Patent ID: 12188679

Like reference numerals indicate like or corresponding elements or components in the drawings.

DETAILED DESCRIPTION

Reference is first made toFIG.1A, which shows a hazardous/combustible materials fire-rated duct or conduit assembly or configuration according to an embodiment of the present invention and indicated generally by reference100. According to an exemplary implementation, the hazardous materials conduit or duct assembly100comprises a closed vertical configuration101with a fire separation floors102, indicated individually by references102aand102b, inFIG.1. In a vertical configuration, the conduit passes through horizontal floors or fire separation barriers. The closed conduit assembly100is intended for hazardous and/or combustible materials and does not have any openings (other than at an originating fire compartment and/or a destination fire compartment), which could allow for the escape of hazardous material and/or spread of fire from one fire compartment to another fire compartment in a building. As will be described in more detail below the conduit assembly100comprises a plurality of modular duct sections that are joined or connected together and configured for the particular application or installation.

FIG.1Bshows an open conduit assembly or configuration according to an embodiment of the present invention and indicated generally by reference120. As shown inFIG.1B, the open conduit assembly120comprises a vertical conduit assembly121which passes through floors122in a building. The floors122comprise fire separation floors indicated individually by references122aand122b. The vertical conduit assembly121includes one or more openings124between the originating fire compartment and the destination compartment. The conduit assembly120is configured for moving air under positive or negative pressures where branch conduits are required to handle air for other parts of the building.

The duct assemblies100and120are also suitable for conduits containing mechanical or electrical systems, and can comprise branch runs or outlets in multiple locations in a building to provide services to those areas. It will also be appreciated that the fire-rated duct assemblies100and120can be configured horizontally to run through walls, including vertical fire barriers, or in combination of vertical and horizontal connected segments or sections, for example, the vertical duct assembly121with a horizontal branch indicated generally by reference126. According to another embodiment, the fire-rated duct assembly comprises a conduit spanning or running between horizontal and/or vertical fire barriers, without penetrating or passing through the barrier(s). For instance, the duct assembly terminates at and is attached to one face of the fire barrier, and the next section in the duct assembly is attached to the opposite face of the fire barrier and continues a run or span to the next fire barrier. According to an exemplary embodiment, the sections of the fire-rated duct assemblies are attached to the face of the fire barriers as described in more detail below with reference toFIGS.3A to3D.

Reference is next made toFIG.2A, which shows a fire-rated conduit or duct assembly according to an embodiment of the invention and indicated generally by reference200. The fire-rated conduit assembly200comprises a plurality of duct sections210, indicated individually by reference210aand210binFIG.2A, and a connection or joint mechanism indicated generally by reference220. According to an exemplary embodiment, the duct sections210have a rectangular cross-section or configuration. The duct sections210are fabricated in a factory before being transported to the installation location or site, and then joined or connected together using connection mechanisms to create a continuous conduit system or assembly, as described in more detail below.

In addition to a rectangular cross-section, the duct sections210can be configured with other cross-sectional shapes or profiles. According to other embodiments, the duct sections210comprise square, round, or oval cross-sectional shapes or profiles. The cross-sectional shape is determined based on various factors, such as the application or intended use, the space available for installing the conduit, and even the designer's personal preference as to conduit cross section. For instance, a round or oval cross-section is often utilized when the duct assembly100is configured for handling combustible particulate materials, as it allows for smoother material flow, and assists in preventing the accumulation of the particulate in any one area of the conduit system reducing the potential for a fire internal to the conduit. In addition, the duct assembly100,120can include other sections or components, such as the branch duct section124shown inFIG.1B, and/or other sections such as elbows and offsets, as well as shapes required to change conduit size such as transitions or reducers.

