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Home My WebLink AboutPV2022-164 - CalcsITSP2= C SLING ?Wi (b0V "►qn 76 North Meadowbrook Drive Scott E Wyssling, PE Alpine, UT 84004 Jon P. Ward, SE, PE office (201) 874-3483 Gregory T. Elvestad, PE swyssling@wysslingconsulting.com June 6, 2022 BUILDING DIVISION Jun 07 2022 Current Insight 2852 W. Amin! Way South Jordan, UT 84095 BY: S.E.C. Re: Engineering Services Baudry Residence 3107 Corte Marin, Newport Beach CA 6.250 kW System To Whom It May Concern: We have received information regarding solar panel installation on the roof of the above referenced structure. Our evaluation of the structure is to verify the existing capacity of the roof system and its ability to support the additional loads imposed by the proposed solar system. A. Site Assessment Information 1. Site visit documentation identifying attic information including size and spacing of framing for the existing roof structure. 2. Design drawings of the proposed system including a site plan, roof plan and connection details for the solar panels. This information will be utilized for approval and construction of the proposed system. B. Description of Structure: Roof Framing: 2 x 10 dimensional lumber spaced at 16" on center Roof Material: Composite Asphalt Shingles Roof Slope: 21 degrees Attic Access: Accessible Foundation: Permanent C. Loading Criteria Used Dead Load o Existing Roofing and framing= 10 psf o New Solar Panels and Racking = 3 psf o TOTAL = 13 PSF • Live Load = 20 psf (reducible) — 0 psf at locations of solar panels • Ground Snow Load = 0 psf • Wind Load based on ASCE 7-16 o Ultimate Wind Speed = 95 mph (based on Risk Category II) o Exposure Category C Analysis performed of the existing roof structure utilizing the above loading criteria is in accordance with the 2019 California Building Code, including provisions allowing existing structures to not require strengthening if the new loads do not exceed existing design loads by 105% for gravity elements and 110% for seismic elements. This analysis indicates that the existing framing will support the additional panel loading without damage, if installed correctly. Page 2 of 2 D. Solar Panel Anchorage 1. The solar panels shall be mounted in accordance with the most recent Unirac installation manual. If during solar panel installation, the roof framing members appear unstable or deflect non - uniformly, our office should be notified before proceeding with the installation. 2. The maximum allowable withdrawal force for a 5/4' lag screw is 235 lbs per inch of penetration as identified in the National Design Standards (NDS) of timber construction specifications. Based on a minimum penetration depth of 2%', the allowable capacity per connection is greater than the design withdrawal force (demand). Considering the variable factors for the existing roof framing and installation tolerances, the connection using one 5/15" diameter lag screw with a minimum of 2'/" embedment will be adequate and will include a sufficient factor of safety. 3. Considering the wind speed, roof slopes, size and spacing of framing members, and condition of the roof, the panel supports shall be placed no greater than 48" on centers. 4. Panel supports connections shall be staggered to distribute load to adjacent framing members. Based on the above evaluation, this office certifies that with the racking and mounting specified, the existing roof system will adequately support the additional loading imposed by the solar system. This evaluation is in conformance with the 2019 California Building Code, current industry standards, and is based on information supplied to us at the time of this report. Should you have any questions regarding the above or if you require further information do not hesitate to contact me. Ah" y your Scott E. fyss4' li , PE California License N 4 WYSSLING co Wyssling Consulting 76 N. Meadowbrook Drive Alpine, UT 84004 V= Exposure K, = Kv = Kd = Ke 9t, _ Roof Angle = Roof Type S.6�r = Atds = 95 C 0.85 1 0.85 1.000 16.7 psf 21 Gable 48 in 11.52 sf Wind Uplift Rooftop Solar Panels Parallel to Roof Surface ASCE 7-16, Section 29.4.4 Basic Wind Speed ASCE 7-16, Section 26.7 Velocity Pressure Coefficient, ASCE 7-16, Figure 26.10-1 Topographic Factor, ASCE 7-16, Section 26.8.2 Directionality Factor, ASCE 7-16, Section 26.6 Ground Elevation Factor, ASCE 7-16, Section 26.9 qh = 0.00256KXvKdK,V2 (ASCE 7-16 Eq. 26.10-1) deg Horizontal spacing of roof anchors Panel Area tributary to each roof anchor (201) 874-3483 swyssling@wysslingconsulting.com Baudry Residence 3107 Corte Marin Newnart RParh CA GCP 5/16 in External Pressure Coefficient, ASCE 7-16, Figure 30.3-2 <r4j Q X'- RoofZone Zone 1 2e 2n 2r 3e 3r No. of Screws -1.50 -1.50 -2.49 -2.49 -2.49 -3.31 - Signed 6-6-22 ga = 0.79 Pressure Equalization Factor, ASCE 7-16 Figure 29A-8 Cu = 9E = 1.00 Edge Array Factor, ASCE 29.4.4 edges < 0.5*building height, and panel spacing < 411. p„. = ghGCPgEg, = Design Wind Pressure, ASCE 7-16, Equation 29.4-7 W = Roof Zone 1 2e 2n 2r 3e 3r 298 Ib/in -20 psf -20 psf -33 psf -33 psf -33 psf -44 psf Min Pressure = -16 psf 745 IN Use 20 psf Use 20 psf Use 33 psf Use 33 psf Use 33 psf Use 44 psf ULTIMATE x 0.6 = 16 psf 16 psf 20 psf 20 psf 20 psf 26 psf ALLOWABLE Connection to Existing Roof Framing F.S. = 1 Additional Factor of Safety applied to withdrawl force, if desired A,db = 11.5 ftp DLpavel = 2 psf Roof Zone 1 2e 2n 2r 3e 3r W.PI;n = 20 psf 20 psf 33 psf 33 psf 33 psf 44 psf Peas = F.S. x A,,, x (0.61)- 0.6W) = Withdrawl force for each roof anchor Roof Zone 1 2e 2n 2r 3e 3r -120.0 Ibs -120.0 Ibs -210.2 IN -210.2 lbs -210.2 lbs -285.2 lbs Connection Capacity db = 5/16 in Lag Screw diameter Dpen = 2 1/2 in Lag Screw penetration into existing framing member No. of Screws 1 Screws per Connection Douglas Fir -Larch Species of wood framing Cu = 1.6 Load Duration Factor for Wind Loading, NDS Table 2.3.2 C, = 0.7 Temperature Factor, NDS Table 10.3.4 W = 266 lb/in Withdrawl Capacity, NDS Equation 11.2-1 W' = Co x C, x W = 298 Ib/in Adjusted withdrawl value P.,.. = Dp,„ x W' = 745 IN Ibis analysts calculates the capacity of the lag screws Roof Zone 1 2e 2n 2r 3e 3r only. For capacity of the DEMAND = 120 lbs 120 lbs 210 lbs 210 lbs 210 lbs 285 lbs complete mounting system, CAPACITY = 745 lbs 745 lbs 745 lbs 7451bs 745 lbs 745 lbs please see manufacturer's up to72in ok up to72in ok up to72in ok up to72in ok up to72in ok up to72in ok recommendations.