16D-021 (3) Richard B. Gordon, P.E.
P.O. Box 4•Farmville•VA 23901
Ph: 434.9423266E-mail: grichardpe@aol.com Bp070/7-131
May 23,2017
Florence Building Department
Florence MA Re: Solar Panels Roof Structural Framing Support
To Whom It May Concern:
I hereby certify that I am a Licensed Professional Engineer in the State of Massachusetts. Please note the following
conclusions regarding framing structure, roof loading,and proposed site location of installation:
1. Roof framing:
Conventional wood framing 2x6 at 16"o.c.with 10'-4"span(horizontal rafter projection).This structure is
definitely capable to support all of the loads that are indicated below for this photovoltaic project.
2. Roof Loading
• 4.33 psf dead load(modules plus all mounting hardware)
• 24 psf snow live load (40 psf ground snow live load reference)
• 6.2 psi dead load roof materials( 1.7 psf 2x6, 1.5 psf sheathing,3 psf fiberglass shingles)
• Exposure Category B, 115 mph wind uplift live load of 19.6 psf(wind resistance)
3. Address of proposed installation: Residence of Daniel Blair,147 N. Main St, Florence. MA
This installation design will be in general conformance to the manufacturer's specifications,and is in compliance
with all applicable laws, codes,and ordinances,and specifically, International Residential Code/IRC 2009. The
spacing and fastening of the mounting brackets is to have a maximum of 64"o.c.span between mounting brackets
and secured using 5116"diameter corrosive resistant steel lag bolts. In order to evenly distribute the load across the
roof rafters,there shall be a minimum of 2 mounting brackets per rafter&min. 3" penetration of lag bolt per bracket,
which is adequate to resist all 115 mph wind live loads including wind shear.
Very truly yours,
1
t
Richard B.G. P.=
Massach - .Li•-nse No.49993
MECHANIC. CIVIL/S RUCTURAL, & ELECTRICAL ENGINEERING
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