[NEW] Patrick Manning Letter SSVSE Project Number: U1991.0724.211
May 6, 2021
All Energy Solar
ATTENTION: Brian Allen
1264 Energy Lane
St Paul, MN 55108
REFERENCE: Patrick Manning Residence (40306): 73 Loudville Road, Northampton, MA 01062
Solar Array Installation
To Whom It May Concern:
Per your request,we have reviewed the existing structure at the above referenced site.The purpose of our review was to
determine the adequacy of the existing structure to support the proposed installation of solar panels on the roof as shown on
the panel layout plan.
Based upon our review, we conclude that the existing structure is adequate to support the proposed solar panel installation.
Design Parameters
Code: Massachusetts State Residential Code (780 CMR Chapter 51, 9th Edition (2015 IRC))
Risk Category: II
Design wind speed: 117 mph (3-sec gust) per ASCE 7-10
Wind exposure category: C
Ground snow load, Pg: 40 psf
Flat roof snow load, Pf: 35 psf
Existing Roof Structure
Roof structure: 2x12 rafters @ 16" O.C.
Roofing material: metal seam
Roof slope: 34°
Connection to Roof
Mounting connection: (1) S-5! N Clamp to min. 24 ga steel at max. 32" o.c. along rails
(2) rails per row of panels, evenly spaced; panel length perpendicular to the rails not to exceed 78 in. Rail cantilever shall
not exceed 50% of connection spacing.
Conclusions
Based upon our review,we conclude that the existing structure is adequate to support the proposed solar panel installation.
See attached calculations.
651 W. Galena Park Blvd., Ste. 101 / Draper, UT 84020 / T (801) 990-1775 / F (801) 990-1776 / www.vectorse.com
VSE Project Number: U1991.0724.211
Patrick Manning Residence
5/6/2021
The solar array will be flush-mounted (no more than 10"above the roof surface)and parallel to the roof surface.Thus,we
conclude that any additional wind loading on the structure related to the addition of the proposed solar array is negligible.
The attached calculations verify the capacity of the connections of the solar array to the existing roof against wind (uplift),
the governing load case.Because the increase in lateral forces is less than 10%,this addition meets the requirements of the
exception in Section 807.5 of the 2015 IEBC as referenced in 780 CMR Chapter 34,9th Edition.Thus the existing lateral
force resisting system is permitted to remain unaltered.
Limitations
Installation of the solar panels must be performed in accordance with manufacturer recommendations.All work performed
must be in accordance with accepted industry-wide methods and applicable safety standards.The contractor must notify
Vector Structural Engineering,LLC should any damage,deterioration or discrepancies between the as-built condition of the
structure and the condition described in this letter be found.Connections to existing roof framing must be staggered,except
at array ends,so as not to overload any existing structural member.The use of solar panel support span tables provided by
others is allowed only where the building type,site conditions,site-specific design parameters,and solar panel configuration
match the description of the span tables.The design of the solar panel racking (mounts,rails,etc.)and electrical engineering
is the responsibility of others.Waterproofing around the roof penetrations is the responsibility of others.Vector Structural
Engineering assumes no responsibility for improper installation of the solar array.
VECTOR STRUCTURAL ENGINEERING, LLC
05/06/2021
_______________________________________________________
Jacob Proctor, P.E.
