Patent Grant
9447580
This invention relates to buildings, building components, building subassemblies, and building assemblies, and to methods of constructing buildings. The invention has particular application to building roof structures that incorporate rafters, purlins, braces that connect rafters to purlins (e.g. to enhance structural integrity), and suspension fabrics. The suspension fabric may be part of a fall protection system, part of an insulation support system, and/or part of a vapor barrier system. The invention also relates to associated articles, systems, and methods.
From time to time, injuries occur during the construction of buildings, including to workers involved in such construction. Workers who are involved, in particular, in the construction of roof structures for buildings are at risk of injury that may result from falling from an elevated height. Standard and required systems and practices have been developed to protect such workers, for example to catch and support them if/when they fall. These systems and practices are referred to as fall protection systems.
One known fall protection system is a passive system wherein a fabric, such as a solid sheet, a woven sheet, or a net-like material, is suspended at or below the work area, optionally supported by a grid of crossing support bands, far enough above any underlying supporting surface to catch and support a worker who falls, thereby to act as a passive fall-protection system.
The Occupational Safety and Health Administration (OSHA) in the U.S. has defined a drop test procedure whereby such a passive fall protection system can be tested. According to the test procedure, a 400 pound weight is dropped onto the fall protection system under stated conditions to determine whether a given system meets the required safety standards. For purposes of complying with government regulations, any system used as a fall protection system need only meet the OSHA-mandated standards related to dropping such 400 pound weight. Of course, the real humanitarian objective is to prevent worker injuries if/when a worker falls from an elevated work location. Thus, any fall protection system which is effective to catch and safely hold a falling worker has operational value, even if such system does not meet OSHA standards.
According to one practice currently in use in the metal building industry, and intended to meet government fall protection standards, a purported fall protection system uses crossing longitudinal and lateral metal bands extending under the eave, under the ridge, and under the intermediate purlins of the roof structure of the building, and a fabric is installed above the bands and under the purlins, extending across the entirety of a respective bay of the building being constructed, thereby providing a suspended fabric intended to catch and support a falling worker in that bay. Insulation is ultimately installed on the top surface of the fabric whereby the fabric ultimately functions both as the vapor barrier portion of the building ceiling insulation system in the finished building and as a catch-and-support fabric in the fall protection system.
In some cases, the design of a building roof structure calls for flange braces to be installed between the rafters and purlins of the building support structure. In some cases, a flange brace has a lower end which attaches to the bottom flange of a rafter, and an upper end which attaches to a neighboring purlin which is supported by the rafter. Such flange braces can enhance the structural integrity of the corresponding roof structure of the building.
However, such flange braces can also pose a challenge to the installation of a large suspension fabric which extends across the bay of a building roof structure. As such a fabric is unfolded in order to extend the fabric along the length of the bay underneath a set of successive purlins, the flange braces may present obstacles to such unfolding and installation of the extended fabric. One known approach to this situation is to disconnect the upper ends of the braces from the respective purlins so that the suspension fabric can be extended, and, after the fabric is in place, attaching the upper ends of the braces to bottom surfaces of the respective purlins. This approach avoids having to create a large hole or opening in the suspension fabric that would be needed to re-attach the upper end of each brace to a more central part of the respective purlin; however, attachment of the brace to the bottom surface of the purlin can be contrary to the building specification, and is otherwise undesirable from a structural integrity standpoint.
In another known approach, the upper ends of the braces are again disconnected from the respective purlins, but, after the extended suspension fabric is in place in the bay beneath the purlins and above the braces, a large opening is cut in the suspension fabric at a location corresponding to each brace so that the upper end of the brace can be re-attached to the respective purlin through such opening. Pieces of patch tape are then applied to the lower surface of the suspension fabric to repair the openings. In some cases, a sealant is also applied at the repair points, e.g. to restore the ability of the suspension fabric (as repaired) to act as a vapor barrier. However, the pieces of patch tape applied to the suspension fabric are typically visible to occupants of the building, e.g. after construction of the roof structure and building is complete, and can be highly unattractive. Furthermore, the patch tape can work loose and delaminate over time with normal expansion and construction of the building components.
Accordingly, there is a need for a novel approach to the challenge of constructing building roof structures which incorporate both extended suspension fabrics (e.g. as part of a fall protection system, or for insulation support, or for use as a vapor barrier) and flange braces which connect rafters to purlins in the roof structure.
These and other needs are alleviated, or at least attenuated, or partially or completely satisfied, by novel products, systems, and/or methods of the invention.
This invention provides brace covers suitable for use in building roof structures; systems and combinations involving such brace covers; methods of making and installing such brace covers, systems, and combinations; and buildings and roof structures which incorporate such brace covers, and kits which include a suspension fabric, banding for supporting the suspension fabric, and brace covers for covering openings in the suspension fabric through which braces will be extended.
For example, a building roof structure may include rafters, purlins, braces, and a suspension fabric. The suspension fabric, which may be part of a fall protection system and/or part of an insulation support system and/or part of a vapor barrier system, extends across a bay or other portion of the roof structure such that the suspension fabric extends onto the tops of the rafters but below the purlins. Braces connect at least some of the purlins to at least some of the rafters, and each brace extends through a corresponding slit or other opening in the suspension fabric. Brace covers are provided for some or all of the braces to conceal the fabric opening, to facilitate sealing around the brace near the suspension fabric opening to prevent passage of air through the suspension fabric opening, and/or to provide support for the suspension fabric near the suspension fabric opening.
In a first family of embodiments, the invention comprehends a building roof structure, comprising rafters and purlins, the purlins extending transversely across the rafters such that the rafters support the purlins; a suspension fabric extending across the roof structure such that the suspension fabric extends across the tops of the rafters and below the purlins; braces connecting at least some of the purlins to at least some of the rafters, each brace, and the respective purlin to which such brace connects, defining a brace/purlin combination, and each brace extending through a corresponding suspension fabric opening in the suspension fabric; and for each of at least some of the brace/purlin combinations, a brace cover having a cover opening through which the brace extends, the brace cover being disposed such that a portion of the suspension fabric is between the brace cover and the purlin.
In some embodiments, for at least some of the brace/purlin combinations, the purlin has a lower flange, and the brace cover is attached to the lower flange of the purlin.
In some embodiments, for at least some of the brace/purlin combinations, the purlin has a central web disposed between a purlin upper flange and a purlin lower flange, and the brace is attached to the central web of the purlin.
