29 -394 99 Brookwood solar-2 Version #49.2
September 23, 2015
Project/Job # 0101421
RE: CERTIFICATION LETTER
Project: Schubach Residence
99 Brookwood DrFlorance, MA 01062
To Whom It May Concern,
Design Criteria:
- Applicable Codes = MA Res. Code, 8th Edition, ASCE 7-05, and 2005 NDS
- Risk Category = II - Wind Speed = 90 mph, Exposure Category C - Ground Snow Load = 40 psf - MP1: Roof DL = 9 psf, Roof LL/SL = 28 psf (Non-PV Areas), Roof LL/SL = 28 psf (PV Areas)
Note: Per IBC 1613.1; Seismic check is not required because Ss = 0.22424 < 0.4g and Seismic Design Category (SDC) = B < D
A jobsite survey of the existing framing system was performed by a site survey team from SolarCity. Structural review was based on
site observations and the design criteria listed below:
I certify that the structural roof framing and the new attachments that directly support the gravity loading and wind uplift loading from
PV modules have been reviewed and determined to meet or exceed structural strength requirements of the MA Res. Code, 8th Edition.
Please contact me with any questions or concerns regarding this project.
On the above referenced project, the components of the structural roof framing impacted by the installation of the PV assembly have
been reviewed. After this review it has been determined that the existing structure is adequate to withstand the applicable roof dead
load, PV assembly load, and live/snow loads indicated in the design criteria above.
09.23.2015
Version #49.2
Project Name:AHJ:
Job Number:Building Code:Customer Name:Based On:Address:99 Brookwood Dr ASCE Code:City/State:Florance,MA Risk Category:Zip Code Upgrades Req'd?Latitude / Longitude:42.321257 -72.680233 Stamp Req'd?
SC Office:PV Designer:
Certification Letter 1
Project Information, Table Of Contents, & Vicinity Map 2
Structure Analysis (Loading Summary and Member Check)3
Hardware Design (PV System Assembly)4
Note: Per IBC 1613.1; Seismic check is not required because Ss = 0.22424 < 0.4g and Seismic Design Category (SDC) = B < D
Latitude: 42.321257, Longitude: -72.680233, Exposure Category: C
99 Brookwood Dr, Florance, MA 01062
1/2-MILE VICINITY MAP
Schubach, Cynthia
ASCE 7-05
0101421
Garren Lewis
No01062
II
Yes
PV System Structural
Design Software
PROJECT INFORMATION & TABLE OF CONTENTS
Springfield
Northampton
MA Res. Code, 8th Edition
IRC 2009 / IBC 2009
Schubach Residence
PV System Load
PV Module Weight (psf)2.5 psf
Hardware Assembly Weight (psf)0.5 psf
PV System Weight (psf)3.0 psf
Roof Dead Load Load
Roof Category Description
Existing Roofing Material ( 2 Layers )5.0 psf
Re-Roof
Underlayment 0.5 psf
Plywood Sheathing 1.5 psf
Board Sheathing
Rafter Size and Spacing 2 x 4 @ 24 in. O.C.0.7 psf
Vaulted Ceiling
Miscellaneous 1.3 psf
Total Roof Dead Load 9.0 psf
Reduced Roof LL Non-PV Areas ASCE 7-05
Roof Live Load Lo Table 4-1
Member Tributary Area AtRoof Slope
Tributary Area Reduction R1 Section 4.9
Sloped Roof Reduction R2 Section 4.9
Reduced Roof Live Load Lr Equation 4-2
Reduced Roof Live Load Lr 19.5 psf
Code
Ground Snow Load pg ASCE Table 7-1
Snow Load Reductions Allowed?From ENP
Snow Guards to be Installed?
