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You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND 
     Various roofing systems have been proposed for metal frame buildings. Generally, these systems include metal beams such as rafters, struts, and purlins arranged to cover the desired building interior space. The roof may also include metal support bands and sheeting along the rafters, struts, and/or purlins. The bands and sheeting provide support for additional materials such as insulation layers that may be placed atop the sheeting. An outer roof layer is placed atop the rafters, struts, and purlins to complete the roof. 
     In the mid 1990&#39;s, OSHA instituted fall prevention regulations. Those regulations may in some cases impact the construction of metal frame buildings. Accordingly, protective netting, harnesses, and edge protection have been employed during such construction. Also, metal support bands underlying the sheeting and insulation have been designed so as to be able to support a person who might fall into the sheeting during construction. 
     In particular, title 29 C.F.R. §1926.502 requires that a roof&#39;s insulation support and fall protection system restrain and support 400 pounds dropped from at least 42 inches above the system. This standard is intended to represent potential impact of a person falling onto the structure. Energy Saver FP™ roofing systems available from Guardian Building Products incorporate structures such as bands and sheeting designed to meet such requirements. Metal roofing systems available from other sources also claim to meet such requirements. One such system requires multiple fasteners be driven through both ends of longitudinal and transverse metal support bands where attached to rafters or struts, with the fasteners being spaced at least two inches from the ends of the bands. 
     SUMMARY 
     Objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention. 
     In accordance with one embodiment of the present disclosure, a connector is disclosed for securing a roofing band to a roofing beam by a threaded fastener, the connector includes, for example, a circumferential flange portion, a first recess extending within the circumferential flange portion, and a second recess extending within the circumferential flange portion substantially parallel to the first recess. The first and second recesses have a length longer than a width of a roofing band. A central portion extends within the circumferential flange portion between the first recess and the second recess, a middle area of the central portion being offset laterally from the circumferential flange portion by a distance enough to permit the roofing band to be slid through the first and second recesses so that the circumferential flange portion is located on a first side of the roofing band and the middle area of the central portion is located on a second side of the roofing band opposite the first side. A single fastener opening is defined through the central portion, the fastener opening sized for receiving a threaded fastener therethrough for fastening the roofing band to a roofing beam. Various options and modifications are possible. 
     In yet another embodiment of the present disclosure, a metal roof assembly is disclosed including, for example, a roofing beam, a roofing band secured to an underside of the roofing beam, and a connector securing the roofing band to the roofing beam, the connector having a circumferential flange portion, a first recess extending within the circumferential flange portion, and a second recess extending within the circumferential flange portion substantially parallel to the first recess, the first and second recesses having a length longer than a width of the roofing band. A central portion extends within the circumferential flange portion between the first recess and the second recess, a middle area of the central portion being offset laterally from the circumferential flange portion. A portion of the roofing band is disposed through the first and second recesses so that the circumferential flange portion is located on a first side of the roofing band facing the roofing beam and the middle area of the central portion is located on a second side of the roofing band opposite the first side. A single fastener opening is defined through the central portion. A threaded fastener extends through the fastener opening, the roofing band, and into the roofing beam to fasten the roofing band to a roofing beam. Again, various options and modifications are possible. 
     In still another embodiment of the present disclosure, a method is disclosed for installing a metal roof, the method including, for example, constructing a roof frame of metal beams, attaching a grid of roof bands to the metal beams using threaded fasteners and connectors, each connector having a circumferential flange portion, a first recess extending within the circumferential flange portion, and a second recess extending within the circumferential flange portion substantially parallel to the first recess, the first and second recesses having a length longer than a width of one of the roofing bands. A central portion extends within the circumferential flange portion between the first recess and the second recess, a middle area of the central portion being offset laterally from the circumferential flange portion. The attaching step includes sliding the connector onto the roofing band so that a portion of the roofing band is disposed through the first and second recesses so that the circumferential flange portion is located on a first side of the roofing band facing the roofing beam and the middle area of the central portion is located on a second side of the roofing band opposite the first side, a single fastener opening defined through the central portion. The attaching step further includes inserting a threaded fastener through the fastener opening, the roofing band, and into the roofing beam to fasten the roofing band to a roofing beam. As above, various options and modifications are possible. 
     Other features and aspects of the present disclosure are discussed in greater detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure, including the best mode thereof, directed to one of ordinary skill in the art, is set forth more particularly in the remainder of the specification, which makes reference to the appended figure in which: 
         FIG. 1  is a perspective view of a structure including portions of a metal roof assembly according to the present disclosure. 
         FIG. 2  is a perspective partial view of a metal roof assembly according to the present disclosure showing various layers atop the metal structure. 
         FIG. 3  is a bottom perspective partial view of a metal roof assembly according to the present disclosure. 
         FIG. 4  is a top perspective partial view of metal roof assembly according to the present disclosure. 
         FIG. 5  is a perspective view of a metal roof assembly according to the present disclosure. 