In some embodiments, at least some of the brace/purlin combinations further comprise a sealant applied around the brace and optionally into the cover opening in order to provide a barrier against ambient air flow through the cover at the cover opening.
In some embodiments, for at least some of the brace/purlin combinations, the brace cover has a perimeter which encompasses the suspension fabric opening.
In some embodiments, at least some of the brace/purlin combinations further comprise one or more pieces of tape applied to the suspension fabric to patch, to thereby at least partially close, the suspension fabric opening.
In some embodiments, a sealant bridges and seals a space between the brace cover and the suspension fabric.
In some embodiments, the sealant defines a closed loop path which is spaced from the suspension fabric opening, which closed loop path encompasses the suspension fabric opening.
In some embodiments, a perimeter of the brace cover defines a closed loop path which encompasses the closed loop path of the sealant.
In some embodiments, for at least some of the brace/purlin combinations, the brace cover comprises a plate, and the plate has a plate aperture which forms at least a portion of the cover opening.
In some embodiments, the plate of at least one of the brace covers has a 1-piece construction.
In some embodiments, the plate of at least one of the brace covers has a 2-piece construction.
In some embodiments, each plate which has the 2-piece construction has a first plate piece attached to a second plate piece, and the plate aperture in each such plate is partially defined by said first plate piece and partially defined by said second plate piece.
In some embodiments, plate aperture has a first L-shaped profile and, when the plate and brace are installed such that the plate is attached to the associated purlin and the brace is attached to the associated rafter and purlin, the plate aperture defines a reference plane, and a cross-section of the brace in the reference plane has a second different L-shaped profile.
In some embodiments, the L-shaped profile has first and second legs, and wherein the first leg is at least 1.5 inches long and the second leg is at least 1.5 inches long.
In some embodiments, the brace cover of at least some of the brace/purlin combinations also comprises a fabric piece attached to the plate and, when installation of the brace cover has been completed, the cover opening further comprises a fabric piece opening in the fabric piece, further comprising a sealant applied at a junction of the brace and the brace cover at the cover opening and optionally into the cover opening in order to provide a barrier against ambient air passing through the cover opening.
In some embodiments, the cover plate has first and second opposing major surfaces, the first major surface facing the purlin, and wherein the brace cover further comprises a fabric piece which covers the second major surface of the plate.
In some embodiments, the fabric piece is made of a same material as the suspension fabric.
In a second family of embodiments, the invention comprehends a building roof structure, comprising building structural roof elements including at least first and second rafters, a space between the first and second rafters defining a first distance between the first and second rafters, each rafter having a top, and opposing first and second ends, the roof structure further comprising an eave, having a length, and extending between the first ends of the first and second rafters, a ridge, having a length, and extending between the second ends of the first and second rafters, and a second distance between the eave and the ridge, the eave and the ridge being disposed on, extending transverse to, and being connected to, the tops of the first and second rafters, and a plurality of intermediate purlins extending between the first and second rafters and spaced from each other between the eave and the ridge, the intermediate purlins being disposed on, and extending transverse to, the tops of the first and second rafters, the building roof structure further comprising a first set of support bands extending from the first rafter to the second rafter and being connected to the building structural roof elements, the first set of support bands being spaced along the lengths of the first and second rafters; a second set of support bands extending from the eave toward the ridge and under the intermediate purlins, the second set of support bands having first and second end portions and being spaced from each other between the first and second rafters; a suspension fabric overlying, and being supported by, the first and second sets of support bands, the suspension fabric being securely attached to structural members of the building, a plurality of braces which collectively connect at least some of the intermediate purlins to one or both of the first and second rafters, each brace extending through a corresponding fabric opening in the suspension fabric; and for each brace which connects a given purlin to a given rafter, a brace cover having a cover opening through which the respective brace extends, the brace cover being attached to the given purlin and having a perimeter which encircles the fabric opening through which the brace extends.
In a third family of embodiments, the invention comprehends a brace cover suitable for use in a building roof structure which includes building roof structure braces, the brace cover comprising a plate having a thickness of at least 0.01 inch, and having an L-shaped aperture, the L-shaped aperture having a first leg at least 1.5 inches long and a second leg at least 1.5 inches long, such that the L-shaped aperture is sized to receive a building roof structure brace; and a fabric piece attached to the plate such that the fabric piece covers the aperture, the fabric piece also being imperforate at least in a region corresponding to the aperture such that the fabric piece seals the aperture.
In some embodiments, the second layer comprises a fabric piece made of a material suitable for use as a suspension fabric in a building fall protection system.
In some embodiments, the second layer has a layer perimeter and the plate has a plate perimeter, and wherein the second layer perimeter substantially matches the plate perimeter.
In some embodiments, the second layer is imperforate.
In a fourth family of embodiments, the invention comprehends a method of fabricating a building roof structure, comprising providing an initial building structure which includes columns, rafters supported by the columns, purlins supported by the rafters, and braces which connect at least some of the rafters to at least some of the purlins, each brace having an upper end which attaches to an associated purlin; detaching the upper ends of the braces from the associated purlins; laying out a suspension fabric across the roof structure above the rafters and below the purlins; and for a given brace, cutting a suspension fabric opening in the suspension fabric near the brace and the associated purlin, thereby to define a cover opening; guiding the upper end of the brace through the fabric opening in the suspension fabric, and re-attaching the upper end of the brace to the associated purlin; and attaching a brace cover to the associated purlin with a portion of the suspension fabric disposed between the brace cover and the purlin, the brace cover having a cover opening through which the brace extends.
In some embodiments, for a given brace, the attaching comprises passing the upper end of the brace through the cover opening before re-attaching the upper end of the brace to the associated purlin.
In some embodiments, the method further comprises, before the attaching the brace cover to the associated purlin, providing the brace cover in an initial state, the brace cover in the initial state including a plate and a fabric piece, the plate having a plate aperture, and the fabric piece being attached to the plate such that the fabric piece covers the plate aperture, the fabric piece being imperforate at least in a region corresponding to the plate aperture such that the fabric piece seals the plate aperture against free flow of ambient air through the fabric piece; and slitting the fabric piece in the region corresponding to the plate aperture to provide the cover opening.