Reference is made toFIG.2B, which shows an exploded view of the individual or modular duct section210according to an embodiment. The duct section210comprises an inner duct230with an inner duct connector232, indicated individually by references232aand232binFIG.2B, at opposing ends of the duct section210. The inner duct connector232comprises a flange or an angled connector which is configured to join respective duct sections210together, for example, using respective bolts234and nuts235, as shown inFIG.2C, or other suitable fasteners, and with the addition of a gasket or joint sealant, as described in more detail below. The inner duct connector232can be formed as a separate component, for instance, an angled connector, that is fastened to the end of the inner duct210, for example, bolted and/or welded. According to another embodiment, the inner duct connector232is formed as integral component of the inner duct210. The modular duct section210comprises an outer protective casing indicated generally by reference240. According to an embodiment, the outer protective casing240comprises top241and bottom 242 panels and side panels indicated individually by references243and245. According to an exemplary implementation, the outer casing240is fabricated from a fire resistant metallic material. In order to provide a thermal insulation cavity, the respective panels of the outer protective casing240are positioned and attached to the inner duct230in a spaced relationship using casing spacers, comprising top and bottom panel casing spacers indicated by references246and side panel casing spacers indicated by references248. According to an exemplary embodiment, the casing spacers246,248are fabricated or formed using a thermally insulating (i.e. thermally non-conductive) material. The outer casing panels240are affixed to the casing spacers, which are held in position or fixed to the inner duct230using suitable fastening techniques. A cavity or void space is formed between the outer casing240and the inner duct liner230and thermal insulation material233is placed inside the cavity, as described in more detail below, and shown, for example, inFIGS.8A-8C and9A-9B. As shown inFIG.2D, the fire-rated conduit or duct assembly includes a joint or connection mechanism220comprises an insulating material235which is applied or positioned on or around the joined or connected ends of the respective duct sections210. The joint mechanism220further comprises a joint cover250. According to an embodiment, the joint cover250comprises top and bottom joint covers indicated by references254and side joint covers indicated by references254to protect and hold the insulating material235in place or position between the joined ends of the duct sections210. According to an exemplary implementation, the joint covers254are fabricated from a fire resistant metal and are configured to slide into the gap between the respective ends of the duct sections210and fixed or held in position using screws or other suitable fasteners, indicated generally by reference255inFIG.2D.

According to an exemplary embodiment, the inner duct liner230is fabricated from flat sheet metal or a continuous metal strip, with a thickness sufficient to remain intact and maintain the conduit shape for the prescribed fire-rating or duration. The thickness of the inner duct230can be increased for applications where the conduit contents impart additional loading or abrasion requirements. The inner duct liner230may be fabricated from carbon, galvanized, stainless, or coated steel. The inner duct230is formed as a tube comprising a rectangular, square, round, or oval cross section, as determined by the specific application or project requirements. For a rectangular or square cross section, the inner duct liner230can be fabricated using four individual panels, a ‘U’ shaped section with a separate closing panel, two ‘L’ shaped sections or a single wrap around section. For a circular or oval cross section, the inner duct230can be fabricated from individual pieces of flat metal formed to the required shape, or formed from a spiral wound continuous strip of metal. In known manner, the abutting longitudinal free edges of the formed or spirally wound tubes are joined or connected using mechanical locks, continuous or stitch welds, lap seams with fasteners or pocket seams with fasteners or stitch welds.

For hazardous or combustible material applications, the duct or conduit assembly100is preferably made with continuously welded longitudinal seams to prevent the hazardous or combustible materials being transported by the conduit assembly100from escaping the inner conduit. For non-hazardous applications, such as air handling, or for routing or housing mechanical and electrical services, the duct or conduit assembly is made with mechanical locks due to their lower cost and ease of use. Where necessary the mechanical locks can also be sealed to reduce any unwanted passage of air from or to the inner conduit.

Reference is again made toFIG.2Cand a process for connecting or joining the two duct sections210aand210btogether to form a section of the duct assembly100. As shown, the first duct section210ais positioned with the mating end, i.e. the inner duct connector232bin spaced position from the inner duct connector232aof the second duct section210b. A gasket or other type of sealing material is applied to the face of one or both of the inner duct connectors232aand232bas required. The two duct sections210aand210bare then brought together and mechanically joined, for example, utilizing respective bolts234and nuts235, or other suitable mechanical fasteners, inserted and tightened in holes236in the corners of the connectors232aand232b. For larger duct sections210, or round or oval duct sections, additional bolts or other types of fasteners, such as screws, cleats, or clamping bands, are utilized for joining or connecting the respective sections.

According to an embodiment, the joint mechanism220is configured to provide the fire-rating for the assembled duct or conduit assembly100(or120). As shown inFIG.2D, the joint mechanism220comprises thermal insulation material235and the joint cover250. According to an embodiment, the inner duct230and the inner duct connectors232are configured to extend beyond the protective outer casing240and when joined together a gap or space is created between the end of the joined duct sections210aand210bas shown inFIG.2Cand indicated by reference221. The gap221is configured to receive the thermal insulation material235, and then the top and bottom joint cover sections254and the side joint cover sections254are installed to seal the gap221and the thermal insulation material235to provide and maintain the required fire-rating of the duct assembly100(or120). According to an exemplary implementation, the joint cover sections254are fabricated from the same material as the panels for the outer casing140.

