HomeMy WebLinkAboutLetterGODWIN ENGINEERING AND DESIGN, LLC
8378 Foxtail Loop, Pensacola, FL 32526 1 (850)712-4219 1 chad0godwineng.com
February 27, 2020
To: St. Lucie County Building Division
RECEIVED
2300 Virginia Avenue
Ft. Pierce, FL 34982
MAR 0 4 20P0
ST. Lucie County, Permitting
Re: Zoerhof Barn- 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 6tb 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 ic) - 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 Metal Panel. 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 metal roof with the Everest
railing and flashings/attachments. The flashings/attachments are the RT mini mounts. The
attachments can be attached up to 48" apart. The mounts should be staggered, where possible, to
allow distribution of the design loads evenly to the structure. The mounts shall be installed with 2 x
MS x 60mm stainless lag screws directly to the roof truss.
FILE CUOPY
Please see attached documents and contact me should you have any questions.
Sincerely,
D. Chad Godwin, PE 81360
Exp.02/28/2021
BUILDING DESIGN PROPERTIES
BASIC WIND SPEED
ROOF PITCH
MEAN ROOF HEIGHT
ROOFSETBACK
ADJUSTMENT FACTOR FOR BUILDING
HEIGHTAND EXPOSURE
TOPIGRAPHICAL FACTOR
EXPOSURE
EFFECTIVE WIND AREA
UNIT
mph Figure 26.5-1C, page 249a
degrees
ft
ft
at
Figure 30.5-1, pg 347
Figure 26.8-1, pg 252
20NE1
ZONEZ
ZONES
VARIABLE DESCRIPTION
SYMBOL
VALUE
VALUE
VALUE UNIT
REFERENCE: ASCE 7.10
NET DESIGN WIN D PRESSURE (UPLIFT)
Pn..
-42.1 73.4 -308.5 psf
Figure 30.5-1, pg 346
NET DESIGN WIN D PRESSURE (DOWN)
PwD
1 20.3
20.3
20.3 psf
Figure 30.5-1, pg 346
NET DESIGN WIND PRESSURE (UP)
pMw
psf
Calculation: Pn<,.n=).x Kdx pmD
NET DESIGN WIND PRESSURE (DOWN)
pm awd
psf
Calmlatlon:P°,1dd„°=1x KaXP11tM
DESCRIPTION
DEAD LOAD
SNOW LOAD
DESIGN WIND LOAD
ASD DESIGN LOAD (UPUFT)
DOWNFORCE CASE 1
DOWNFORCECASE2
DOWNFORCECASE3
DESCRIPTION
MODULE LENGTH
MODULE WIDTH
DISTRIBUTED LOAD (UPLIFT)
DISTRIBUTED LOAD (DOWNFORCEI
RAILSPAN BETWEEN ANCHORS POINTS
POINT LOAD(UPUFT)
POINT LOAD(DOWNFORCE)
L-FOOT CONNECTED BY WOOD SCREW
Specific Gravity, Rafter
Min. Dia. of Lag Screw, 1/4
Pullout Value of
1f of Lag screws
Thread Length
Design Pullout Value per Mount
SAFTEY FACTOR
-50.94
-88.81
-131.29
24.56
24.56
14.56
SYMBOL VALUE VALUE VALUE
D
S
W
Pa
Paxm
Pamm
Pmadr,
m30131.29.99.37327.5621A
SYMBOL VALUE VALUE VALUE
C
B
T
w
w
L
R
R
G
D
W
Td
Wt
SF
5.42
3.25
-653.73
-1170.2
-1749.31
-100.57
-180.03
.269.22
44.79
44.79
44.79
4
2
1
402.30
-360.05
-269.1
179.16
89.58
44.79
0.5
0.5
0.5
0.25
0.25
0.25
225
225
225
2
2
2
1.75
1.75
1.75
787.5
787.5
787.5
1.96
2.19
2.93
aq LDDw1siMJlm.(netl�D
V1g4(L�IdaLlgJa 4dYu1v Jtbp,vl0
pmmtn Y�xxl�m DRF4Y.14
L1el�amabnw� �PdTDe• ���
H
xml.tw(Bs>7 c.erRewp•
UNIT
psf
psf
psf
psf
Caloulation: Pd„y°=DKQRT(0.6)W(asd)
psf
Calculation: PdHq=1.01)a1.05
psf
Calculation: P&,Iv 1.00a1.OW
psf
Calculatlon: Parry°=. 1.ODa035SW35W
UNIT
It
ft
Ibs
Calculation:T=Area •W
plf
Calculation: w=T/02•"sonui°`anso.-
plf
Calculation:w=PB/2•a'0"nMs,°""-
ft
Ibs
Caiculatlon: R=PLB/2•",-pf0:oe„°.
Ras
Calculation: R=PUB/2 •""""""'°�a°"'°=
Table 11.2A, NDS 2005, page 68 (Southern Pine)
In
Ibs/in W=1800 G'1'D'1a
In Table L2, NOS 2005
W, = W • 4 of Lags •Td
Calcula0on: SF=WVR (Uplift)
❑ bavSm. ® DM lew ■ I:Onw tow
W .L IMva-L�. .r-1�Lw�.xsF W.Iw,I
a.� uamtMM+o..�4rhHaaw New4o�.M..•1.