In some embodiments, the method further comprises, for a given brace, after re-attaching of the upper end of the brace to the associated purlin, and before attaching the brace cover to the associated purlin, sliding the brace cover upwardly along the brace toward the associated purlin.
In some embodiments, for a given brace, assembling the brace cover about the brace and thereby defining a brace cover opening through which the brace extends.
In some embodiments, for a given brace, the brace cover comprises a plate having a plate aperture, the plate aperture being at least a portion of the cover opening, the plate also having a 2-piece construction comprising a first plate piece and a second plate piece, and wherein the assembling of the brace cover about the brace comprises joining the two plate pieces to each other and thereby forming the plate aperture about the brace.
In some embodiments, each brace cover has a perimeter and wherein, for a given brace, the attaching of the brace cover to the associated purlin comprises positioning the brace cover so that the perimeter of the brace cover encompasses the fabric opening.
In some embodiments, the invention further comprises, for a given brace, sealing the brace cover to the suspension fabric using a sealant in a closed loop path which is laterally spaced from the fabric opening and which encompasses the fabric opening.
In some embodiments, the invention further comprises, for a given brace, sealing the cover opening from ambient air flow by applying a sealant at a junction of the brace and the brace cover at the cover opening and optionally into the cover opening in order to provide a barrier against ambient air flow through the cover opening.
In a fifth family of embodiments, the invention comprehends a method of installing a brace cover on a brace in relation to a building roof structure, the method comprising providing a brace cover in an initial state, the brace cover in the initial state including a plate and a fabric piece, the plate having a plate aperture, and the fabric piece being attached to the plate such that the fabric piece covers the plate aperture, the fabric piece being imperforate at least in a region corresponding to the plate aperture such that the fabric piece seals the plate aperture; providing a brace having a first end; forming a slit in the fabric piece in the region corresponding to the plate aperture; and passing the first end of the brace through the slit and through the plate aperture.
In some embodiments, the brace has a second end opposite the first end, and wherein the second end is secured to building roof support structure under the building roof structure during the passing of the first end of the brace through the slit and through the plate aperture.
In some embodiments, the brace has an L-shaped cross-section, and wherein the forming of the slit forms the slit in an L-shape configuration.
In a sixth family of embodiments, the invention comprehends a suspension fabric kit, comprising a length of support banding suitable for extending a first set of support bands from a first rafter of a building to a second rafter of such building, and a second set of support bands, for crossing the first set of support bands and extending from an eave of such building, under intermediate purlins, to a ridge of such building; a suspension fabric suitable for extending from such first rafter to such second rafter and from such eave to such ridge, with the first and second sets of support banding supporting the suspension fabric; and a plurality of brace covers adapted and configured to extend about braces which are secured to ones of such rafters and ones of such purlins, and wherein such braces extend through apertures in the brace covers, the brace covers, in combination with sealants applied to the brace covers, bridging edges of the brace cover apertures and surfaces of such braces, and thereby providing a barrier against flow of ambient air through the respective cover apertures.
Related methods, systems, and articles are also discussed.
These and other aspects of the present application will be apparent from the detailed description below. In no event, however, should the above summaries be construed as limitations on the claimed subject matter, which subject matter is defined solely by the attached claims, as may be amended during prosecution.
Illustrative embodiments of the invention are described hereinafter, by way of example only, with reference to the accompanying drawings, wherein:
The invention is not limited in its application to the details of construction, or to the arrangement of the components or to the methods of construction, set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various other ways. Also, it is to be understood that the terminology and phraseology employed herein is for purpose of description and illustration and should not be regarded as limiting. Like reference numerals are used to indicate like components.
The description below, begins with a discussion in
According to the embodiments illustrated in
Ridge members 22, expressing “Z”-shaped cross-sections as illustrated in
The ridge members and the eave members overlie, extend transverse to, and are attached to, the upper surfaces of the respective rafters 16, and are spaced from each other by distances which generally correspond to the lengths of the respective rafters between ends 16B and 16C.
Intermediate purlins 24 express “Z”-shaped cross-sections. The intermediate purlins overlie, extend transverse to, and are attached to, upper surfaces 16A of the respective rafters. Purlins 24 are spaced from each other along the lengths of the rafters. The purlins extend parallel to each other and parallel to any ridges and eaves and, overall, span the length of the bay, whereby the purlins are displaced from each other and from any ridges and eaves along the spaces between the respective eave and the ridge.
As shown in
Support bands 26, 28 support a high strength fabric 32, the fabric being shown partially unfolded in
Starting with the structural skeleton of the building as illustrated in
A length of a given longitudinal band 26 extends across a given bay and is extended across the upper surface of each rafter overlain by the respective band, and is attached to the upper surfaces, or other surfaces, of the respective rafters. Where the longitudinal band 26 extends across multiple bays, the longitudinal band is secured, for restrained longitudinal movement, to the upper surfaces of those rafters which are most remote from one another. Optionally, but not necessarily, the longitudinal band may be secured to one or more intermediate rafters.
Longitudinal bands 26 are fastened to the rafters, rake channels, or rake angle(s) (not shown) which correspond with the end portions of the bands, by conventional attachment means such as by self-drilling screws. Longitudinal bands 26 are pulled tight between the rafters so as to, in part, and at this stage of installation, begin to define the afore-mentioned band grid, and the imaginary plane of support provided by the band grid, immediately under the intermediate purlins. Band attachment tools, known in the art, may be used in attaching the bands, either temporarily or permanently, to the rafters or rake channels, thus to instill a suitable, conventionally known, level of tension in bands 26 as the bands are being installed.
Each eave has a top flange 34, a bottom flange 36, and an upstanding web 38 extending between the top and bottom flanges, and connecting the top flange to the bottom flange. The top and bottom flanges are arranged such that the profile of the eave defines a generally “C”-shaped structure, perhaps best seen in
While the eave profiles shown define generally perpendicular turns between the flanges 34 and 36, and upstanding web 38, actual eave profiles typically define a modest acute angle (not shown) between the bottom flange and the upstanding web and a corresponding modest obtuse angle (not shown) between the top flange and the upstanding web. Such acute and obtuse angles adapt the eave to the specific slope of the roof for which the eaves are designed, while providing that the upstanding web conforms to the vertical orientation of the respective side wall of the building.