The thermal insulation material235is selected to have sufficient density and thermal conductivity to limit the transfer of heat from the fire exposed side of the conduit to the non-exposed side so as not to exceed the temperature rise limits of the building construction and materials test standard used to qualify the fire resistance rating of the fire rated conduit. Typical temperature rise limits for nationally recognized codes restrict the average temperature rise to an average of all temperature rise measurements of 250° F. with a maximum single temperature rise measurement of 325° F. Once the opening is filled with the thermal insulation, slide on joint covers, formed of the same material and material thickness as the outer protective casing, are installed by first positioning the ends of the overlapping returns formed on the longitudinal edges of the slide on joint cover parallel to and adjacent to the ends of the returns formed on the outer protective casings.

According to an embodiment, the joint cover sections254are configured to be pushed or slid into and held in place by respective returns256formed in the panels241,242,244and245of the outer casing240, as shown inFIGS.2B and2D. The returns256in the outer casing240interlock with returns formed in the joint cover sections254. For a rectangular configuration, installation of the top, bottom and side joint cover sections254envelopes the gap221, i.e. perimeter ends of the outer casing240. According to an embodiment, the joint cover sections254have a 90° fold or flange formed at one end as shown inFIG.2Dand indicated by reference257. The flanges257facilitate the connection of abutting joint cover sections254, for example, utilizing screws or other mechanical fasteners, to secure or lock the joint cover sections254in place. According to another embodiment, the flange comprises a separately formed angle piece that is fastened to the end of the joint cover section254at one surface, and the other surface of the formed angle piece is joined or fastened to the end of the abutting joint cover section. According to another aspect, formed angle piece is positioned under or over the interface between the adjacent joint cover section so that the thermal insulation is fully enclosed and protected.

Reference is next made toFIG.3A, which shows a sectional view of a three-sided conduit assembly according to an embodiment of the invention and indicated generally by reference300. The three-sided conduit assembly300is configured to be secured and sealed against a surface of the fire barrier102(or122inFIG.1) as indicated by reference104. The three-sided conduit assembly300is suitable for applications where the porosity of the fire barrier or separation floor or wall102does not adversely affect the performance of the system, for example, to enclose mechanical and/or electrical services, or to function as an air handling conduit, in horizontal or in vertical configurations.

As shown inFIG.3A, the three-sided conduit assembly300comprises a three-sided configuration with an open side or surface indicated by reference302. The three-sided conduit300comprises an inner duct liner310and an outer casing312. The outer casing312and the inner duct liner310are separated by casing spacers314, for example, as described above. As shown inFIG.3A, each side wall of the conduit assembly300includes a conduit mounting channel indicated by reference316. The conduit mounting channel316is configured to provide a joint surface for mounting or securing the respective side wall to the surface104of the fire barrier102. According to an embodiment, an anchor or fastener105is installed in the surface104of the fire barrier102and utilized to attach and secure the conduit mounting channel316. According to an exemplary implementation, the fastener105comprises a threaded stud and the conduit mounting channel316(and side wall of the conduit assembly300) is attached with a threaded nut107, which is accessed through an opening317. The opening317can be filled with thermal insulation material (as described above) and the opening317and conduit mounting channel316is closed or sealed with a slide joint cover section indicated by reference318. The slide joint cover section318is secured with one or more screws319.

According to an embodiment, the conduit mounting channels316include a 90° fold or flange321which aligns with returns315on the outer casing314, as shown inFIG.3A.

To install the three-sided conduit300, a gasket or other suitable sealing material is affixed or applied to either the surface104of the fire barrier102or to the face of the conduit mounting channel, to create a seal between two mating surfaces and between the inner conduit310and the holes in the conduit mounting channel316. The conduit assembly300is moved into position and secured with the conduit fastener or mounting nuts107to the anchors105. The joint cover section318includes a return323that is formed only along one longitudinal edge. The return323in the slide joint cover section318is slid over the corresponding return315in the outer casing314to interlocking the two sections. The slide joint cover sections318are secured into place with joint cover section retaining screws319, and the joint section in the three-sided conduit300is enclosed and configured to provide the required fire-rating.

According to another embodiment, the anchors105in the fire barrier102comprise threaded sockets and the conduit mounting nut319is replaced with a matching threaded bolt.

Reference is next made toFIGS.3B to3D, which depict exemplary implementations and applications of the three-sided conduit assembly300.FIG.3Bshows the three-sided conduit assembly300configured or installed as a services conduit, in a horizontal or a vertical configuration, and indicated generally by reference320. In an exemplary installation, mechanical322and/or electrical324service fixtures or components, are affixed to a surface mount326and enclosed by the conduit formed between the three-sided conduit assembly300and the surface104of the fire barrier102.FIG.3Cshows the three-sided conduit assembly300configured as a services conduit330where the mechanical322and electrical services324are supported or carried by a suspended mounting platform332as shown.FIG.3Dshows the three-sided conduit assembly300configured as an air conduit340. The three-sided conduit assembly300can be configured to run a horizontal air duct or a vertical air duct according to the orientation of the fire barrier102, e.g. ceiling or wall. In addition to the generally rectangular cross-sectional shape, the three-side conduit assembly300can be configured with duct sections having other profile shapes, for instance, a half-circle or half-oval shape.

