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• <br />sm_ Starling Madison Lofquist, Inc. <br />5224 South 391h Sheet, Phoenix, Arizona $5040 <br />tel: (602) 438-2500 fox: (602) 438-2505 www.smieng.com <br />IronRidge June 8.2011 <br />1435 Baeehtel Rd. <br />Willits, CA 95490 page 1 of <br />Attn: Mr.Williarn Kim, Chief Executive Officer <br />Subject: XRS Rail, Roof Flush Mount System — Structural Analysis <br />Dear Sir. <br />We have analyzed the subject solar panel support system and determined that, for the <br />configurations and criteria described below, it is in compliance with the structural requirements <br />of the referenced Building Codes. <br />Reference documents, by tronRidge: Exhibit A . attached <br />Codes: ASCE/SE17.05 Min. Design Loads for Buildings & Other Structures <br />International Building Code, 2006 & 2009 Editions <br />Aluminum Design Manual, 2005 Edition <br />The XRS rail is an extruded aluminum section with an overall depth of 3.00 in. and a net area <br />of 0.807 sq.in. The rails are used to support soar panels, typically, on the roof of a building. <br />The rails are clamped to aluminumangle brackets that are either attached directly to the roof <br />framing or attached to a stand that is screwed to the roof fuming. The rails are mounted across <br />the slope with a small clearance (flush mount) to the underlying roof structure. The installed <br />solar panels arc at the same slope as the underlying roof structure. <br />All loads are transferred to the roof framing through the angle brackets by simple flexure of the <br />rails. The maximum span of the rails is governed by either the mid -span flexural stresses or the <br />deflection requirement that the rail not come into contact with the roof. <br />The maximum allowable spans for the rails are shown in Tables 1, 2 & 3 below. <br />Our analysis assumes that the rails, including the connections and associated hardware, are <br />installed In a workmanlike manner In accordance with the "XRS Solar Rail Installation <br />Manual' by tronRidge and generally accepted standards of construction practice. <br />The adequacy ortlte supporting roof framing is to be determined by others. <br />Starting Madison Lofquist, Inc. Consulting Structural and Forensic Engineers <br />