Correspondingly, each ridge has a top flange 40, a bottom flange 42, and an upstanding web 44 extending between the top and bottom flanges, and connecting the top flange to the bottom flange. The top and bottom flanges are arranged such that the profile of the ridge defines a “Z”-shaped structure, as illustrated in
Similarly, each intermediate purlin has a top flange 46, a bottom flange 48, and an upstanding web 50 extending between the top and bottom flanges, and connecting the top flange to the bottom flange. The top and bottom flanges are arranged such that the profile of the respective purlin defines a “Z”-shaped structure, illustrated in
Lateral bands 28 are installed after the longitudinal bands 26 are in place. Lateral bands 28 extend transverse to, typically perpendicular to, the longitudinal bands. Lateral bands 28 generally underlie and support longitudinal bands 26. Lateral bands 28 may be first attached to the respective ridge 22. Bands 28 may be attached to any suitable surface of the ridge which enables the band to pass, from the location of attachment, under and in tensioned contact with, the bottom flange of the ridge. For example, a lateral band can be attached to the bottom surface of the bottom flange of the ridge, with intervening fabric 32, and extend from there toward the eave.
As an alternative, one end of a given lateral band can extend up alongside, and be fastened to, the surface of the upstanding ridge web 44 which faces away from the eave on the respective slope of the roof. The band passes downwardly alongside web 44, and turns about the edge of the bottom flange of the ridge which faces away from the respective eave, and then passes under, and in general contact with, the bottom surface of the bottom flange, again with intervening fabric, and extends from there toward the eave.
As a still further example of attachment of a lateral band to the ridge, the band can be attached to the top surface of the top flange, turn about the upper edge of the top flange which is away from the respective eave, extend from there down toward the bottom ridge flange, turn about the edge of the bottom flange and pass alongside, and in general contact with, the bottom surface of the bottom flange, and extend from there toward the eave, again with the fabric between the band and the ridge.
The lateral bands are extended, from the bottom surface of the bottom flange of the ridge toward the respective eave, passing under the longitudinal bands, and pulled tight to minimize sag in both the lateral bands and the respective overlying longitudinal bands. The so-tightened lateral bands are in general contact, again with intervening fabric, with the bottom surface of the bottom flange of the respective eave. With the so-tightened lateral bands in contact with the bottom surface of the bottom flange of the respective eave, the lateral bands are fastened to the eave so as to maintain the tension in the lateral bands, thus to lift the lateral bands toward the bottom flanges of the overlying intermediate purlins.
The number of lateral bands 28 to be used between a respective pair of next-adjacent rafters, and the spacing between the lateral bands, varies with the distance between the rafters. Typically, the lateral bands are 36 inches to 40 inches apart, optionally up to 48 inches apart in some cases.
Traditional banding stock used for bands 26 and 28 is a hot-dip zinc/aluminum alloy-coated Grade 80 structural steel, 0.023 inch thick, having longitudinal tensile yield strength of at least 93 ksi, such Grade 80 banding sometimes being referred to in the industry as “full hard”. Such steel banding is typically about 1 inch wide and continuous length. Such traditional “full hard” steel banding is available from Steelscape, A BlueScope Steel Company, Kalama, Wash. as ZINCALUME® Steel Grade 80 (Class 1).
Representative properties of such Grade 80 (Class 1) banding, 0.023 inch thick, from Steelscape are as follows:
Yield strength—100.1 ksi average, 93.9-104.1 ksi range
Tensile strength—102.2 ksi average, 95.4-105.3 ksi range
Elongation in 2 inch sample—10% average, 9.6-10.3% range
Hardness, Rockwell B Scale—93.4 average, 92-95 range
“Ksi” means “thousands of pounds per square inch”.
Certain fabrics are known in the art for use as suspension fabrics in roof insulation systems, and such fabrics may also be acceptable in fall protection systems, provided for example that the bands used in the band grid-work are sufficiently close together. An exemplary fabric for use with the band grid-work disclosed herein is available as Type 1070 Vapor Retarder fabric from Intertape Polymer Group, Bradenton, Fla. The Type 1070 fabric is a woven HDPE scrim having the following characteristics as specified by the fabric supplier:
Nominal thickness—9 mils (0.23 mm)
Nominal weight—4.3 oz/yd2 (149 g/m2)
Grab Tensile—Warp 136 lb (605 N)/Weft 126 lb (559 N)
Strip Tensile—Warp 100 lb/in (877)/Weft 90 lb/in (799)
Tongue Tear—Warp 50 lb (222 N)/Weft 45 lb (200 N)
Mullen Burst—245 psi (1690 kPa)
Moisture vapor transmission—0.02 perms.
A typical bay 18 is about 25 feet wide, between pairs of next-adjacent rafters. Within a given bay, lateral bands 28 extend parallel to each other, parallel to the respective rafters which define the bay, and are generally spaced apart by about 36 inches to 40 inches, but no more than 48 inches. Thus, a desired spacing between lateral bands 28 is 36-40 inches; but up to 48 inches is accepted where the increase from 40 inches e.g. up to 48 inches can reduce the number of bands.
A leading edge of fabric 32 can be placed inside the eave. A leading edge of the fabric enters the eave above bottom flange 36, passes across the top of the bottom flange to web 38, passes along the inside surface of web 38 and up to upper flange 34 and thence toward the ridge, to the eave opening which faces the ridge. By traversing such path inside the cavity defined inside the eave, the fabric can substantially encase the edge of any insulation which is to be installed on top of the fabric in the space between the eave and the next-adjacent purlin.
In the alternative, the edge of the fabric, at the eave, can be trapped between the lateral banding and the lower surface of the bottom flange of the eave as suggested in
If/When a falling/dropping impact force arrives on the suspension fabric, the force received by the suspension fabric has a first directional force component and a second velocity/shock/suddenness component. The force component of the impact is resisted by, absorbed by, the deflection characteristics of the materials in the fall protection system. The velocity/shock/suddenness component of the impact addresses the rate at which the respective materials can deflect as the force of the impact is applied to the respective building elements.
Where a given lateral band 28 is one of the closest lateral bands to the point where the impact force is received, a first portion of that force, which is received at the fall protection system, is transferred, as first tensile forces, into the respective lateral band and is absorbed, dissipated, at least in part, by tensile elongation of the respective lateral band.
A second portion of that received force is transferred, by the lateral band to the next-adjacent purlins which are closest to the location of the impact.