Reference is next made toFIG.4A, which shows a sectional view of a two-sided conduit assembly according to an embodiment of the invention and indicated generally by reference400. The two-sided conduit assembly400is configured to be secured and sealed against two surfaces of a fire barrier110indicated by reference111and112, respectively, as shown inFIG.4A. The two-sided conduit assembly400is suitable for applications where the porosity of the two surfaces of the fire barrier or separation floor or wall110does not adversely affect the performance of the system, for example, to enclose mechanical and/or electrical services, or to function as an air handling conduit, in horizontal or in vertical configurations.

The two-sided conduit300comprises an inner duct liner410and an outer casing412. The outer casing412and the inner duct liner410are separated by casing spacers414, for example, as described above. As shown inFIG.4A, each side wall401and402of the conduit assembly400includes a conduit mounting channel indicated by references416. The conduit mounting channel416is configured to provide a joining surface for mounting or securing the respective side wall401,402to the respective surface111,112of the fire barrier110. According to an embodiment, a respective anchor or fastener114is installed in the surface111,112of the fire barrier110and utilized to attach and secure the conduit mounting channels416. According to an exemplary implementation, the fastener114comprises a threaded stud and the conduit mounting channel416(and side wall of the conduit assembly401,402) is attached with a threaded nut115, which is accessed through an opening417. As described above, the opening417may be filled with a thermal insulation material435(FIG.4B) and the opening417and conduit mounting channel416is closed or sealed with a slide joint cover section indicated by reference418. The joint cover section418is secured with one or more screws419.

The conduit mounting channels416include a 90° fold or flange421which aligns with returns415on the outer casing412, as shown inFIG.4A.

To install the two-sided conduit400, a gasket or other suitable sealing material is affixed or applied to the respective surfaces111,112of the fire barrier110or to the faces of the conduit mounting channels416, to create a seal between two mating surfaces and between the inner conduit410and the holes in the conduit mounting channel416. The conduit assembly400is moved into position and secured with the conduit fastener or mounting nuts115to the respective anchors114. Gaskets and/or sealing materials may be applied as required. The thermal insulation435is added in the cavity. The joint cover sections418include a slide or return421that is formed only along one longitudinal edge. The return421in the joint cover section418is slid over the corresponding return415in the outer casing414to interlock the two sections. The joint cover sections418are secured into place with joint cover section retaining screws419, and the joint section in the two-sided conduit400is enclosed and configured to provide the required fire-rating. Adjacent conduit sections or modules for a run comprising the two-sided conduit assembly400are connected together in a manner similar to that described above with reference toFIG.2.

Reference is next made toFIGS.4B to4D, which depict exemplary implementations and applications of the two-sided conduit assembly400.FIG.4Bshows the two-sided conduit assembly400configured or installed as a services conduit, in a horizontal or a vertical configuration, and indicated generally by reference420. In an exemplary installation, mechanical422and/or electrical424service fixtures or components, are affixed to a surface mount426and enclosed by the conduit formed between the two-sided conduit assembly400and the respective surfaces111,112of the fire barrier110.FIG.4Cshows the two-sided conduit assembly400configured as a services conduit430where the mechanical422and electrical services424are supported by a suspended mounting platform432as shown.FIG.4Dshows the two-sided conduit assembly400configured as an air conduit440. The two-sided conduit assembly400can be configured to run a horizontal air duct or a vertical air duct according to the orientation of the fire barrier110, e.g. ceiling or wall. In addition to the generally rectangular cross-sectional shape, the two-side conduit assembly400can be configured with duct sections having other profile shapes, for instance, a semi-circle or semi-oval shape.

Reference is next made toFIG.5A, which shows a sectional view of a single-sided conduit assembly according to an embodiment of the invention and indicated generally by reference500. The single-sided conduit assembly500is configured to be secured and sealed against a recess or channel132formed in a fire barrier130, for example, comprising parallel fire-barrier projections or walls134aand134b, as shown inFIG.5A. The single-sided conduit assembly500is suitable for applications where the porosity of the three surfaces of the fire barrier or separation floor or wall130and the projections or walls134do not adversely affect the performance of the system, for example, to enclose mechanical and/or electrical services, or to function as an air handling conduit, in horizontal or in vertical configurations.