Effective Roof Slope
Horiz. Distance from Eve to Ridge W From ENP
Snow Importance Factor Is Table 1.5-2
Eq: 7.3-170%
ASCE Eq: 7.4-1
70%
ASCE Eq: 7.4-1
70%
Design Snow Load Over PV
Modules ps-pv ps-pv = (Cs-pv) pf28.0 psf
ASCE Design Sloped Roof Snow Load Over PV Modules
Surface Condition of PV Modules Cs -pv Unobstructed Slippery Surfaces Figure 7-21.0
Design Roof Snow Load Over
Surrounding Roof ps-roof ps-roof = (Cs-roof) pf28.0 psf
Figure 7-21.0
Flat Roof Snow Load pf pf = 0.7 (Ce) (Ct) (I) pg; pf ≥ pf-min28.0 psf
ASCE Design Sloped Roof Snow Load Over Surrounding Roof
Surface Condition of Surrounding Roof Cs -roof All Other Surfaces
1.1
Minimum Flat Roof Snow Load (w/
Rain-on-Snow Surcharge)pf-min 28.0 psf 7.3.4 & 7.10
Snow Thermal Factor Ct Structures kept just above freezing Table 7-3
1.0
Snow Exposure Factor Ce Fully Exposed Table 7-20.9
Yes
No
20°
13.0 ft
Reduced Ground/Roof Live/Snow Loads
40.0 psf
5/12
1
0.975
Lr = Lo (R1) (R2)
19.5 psf (MP1)
Miscellaneous Items
9 psf (MP1)
Value
20.0 psf
< 200 sf
No
Roofing Paper
Yes
None
No
LOAD ITEMIZATION - MP1
Material
MP1
Comp Roof
Component Solutions™TrussVersion: 5.18.50 [Build 11]
Simpson Strong-Tie Truss: MP1
Project Name: JB-0101421-00
Date: 9/23/2015 11:38:51 AM
Page: 1 of 1
Span Pitch Qty OHL OHR CANT L CANT R PLYS Spacing WGT/PLY22-0-0 5 /12 1 1-2-0 1-2-0 0-0-0 0-0-0 1 24 in 72 lbs
NOTICE A copy of this design shall be furnished to the erection contractor. The design of this individual truss is based on design criteria and requirements supplied by the Truss Manufacturer and relies upon the accuracy and completeness of the information set forth by the Building Designer. A seal on this drawing indicates acceptance of professional engineering responsibility solely for the truss component design shown. See the cover page and the ”Important Information & General Notes” page for additional information. All connector plates shall be manufactured by Simpson Strong-Tie Company, Inc in accordance with ESR-2762 . All connector plates are 20 gauge, unless the specified plate size is followed by a “-18” which indicates an 18 gauge plate, or "S# 18", which indicates a high tension 18 gauge plate.
Simpson Strong-Tie Company
24-4-0
1-2-0 1-2-05-6-0
5-6-0
5-6-0
11-0-0
5-6-0
16-6-0
5-6-0
22-0-0
0-0-0
7-6-10
7-6-10
6-10-13
14-5-6
7-6-10
22-0-0
0-0-05-4-104-11-10-4-15
12
5
12
8
13x6 -
21x4 \
34x6 -
41x4 /
53x5 -
9
63x4 -73x4 -
Loading
Load (psf)
Roof Snow (Ps) : 28 psfTCDL : 9(rake)BCLL : 0BCDL : 6
General
Bldg Code : IBC 2012/
TPI 1-2007Rep Mbr Increase : YesD.O.L. : 125 %
CSI Summary
TC : 0.41 (2-3)
BC : 0.58 (7-1)Web : 0.23 (3-7)
Deflection L/ (loc) Allowed
Vert TL: 0.17 in L / 999 (5-6) L / 180
Vert LL: 0.04 in L / 999 (5-6) L / 240Horz TL: 0.05 in 5Creep Factor, Kcr = 1.5 Plate Offsets (Jnt:X,Y,Ang): (1:3-14,2-3,0.) (2:0-0,3-13,44.) (3:0-0,3-13,0.) (4:0-0,3-13,44.) (5:3-14,2-3,0.) (6:0-0,3-8,0.) (7:0-0,3-8,0.)
Reaction Summary
JT Type Brg Combo Brg Width Material Rqd Brg Width Max React Max Grav Uplift Max MWFRS Uplift Max C&C Uplift Max Uplift Max Horiz
1 Pin (Wall) 1 3.5 in Steel 1.74 in 1,112 lbs - - - - 0 lbs 5 H Roll (Wall) 1 3.5 in Steel 1.68 in 1,069 lbs - - - - 0 lbs
Material Summary Bracing Summary
TC SPF #2 2x4 TC Bracing: Sheathed or Purlins at 3-8-0, Purlin design by Others.
BC SPF #2 2x4 BC Bracing: Sheathed or Purlins at 10-0-0, Purlin design by Others.Webs SPF Stud 2x4
Loads Summary
1) This truss has been designed for the effects of a balanced design snow load (Ps = 28 psf) for hips/gables in accordance with ASCE7 - 10 except as noted, with the following user
defined input: 28 psf ground snow load (Pg). NOTE: All flat/sloped roof factors have been ignored and the ground snow load has been used for the roof snow load (Ps = Pg), DOL = 1.15.2) This truss has not been designed for the effects of unbalanced snow loads.3) In addition to the snow loading specified on this drawing, this truss has also been designed for a roof live load (TCLL) of 0 psf.
