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Where: Pf is the pull out force. S is the strength, or retention force of the lag in lbs. per inch (from above). L is the length of thread that is imbedded in wood. Our 11 panel system above will have 48 bolts, 1/4" x 4" securing the panel frames to the roof system and into wood joists. The bolts will run through the retaining clips, having three inches of bolt length imbedded in the wood. The pull out force is calculated as follows: 260 x 3 = 780 x 48 bolts = 37,440 lb. of retention force with wood at 0.55 specific gravity. This pull out force is greater than the uplift force determined for our 11 panel array. Fewer than 11 panels may be used per collector array, since the anchorage is proportional to the number of panels in the array. Do not exceed 11 panels per array, as this will degrade performance. Pilot holes should always be drilled for lag bolts, to improve holding power. The pull out force of the thrust washer is .5 x 3.14159 x .125 x 60,000 = 11,775 lb. This pull out force exceeds the retaining clip bolt strength of 2209 lb. You must use thrust washers to prevent the bolt head from pulling through the clips. Where roofing materials require the use of roof jacks to allow the array to clear the shingles or tiles, roof jacks should be made and spaced according to sheet 3 of the drawing set, and installed per the framed series installation instructions. With blocks spaced at 24" intervals, the pull out of the stringer arrangement can be expressed as above. Applying the same formula, each block has a retention capability of 3901b. x 3, or 11701b. The array will have an arrangement of stringers and roof jacks equal to the number of panels + 1, multiplied by the number of stringers called for in the table located on sheet 3 of the drawing set for framed series collectors. I have included a series of worksheets that calculate the uplift forces and retention forces for an array consisting of two to 11 panels, at a design pressure of 61.5 psf. This is the design pressure for coastal communities to meet the 2003 code revision. Using the recommended number of attachment points in the charts for the number of collectors in a given array will assure a wind — safe installation. FP- Series Unframed Panels: The same force applies to the frameless panel since the frameless panel sizes are identical in aperture to the framed series panels. The mounting system for this series consists of surface mount tie downs (part # 3552) and retaining straps that provide a multi -point secure mounting system that allows for expansion and contraction of the solar array while providing wind resistance to a force of up to 155 M.P.H. velocity. Each tie -down Page 3 of 4