The one or single-sided conduit500comprises an inner duct liner510and an outer casing512. The outer casing512and the inner duct liner510are separated by casing spacers514, for example, as described above. As shown, thermal insulation material533is placed in the void formed between the inner duct liner510and the outer casing512as shown inFIG.5A. The single-sided conduct assembly500includes a conduit mounting channel at each end indicated by references516. The conduit mounting channel516is configured to provide a joining surface for mounting or securing the conduit assembly500to the respective fire-barrier wall134aand134b. According to an embodiment, an anchor or fastener136is installed on a mounting surface of each fire-barrier walls134aand134b, as shown, and utilized to attach and secure the respective conduit mounting channels516. According to an exemplary implementation, the fastener136comprises a threaded stud and the conduit mounting channel516is attached with a compatible threaded nut137, which is accessed through an opening517. In a manner similar to that described above, the opening517may be filled with thermal insulation material519(as shown inFIGS.5B to5D) and the opening517and conduit mounting channel516are closed or sealed with a slide joint cover section indicated by reference518. The joint cover section518is secured with one or more screws521(FIGS.5B to5D).

To install the one-sided conduit assembly500, a gasket or other suitable sealing material is affixed or applied to the respective mounting surfaces of the fire-barrier projections or walls134aand134b, to create a seal between two mating surfaces and between the inner conduit510and the holes in the conduit mounting channel516. The conduit assembly500is moved into position and secured with the conduit fastener or mounting nuts137to the respective anchors136. According to an embodiment, the joint cover sections518include a slide or return that is formed along one longitudinal edge. The return in the joint cover section518is slid over a corresponding return in the outer casing514to interlock the two sections. The joint cover sections518are secured into place with the joint cover section retaining screws521, and the joint section in the single-sided conduit assembly500is enclosed and configured to provide the required fire-rating. Adjacent duct sections or module are connected together to form the one-sided conduit assembly in a manner similar to that described above.

Reference is next made toFIGS.5B to5D, which depict exemplary implementations and applications of the one or single-sided conduit assembly500.FIG.5Bshows the one-sided conduit assembly500configured or installed as a services conduit, in a horizontal or a vertical configuration, and indicated generally by reference520. In an exemplary installation, mechanical522and/or electrical524service fixtures or components, are affixed to a surface mount526and enclosed by the conduit formed between the one-sided conduit assembly500and the two fire-barrier walls or projections134aand134bof the fire barrier130.FIG.5Cshows the one-sided conduit assembly500configured as a services conduit530where the mechanical522and electrical services524are supported by a suspended mounting platform532as shown.FIG.5Dshows the one-sided conduit assembly500configured as an air conduit540. The one-sided conduit assembly500can be configured to run a horizontal air duct or a vertical air duct according to the orientation of the fire barrier walls or projections134aand134b, e.g. formed on the ceiling or on the wall of the fire barrier130. In addition to the generally rectangular cross-sectional shape, the one-side conduit assembly500can be configured with duct sections having other profile shapes, for instance, a half-circle or half-oval shape.

As described above with reference toFIGS.2A to2D, the inner duct liners230include respective external mechanical connectors232at each end. According to this aspect of the present invention, the external mechanical connectors232are fabricated according to the intended application or operating environment of the fire-rated conduit assembly.

For installations involving hazardous or combustible materials or liquids, the connection must be liquid or air tight connection. According to an embodiment, the inner duct liner230is configured with a bolted flange connector as shown inFIGS.6A and6B, and indicated by reference610. The bolted flange connector610comprises an angle flange indicated by reference612inFIGS.6A and6B. The angle flange612is affixed or attached to the end of the inner duct liner230. As shown, the inner duct liner230may include a flange or lip238that is configured to also hold or attach the angle flange612. According to an exemplary implementation, the traverse surface of the angle flange612is attached to the end edges of the inner duct liner230via continuous or stitch welding, and also along the end edges of the angle flange612adjacent the side edges of inner duct liner230. According to another aspect, and where air or liquid tightness is required for the conduit, additional sealant is applied at the longitudinal joints or connectors to achieve the required seal. The vertical leg of each bolted flange connector610includes a plurality of holes for receiving mechanical fasteners, e.g. bolts and nuts.

To provide increased rigidity for achieving tight (and leak proof) connections, the bolted flange connectors610comprise a SMACNA type angle connector, which is welded to the opposing ends of the inner duct liner230, for example, as described above. The angle connectors are sized according to the conduit dimensions, and/or any internal pressure or material loading requirements.