4) Minimum storage attic loading in accordance with IBC Table 1607.1 has not been applied5) In accordance with IBC Table 1607.1, minimum BCLL's do not apply.
Load Case Lr1: Std Live Load
Distributed LoadsMember Location 1 Location 2 Direction Spread Start Load End Load Trib Width
Top Chd 11-0-0 23-2-0 Down Proj 19.5 psf 19.5 psf 24 in
Load Case D1: Std Dead Load
Distributed Loads
Member Location 1 Location 2 Direction Spread Start Load End Load Trib WidthTop Chd -1-2-0 11-0-0 Down Rake 3 psf 3 psf 24 in
Member Forces Summary Table indicates: Member ID, max CSI, max axial force, (max compr. force if different from max axial force)
TC 8-1 0.134 37 lbs 1-2 0.392 -2,070 lbs
2-3 0.407 -1,753 lbs 3-4 0.406 -1,720 lbs
4-5 0.357 -2,010 lbs 5-9 0.124 34 lbs
BC 5-6 0.560 1,799 lbs 6-7 0.392 1,220 lbs 7-1 0.577 1,850 lbs
Webs 2-7 0.131 -454 lbs 3-7 0.228 531 lbs
3-6 0.212 493 lbs 4-6 0.119 -413 lbs
Notes:
1) When this truss has been chosen for quality assurance inspection, the Plate Placement Method per TPI 1-2002/A3.2 shall be used. Cq = 1.17.
Roofing Material
PV System Type
Spanning Vents
Standoff (Attachment Hardware)
Roof Slope
Rafter Spacing
Framing Type / Direction
Purlin Spacing X-X Purlins Only
Tile Reveal Tile Roofs Only
Tile Attachment System Tile Roofs Only
Standing Seam/Trap Spacing SM Seam Only
Wind Design Code
Wind Design Method
Basic Wind Speed V Fig. 6-1
Exposure Category Section 6.5.6.3
Roof Style Fig. 6-11B/C/D-14A/B
Mean Roof Height h Section 6.2
Wind Pressure Exposure Kz Table 6-3
Topographic Factor Kzt Section 6.5.7
Wind Directionality Factor Kd Table 6-4
Importance Factor I Table 6-1
Ext. Pressure Coefficient (Up)GCp (Up)Fig. 6-11B/C/D-14A/B
Ext. Pressure Coefficient (Down)GCp (Down)Fig. 6-11B/C/D-14A/B
Design Wind Pressure p Equation 6-22
Wind Pressure Up p(up)Wind Pressure Down p(down)
Y-Direction
Max Allowable Standoff Spacing Landscape 39''Max Allowable Cantilever Landscape NA
Standoff Configuration Landscape
Max Standoff Tributary Area Trib
PV Assembly Dead Load W-PV
Net Wind Uplift at Standoff T-actual
Uplift Capacity of Standoff T-allow
Standoff Demand/Capacity DCR
Y-Direction
Max Allowable Standoff Spacing Portrait 65''
Max Allowable Cantilever Portrait NA
Standoff Configuration Portrait
Max Standoff Tributary Area Trib
PV Assembly Dead Load W-PV
Net Wind Uplift at Standoff T-actual
Uplift Capacity of Standoff T-allow
Standoff Demand/Capacity DCR
22 sf3.0 psf
-247 lbs500 lbs
49.4%
500 lbs
44.6%
X-Direction
48''17''Staggered
Staggered
20 sf3.0 psf-223 lbs
10.0 psf
ALLOWABLE STANDOFF SPACINGS
X-Direction
72''
0.45
p = qh (GCp)
-13.1 psf
24''
qh qh = 0.00256 (Kz) (Kzt) (Kd) (V^2) (I)Equation 6-1515.0 psf
Wind Pressure
-0.88
Wind Pressure Calculation Coefficients
0.85
1.00
0.85
1.0
Velocity Pressure
15 ft
Wind Design Criteria ASCE 7-05
Partially/Fully Enclosed Method
90 mph
NA
C
Gable Roof
NA
NA
Y-Y Rafters
NA
No
Comp Mount Type C
20°
24'' O.C.
CALCULATION OF DESIGN WIND LOADS - MP1
Mounting Plane Information
Comp Roof
SolarCity SleekMount™