         FIG. 6  is a perspective view of a connector as in  FIG. 5 , with a roofing band inserted therein. 
         FIG. 7  is a perspective partially-exploded view of a roofing band securable to a roofing beam using a connector according to the present disclosure with one type of fastener. 
         FIG. 8  is a perspective partially-exploded view as in  FIG. 7 , with an alternate fastener. 
     
    
    
     Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the disclosure. 
     DETAILED DESCRIPTION 
     Reference now will be made in detail to various embodiments of the disclosure, one or more examples of which are set forth below. Each example is provided by way of explanation of the disclosure, not limitation of the disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the disclosure. For instance, features illustrated or described as part of one embodiment, can be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present disclosure covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
     The present disclosure is generally directed to connectors, building assemblies, and methods useful in constructing metal buildings. Use of the connectors, structures and methods disclosed herein provide a safe, efficient, and advantageous design and building process. 
     Referring to  FIG. 1 , a partial view of a metal building  10  is shown. Building  10  includes beams such as upright columns  12 , rafters  14 , struts  16 , and purlins  18 . It should be understood that the present disclosure is not limited to any particular metal building or roofing configuration. As shown, columns  12  and rafters  14  are integral. However, these parts could be separate parts connected together, as in known designs. Further various types of metal beams, and various shapes of beams such as rafters, struts, and purlins are also capable of being employed with the present disclosure. No limitation as to any of the above is intended by this disclosure. 
     As shown, roof portion  20  of building  10  includes struts  16  and purlins  18  mounted atop rafters  14 . Criss-crossing metal bands  22 ,  24  are attached to a bottom surfaces of struts  16  and purlins  18 , and well as a top surface of the rafters  14  on ends of building  10  (i.e., the end rafters). 
     Bands  22 ,  24  may be made of steel. If desired, the steel may be galvanized and painted white for aesthetics. The bands may be Energy Saver FP™ banding available from Guardian Building Products. Sheeting material  26  is installed above bands  22 ,  24  and rafters  14  but below the struts  16  and purlins  18  (See  FIGS. 2 and 3 ). Sheeting  26  can be notched, installed in sections, etc. to ensure coverage of the entire roof area. Edges of sheeting  26  can be glued in place to maintain a smooth and environmentally tight structure. If desired the sheeting material may be Energy Saver FP™ fabric available from Guardian Building Products. Such fabric provides fall protection, strength, condensation control, fire and smoke retardation and other benefits. 
     At least one insulation layer is typically located atop sheeting  26 . As shown, a first insulation layer  28  is laid parallel to and substantially between purlins  18 , and a second insulation layer  30  is laid perpendicularly across the first insulation layer. Outer roofing material  32 , which can be for example formed metal panels or the like, is then attached to purlins  18 . If desired, second layer  30  could be omitted and spacers  34  could be attached to a top surface of purlins  18  for attachment of outer roofing material  32  with reduced heat transfer. Such spacers or other alternate attachment elements could also be used with the double layer insulation structure if desired. If desired in a particular application, the insulation layers could be omitted, although such is not generally recommended for best performance. 
     A connector  40  is shown in  FIG. 5 . Connector  40  includes a circumferential outer flange  42  and two recesses  44 ,  46 . Between recesses  44 ,  46  is a central portion  48  having a middle area  50 . As shown, middle area  50  is offset slightly from circumferential outer flange  42  by sufficient distance that a roofing band  22  may be slid through recesses, as shown in  FIG. 6 . A fastener opening  52  is provided in middle area to receive a threaded fastener, such as a screw  54  (see  FIG. 7 ) or a screw with a washer  54   a  (see  FIG. 8 ). 
     If desired, threaded fasteners may be self-drilling fasteners, such as teks screws. Accordingly, fasteners  54  may be #12-24×1¼ inch hex washer head carbon steel plated Tek 5 self-drilling screws, and fasteners  54   a  may be 12-14×¾ inch hex washer head carbon steel plated Tek 3 self-drilling screws, and provided with G90 galvanized bonded washer having an EPDM rubber ¾ inch OD, both available from Rosko Fasteners. Fasteners  54  may be used with connectors  40  at end rafters  14  (see locations in  FIG. 2 ) and fasteners  54   a  may be employed through connectors  40  at struts  16  (see locations in  FIG. 3 ), although other fasteners and arrangements are possible. Also, fasteners with washers such as fasteners  54   a  may be employed throughout the roof in central locations without connectors to secure bands to the underside of purlins  18 . If building size or layout requires an overlap (splice) between two bands  22  to span a given area, a connector  40  can be slid over the band further from (above) non-end rafter  14  or (below) purlin  18  at the splice location, sandwiching the other band between the rafter or purlin and the first band with the connector on it, and driving a threaded fastener through all. 
