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Home My WebLink AboutDESIGNAFFVSE Project Number: U3573.0444.201 March 4, 2020 SunPro Solar ATTENTION: Dean Scott 22171 MCH Road Mandeville, LA 70471 REFERENCE: Billy Webb Residence (PROJ-12405): 11 Placido Lane, Port St. Lucie, FL 34952 Solar Array Installation To Whom It May Concern: Per your request,we have reviewed the existing structure at the above referenced site.The purpose of our review was to determine the adequacy of the existing structure to support the proposed installation of solar panels on the roof as shown on the panel layout plan. Based upon our review, we conclude that the existing structure is adequate to support the proposed solar panel installation. Design Parameters Code: Florida Building Code, 2017 Edition (2015 IBC) Risk Category: II Design wind speed: 160 mph (3-sec gust) per ASCE 7-10 Wind exposure category: C Ground snow load: 0 psf Existing Roof Structure Roof structure: 2x4 manufactured trusses @ 24" O.C. Roofing material: metal seam Roof slope: 18° Connection to Roof Mounting connection: (1) S-5! SolarFoot at max. 48 in. O.C. (2) rails per row of panels, evenly spaced; panel length perpendicular to the rails not to exceed 67 in Conclusions Based upon our review,we conclude that the existing structure is adequate to support the proposed solar panel installation. In the area of the solar array,other live loads will not be present or will be greatly reduced (2017 FBC,Section 1607.12.5). The gravity loads,and thus the stresses of the structural elements,in the area of the solar array are either decreased or increased by no more than 5%.Therefore,the requirements of Section 807.4 of the 2015 FEBC are met and the structure is permitted to remain unaltered. 651 W. Galena Park Blvd., Ste. 101 / Draper, UT 84020 / T (801) 990-1775 / F (801) 990-1776 / www.vectorse.com VSE Project Number: U3573.0444.201 Billy Webb Residence 3/4/2020 The solar array will be flush-mounted (no more than 6"above the roof surface)and parallel to the roof surface.Thus,we conclude that any additional wind loading on the structure related to the addition of the proposed solar array is negligible. The attached calculations verify the capacity of the connections of the solar array to the existing roof against wind (uplift), the governing load case.Because the increase in lateral forces is less than 10%,this addition meets the requirements of the exception in Section 807.5 of the 2015 FEBC.Thus the existing lateral force resisting system is permitted to remain unaltered. Limitations Installation of the solar panels must be performed in accordance with manufacturer recommendations.All work performed must be in accordance with accepted industry-wide methods and applicable safety standards.The contractor must notify Vector Structural Engineering,LLC should any damage,deterioration or discrepancies between the as-built condition of the structure and the condition described in this letter be found.Connections to existing roof framing must be staggered,except at array ends,so as not to overload any existing structural member.The use of solar panel support span tables provided by others is allowed only where the building type,site conditions,site-specific design parameters,and solar panel configuration match the description of the span tables.The design of the solar panel racking (mounts,rails,etc.),and electrical engineering is the responsibility of others.Waterproofing around the roof penetrations is the responsibility of others.Vector Structural Engineering assumes no responsibility for improper installation of the solar array. VECTOR STRUCTURAL ENGINEERING, LLC FL Firm License: COA 26626 03/04/2020 _______________________________________________________ Jacob Proctor, P.E. FL License: 74277 - Expires: 02/28/2021 Project Engineer Enclosures JSP/isg 03/04/2020 651 W. Galena Park Blvd., Ste. 101 / Draper, UT 84020 / T (801) 990-1775 / F (801) 990-1776 / www.vectorse.com This item has been electronically signed and sealed using a Digital Signature. Printed copies of this document are not considered signed and sealed and the signature must be verified on any electronic copies. VECTOR STRUCTURAL ENGINEERS JOB NO.:U3573.0444.201 SUBJECT:CONNECTION PROJECT:Billy Webb Residence SolarFoot Connection Capacity:Demand: Fastener: 1 25.5 4.0 11.2 285 Total Capacity:374 lbs Demand< Capacity:CONNECTION OKAY *Capacity per ICC Report or Manufacturer Recommendations Pressure (0.6 Wind) (psf) Max Spacing (ft) Max. Trib. Area (ft2) Max. Uplift Force (lbs) Zone SolarFoot VECTOR STRUCTURAL ENGINEERS JOB NO.:U3573.0444.201 SUBJECT:GRAVITY LOADS PROJECT:Billy Webb Residence CALCULATE ESTIMATED GRAVITY LOADS ROOF DEAD LOAD (D) Increase due to pitch Original loading Roof Pitch/12 3.9 Metal Seam 2.6 1.05 2.5 psf 1/2" Plywood 1.1 1.05 1.0 psf Framing 3.0 psf Insulation 0.5 psf 1/2" Gypsum Clg.2.0 psf M, E & Misc 1.5 psf DL 11 psf PV Array DL 3 psf ROOF LIVE LOAD (Lr) Existing Design Roof Live Load [psf]20 ASCE 7-10, Table 4-1 Roof Live Load With PV Array [psf]0 2017 FBC, Section 1607.12.5 SNOW LOAD (S):Existing w/ Solar Panel Array Roof Slope [x:12]:3.9 Roof Slope [°]:18 Snow Ground Load, pg [psf]:0 ASCE 7-10, Section 7.2 Terrain Category:C ASCE 7-10, Table 7-2 Exposure of Roof:Fully Exposed ASCE 7-10, Table 7-2 Exposure Factor, Ce:0.9 ASCE 7-10, Table 7-2 Thermal Factor, Ct:1.1 ASCE 7-10, Table 7-3 Risk Category:II ASCE 7-10, Table 1.5-1 Importance Factor, Is:1.0 ASCE 7-10, Table 1.5-2 Flat Roof Snow Load, pf [psf]:0 ASCE 7-10, Equation 7.3-1 Minimum Roof Snow Load, pm [psf]:0 ASCE 7-10, Section 7.3.4 Unobstructed Slippery Surface?No ASCE 7-10, Section 7.4 Slope Factor Figure:Figure 7-2b ASCE 7-10, Section 7.4 Roof Slope Factor, Cs:1.00 ASCE 7-10, Figure 7-2 Sloped Roof Snow Load, ps [psf]:0 ASCE 7-10, Equation 7.4-1 Design Snow Load, S [psf]:0 Figure 7-2b 0.87 0 0 3.9 18 0 C Fully Exposed 0.9 1.1 II 1.0 0 0 Yes JOB NO.:U3573.0444.201 SUBJECT:LOAD COMPARISON PROJECT:Billy Webb Residence Summary of Loads Existing With PV Array D [psf]11 14 Lr [psf]20 0 S [psf]0 0 Maximum Gravity Loads: Existing With PV Array (D + Lr) / Cd [psf]25 15 ASCE 7-10, Section 2.4.1 (D + S) / Cd [psf]12 15 ASCE 7-10, Section 2.4.1 Maximum Gravity Load [psf]:25 15 Ratio Proposed Loading to Current Loading:62%OK The gravity loads and; thus, the stresses of the structural elements, in the area of the solar array are either decreased or increased by no more than 5%. Therefore, the requirements of Section 807.4 of the 2015 FEBC are met and the structure is permitted to remain unaltered. (Cd = Load Duration Factor = 0.9 for D, 1.15 for S, and 1.25 for Lr)