A third portion of that force is received into the respective longitudinal band, or bands, and is absorbed, dissipated, at least in part, by tensile elongation of the respective longitudinal band or bands.
A fourth portion of that received force is received by the respective longitudinal band or bands, and transferred by the longitudinal bands, to the respective rafters 16.
A fifth portion of that received force is distributed about the respective affected area of the suspension fabric. While choosing to not be bound by theory, the inventor herein contemplates that the fabric absorbs both a portion of the directional component of the force of the impact and a velocity/shock/suddenness component of the force of the impact.
Turning again to the responses of the bands, the tensile forces so imposed on the longitudinal bands and the respective lateral band or bands are distributed along the full lengths of the respective longitudinal bands and along that portion of the respective lateral band or bands which is/are between the two purlins which are next adjacent the location on the fall protection system where the impact of the drop is received. Thus, the elongation properties of both the longitudinal bands and the lateral bands are utilized in transferring portions of the impact force to the roof structural elements, namely one or more intermediate purlins, and optionally to ridges or eaves, and to the rafters or rake channel(s) or rake angle(s).
Installation of a fall protection system may begin after the columns, rafters, ridges, eaves, and intermediate purlins are in place about at least a given bay. Typically, installation of the fall protection system begins after erection/emplacement of all of the columns, rafters, ridges, eaves, and purlins.
Installation of the fall protection system begins by installing longitudinal bands 26. A given longitudinal band is installed by unwinding band material from a roll and extending the band material over the tops of the respective rafters and across a given bay or bays. At least one longitudinal band is extended, between each next-adjacent pair of purlins to at least the next rafter, and is cut to length. The longitudinal bands are manually stretched tight with hand tools, and the so-tightened bands are fastened to the respective rafters with Tek screws. As illustrated in the drawings, the longitudinal bands typically extend perpendicular to the rafters, rake channel(s), or rake angle(s). The so-partially-installed, tightened, longitudinal bands extend from rafter to rafter at generally the height of the tops of the rafters, but some nominal amount of sag of the longitudinal bands exists between the rafters at this stage of installation.
Typically, the purlins are spaced no more than 5 feet apart. A single band may be installed between each pair of next-adjacent purlins so long as the purlin spacing is no more than the typical maximum of 5 feet. Where the purlin spacing approaches, or exceeds, the typical 5-feet maximum, an additional longitudinal band 26 may be used in one or more of the spaces between the purlins.
Once the longitudinal bands 26 have been emplaced and tightened, banding for lateral bands 28 is unrolled under the longitudinal bands, and one end of the banding is secured to the respective ridge or purlin, or to an opposing eave. The lateral banding material is extended to the eave of the respective bay and then tightened sufficiently to raise both the lateral band and the overlying longitudinal bands into close proximity with the intermediate purlins. This process is repeated along the width of the bay, e.g. between the rafters, until the desired number of lateral bands has been emplaced across the width of the bay.
With the band grid system thus temporarily in place, a zigzag-folded roll of the suspension fabric is elevated to the height of the rafters, typically adjacent a rafter at an end of the building or bay. The fabric is then unrolled on top of the band grid in one of the spaces between next-adjacent ones of the purlins such that one end of the fabric faces the eave and the opposing end of the fabric faces the ridge. The ends of the fabric are then pulled, individually, toward the eave and the ridge, working the leading ends of the fabric under the intervening intermediate purlins and above the band grid. The initial phase of the process of so-extending the fabric is illustrated in
With the fabric having been generally extended the full length and width of the bay over which the fabric is to be suspended, namely over the band grid and under the intermediate purlins, the lateral bands are then attached to the intermediate purlins, one self-drilling Tek screw through each lateral band and the fabric, at each purlin, typically beginning at the ridge and working toward the eave. As a such Tek screw/washer is driven tight against the bottom surface of the fabric, the fabric is correspondingly driven tight against the bottom surface of the lower flange of the purlin. The fabric is thus tightly trapped between the washer and the lower flange of the purlin. Screws 66 are driven through each lateral band 28 at each purlin, fastening the lateral bands directly to the purlins as illustrated in
Once the attachments to the intermediate purlins have been completed, the temporary attachments of the bands to the eave are released, and the lateral bands are permanently attached to the eave, e.g. using screws 66 driven through the lateral bands, e.g. as illustrated in
Sides of the fabric are then cut around the purlins at each rafter, as known in the art, and edges of the fabric are secured to the top surfaces of the rafters such as by adhesive, also as known in the art.
With both the longitudinal and lateral bands so secured to the roof structure, and with the fabric so secured to the ridge and eave by the lateral bands and secured to the rafters by e.g. adhesive, installation of the fall protection system of the invention is thus complete and ready to protect workers who subsequently install other elements of the building while working at the roof elevation; such elements as the roof insulation and the roof panels.
Suspension fabric 32, which in the preferred embodiment is or includes a vapor barrier material, is trimmed to size before installation. Specific trimming of the suspension fabric 32 in the form of notches may also be performed before or during installation at locations where purlins contact the upper surfaces of rafters. A notch in the fabric at such a location allows the edge of the fabric to more fully cover the top surface of the rafter immediately adjacent the point of contact with the purlin, while also allowing the fabric to extend longitudinally across substantially the entire accessible length (between adjacent rafters) of the bottom flange of the purlin. This is shown and described below in connection with
The suspension fabric has been cut, prior to installation, to a size having a dimension a few inches longer, at each side and each end, than the dimensions of the bay to be overlaid, and is Z-folded for easy spreading above the band grid. For this purpose a zigzag type fold, as shown in
The fall protection systems discussed herein can be designed to be of sufficient strength to catch and support a man's weight, generally between 250 and 400 pounds. The system is tested by dropping a 400 lb. weight, with the center of gravity of the weight, before the weight is dropped, being 42 inches above a worker's walking height, thus 42 inches plus the height of the purlins, namely about 50.5 inches above the fabric. To pass the test, the system must effectively stop the falling weight at any point in the bay which is so protected. In one test specified by OSHA, 400 lb. of washed gravel or sand is placed into a reinforced bag that can tolerate being dropped repeatedly. The test bag is 30 inches in diameter. The 400 pound bag is hoisted above the fall protection system to a height of 42 inches above the plane of the intermediate purlins, measuring from the center of the so-filled bag. A cord supporting the weight of the bag is then released, allowing the weight to free fall in one concentrated load. The weight can be dropped onto any part of the fall protection system to test different areas.
