Laserfiche WebLink
structural <br /> ENGINEERS <br /> Ultra Rail Racking System with UR-40 Rail: <br /> The SnapNrack Ultra Rail Racking System is intended for the rooftop installation of solar photovoltaic modules and is <br /> constructed from an assortment of modular parts as described in this report. <br /> 1.500" <br /> Y UR-40 Rail <br /> 0.750"1-0.750" Material: 6005-T5 Aluminum Extrusion <br /> Area of Cross-Section,A 0.357 in <br /> P7N <br /> I I Moment of Inertia,Ix,: 0.125 in" <br /> Moment of Inertia,I,: 0.132 in <br /> CR0 <br /> Centroid,Y(Bottom): 0.792 in <br /> X i77 PF <br /> X Centroid,X(Left): 0.750 in <br /> nSection Modulus,Stop: 0.150 in <br /> Section Modulus,Sb�ttom•• 0.158 in <br /> -� Section Modulus,Si,.: 0.175 in <br /> Y <br /> Figure 1: Diagram of UR-40 Rail Profile Covered by This Report (with Section Properties) <br /> Flush-Mount System Geometry Limitations: <br /> Flush-Mounted PV modules are designed per the Components and Cladding provisions of ASCE 7. Flush-Mounted PV <br /> modules shall be oriented parallel to the plane of the roof surface, and shall be located between 2"to 10" clear from the <br /> surface of the roof to the PV module. The maximum cantilever length of the rail is L/3,where "L" is the maximum rail <br /> span after adjustments, provided there is at least 1 module length between maximum cantilevers. The modules shall be <br /> centered between the rails with consideration of industry standard tolerance. The A"gap between each PV module has <br /> been considered in the span charts, and shall not be obstructed. Installations utilizing the Tile Replacement or Tile Hook <br /> attachment devices are permitted to have panels offset from the centerline of the rails. <br /> Attachment to Roof: <br /> The attached span tables include consideration of the attachment device capacity, based on UL 2703 load testing <br /> performed by SnapNrack. Tested load values are developed with 5/16" 0 lag screws with an effective embedment of 2- <br /> 1/2" into a Douglas Fir substrate,with a reference withdrawal (uplift or pullout) load capacity of 532 Ib, and a reference <br /> shear(side or lateral) load capacity of 270 lb for resisting short-term wind or seismic loads. Reference values are the <br /> base values, before any adjustment is made per the NDS. Installations into alternate substrates or which use alternate <br /> fasteners shall be permitted; provided that the fastener has tested or code-derived allowable load capacities, and meets <br /> one of the following two criteria: A)The allowable load values for the alternate fastener shall meet or exceed the <br /> allowable values noted above for the 5/16" 0 lag screws in Douglas Fir; or B)the span length identified in the "span <br /> tables"shall be reduced according to the more restrictive of the following two formulas: <br /> Alternate Reference Withdrawl Capacity <br /> Rail Span = Table Span * 532 lb <br /> Or <br /> Alternate Reference Shear Capacity <br /> Rail Span = Table Span <br /> 270 lb <br /> These formulas shall not be used to increase the allowable span beyond the spans listed in the span tables. <br /> 1478 Stone Point Drive,Suite 190, Roseville,CA 95661 <br /> 916.961.3960 916.961.3965 www.pzse.com 2/923 <br />