HomeMy WebLinkAboutengineer lett` � A • GODWIN ENGINEERING AND DESIGN, LLC �"l � • �JI I
8378 Foxtail Loop, Pensacola, FL 32526 1 (850)712-4219 1 chad@godwineng.com
July 8, 2019
To: St. Lucie County Building Division
2300 Virginia Avenue
Ft. Pierce, FL 34982
Re: Gibbs — Residential PV Roof Mount Installation
17 Flamenco Way
Port St. Lucie, FL 34952
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 6th 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„it)-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 panel roof with the
Ironridge railing and flashings/attachments. The attachments are the proteabracket metal mounts
and can be attached up to 48" apart in roof zone 1 and 24" in roof zone 2, with no mounts in roof
zone 3. The mounts should be staggered, where possible, to allow distribution of the design loads
evenly to the structure. The mounts shall be installed with 4 x 6mm x 25mm Bi-metal self -piercing
screws.
Please see attached documents and contact me should you have any questions.
Sincerely,
D. Chad Godwin, PE 81360
Exp.02/28/2021
-G.
\C E Iys O�ly�//
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BUILDING DESIGN PROPERTIES
SYMBOL VALUE
UNIT
BASIC WINDSPEED
V
160 i:�
mph
Figure 26-5-1C, page 249a
ROOF PITCH
9
1 > 7 to 27
degrees
MEAN ROOF HEIGHT
ft
ROOF SETBACK
a
3
ft
ADJUSTMENT FACTOR FOR BUILDING
x
1.21
Figure 30.5-1, pg 347
HEIGHT AND EXPOSURE
TOPIGRAPHICAL FACTOR
K,r
1
Figure 26.8-1, pg 252
EXPOSURE
C
EFFECTIVE WIND AREA
in �
sf
ZONE1 ZONE2 ZONE
VARIABLE DESCRIPTION SYMBOL VALUE VALUE VALUE UNIT
NET DESIGN WIND PRESSURE (UPLIFT)
Pn.r3uE24.56
-73.4 -108.5
psf
NET DESIGN WIND PRESSURE (DOWN)
C"
20.3
20.3
psf
NET DESIGN WIND PRESSURE (UP)
Pner up
-88.81
-131.29
psf
NET DESIGN WIND PRESSURE (DOWN)
I'M d.wn
24.56
24.56
psf
DESCRIPTION
SYMBOL
VALUE
VALUE
VALUE UNIT
DEAD LOAD
D
SNOW LOAD
S
DESIGN WIND LOAD
W
ASD DESIGN LOAD (UPLIFT)
Pd.,1gn
DOWNFORCE CASE 1
Pd.:fgn
DOWNFORCE CASE 2
Pd.agn
DOWNFORCE CASE 3
Pd.,10
psf
psf
psf
psf
psf
psf
psf
DESIGN FACTORS & CALCULATIONS FOR THE USE OF bracket to METAL Purlin
DESCRIPTION SYMBOL VALUE VALUE VALUE UNIT
3
3
3
0
0
0
-50.94
-88.81
-131.29
-37.13
-66.47
-99.37
3
3
3
27.56
27.56
27.56
21.421
21.42
21.42
MODULE WIDTH
B
TOTAL DESIGN LOAD (UPLIFT)
P
TOTAL DESIGN LOAD (DOWNFORCE)
P
DISTRIBUTED LOAD (UPLIFT)
w
DISTRIBUTED LOAD (DOWNFORCE)
w
RAIL SPAN BETWEEN ANCHORS POINTS
L
POINT LOAD (UPLIFT)
R
POINT LOAD (DOWNFORCE)
R
3.28
3.28
3.28
-37.13
-66.47
-99.37
27.56
27.56
27.56
-60.90
-109.01
-162.97
45.20
45.20
45.20
4
2
0
243.61
-218.03
0.00
180.811
90.411
0.00
ft
psf
psf
PH
plf
ft
Ibs
Ibs
L-FOOT CONNECTED BY METAL TO
METAL SCREW
_
Ultimate Load - 4 x 6mm x 25mm
W 1266 1266 1266 Ibs
Allowable Load - 4 x 6mm x 25mm
Wr
422
422
422
l.ep a: vcle lw ll fln t,nnd-p
U.mx Rmf7on.5rd-k L-rA, a, do<1s5nr Ih°-f -
4r.riw.. i.g wywr r.+,f 1.j.•., "J2., hp..r mew.l°f•-..
U.Efmiu In � LIcA r°.! rner yaa Prnttn Ie I--d. 7-1
h'.-2 F.
Flat Roof
s HYP
^
Gable Reel (B 5 7•�- \_ GaW
Is
REFERENCE: ASCE 7-10
Figure 30.5-1, pg 346
Figure 30.5-1, pg 346
Calculation: P_ u,= A x l< � x P_3e
Calculation: Pnrrdown=lax Krtx P_,30
Calculation: Pd,ign= D+SQRT(0.6)W (asd)
Calculation: Pd.g;gn= 1.OD+1.OS
Calculation: Pd,lgn= 1.OD+1.OW
Calculation: Pdgugn= 1.OD+0.75S+0.75W
Calculation: w = PB/2 ,.r :°m.:21aIs
Calculation: w= PB/2 As--2` ,%°"`°"'
Calculation: R = PLB/2'' 11-2101 K,row
Calculation: R = PLB/2'A50- 2 ran: prr row
Pullout value per manufacture
Calculation: SF=WVR (Uplift)
( j Inrmw zon.l ❑ Ed Z-, - ,■ Comer Zones
uYeN�-7e••INh'^.7nr�, Km --.-.2 V1.0r-7 S X-h.7-1
Lnr: wfiL'f:l r0f .y.r... p<rt• taw:..V 2..V -,i+J w<.:v..a-...awz� L c <r
• " . �� _,�� Fes'. - `
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