Having generally described exemplary building and roof structures and passive fall protection systems and related systems and components, we now turn to
Flange braces can come in a variety of sizes and shapes, but a typical flange brace 110 is shown schematically in
A given flange brace may be characterized or described in terms of its length, its cross-sectional shape, and by any other relevant features and dimensions. Braces of the type shown in
Alternative brace designs that may be suitable for a given building structure, depending on the size of the building and the elements used in the building structure, include braces which can be made by providing a length of hollow metal tubing, the length equal to the length of the desired brace, each of the two ends of the tube optionally, but typically, having been flattened, e.g. by hammering or pressing the tube flat at the ends, including rotating the tube by nominally 90 degrees between effecting such flattening activities such that the flattened ends are nominally oriented perpendicular to each other. As with the embodiment illustrated in
A plate aperture 118 extends through plate 116. Aperture 118 is sized so as to be able to receive brace 110. Aperture 118 is sometimes herein referred to as a cover opening 124, namely where there are no other elements which form part of the cover opening besides plate 116. That is, plate aperture 118 has an appropriate size and shape so that an end of brace 110 can pass through aperture 118. E.g. upper end 112 of the brace can be made to pass through aperture 118 by holding the brace stationary and moving the plate, or by holding the plate stationary and moving the brace, or by moving both the brace and the plate. The size and shape of plate aperture 118 is such that e.g. end 112 of brace 110 can pass through the aperture at an oblique, namely a non-perpendicular, angle corresponding to an orientation angle the brace makes with the plate in the installed system. Preferably, the aperture is not so large that a large gap remains between brace 110, as installed, and the rigid/metal or rigid/plastic portion of plate 116. Stated differently, the plate aperture preferably has a shape which is similar to a cross-sectional shape of the brace, e.g., a transverse cross-section of the brace, or a cross-section of the brace in a reference plane parallel to the aperture, as described further below. For example, in the case of
In alternative embodiments, plate aperture 118 can be made rectangular while the cross-section of brace 110 remains L-shaped, the rectangular aperture being sized so that two edges of the rectangular aperture are close to or touching the outer surfaces of the two angled walls of the brace. An example of this is shown below in
Plate 116 is typically made of metal, but other suitable materials, such as hard plastics, may also be used. However, as suggested by the term “plate”, the material used for the plate preferably has a sufficient thickness so that the plate 116 has a substantial mechanical rigidity or stiffness. The desired rigidity is preferably enough so that, when the plate, and thus the brace cover, is installed, e.g. attached to a purlin on one side of the brace, the edge of the plate on the other side of the brace does not droop or sag, but rather provides enough support to the suspension fabric above the plate to hold that portion of the fabric in a visually consistent orientation relative to the surrounding portions of the fabric. In an exemplary embodiment, plate 116 is made of a single piece of 0.015 inch thick steel, and has a plate perimeter 120 which is nominally square, each side of the square being 12 inches long. In this embodiment, aperture 118 is L-shaped, each leg of the aperture being 3 inches long, and aperture 118 is located at or near the center of the square-shaped plate. Metals other than steel, such as aluminum, as well as layered/laminated materials, can also be used in fabricating plate 116. In cases where plate 116 is made of metal, a typical thickness e.g. from about 0.010 inch to about 0.050 inch, but this range should not be construed in an unduly limiting manner so long as the plate serves in the above-described capacity.
The particular plate embodiment mentioned above uses a 12 inch square, e.g. each side 12 inches long, plate perimeter. Other perimeter sizes and shapes, including rectangular, polygonal, circular, or elliptical, may also be used. Whatever the shape, the overall length and/or width of the plate 116 is typically at least about 8 inches, or at least about 10 inches, or at least about 12 inches, e.g. in order to fully conceal, and/or seal around, the opening in the suspension fabric. Further in this regard, plate perimeter 120 is also preferably sized so that, when the brace cover is installed, the plate perimeter, as well as the cover perimeter, encircles the opening in that suspension fabric which the brace extends through.
Plate 116 of
Turning to
Fabric piece 126 is preferably made of the same or similar material as the suspension fabric 32 against which brace cover 122 is intended to be ultimately placed or installed. In this regard, cover 122 is installed in the building structure such that the major surface of plate 116 which has no fabric applied faces generally upwardly, facing the suspension fabric and the respective purlin, and the major surface of the plate which does have the fabric applied, faces generally downwardly, and is typically exposed and visible to occupants of the building, against the background of the surrounding suspension fabric. By ensuring that the surface of fabric piece 126 which faces toward the occupants of the building has an outer appearance, e.g., color and texture, which is the same as or similar to the appearance of the suspension fabric, the brace covers can visually “blend in” and become inconspicuous substantially un-noticeable, to building occupants who look upward toward the ceiling/roof. In this manner, the brace cover conceals the opening in the suspension fabric, and may conceal any patch tape or other products which may have been applied at the fabric opening.
A view of brace cover 122 from below is illustrated schematically in
In many (but not all) cases, the fabric piece covers substantially the entire major surface of plate 116 such that the perimeter of fabric piece 126 matches the plate perimeter 120. Regardless of the coverage of the fabric piece over the major surface of plate 116, in at least the region of plate aperture 118, the fabric piece is initially preferably imperforate, i.e., without significant holes or other openings, such that the fabric piece seals the plate aperture. Typically, although not necessarily, the entire fabric piece 126, not merely the portion proximate the plate aperture 118, is continuous and imperforate in the initial state shown in
Besides serving a possible aesthetic purpose or function, fabric piece 126 in particular facilitates sealing around the brace by more closely conforming to the outer surfaces of the brace than does aperture 118 in plate 116, after the brace cover is fully and completely installed about the brace. Stated differently, in the installed configuration, there are typically gaps between the brace and the plate, due to portions of the plate aperture being spaced from the surface of the brace. Because the passageway through the fabric piece is made by slitting the fabric piece, typically without any substantial removal of material from the fabric piece, gaps between the brace and fabric piece 126 can be substantially smaller than the gaps between the plate and the brace, due to the conformable, flexible nature of the fabric whereby edges of the fabric readily conform to articles with which the fabric comes into contact. In a final or near final step of installation, a sealant can be applied around the brace, both at the suspension fabric and at the brace cover fabric, to fill such gaps, spaces in order to restore the ability of the suspension fabric and/or the brace cover fabric (as repaired) to act as an effective vapor barrier and/or barrier to air flow.