     If desired, alignment elements  56  may be formed on connector  40 . Alignment elements  56  are spaced so as to allow connector  40  to be readily slid onto a band  22  or  24  while maintaining a desired orientation. As shown, four such alignment elements  56  are provided so as to center band  22  within recesses  44  and  46 , and so as to center band  22  with reference to fastener opening  52 . Therefore, upon driving of threaded fasteners  54 ,  54   a  through fastener opening, band  22  and into rafter  14 , forces and stresses are distributed away from the hole (not shown) in band  22  made by the threaded fastener. 
     Connector  40  is configured to provide secure mounting of bands  22 ,  24  to beams within building  10 . In particular, connector  40  is useful in mounting ends of bands  22 ,  24  to beams such as end rafters  14  and struts  16 . As compared to previous structures without such connectors or where multiple screws were employed, a stronger connection can be achieved. Applicant believes that such strengthened connection is due at least in part to the larger area of contact all across bands  22 ,  24  created by connector  40  and threaded fastener  54 ,  54   a , as compared to use of a single threaded fastener alone or with a washer, or use of two threaded fasteners with or without washers. Use of threaded fasteners without connectors  40  or washers may concentrate stresses at the threaded fastener/opening interfaces, leading to extension and failing at those points earlier than with the connectors. This can be particularly problematic at end points such as end rafters  14  and struts  16   
     Connector  40  may be formed of galvanized, high carbon steel, although other materials could be employed. Connector  40  could be formed by forging, stamping, coining, etc., as desired. 
     As shown in  FIG. 5 , connector  40  may be slid over bands  22 ,  24  and attached at a desired location. Therefore, a connector  40  could be attached to a beam such as an end rafter  14  ( FIG. 1 ) or an end strut  16  ( FIG. 2 ) along the side of building  10 . Alternatively, (not shown) a connector may be employed to attach a band to an intermediate rafter  14 , strut  16  or purlin  18  in the center or a building. However, typically connectors  40  are used only along the perimeter of a building or building section. 
     To install a connector  40  on a given beam, one need only slide the given connector over the band  22  or  24  until the connector reaches a desired position. Then, the threaded fastener is driven through the connector  40  via the opening  52 , the band  22  and into the beam. If such positions are at side rafters, such attachment can be done on one end prior to feeding of bands across the structure between struts and/or purlins and atop rafters, as is conventionally done. Then, attachment can be made at the other end rafter. If connectors are to be used at some or all other attachment portions along the roof, then additional connectors should be slid onto the particular band, and care should be taken to connect them tightly and in order. However, this is typically not done. Cross bands can be attached by connectors to eave struts  16  on either end, and optionally could be attached to purlins from below where cross points occur. Cross bands can be woven in alternating over/under fashion across the area. 
     Typically, sheeting  26  would be placed atop bands. Once sheeting  26  is in place, the other layers such as one or more insulation layers  24 ,  30 , outer roofing layers  32 , etc., may be attached. 
     Therefore, by use of such structures, a method of installing a metal roof can be carried out, including the steps of constructing a roof frame of metal beams and attaching a grid of roof bands to the metal beams using threaded fasteners and connectors. It should be understood that the preceding does not mean that connectors must be used at all such threaded fasteners along any given beam, whether it be a perimeter location or central location. The attaching step includes sliding the connector onto the roofing band so that a portion of the roofing band is disposed through first and second recesses in the connector so that a circumferential flange portion of the connector is located on a first side of the roofing band facing the roofing beam and a middle area of a central portion is located on a second side of the roofing band opposite the first side. The attaching step further includes inserting a threaded fastener through the single fastener opening in the connector, the roofing band, and into the roofing beam to fasten the roofing band to a roofing beam. If the location is where sheeting is present, the sheeting may be installed around the fasteners and optionally glued down. Such method may include further sequential attachment of bands at end rafters and eaves until a grid is in place with sheeting on top. At that point, additional steps of adding insulation layers, outer roofing layers etc. can be carried out. Also, attachment to side walls of buildings can also be carried out using the disclosed structure to provide a strengthened structure, although fall prevention is not a concern with side walls. 
     Use of the above structures and methods provides a reliable, efficient, and simple to install roofing structure. Fall prevention is bolstered by improved fall resistance loading at minimal additional cost without drastic redesign to roofing systems. 
     These and other modifications and variations to the present disclosure can be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present disclosure, which is more particularly set forth in the appended claims. In addition, it should be understood that aspects of the various embodiments can be interchanged in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the disclosure so further described in such appended claims.

Summary:
A connector for securing a roofing band to a roofing beam by a threaded fastener may include a circumferential flange portion, first and second recess extending within the circumferential flange portion sized to accept a roofing band, and a central portion extending within the circumferential flange portion between the first recess and the second recess, a middle area of the central portion being offset laterally from the circumferential flange portion by a distance enough to permit the roofing band to be slid through the first and second recesses so that the circumferential flange portion is located on a first side of the roofing band and the middle area of the central portion is located on a second side of the roofing band opposite the first side. A single fastener opening defined through the central portion, the fastener opening sized for receiving a threaded fastener therethrough for fastening the roofing band to a roofing beam. Related roofing assemblies and methods of construction are disclosed.