Loading...
25-007 142 Riverbank Solar 2019152 S. Broad St. Lansdale, PA 19446(215)361-8040 April 30, 2019 Valley Solar340 Riverside DrNorthampton, MA 01062 RE:Neubert Residence142 Riverbank Rd, Northampton, MA 01060Client Project #: 142NEUBPFE Project #: 192599 On behalf of Valley Solar, Penn Fusion Engineering LLC (PFE) performed a structural analysis of the roof at the abovereferenced location. The purpose of our analysis was to determine if the existing roof system is structurally sufficient tosupport the new photovoltaic moudles in addition to the code required design loads. Our analysis is based on the informationprovided by Valley Solar and is isolated only to the areas where the modules are intended to be placed. System Specifications:Total System Size: 5.7 kW/DCPanel Specs: (17) LG Solar - LG335N1C-A5Inverter Specs: (17) Enphase - IQ7Racking System: SnapNRack - Series 100 UL The modules are to be located on the following roof planes: MountingPlane RafterSize RafterSpacing HorizontalSpan CollarTies Collar TieSpacing Sheathing ShingleType Number ofShingle Layers CeilingProfile 1 True2x8 24"12ft. 0in.N/A 0"CDX 1/2"AsphaltShingles 1 Flat 2 2x6 24"6ft. 10in.N/A 0"CDX 1/2"AsphaltShingles 1 Flat The roof design has been analyzed in accordance with the 2015 International Residential Code and MassachusettesAmendments 9th Edition with design loads as follows: Ground Snow (Pg): 40 psfWind Speed (V): 117 mph Mounting Plane 1The calculations for these structural members are attached. It has been determined by this office that the roof, as specifiedabove, is adequate to support the new PV modules in addition to the code required design loading. Attach the module rail brackets to the roof with 5/16" lag bolts at 48 on center maximum. Provide a minimum of 2" ofpenetration into the wood members. Mounting Plane 2The calculations for these structural members are attached. It has been determined by this office that the roof, as specifiedabove, is adequate to support the new PV modules in addition to the code required design loading. Attach the module rail brackets to the roof with 5/16" lag bolts at 48 on center maximum. Provide a minimum of 2" ofpenetration into the wood members. This office has determined that the installation of the PV System as specified above will meet the structural requirements ofthe 2015 International Residential Code with Massachusettes Amendments 9th Edition and ASCE7-10 when installed inaccordance with the manufacture's instructions. If you have any questions regarding this analysis, please feel free to contact us. Best Regards,Penn Fusion Engineering LLC Andrew D. Leone, P.E.Principal 152 S. Broad St. Lansdale, PA 19446(267)640-2758 Client Name:Valley Solar PFE Project Number:192599 Client Project Number:142NEUBProject:Neubert Residence Address:142 Riverbank RdNorthampton, MA 01060Description:Mounting Plane 1 Calculations By:ADLDate:April 30, 2019 Roof Construction True 2x8 Rafters at 24" on center A=13.56 in2 Ix=67.88 in4 Sx=17.52 in3 Wood Species=Doug-Fir Larch #2 Fb=900 psi Fv=180 psi E=1600000 psi Roof Slope=34 ° Rafter Span=12.01 ft Ceiling Attached to Rafters?:No Design Criteria Ground Snow (Pg):40 psf Design Wind Speed:117 mphLive Load:20 psfDead Load:5.04 psfPV Modules:3.62 psf Wind Calculations Directionality Factor (Kd):0.85 Topographic Factor (Kzt):1 Velocity Pressure Exposure Coefficient(Kz):0.7 Importance Factor (I):1 Velocity Pressure (qz):20.85 psf Tributary Square Footage onComponent:10.83 ft2 Component Roof Pressures:22.45 / -28.63 psf Snow Load Calculations Exposure Factor (Ce):1 Thermal Factor (Ct):1 Importance Factor (I):1Flat Roof Snow Loads (Pf): Roof Slope Factor (Cs):0.9 Sloped Snow Loads (Ps): Unbalanced Snow Load:40 psf 35 psf 31.5 psf Member Calculations Bending Md:1754.68 ft*lb fb:1201.95 psi Load Duration Factor (Cd):1.15 Stability Factor (CL):1 Wet Service Factor (CM):1 Temperature Factor (CT):1 Size Factor (CF):1.2 Flat Use Factor (Cfu):1 Incising Factor (Ci):1 Repetitive Member Factor (Cr):1.15 Fb:900 psi F'b:1428.3 psi 1201.95<=1428.3 OK in Bending Shear Vd:584.39 lb fv:64.63 psi Load Duration Factor (Cd):1.15 Wet Service Factor (CM):1 Temperature Factor (CT):1 Size Factor (CF):1.2 Flat Use Factor (Cfu):1 Incising Factor (Ci):1 Fv:180 psi F'v):207 psi 64.63<=207 OK in Shear Deflection Live Load Deflection (ΔL):0.34 in L/418 OK in Live LoadDeflection Total Load Deflection (ΔT):0.42 in L/344 OK in Total LoadDeflection Uplift Calculation Tributary Square Footage onComponent:10.83 ft2 Uplift Pressure:-28.63 psfUplift per Lag:-310.15 lbs Lag Screw Diameter:5/16 inAllowable Withdrawal per Inch:490.99 lbs/inMinimal Screw Penetration:0.63 in Install 5/16" diameter lag screws @ 48 on center withminimum penetration of 2" into rafter. 152 S. Broad St. Lansdale, PA 19446(267)640-2758 Client Name:Valley Solar PFE Project Number:192599 Client Project Number:142NEUBProject:Neubert Residence Address:142 Riverbank RdNorthampton, MA 01060Description:Mounting Plane 2 Calculations By:ADLDate:April 30, 2019 Roof Construction 2x6 Rafters at 24" on center A=8.25 in2 Ix=20.8 in4 Sx=7.56 in3 Wood Species=Doug-Fir Larch #2 Fb=900 psi Fv=180 psi E=1600000 psi Roof Slope=14 ° Rafter Span=6.79 ft Ceiling Attached to Rafters?:No Design Criteria Ground Snow (Pg):40 psf Design Wind Speed:117 mphLive Load:20 psfDead Load:3.83 psfPV Modules:3.09 psf Wind Calculations Directionality Factor (Kd):0.85 Topographic Factor (Kzt):1 Velocity Pressure Exposure Coefficient(Kz):0.7 Importance Factor (I):1 Velocity Pressure (qz):20.85 psf Tributary Square Footage onComponent:10.83 ft2 Component Roof Pressures:14.03 / -57.53 psf Snow Load Calculations Exposure Factor (Ce):1 Thermal Factor (Ct):1 Importance Factor (I):1Flat Roof Snow Loads (Pf): Roof Slope Factor (Cs):1 Sloped Snow Loads (Ps): Unbalanced Snow Load:40 psf 35 psf 35 psf Member Calculations Bending Md:541.15 ft*lb fb:858.69 psi Load Duration Factor (Cd):1.15 Stability Factor (CL):1 Wet Service Factor (CM):1 Temperature Factor (CT):1 Size Factor (CF):1.3 Flat Use Factor (Cfu):1 Incising Factor (Ci):1 Repetitive Member Factor (Cr):1.15 Fb:900 psi F'b:1547.33 psi 858.69<=1547.33 OK in Bending Shear Vd:318.7 lb fv:57.94 psi Load Duration Factor (Cd):1.15 Wet Service Factor (CM):1 Temperature Factor (CT):1 Size Factor (CF):1.3 Flat Use Factor (Cfu):1 Incising Factor (Ci):1 Fv:180 psi F'v):207 psi 57.94<=207 OK in Shear Deflection Live Load Deflection (ΔL):0.12 in L/708 OK in Live LoadDeflection Total Load Deflection (ΔT):0.14 in L/604 OK in Total LoadDeflection Uplift Calculation Tributary Square Footage onComponent:10.83 ft2 Uplift Pressure:-57.53 psfUplift per Lag:-623.25 lbs Lag Screw Diameter:5/16 inAllowable Withdrawal per Inch:490.99 lbs/inMinimal Screw Penetration:1.27 in Install 5/16" diameter lag screws @ 48 on center withminimum penetration of 2" into rafter.