Before the brace cover can be installed on the brace, the intact, continuous nature of the fabric piece in the vicinity of plate aperture 118 is removed or eliminated by cutting a slit or other opening in the fabric piece in that vicinity. Such cut fabric is illustrated schematically in FIG. 12B, where the same brace cover 122 is shown in the same cross-sectional view as
Opening 128 is depicted in
Fabric piece 126 has been discussed above as being the same material as suspension fabric 32. In the alternative, fabric piece 126 can be any of a variety of materials. The functional requirements of fabric piece 126 are that fabric piece 126 provide an air barrier, and be readily penetrable over the plate aperture in order to provide a passageway for brace 110, through the fabric piece. Desirably, but not as a limitation, fabric piece 126 also provides a visually pleasing, or at least neutral, appearance.
As long as those minimal limitations are met, fabric piece 126 can be any of a variety of materials. The fabric piece was described above in terms of being made of the same material as the suspension fabric. The fabric piece can also be any film or sheet material, or multiple layers of film or sheet material, which collectively provide the necessary functional performances. Thus there can be mentioned fabrics made of woven or non-woven fiber and/or plastic threads, plastic films, combinations of one or more layers of plastic film, optionally combined and/or laminated with, one or more layers of threaded material. Thread materials may be any of the natural fibers, any of the polymeric fibers. As the plastic films, there can be mentioned as examples, but without limitation, various of the olefin or olefin-based materials, including olefin-based homopolymers and copolymers, such as polyethylene, polypropylene, ethylene propylene copolymer, ethylene vinyl acetates, polyamides and polyamide derivatives, acrylics, polyesters, and the like, so long as the resulting fabric provides both a barrier to passage of air and susceptibility to being readily cut to create slit/opening 128.
Purlin 24 expresses a “Z”-shaped cross-section, as shown above in
Rafter 16 may be an I-beam with an I-shaped cross-section as shown, but in any case the rafter includes a bottom flange 17. In a typical but non-limiting example, the vertical dimension (height or depth) of rafter 16 may be 16 inches, and the transverse dimension (width) of the entire lower flange may be 4 inches.
A flange brace 110 connects purlin 24 to rafter 16, e.g. to enhance the structural strength, and thus the integrity, of the building structure. More particularly, flange brace 110 is securely fastened or attached to bottom flange 17 of the rafter at lower end 114 of the brace. At the upper end 112, brace 110 is securely fastened or attached to web 50 of purlin 24, preferably at a central location half way between top and bottom flanges 46, 48 of the purlin. The secure attachment at the ends of brace 110 may be made by an appropriately sized nut 130A and bolt 130B combination, which may extend through holes 115 in brace 110 such holes 115A, 115B being shown at both ends of the brace in
A given brace 110, and the purlin which the respective brace connects to, may be considered a brace/purlin combination. Although brace 110 is shown as an angle brace in
In
The overall objective of use of the suspension fabric is to install the fabric below the purlins and above the rafters, in such a manner that the fabric spans substantially the entire distance between the rafters in a given bay, even at and proximate braces 110. As the fabric is installed, the fabric is first generally laid out across the bay, and along the lengths of the respective rafters. With the fabric so laid out and extending rafter-to-rafter across the bay, a given brace is individually temporarily disengaged, and temporarily moved out of the way of the space to be occupied by the suspension fabric. The necessary work is then done to extend that brace through the fabric, to position and mount the cover about the brace, and to seal about the cover so as to prevent movement of air from the bottom of the fabric to the top of the fabric, or vice versa.
The respective braces are thus disconnected one at a time, or a few at a time, while leaving the majority of the braces fully connected to their respective rafters and purlins such that the building structure continues to benefit from the structural strength provided by the braces, as a brace set, even while the process of installing the brace covers, and sealing about brace covers, is taking place.
Thus, a given brace, which has first been connected to both the respective rafter at the lower end of the brace, and the respective purlin at the upper end of the brace, is disconnected from the purlin and moved out of the way of the fabric. After the respective portion of the fabric has been positioned across the space previously occupied by that brace, the upper end of that brace is reconnected to the purlin. Typically, only after that brace has been fully re-connected to the purlin does the respective worker or worker team move on to disconnect another brace.
Certainly, multiple workers can be working on multiple braces in a given building at the same time. But overall, at any given point in time, most of the braces, at both their upper and lower ends, are connected to their respective rafters and purlins whereby the benefits of the use of braces remains in effect in the building structure even while the braces are being worked through the fabric.
The invention contemplates that, in some instances, the upper ends of a small fraction of the braces may not be connected to the respective purlins before the suspension fabric is installed. However, that, fraction of braces which are not installed is small enough to assure the contractor that the building structure is adequately braced against most weather conditions for which the building is designed, and against all of the weather conditions expected to occur before all of the braces are fully connected, both to the respective rafter and to the respective purlin.
In
In
In
With the suspension fabric extending across the bay, under the purlins and over the respective rafters, a slit is cut in the suspension fabric near the location of brace 110 so that brace 110 can be pushed/bent up through the slit in fabric 32 and re-attached to the overlying purlin. The cutting provides the slit or opening 32A in the fabric 32, shown generally in
While upper end 112 of the brace is disconnected from purlin 24 as illustrated in e.g.
In other embodiments, brace cover 122 further includes a fabric piece 126 mounted on plate 116 as illustrated and discussed in connection with
After the step shown in
For example, patch tape 136 (
After upper end 112 of brace 116 has been reattached to the purlin at aperture 133, brace cover 122 can be installed at its intended position, as shown schematically in
A brace cover 122 having a 2-piece plate 116, such as any of those described further below, can be installed in a similar way as the 1-piece plate, except that there is no need for the preliminary pre-installation step of passing the plate through the brace while the end of the brace is unattached. Rather, the 2-piece plate can be installed around the flange brace 110 even when the ends of the brace 110 are secured to their respective rafter and purlin whereby the steps of disconnecting and reconnecting the upper end of the brace from and to the purlin can be omitted.