As shown inFIGS.6A and6B, the casing spacers248are secured between the inner duct liner230and the outer casing240. The casing spacers248are positioned to maintain a gap or void between the casing240and the duct liner230and ensure that thermal insulation233is equally compressed once the duct sections210are assembly together and the conduit assembly100is installed on site. The casing spacers248are configured to transfer loading from the inner duct liner230to the outer protective casing240and on to the mechanical structure supporting the assembly. The casing spacers248are made from a thermally insulative material which is strong or rigid enough to not be deformed or compressed, while also minimizing the amount of heat conducted though the spacer248to the unexposed face of the conduit. According to an exemplary implementation, the casing spacers248are formed from an insulation material such as cement or calcium silicate board. For higher load applications, the casing spacers248comprise one or more continuous configurations around the perimeter of the inner duct liner230. For lighter load applications, on the other hand, the casing spacers248are segmented and positioned at the end sections of the inner duct liner230, for example, as shown inFIG.2B.

Referring back toFIGS.6A and6B, the casing spacer248is attached to the inner surface of the outer casing240utilizing mechanical fasteners249, for example, metal screws, nails, or staples. According to another implementation, the casing spacer248is secured to the inner surface of the outer casing240utilizing a suitable adhesive. To maintain the integrity of the inner duct liner230, the casing spacer248is not affixed to the outer surface of the inner duct liner230. As shown, a casing spacer angle flange614is provided to locate and restrain the casing spacer248relative to the inner duct liner230. The angle flange614is attached using continuous, stitch, or spot welding techniques. According to another implementation, the casing spacer248is secured to the outer surface of the inner duct liner230utilizing a suitable adhesive.

As shown inFIG.6A, the outer casing240is configured with a raised joint attachment end which is formed “proud” of the casing240, as indicated by reference602. The raised joint attachment end602is configured to receive and secure the joint covers254in a raised configuration in duct assemblies800and810, as shown inFIGS.8A and8B, respectively. The raised joint attachment602includes a return802which is configured to interlock with a corresponding return803(e.g. connection edge or mechanism) formed on each edge of the joint cover254. According to an exemplary embodiment, the return803comprises a pocket or formed slot as shown inFIG.8A(FIGS.8B and8C) which slides over and receives or engages the return802formed in the outer casing. The inner duct flange connectors232a(i.e. the bolted flange connector610a) and232b(i.e. the bolted flange connector610b) are secured together with mechanical fasteners804, for instance bolts and nuts, as shown inFIGS.8A and8B. According to an exemplary implementation, a gasket806, or a suitable sealant, is applied between the mounting faces of the bolt flange connectors610. The cavity or void between the adjacent duct sections210is filled with thermal insulation material235, and the joint cover254is slid into place in the raised joint attachments602, and may be further secured by one or more mechanical screws. The duct assembly800with the raised joint attachment inFIG.8Acomprises a thin profile conduit assembly (and includes thinner casing spacers249), whereas the duct assembly820inFIG.8Bcomprises a standard profile for the conduit assembly.

The duct assembly800depicted inFIG.8Ais configured for application or installations where fire-rating durations of 2 hours or less are required. Due to the physical characteristics of a thinner configuration the weight of materials/components and loading will be lower, and therefore smaller/thinner casing spacers249can be utilized, and with the raised joint cover configuration standard, or additional thickness, thermal insulation material235can be utilized based on the rating.

The duct assembly820depicted inFIG.8Bis configured to provide a fire-rating of 4 hours or less. The configuration of the raised joint casing provides a larger cavity for receiving additional or thicker material for the thermal insulation235.

Reference is next made toFIG.6B, which shows the outer casing240configured with a flat joint attachment end indicated by reference622. As shown the flat joint attachment end is formed substantially flush with the exterior surface of the outer casing240. The flat joint attachment configuration provides a conduit assembly with smaller outer dimensions. To maintain or increase fire-ratings, thermal insulation235with higher performance characteristics is utilized, for example, the thermal insulation235will have higher performance characteristics than the thermal insulation233between the inner duct liner230and the outer casing240.

The flat joint attachment end622is configured to receive and secure the joint covers254in a flat configuration in a duct assembly830, as shown inFIG.8C. The flat joint attachment622includes a return832which is configured to interlock with a corresponding return834formed on each edge of the joint cover254. The inner duct flange connectors232a(i.e. the bolted flange connector610a) and232b(i.e. the bolted flange connector610b) are secured together with mechanical fasteners804, for instance bolts and nuts, as shown inFIG.8C. A gasket806, or a suitable sealant, is applied between the mounting faces of the bolt flange connectors610. The cavity or void between the adjacent duct sections210is filled with a thermal insulation material235, and the joint cover254is slid into place in the flat joint attachments602.

The duct assembly830depicted inFIG.8Ccomprises a standard profile conduit assembly and is configured to provide a fire-rating of 4 hours or less. The flat or flush mounting of the joint covers254reduce the thickness of the thermal insulation235at the inner conduit external connectors, which effectively reduces the thermal protection. To limit the thermal transfer (thereby increase the fire-rating) between the inner duct liner230, the external connectors and the joint cover254, the thermal insulation235comprises an insulating material with a lower thermal conductivity and/or higher density, in order to meet established thermal transmission parameters.

