HomeMy WebLinkAboutStamped_CELetter3_222R-012RIZI - Rev A2Astra v.1.65
April 11, 2022 PIL
#AStamp CAT 2
Subject : Structural Certification for Proposed Residential Solar Installation.
Job Number: 222R-012RIZI; Rev A2
Client: Ghazal Rizi
Address: 12 Sturgis St, Chelsea, MA, 02150
Attn: To Whom It May Concern Signed on: 4/11/2022
A field observation was performed by a qualified Sunrun Technician to document the existing structure of the above mentioned address. From
the field observation, the existing roof structure was observed as the following:
• AR-01: Shingle roofing over plywood supported by True 2x6, SPF #2 Rafters @ 30" OC. Framing verified via Attic Access.
Design Criteria:
• MA 9th Ed. CMR 780 (2015 IRC/IBC/IEBC), 7-10 ASCE & 2015 NDS
• Basic Wind Speed V = 128 mph, Exposure B
• Ground Snow Load = 40 psf, Min Flat Roof Snow Load = 30 psf
Based on this evaluation, I certify that the alteration to the existing structure by the installation of the PV system meets the requirements of the
applicable existing and/or new building code provisions referenced above.
Additionally, I certify that the PV module assembly including all attachments supporting it have been reviewed to be in accordance with the
manufacturer's specifications.
Results Summary (Hardware Check Includes Uplift Check on Attachments/Fastener, Structure Check Considers Main Structure)
AR-01
Orientation Attachment Spacing/Cantilever Configuration Governing
DCR Result
Landscape 60 / 24 Staggered 48%Pass
Portrait 30 / 15 Staggered 53%Pass
Roofing Material Pitch Structure Check
Comp Shingle 34°Pass
225 Bush St. Suite 1400 San Francisco, CA 94104
Signed on: 4/11/2022
AR-01
Roofing Material Roof Pitch Spacing Hardware Results Structural Results
Comp Shingle 34°30''Pass Pass
Hardware Calculations
Attachment Information
Attachment:RL-U Uplift Force: 0.6 x p x trib area = 142 lb Uplift Capacity: 623 lb
Wind Design Criteria (Partially/Fully Enclosed Method, ASCE 7-10)
Basic Wind Speed V 128 mph Wind Speed - Category II
Wind Pressure Exposure Kz 0.70 Section 30.3.1
Topographic Factor Kzt 1.0 Equation 26.8-1
Wind Directionality Factor Kd 0.85 Section 26.6
Velocity Pressure qh = 0.00256 x Kz x Kzt x Kd x V²21.51 psf Equation 27.3-1
Solar Adjustment Factors γe (Port/Land) =1.5, (1,1.02)γa =0.6 (wind tunnel value)7-16; Figure 29.4-8
Up Down
Ext Pressure Coefficient GCp -1.14 0.87 Figure 30.4-2
Ultimate Design Wind Pressure p = qh x GCp -16 psf 16 psf Equation 30.4-1
Mod Orientation X-Spacing Cantilever Trib Area Demand DCR Final Result
Landscape 60''24''16.9 ft²17.8 psf 48%Pass
Portrait 30''15''15.2 ft²17.8 psf 53%Pass
Structural Calculations
Gravity Loading Summary
Load Definitions Initial Code Factors Pre-PV Load Post-PV LoadPg = 40 psf | Pf = 0.7 x Ce x Ct x Pg Ps = Cs x Pf
Roof Dead Load (D)DL 12.0 psf 12.0 psf 12.0 psf
PV Dead Load (D)PV DL 3.0 psf 0.0 psf 3.0 psf
Roof Live Load (Lr)RLL 20.0 psf 0.76 15.3 psf 0.0 psf
Sloped Snow Load (Pf --> Ps)LL/SL 30.0 psf 1.00 0.60 30.0 psf 18.0 psf
Total Design Load 42.0 psf 33.0 psf
Cd Factor of Governing LC 1.15 (D+S)1.15 (D+S)
Total Design Load (Normalized)36.5 psf 28.7 psf
IEBC 5% Check
Net Design Gravity Loading Change (Normalized w/ Cd Factor)-7.8 psf DCR: 79%Pass
Detailed Loading Summary
Total Span (Horiz.)13'-2"Support Type Rafter Top Lat Bracing Full
Overhang 0'-9"Wood Species SPF Bot Lat Bracing At Supports
Span 1 12'-4"Wood Grade #2 A(in^2)11.37
Member Size 2x6 Sx(in^3)11.21
Actual Breadth 1.92''Ix(in^4)33.20
PV Locations Start End Actual Depth 5.92''No Upgrades Required
Array 1 Location 0'-9"12'-5"OC Spacing 30''
Sheathing 7/16" OSB
Framing Analysis Results
Governing LC Cd CL(+)CL(-)CF Cr
D+S 1.15 1 1.00 1.3 1.00
Demand Capacity DCR Final Result
fb(+)1828 psi Fb'(+)1308 psi 140%Pass per IEBC
fb(-)42 psi Fb'(-)1308 psi 3%Pass
fv 62 psi Fv'155 psi 40%Pass