Finally, as shown in
Also in
In an embodiment not shown, after brace 110 has been inserted through slit/opening 32A as illustrated in
At this stage of the process of installing the brace covers through the fabric, the fabric is typically stretched into a generally taught, generally horizontal orientation. With both the fabric and the cantilevered portion of the brace cover being in generally horizontal orientations, with the fabric trapped between the brace cover and the bottom flange of the purlin, and with the fabric subject to a modest drape due to the force of gravity, the cantilevered portion of the brace cover and the overlying portion of the fabric are extending generally parallel to each other and in surface-to-surface contact with each other.
Given the tight entrapment of the fabric between the brace cover and the bottom flange of the purlin and the parallel contacting surfaces of the fabric and the cantilevered portion of the brace cover, and with application of a thick enough bead of the tube sealant, the entirety of the closed loop of sealant 134 bridges the distance between fabric 32 and brace cover 110 about the entirety of the closed loop of sealant. Thus, the closed loop of sealant provides a second line of defense against movement of cold air through passageway 148 and into the interior of the building.
Accordingly, any cold air which manages to get past tape 136 at passageway 148 is prevented from entering the enclosed space of the building by lateral movement between brace cover 110 and fabric 32, by dosed loop 134 of tube sealant.
Accordingly, the invention provides three lines of defense against infiltration of ambient air into the space enclosed by the building. The first line of defense is tape 136 which closes off most of passageway 148 at the fabric. The second and third lines of defense prevent substantially all passage of any residual air which gets past tape 136, into the space enclosed by the building. Closed loop 134 prevents movement of such residual air into the building by way of transverse paths between the fabric and the brace cover. Tube sealant 132 prevents movement of such residual air into the building by way of aperture/opening 118/124 in brace cover 122.
Two piece plate covers illustrated in
Although the invention has been described with respect to various embodiments, the invention is also capable of a wide variety of further and other embodiments within the spirit and scope of the appended claims.
Those skilled in the art will now see that certain modifications can be made to the apparatus and methods herein disclosed with respect to the illustrated embodiments, without departing from the spirit of the instant invention. And while the invention has been described above with respect to certain preferred embodiments, the reader will readily understand that the invention is adaptable to numerous rearrangements, modifications, and alterations, and all such arrangements, modifications, and alterations are intended to be within the scope of the appended claims.
To the extent the following claims use means plus function language, it is not meant to include there, or in the instant specification, anything not structurally equivalent to what is shown in the embodiments disclosed in the specification.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/951,505 filed Mar. 11, 2014, the entirety of the preceding application being incorporated herein by reference in its entirety.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3969863 | Alderman | Jul 1976 | A |
| 4047346 | Alderman | Sep 1977 | A |
| 4069636 | Kessler | Jan 1978 | A |
| 4075807 | Alderman | Feb 1978 | A |
| 4147003 | Alderman | Apr 1979 | A |
| 4318260 | Siegel | Mar 1982 | A |
| 4408423 | Lautensleger | Oct 1983 | A |
| 4446664 | Harkins | May 1984 | A |
| 4573298 | Harkins | Mar 1986 | A |
| 4635423 | Ward | Jan 1987 | A |
| 4637188 | Crothers | Jan 1987 | A |
| 4711060 | Scherrer | Dec 1987 | A |
| 4875320 | Sparkes | Oct 1989 | A |
| 5357722 | Kessler | Oct 1994 | A |
| 5406764 | Van Auken | Apr 1995 | A |
| 5901518 | Harkins | May 1999 | A |
| 5953875 | Harkins | Sep 1999 | A |
| 6003282 | Alderman | Dec 1999 | A |
| 6041568 | Alderman | Mar 2000 | A |
| 6226945 | Henry | May 2001 | B1 |
| 6247288 | Harkins | Jun 2001 | B1 |
| 6363684 | Alderman | Apr 2002 | B1 |
| 6393797 | Romes | May 2002 | B1 |
| 6401426 | Alderman | Jun 2002 | B1 |
| 6595455 | Romes | Jul 2003 | B2 |
| 6769223 | Alderman | Aug 2004 | B2 |
| 7114301 | Bibaud | Oct 2006 | B2 |
| 7448836 | Clarke | Nov 2008 | B2 |
| 7797905 | Smalley | Sep 2010 | B1 |
| 8479455 | Schaefer | Jul 2013 | B2 |
| 8528301 | Robbins | Sep 2013 | B1 |
| 8590245 | Peng et al. | Nov 2013 | B2 |
| 8844230 | Harkins | Sep 2014 | B2 |
| 20020020584 | Cjepa | Feb 2002 | A1 |
| 20020124507 | Atkins | Sep 2002 | A1 |
| 20030114055 | Burton et al. | Jun 2003 | A1 |
| 20030167718 | Alderman | Sep 2003 | A1 |
| 20100005749 | Abdel-Sayed | Jan 2010 | A1 |
| 20100024325 | Robbins | Feb 2010 | A1 |
| 20110061311 | Peng | Mar 2011 | A1 |
| 20110067345 | Crostic, Jr. | Mar 2011 | A1 |
| 20110258955 | McCarron | Oct 2011 | A1 |
| Number | Date | Country |
|---|---|---|
| WO 2012145783 | Nov 2012 | WO |
| Entry |
|---|
| Silvercote Lamination, ES Energy Saver FP, brochure, Copyright 2014, 20 pages, Silvercote Laminations, Greer, South Carolina. |
| Guardian Building Products Distribution, Inc., Guardian ES Energy Saver FP, Product Specification Sheet, Copyright 2011, 2 pages, Guardian Building Products, Greer, South Carolina. |
| Harris Steel, Industry properties for Steel Sheets—Cold Rolled & Hot Dipped Zinc Coated, Specification Sheet, 2 pages, Harris Steel. |
| Steelscape, A Bluescope Steel Company, Zincalume Steel Grade 50 (Class 1), Grade Data Sheet, Jul. 1, 2012, 1 page, Steelscape. |
| Steelscape, A Bluescope Steel Company, Zincalume Steel Grade 80 (Class 1), Grade Data Sheet, Jul. 1, 2012, 1 page, Steelscape. |
| Maple Leaf Sales, K-Grip 514 Flammable Foam, Product Data Sheet, 1 page. |
| Maple Leaf Sales II, Inc., 514 Macroplast Adhesive, Material Safety Data Sheet, dated Jul. 16, 2010, 3 pages. |
| Number | Date | Country | |
|---|---|---|---|
| 20150259907 A1 | Sep 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61951505 | Mar 2014 | US |
