be poured with the housing arranged such that the lower end of the passage is at or adjacent the formwork; and

driving a screw through the passage from the upper end so as to pass through the locating means and into the formwork. In such form, it is preferred that the housing include a cap or closure portion extending across the passage at or near its upper end to at least substantially close the passage and that the screw is screwed through the cap or closure portion and engages therewith to secure the fire collar to the formwork.

In still yet another aspect, the invention resides broadly in a method of installing an in-cast fire collar in a concrete floor to be constructed, the fire collar having a housing defining a passage with an upper end and a lower end and adapted to receive a conduit therethrough, heat reactive blocking means in the housing arranged to substantially block the passage upon reaching a predetermined temperature, and locating means extending at least partially across the passage, the locating means being connected to or operatively engaged with the housing and arranged so as to prevent or substantially inhibit lateral movement of the housing relative thereto, the method including:

placing the fire collar on formwork on which a concrete floor is to be poured with the lower end on or adjacent the formwork;

driving a screw through the passage from the upper end so as to pass through the locating means and into the formwork to secure the fire collar to the formwork.

The terms "upper", "lower", "side" and similar terms are used herein for the purposes of describing the invention in its normal in use position in a building floor unless the context clearly indicates another meaning and are not intended to limit the invention to use in any particular orientation. It is to be understood that the invention could be used in floors, walls, ceilings and other barriers of various types and orientations. It is also to be understood that the term "longitudinal" used herein refers to the direction of a conduit as it passes through a fire collar according to the invention unless the context clearly indicates otherwise.

Brief description of the drawings

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings wherein:

Fig. 1 is a pictorial representation of a fire collar according to the invention with one quarter section cut away;

Fig. 2 is an elevation of the fire collar of Fig. 1;

Fig. 3 is a bottom plan of the fire collar of Fig.

Fig. 4 is cross-sectional elevation of the fire collar of Fig. 1 along line 4-4;

Fig. 5 is the same cross-sectional elevation of the fire collar of Fig. 1 in isometric view:

Fig. 6 is a pictorial representation of another fire collar according to the invention with one quarter section cut away;

Fig. 7 is an elevation of the fire collar of Fig. 6;

Fig. 8 is a bottom plan of the fire collar of Fig. 1;

Fig. 9 is cross-sectional elevation of the fire collar of Fig. 6 along line 8-9;

Fig. 10 is the same cross-sectional elevation of the fire collar as in Fig. 6 but in isometric view;

Fig. 11 is a cross sectional elevation of another fire collar according to the invention along a vertical diametral plane; and

Fig. 12 is a cross-sectional elevation of the fire collar of Fig. 11 in isometric view.

Detailed description of the drawings

The cast-in fire collar 10 illustrated in Fig. 1 includes a housing 11 having a bottom part 11a and a top part lib which are both constructed of a plastics material and fitted together as will be described in more detail later.

The bottom part has a generally cylindrical side wall 12a defining a bottom opening 13 at its lower end and terminating in an outwardly extending bottom flange 14 about the bottom opening contiguous with the side wall and an inwardly extending flange 16 at its upper end also contiguous with the side wall which terminates in a cylindrical guide ring 17 defining an opening 18. Suitably, the upper and lower openings are coaxial with the cylindrical wall along axis 19, and the cylindrical wall tapers slightly inwards towards the upper opening forming a slightly expanding passage 20 therebetween.

The top part lib has a top wall 12d from which a skirt or side wall 12b of generally cylindrically form depends which at its lower end is fitted within the guide ring 17 and secured thereto by nibs 12c. It will be appreciated that the bottom part side wall 12a, the top flange 16, the guide ring 17 and the top part side wall 12b form a contiguous side wall of the housing 11. Advantageously, a screw hole 12e is provided in the top wall on axis 19 as will be referred to later.

The bottom flange is adapted to rest against a sheet of concrete formwork and be secured thereto so that a concrete wall or floor can be poured around the housing. A plurality of screw holes 21 are provided around the flange for securing the housing to the formwork. Advantageously, the holes are provided in frangible portions 22 of the flange which break off upon removal of the form work and remain therewith.

Three elongate generally rectangular openings 23, 24 and 25 are provided in the side wall and two spaced apart radial walls 26 and 27 and a planar outer wall 28 parallel to the side wall 12 (although the outer wall can be concentric with the side wall if desired) extend outwardly therefrom to define equi-angularly spaced recesses 31, 32 and 33. Each recess houses therein a torsion spring 34 which is retained by a pin 36 extending through the recess and being secured in the spaced apart radial walls on the spring axis 37. The opposed tails 38 and 39 of the spring are held together in the loaded position by a fusible link 41 as can be seen in Fig.l.