For an installation comprising standard supply, return, or exhaust air applications, as well as for electrical service applications where fire resistance is the primary concern, the external mechanical connectors232are formed as an integral component of the inner duct liner230, or alternatively, as a separate component that is affixed or attached to the end of the inner duct liner230. According to an exemplary implementation, the external mechanical connector232comprises a SMACNA type T-25 series connector, which has a profile similar to that shown inFIGS.6C and6D. Other SMACNA or similar mechanical connectors can be used for the external mechanical connector232provided the resulting connection between duct modules210meets the required fire-ratings for the application or installation.

The duct assemblies according toFIGS.6C and6Dare particularly suited for applications comprising conduits for moving air under positive or negative pressure, as well as conduits containing mechanical or electrical services. It will be appreciated that these applications do not necessarily require conduit assemblies with liquid and joint tight configurations as described above with reference toFIGS.6A and6B.

Reference is made toFIG.6C, which shows a duct assembly630configured with a raised joint attachment end which is formed “proud” of the casing240, as indicated by reference631. The raised joint attachment end631is configured to receive and secure the joint covers254in a raised configuration, in a manner similar to that described above with reference toFIG.6A. It will be appreciated that the configuration of the raised joint attachment provides increased rigidity to the lateral edges of the outer casing240, in addition to providing a larger joint cavity for receiving additional or thicker thermal insulation material235(FIG.8).

According to another aspect and as shown inFIG.6C, the exterior connector232for the inner duct liner230comprises a SMACNA type T-25 series connector indicated by reference634. The connector634is formed as an integral component of the end section of the inner duct liner230, or as a separate component which is mechanically attached to the end of the inner duct liner230. According to an exemplary implementation, the T-25 connector634is configured for a “four bolt connection” at the four corners of the exterior connector232. For larger conduit sizes or installation, the exterior connector232can be configured with additional holes for receiving additional bolt and nut fasteners.

As also shown inFIG.6Cand according to an exemplary implementation, the casing spacer248is mechanically fastened to the outer surface of the inner duct liner230, for example, using one or more mechanical fasteners indicated generally by reference231. According to another implementation, the casing spacer248is secured to the outer surface of the inner duct liner230utilizing a suitable adhesive.

It will be appreciated that the raised joint cover attachment configuration provides additional rigidity to the lateral edges of the outer casing240. In addition, the size of the angle flange612can be varied, for example, increased in size to provide increased thermal insulation at the joint formed between adjacent duct modules.

Reference is next made toFIG.6D, which shows the outer casing240configured with a flat joint attachment end indicated by reference642. The flat joint attachment end642is formed substantially flush with the exterior surface of the outer casing240. The flat joint attachment end642is configured to receive and secure the joint covers254in a flat or substantially flush configuration, in a manner similar to that described above with reference toFIG.6B. As also described above, the flat joint attachment configuration provides a conduit assembly with smaller outer dimensions.

As also shown inFIG.6D, the exterior connector232for the inner duct liner230comprises a SMACNA type T-25 series connector634as described above. The connector634is formed as an integral component of the end section of the inner duct liner230, or as a separate component which is mechanically attached to the end of the inner duct liner230, as also described above.

The exterior of the duct assembly100and110comprises the outer casing240, which according to an exemplary implementation comprises a metallic material formed from flat sheet metal or continuous strip. The outer casing240is formed or fabricated with a minimum thickness required to remain intact and maintain the protective casing shape and integrity for the duration under the required fire-rating.

Using known techniques as will be within the understanding of those skilled in the art, the outer protective casing is formed into a tube from a single or multiple pieces of metal to create a cross-section as described herein. According to another aspect, rectangular or square cross-sections can be fabricated utilizing four individual panels, a ‘U’ shaped bottom with a separate top panel, two ‘L’ shaped sections or a single wrap around section. Round and oval cross-sectional profiles for the outer casing240can be formed from individual pieces of flat metal or created from a spirally wound continuous strip of metal. In known manner, the abutting longitudinal free edges of the formed or spirally wound tubes are joined or connected using mechanical locks, continuous or stitch welds, lap seams with fasteners or spot welds or pocket seams with fasteners or stitch welds.

As described above, the opposite ends of each of the outer casing panels or tubes have an integrally formed return, or added, to each panel or tube edge. The returns on the outer casing can be formed or comprise a raised joint cover configuration or a flat or flush joint cover configuration, with the returns running parallel to the edges of the outer casing and located adjacent to the outer casing, as described above.

