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SolarMount Unirac Code-Compliant Installation Manual :FUNIRAC <br />Step 6: Determine the Uplift Point Load, R (lbs), at <br />each connection based on rail span <br />You must also consider the Uplift Point Load, R (lbs), to <br />determine the required lag bolt attachment to the roof <br />(building) structure. <br />Table 11. Uplift Point Load Calculation <br />Total Design Load (uplift): P psf Step I <br />Module length perpendicular to rails: B x ft <br />Rail Span: L x ft Step 4 <br />11 <br />Uplift Poiht Load: R lbs <br />Table 12. Lag pull-out (withdrawal) capacities (lbs) <br />Specific <br />gravity <br />Douglas Fin Larch <br />Douglas Fin South <br />Engelmann Spruce, Lodgepole Pine <br />(MSR 1650 f & higher) <br />Hem, Fir, Redwood (close grain) <br />Hem, Fir (North) <br />Southern Pine <br />Spruce, Pine, Fir <br />Spruce, Pine, Fir <br />(E of 2 million psi and higher <br />grades of MSR and MEL) <br />in typical roof lumber (ASD) <br />Lag screw spedfications <br />96" shaft* <br />per:inch thread depth <br />0.50 266 <br />0.46 235 <br />0.46 235 <br />0.43 212 <br />0.46 235 <br />Thread <br />0.55 307 depth <br />0.42 205 <br />L_ <br />0.50 266 <br />Use Table 12 to select a lag bolt <br />size and embedment depth to <br />satisfy your Uplift Point Load <br />Force, R (lbs), requirements. <br />Divide the uptift pointload (from <br />Table 11) by the withdrawal <br />'capacity in the 2nd column of <br />Table 12. This results in inches <br />of 5/16 lagbolt embedded thread <br />depth needed to counteract the <br />uplift force. If other than lag <br />bolt is used (as with a concrete <br />or steel), consult fastener mfr <br />documentation. <br />It is the installer's tesponsibility <br />to verify that the substructure <br />and attachment method is <br />strong enough to support the <br />maximum point loads calculated <br />according to Step 5 and Step 6. <br />Sources:American Wood Councit NDS 2005,Table f l.2A, 1 1.3.2A. <br />Notes: (/) Threod must be embedded in the side grain of a ro fter or other structural member integrod with the <br />building structure. <br />(2} Log bolts must be located in the middle third ofthe structural friembet. <br />(3) These values are not valid for wet service. <br />(4) This tobie does notindude shear copacities. Ifnecessary, contact aiocalengineer to specifiylog boltsize <br />with regard to shear forces. <br />(5) Insta# log bons with head and washer flush to surface (no gap) Do not over-torque. <br />(6) Withdrawd design values for log screw connections sholl be multiplied by applicable adjustment foctors if <br />necessary. See Table JO.3. / in the American Wood Counci/ NDS for Wood Construction. <br />*Use Bat washers with lag screws. <br />Page <br />13