HomeMy WebLinkAboutLetterGODWIN ENGINEERING AND DESIGN, LLC
8378 Foxtail Loop, Pensacola, FL 32526 1 (850)712-4219 1 chad(@godwineng.com
February 27, 2020 =RECEIVEDTo: St. Lucie County Building Division2300 Virginia Avenue Ft. Pierce, FL 34982
Re: Zoerhof House - Residential PV Roof Mount Installation
10020 Orange Ave.
Fort Pierce, FL 34945
Plan Reviewer,
This letter is regarding the installation of a new roof mounted Solar PV System on the existing
residential structure at the address above. I have reviewed the attachment plan and have
determined that the roof mounted PV system is in compliance with the applicable sections of the
following Codes as amended and adopted by the jurisdiction:
2017 Florida Building Code 61h Edition, FBC
ASCE 7 Min. Design Loads for Buildings & Other Structures
Per 2017 FBC, the Roof Mounted PV system will be subject to the following design criteria:
Design Wind Speed(V i1) - 160mph 3sec gust, Exposure Category - C
The PV System consist of the modules, railing, and connection hardware. The system will add a
dead load of approximately 3 psf to the roof.
The existing roof covering is Asphalt Shingle with min. 1/2" plywood decking and 2" x 4" roof trusses
24" O.C. The roofing, decking, and roof trusses are in good condition. The existing structure will be
adequate for supporting the additional PV dead load and wind loads.
The securement method of the PV system is to be flush mounted to the asphalt shingle roof with
Everest railing and (lashings/attachments. The attachments can be attached up to 48" apart and
should be staggered, where possible, to allow distribution of the design loads evenly to the
structure. The mounts shall be installed with a min. 5/16" lag screw with minimum 2-5/16" thread
length.
Please see attached documents and contact me should you have any questions.
Sincerely,
D. Chad Godwin, PE 81360
Exp.02/28/2021
1360 Z =
O R
I
BUILDING DESIGN PROPERTIES
BASIC WIND SPEED
ROOF PITCH
MEAN ROOF HEIGHT
ROOF SETBACK
ADJUSTMENT FACTOR FOR BUILDING
HEIGHTAND EXPOSURE
TOPIGRAPHICAL FACTOR
EXPOSURE
EFFECTIVE WINDAREA
VARIABLE DESCRIPTION
NET DESIGN WIND PRESSURE (UPLIFT)
NET DESIGN WIND PRESSURE (DOWN)
NET DESIGN WIND PRESSURE (UP)
NET DESIGN WIND PRESSURE (DOWN)
DESCRIPTION
DEAD LOAD
SNOW LOAD
DESIGN WIND LOAD
ASO DESIGN LOAD (UPLIFT)
DOWNFORCE CASE I
DOWNFORCE CASE 2
DOWNFORCE CASE 3
DESCRIPTION
MODULELENGTH
MODULE WIDTH
DESIGN LOAD PER MODULE
DISTRIBUTED LOAD (UPLIFT)
DISTRIBUTED LOAD (DOWNFORCE)
RAIL SPAN BETWEEN ANCHORS POINTS
POINTLOAD(UPUFT)
POINT LOAD (DOWNFORCE)
L-FOOT CONNECTED BY LAG SCREW TO
ROOF TRUSS/ RAFTER
Specific Gravity, Rafter
Min. Dia. of lag Screw, 5/16
Pullout Value of
N of Lag screws
Thread Length
Design Pullout Value per Mount
SAFTEY FACTOR
ZONE1
ZONE2
SYMBOL
VALUE
VALUE
ZONES
VALUE
-02.1
-73.4
-308.5
20.3
20.3
20.3
-50.94
-88.
SYMBOL VALUE VALUE VALUE
D
S
W
Pdrdsn
N-aa
Pd.',.
Pdaw
0
-131.29
M3
-99.37
3
27.56
21.42
SYMBOL VALUE VALUE VALUE
C
B
T
w
w
L
R
R
G
D
W
Td
W,
SF
5.22
3.28
-635.4
-1137.4
-1700.27
-96.86
-173.38
-259.19
45.20
45.20
45.20
4
4
2
-387.44
-693.52
-518.38
180.81
180.81
90.91
0.55
0.55
0.55
0.3125
0.3125
0.3125
306.87
306.87
306.87
1
1
1
2.8125
2.8125
2.8125
863.07
863.071
863.071
2.23
1.24
1.66
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llpFanslyeri.ual
aY�3YJ�NWWgaNdnl,
IW hoar
'Cc
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❑aure.Zma, � 4a
Y.xr nWs-!�, ar
�.: uxsvaa.r�ss.rr a.a+,.Yror. r.a.a..�c=11.
6W6a RmatLT' <4 S
UNIT
mph Figure 26.5-IC, page 249a
degrees
it
it
Figure 3D.5-1, pg 347
Figure 26.8-1, pg 252
sf
UNIT
REFERENCE: ASCE 7.10
psf
Figure 3D.5-1, pg 346
psf
Figure 3D.5-1, pg 346
psf
falmlatlon: Pn""p=Ax Knx P„ .
psf
Calculation: PI d.,= Ax Kdx Pn".
UNIT
psf
psf
PSI
psf
Calculation: Pd ..=D+SORT(0.6)W(aid)
psf
Calculation: Pd. 1.DD+1.05
Pat
Calculatlon: Pd ,,= 1.OD+1.OW
Pat
Calxulatian: Pd"Y+ 1.OD+0.755a0.75W
UNIT
it
It
to,
Calculation: T=Area •W
pN
Calculation, w=T/B•2••d"'°" zna Pno.
pit
Cal.latlon: w=PB/2•.'"m"znie Pei
It
Its
Calculation: R=PLB/2 2"6P"'°'
pas
Calculation: R=PLB/2 •"ttuine Q 1'a P"1O'"
Table 11.2A, Nos 2005, page 68 (Southern Pine)
In
IIts/in W=1800GsADv
In Table L2, ND52005
Wr= W • 4 of Lags •Td
Calculation: SF=WVR (UpllN)