A layer of intumescent material, typically neoprene based or high density polypropylene, formed into a cylinder 43 and enclosed by a layer of stainless steel gauze 44, is fitted within the housing adjacent the inner face of the cylindrical wall 12a. The cylinder formed by the intumescent material and the gauze also tapers slightly inwards towards the upper opening to more easily allow a PVC duct or pipe to be fitted therethrough from the lower opening so that the intumescent material forms a sleeve thereabout. In this particular embodiment, the intumescent material and the surrounding gauze is secured to the wall 12 near its upper end (that is near the flange 16) by a plurality of spaced apart staples. However, in other embodiments the intumescent material is held purely by friction between it, the gauze and the housing.

An upper locator part 51 is fitted in the housing 11 as can be seen in Fig.l, the locator part being generally cylindrical in form and having top wall 52 with a skirt 53 depending therefrom and terminating at its bottom end in an opening 54. Suitably, the upper part of the skirt 53 abuts the inner face of side wall 12b along its lower part and is held tightly thereagainst by virtue of the taper of side wall 12b and the matching taper of the skirt 53 while the lower part of the skirt abuts the inner face of the layer of intumescent material in the housing part 12a. Advantageously, a screw hole 56 is provided in the top wall on axis 19 for receiving screw 57.

A lower locator part 61 also of generally cylindrical form is fitted in the first locator part adjacent its bottom end, the second locator part having a top wall 62 with a skirt 63 depending therefrom terminating at its bottom end in opening 64, the skirt abutting the inner face of the skirt 53 of the first locator part and being held tightly therein by virtue of the matching tapers of the two skirts. The upper locator part also has a screw hole 66 centred on axis 19 for receiving screw 57 therethrough.

A load bearing washer or cap 71 rests on top wall 12d of the upper housing part, the washer having a screw hole 72 therethrough on axis 19 for receiving screw 57 therethrough.

In use, the upper locator part 52 is fitted to the housing 11 by sliding it through bottom opening 13 until it becomes tight and the bottom opening 54 aligns with opening 3 in the housing. The lower locator part is then fitted into the upper locator part through opening 54 until it becomes tight and the opening 64 therein aligns with opening 54 in the upper locator part. The fire collar is then placed on the formwork whereupon screw 57 can be driven through the centre of the housing through washer 71, top wall 12d of the upper housing part, top wall 52 of the upper locator part and top wall 61 of the lower locator part and into the formwork with the screw head 57a locating against the upper face of the load bearing washer 71.

When the concrete has been poured and has set, the screw 57 can be unscrewed to release the formwork from the fire collar. Once the screw 57 has been removed, the portion of the upper housing part above the concrete top surface can be cut off and then the upper and lower locator parts can be pushed out of the housing 11 through bottom opening 13 once the formwork has been removed thereby leaving no exposed screws, the screw 57 being the only screw securing the fire collar to the formwork.

In another form of the invention, the upper locator part is omitted and only lower locator part 61 is fitted within the housing at its lower end. In such case, the lower locator part may be provided with a flange, lugs or other suitable formations arranged to engage with the housing to hold it adjacent the bottom opening 13 thereof.

The fire collar 110 illustrated in Fig.6 is the same as that illustrated in Fig. 1 in most respects and consequently the same reference numbers are used for corresponding parts except prefaced by a "1". The main difference between the two fire collars is that the screw 157 does not engage the top wall 112d of the housing but instead engages the top wall of the upper locator part 152 and consequently is shorter. To facilitate operation of the screw 57, the hole 172 which is formed in the top wall 112d is large enough to pass the head of screw 157 therethrough and large enough to pass a screw driver therethrough to turn the screw by its head. Additionally, it will be appreciated that the washer 171 rests on top wall 152 instead of top wall 112d.

If desired, fire collars according to the invention may be pre-assembled with the upper and lower parts of the locator fitted in the housing and the screw and washer fitted to hold them in place.

The fire collar 210 illustrated in Fig. 11 is similar to fire collar 10 illustrated in Fig. 1 but does not have an upper locator part 51 nor a load bearing cap 71 as with fire collar 10. Rather, the top wall 212d is significantly thicker than top wall 12d and has a shank or stem 212g depending therefrom to support a screw therein through bore 215 and angularly spaced corner ribs 212h extending from the top wall 212d to the outer housing wall 212b to hold the top part 211b of the housing more rigid. Advantageously, such arrangement avoids the need for the upper locator part in some cases. A recess 212j is formed in the top wall for housing the head 257a of screw 257 therein. In this particular embodiment of the invention, a locator disc 262 is fitted within the lower end portion of the housing to engage with the side wall 212a so as to ensure movement of the housing is prevented during pouring of the concrete but in cases where the concrete floor is thinner, the disc may be omitted.

The foregoing description has been given by way of illustrative example of the invention and many modifications in variations which will be apparent to persons skilled in the art may be made without departing from the spirit and scope of the invention as defined by the appended claims.