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McPherson Engineering By: T.C. <br />Date: 1/30/23 <br />Rooftop Solar Panels Wind Pressures (Section 29.4, ASCE 7-16) <br />Vult = 115 mph Kzt = 1.00 (sec 26.8.2) h = 15 ft <br />Exposure Category = C Kz = 0.85 (sec 26.10.1) <br />Roof Zone = 2 Kd = 0.85 (sec 26.6) <br />Roof θ = 7-27 deg Ke = 1.00 (sec 26.9) <br />qh = 0.00256 Kz Kzt Kd Ke V 2 qh = 24.46 (eq. 26.10-1) <br />GPp = -2 uplift γE = 1.5 (sec 29.4.4) <br />γa = 0.69 (fig 29.4-8) <br />γE = 1.5 FIG 29.4-7)γc = 0.97 (fig 29.4-7) hpt = 0 <br />γa = 0.69 (fig 29.4-8)γp = 0.9 (fig 29.4-7) ω = 0.00 deg (panel tilt) <br />GPp = -2 uplift GCrm = 1.4 uplift <br />p = qh (GPp) γE γa (eq 29.4-7)p = qh (GCrn) γE γC γp (eq 29.4-6) <br />p = -50.9 p.s.f.p = 44.8 p.s.f. <br />Check Anchorage to Existing Structure <br />0.6DL - 0.6W controlling load combination (eq. 16-15 for ASD) <br />DL = 2.8 p.s.f.dead load of panel (inlcuding rack system) <br />W = 50.9 p.s.f.wind load normal to face of panel <br />Arealag = 18.5 sq. ft.area tributary to each anchor <br />SPanc = 6.0 ft.spacing of anchors <br />Puplift = Arealag (0.6DL - 0.6W) = 533.6 lbs total uplift on anchor <br />Material = DFL lumber anchor material <br />Dialag = #12 in. diameter of screw <br />Penlag = 2 in. min. penetration to existing framing <br />Wlag = 154 lb/in. withdrawal load per in. of penetration per NDS Table 11.2A <br />CD = 1.6 load duration factor for wind per NDS Table 2.3.2 <br />Ct = 0.8 temperature factor per NDS Table 2.3.3 <br />Noscrews = 2 number of screws in withdrawal <br />Pallow = Penlag (Wlag CD Ct) * Noscrews = 788.48 lbs total allowable withrawal on anchor <br />Puplift <br />Pallow <br />Anchorage = USE (2) #12IN. DIA. LAG SCREW(S) AT 6FT. MAX. O.C. W/ 2.IN. MIN. PENETRATION <br />Wind Uplift Anchorage <br />Flush Mounted Panels - ASCE Section <br />29.4.4 (where applicable) <br />Flat Roof Panels - ASCE Section 29.4.3 <br />(where applicable) <br />= 0.68 < 1.00 Anchor is OK! <br />1/30/2023 8:53 AM <br />6 of 7 <br />©McPherson Engineering <br />1644 W McFadden <br />Ave08/31/23