MA License: 54953 - Expires: 06/30/2022
Project Engineer
Enclosures
JSP/fdh
05/06/2021
651 W. Galena Park Blvd., Ste. 101 / Draper, UT 84020 / T (801) 990-1775 / F (801) 990-1776 / www.vectorse.com
JOB NO.:U1991.0724.211
SUBJECT:WIND PRESSURE
PROJECT:Patrick Manning Residence
Label:Note: Calculations per ASCE 7-10
SITE-SPECIFIC WIND PARAMETERS:
Basic Wind Speed [mph]:117 Notes:
Exposure Category:C
Risk Category:II
Importance Factor, I:
ADDITIONAL INPUT & CALCULATIONS:
Height of Roof, h [ft]:15 (Approximate)
Comp/Cladding Location:No
Enclosure Classification:
Zone 1 GCp:1.0 Figure 30.4-2C (enter negative pressure coefficients)
Zone 2 GCp:1.0
Zone 3 GCp:1.0
α:9.5 Table 26.9-1
zg [ft]:900 Table 26.9-1
Kh:0.85 Table 30.3-1
Kzt:1 Equation 26.8-1
Kd:0.85 Table 26.6-1
Velocity Pressure, qh [psf]:25.3 Equation 30.3-1
GCpi:0 Table 26.11-1
PRESSURES:Equation 30.9-1
Zone 1, p [psf]:25.3 psf (1.0 W, Interior Zones, beyond 'a' from roof edge)
Zone 2, p [psf]:25.3 psf (1.0 W, End Zones, within 'a' from roof edge)
Zone 3, p [psf]:25.3 psf (1.0 W, Corner Zones, within 'a' from roof corner)
(a= 3 ft)
Solar Panel Array
Gable Roofs 27° < θ ≤ 45°
Enclosed Buildings
Components and Cladding Wind Calculations
piphGCGCqp
JOB NO.:U1991.0724.211
SUBJECT:CONNECTION
PROJECT:Patrick Manning Residence
Calculate Uplift Forces on Connection
Pressure
(0.6 Dead -0.6 Wind)
(psf)
Max Connection
Spacing1
(ft)
Max Trib.
Area2
(ft2)
Max Uplift
Force
(lbs)
Zone 1 13.4 2.7 8.7 116
Zone 2 13.4 2.7 8.7 116
Zone 3 13.4 2.7 8.7 116
Calculate Connection Capacity
Roof Connector:
Additional Connection Info:
Ultimate Capacity3 [lbs/in]:1005
Factor of Safety:3
Qty. of Connectors:1
Prying Coefficient:1
Total Capacity [lbs]:335
Determine Result
Maximum Demand:116
Connection Capacity:335
Result:Capacity > Demand, Connection is adequate.
Notes
1. 'Max Connection Spacing' is the spacing between connections along the rails.
3. Ultimate capacity values are from manufacturer testing. Metal gauge has been verified in field. Roof deck
model is unknown or has not been tested for this connector. The capacity used is based on conservative values
from testing of the connector on similar roof deck model.
4. Install metal roof connector per manufacturer's written instructions with recommended fasteners when
indicated.
2. 'Max Trib Area' is the product of the 'Max Connection Spacing' and 1/2 the panel width/height perpendicular
to the rails. (2) rails per row of panels. Length of panels perpendicular to the rails shall not exceed 78".
S-5! N Clamp
to min. 24 ga steel
VECTOR STRUCTURAL ENGINEERS
JOB NO.:U1991.0724.211
SUBJECT:GRAVITY LOADS
PROJECT:Patrick Manning Residence
GRAVITY LOADS Roof Pitch: 8.1 :12
ROOF DEAD LOAD (D)
Increase due to