Reference is next made toFIGS.7A to7C, which show the casing spacer according to other embodiments or implementations. To achieve the thermal transmission requirements for a fire-rating, the cavity formed between the inner duct liner230and the outer casing240is filled with thermal insulating material233as described above. According to an exemplary implementation, the thermal insulating material has a sufficient thickness and composition to provide the required thermal resistance to limit the temperature rise through the insulating material to an average of 250° F. (139° C.) or to a maximum single measurement of 325° F. (180° C.) when tested for the required fire-rating duration. The thermal insulating material comprises a batt or blanket material, which allows an insulation layer to be formed around the exterior surface of the inner duct liner, or around the corners of the square and rectangular sections. According to another implementation, the thermal insulating material is formed in boards or sheets. According to another implementation, the thermal insulating material is comprised of loose insulating fibers, granules, or powder. Suitable compositions for the thermal insulating material include soluble ceramic, or mineral or rock wool compositions (particularly suited for larger insulation cavities).

As described above, the casing spacers248are configured to create a cavity or space between the inner duct liner and the outer casing for containing a thermal insulation material without unnecessary compression. The casing spacers248are configured to transfer the load from the inner duct liner230though to the outer casing240and any connected support structures or surfaces. The casing spacers are typically located in the end section of the duct or conduit module. For configurations with higher loads, one or more additional and intermediately located casing spacers are utilized (for example, as described above).

Reference is made toFIG.7A, which shows a duct or conduit module210with a stepped casing spacer according to an embodiment and indicated by reference710. The stepped configuration is particularly suited to materials that are less compressible in order to hold the insulation material in place and also providing structural integrity for installing the joint covers. As shown, an angular retainer614is also provided to secure the casing spacer248.FIG.7Bshows another embodiment of a stepped casing spacer720comprising first721and second722sections. The stepped casing spacer720is secured by the angular retainer614as shown. According to another embodiment, the casing spacer comprises a single column or support structure as shown inFIG.7Cand indicated by reference730. This configuration is suited for use with thermal insulation233that is compressible and will stay in place through friction with adjacent surfaces.

According to another aspect, the casing spacers248are configured to also function as connectors to secure the inner duct liner230to the outer casing240and reduce shifting or movement between the outer casing240and the inner duct liner230during shipping and installation.

As shown inFIGS.7A to7C, the outer casing240is mechanically fastened to one end of the casing spacer248, for example, utilizing mechanical fasteners such as staples, nails, or screws. It will be appreciated that the connection techniques for coupling the outer casing240to the inner duct liner230will depend in part on the application of the duct assembly. For typical air handling applications where absolute liquid and air tightness is not required, mechanical fasteners231(similar to the mechanical fasteners241used to connect the outer casing240to the casing spacer248) are utilized to attach the inner duct liner230as shown inFIGS.6C and6D. The fasteners231can be sealed as needed. For applications or installations requiring a liquid tight seal or for applications involving combustible materials, the casing spacers248are secured to the inner duct liner230utilizing the retainer angles614, as shown inFIGS.6A and6B. As described above, the retainer angles614are affixed to the exterior surface of the inner duct liner230, for example, utilizing spot, stitch, or continuous welding techniques. The retainer angle614will have a size, thickness, and length based on the dimensions of the inner duct liner230and/or the loading characteristics.

Reference is next made toFIGS.9A and9B, which show joint cover configurations according to other embodiments of the present invention. The embodiments depicted inFIGS.9A and9Bare suited for installations having tight clearances or other obstructions where there is insufficient space to utilize slide joint covers as described above.

FIG.9Ashows a raised joint cover configuration indicated by reference900comprising a raised return910on each end of the outer casing240. The joint cover254comprises a fold912, for example, a 90° fold, formed along each longitudinal edge. The folds912can be factory formed, or field modified. As shown, the joint cover254is attached to the respective raised returns910utilizing mechanical fasteners911, for instance, screws inserted through the folds912and secured into the returns910on the outer casing240. The mechanical joint that is formed also provides increased rigidity to the later edges of the outer casing.

FIG.9Bshows a flat joint cover configuration920for screw attachment. As shown, the flat joint cover920comprises a slight fold922along each longitudinal edge. The slight fold922can be factory formed or field modified. Each end of the outer casing240is configured with a flush return924. The flat joint cover920is secured to the outer casing240using screws923fastened through the slight folds922into the respective flush returns924, as shown inFIG.9B. It will be appreciated that this configuration provides additional edge stiffness or rigidity and field installation is facilitated because the slight fold922comprises a single material thickness for attaching the joint cover920.

The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Certain adaptations and modifications of the invention will be obvious to those skilled in the art. Therefore, the presently discussed embodiments are considered to be illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.