pitch
Material weight
[psf]
Metal Seam 1.21 2.5
1/2" Plywood 1.21 1.0
Framing 1.00 3.0
Insulation 1.00 0.0
1/2" Gypsum Clg.1.21 0.0
M, E & Misc 1.00 2.0
Total Existing Roof DL
PV Array DL 1.21 3
DL:1.21
ROOF LIVE LOAD (Lr)
Existing Design Roof Live Load [psf]20 ASCE 7-10 Table 4-1
Roof Live Load With PV Array [psf]0
SNOW LOAD (S):w/ Solar Array
Roof Slope [x:12]:8.1
Roof Slope [°]:34
Ground Snow Load, pg [psf]:40 ASCE 7-10, Section 7.2
Terrain Category:C ASCE 7-10, Table 7-2
Exposure of Roof:Fully Exposed ASCE 7-10, Table 7-2
Exposure Factor, Ce:0.9 ASCE 7-10, Table 7-2
Thermal Factor, Ct:1.1 ASCE 7-10, Table 7-3
Risk Category:II ASCE 7-10, Table 1.5-1
Importance Factor, Is:1.0 ASCE 7-10, Table 1.5-2
Flat Roof Snow Load, pf [psf]:35 ASCE 7-10, Equation 7.3-1
Minimum Roof Snow Load, pm [psf]:0 ASCE 7-10, Section 7.3.4
Unobstructed Slippery Surface?No ASCE 7-10, Section 7.4
Slope Factor Figure:Figure 7-2b ASCE 7-10, Section 7.4
Roof Slope Factor, Cs:1.00 ASCE 7-10, Figure 7-2
Sloped Roof Snow Load, ps [psf]:35 ASCE 7-10, Equation 7.4-1
Design Snow Load, S [psf]:3521
8.1
34
40
C
Fully Exposed
0.9
1.1
II
1.0
35
0
Yes
Figure 7-2b
0.60
21
Design material
weight [psf]
3.0
1.2
3.0
0.0
0.0
2.0
9.2
3.6
#VALUE!
Massachusetts State Building Code (780 CMR Chapter
16, 9th Edition (2015 IBC)), Section 1607.12.5
Existing
Abbrev GRADES
Fbxx
(psi)
Fvxx
(psi)
g
(lb/ft3)
JOB NO.:U1991.0724.211 DFL#1 DFL#1 1,000 180 32
DFL#2 DFL#2 900 180 32
DF1 (5X)DFL#1 5X5 & LARGER 1,350 170 32
SPF#2 SPF#2 875 135 26.2
SP#2 SP#2 1,100 175 34.3
PROJECT:Patrick Manning Residence SUBJECT:BEAMS 24F-V4 24F-V4 2,400 240 32
24F-V8 24F-V8 2,400 240 40
LVL (1.9)LVL (1.9X106E)2,600 285 40
DESIGN LOADS:Load Types:Snow Live Dead LVL (2.0)LVL (2.0X106E)2,200 285 42
Roof 35 20 9 CRITERIA (L/)DTL DLL DDL LSL LSL (1.3X106E)1,700 400 42
Solar 3.6 A(BLANK)120 180 STL36 GRADE 36 STEEL 21,600 14,400 490
STL46 GRADE 46 STEEL 27,700 16,500 490
STL50 GRADE 50 STEEL 30,000 20,000 490
Label
Length
'L' (ft)
Roof
Trib
(ft)
Floor
Trib
(ft)
Wall
Trib
(ft)
Add'l
Live
Load
(plf)
Add'l
Solar
Load
(plf)
Point
Load
From React (A,B)Dist
'a'
(ft)
Point
Live
Load
'PLL'
(lb)
Point
Dead
Load
'PDL'
(lb)# PLIESGrade Size "BM/HDR"D CRITERIACr CD CF,V Ra (lb)Rb (lb)
Mmax
(ft-lb)
Mallow
(ft-lb)
Vmax
(lb)
Vallow
(lb)
DTL
(in)
DTLallow
(in)
DLL
(in)
DLLallow
(in)
1.5DL
GLB
Camb Check
Rafter 11 1.33 4.8 (1)SPF#2 2x12 1.15 1.15 1.00 356 356 994 3051 296 1747 0.090 1.117 0.066 0.744 0.33 M
Exx (psi)
1,800,000
29,000,000
29,000,000
1,700,000
1,800,000
1,900,000
1,400,000
1,600,000
1,600,000
1,400,000
29,000,000
2,000,000
1,300,000
VECTOR STRUCTURAL ENGINEERS
JOB NO.:U1991.0724.211
SUBJECT:SOLAR LAYOUT
PROJECT:Patrick Manning Residence
LOUDVIL
ARRAY 1