determining_wind_and_snow_loads_for_solaR PANELS EXAPMPLE USA-1-1.pdf

determining wind and snow
loads for solar panels
America’s Authority on Solar

The purpose of this paper is to discuss the mechanical
design of photovoltaic systems for wind and snow
loads in the United States, and provide guidance
using The American Society of Civil Engineers (ASCE)
Minimum Design Loads for Buildings and Other
Structures, ASCE 7-05 and ASCE 7-10 as appropriate.
With the introduction of the ASCE 7-10, there are two
potential design principles used for calculating wind
and snow loads for PV systems in the U.S. until all state
building codes have transitioned to ASCE 7-10. This
paper will show how to calculate for wind and snow
loads using both design principles.
SolarWorld modules have been tested according
to UL and IEC standards and the maximum design
loads for various mounting methods are provided
in the Sunmodule User Instruction guide. Once we
have gone through the sample calculations and
have the applicable wind and snow loads, we will
compare them to SolarWorld’s higher mechanical
load capacities to ensure that the Sunmodule solar
modules are in compliance.
As one of the largest and most established vertically integrated photovoltaic
(PV) manufacturers on the planet, SolarWorld is intimately involved with every
step of the solar PV value chain from raw silicon to installed systems to end of
life recycling. This complete knowledge base combined with our extensive
history provide the critical insight required to lead the solar industry on
technical topics.
introduction
Determining wind and snow loads for solar panels 1
The design methodology in this document has been third party reviewed. Please see certiied letter at the end of this document for more details.

U.S. model building codes have used ASCE 7-05 as the
basis for several years, which largely follows the design
principles of Allowable Stress Design. Recently ASCE
7-10 was published and has become the basis for the
2012 series of the International Codes (I-Codes). ASCE
7-10 represents a shift in design principles toward Load
Resistance Factor Design. A few states have already
adopted the 2012 International Building Code 2012
(IBC) that includes references to ASCE 7-10 and, for the
irst time, speciically mentions PV systems. There are
several key differences between these two versions
of ASCE 7 standards. This paper provides sample
calculations following both ASCE 7 standards that are
relected in the 2012 IBC and earlier versions.
Figure 1. A typical rooftop solar installation.

iBc 2012 (asce 7-10) code references
1509.7.1 Wind resistance. Rooftop mounted pho-
tovoltaic systems shall be designed for wind loads
for component and cladding in accordance with
Chapter 16 using an effective wind area based on
the dimensions of a single unit frame.
1603.1.4 Wind Design data. The following information
related to wind loads shall be shown, regardless of
whether wind loads govern the design of the lateral
force resisting system of the structure:
1) Ultimate design wind speed, V
2) Risk category
3) Wind Exposure
4) Internal pressure coeficient
5) Component and cladding
1608.1 Design snow loads shall be determined
in accordance with Chapter 7 of ASCE 7, but
the design roof load shall not be less than that
determined by section 1607.
1609.1.1 Determination of wind loads. Wind loads
on every building or structure shall be determined
in accordance with Chapter 26 to 36 of ASCE 7 or
provisions of the alternate all-heights method in
section 1606.6.
1609.4.1 Wind Directions and Sectors. For each
selected wind direction at which the wind loads
are to be evaluated, the exposure of the building
or structure shall be determined for the two upwind
sectors extending 45 degrees either side of the
selected wind direction. The exposures in these two
sectors shall be determined in accordance with
Section 1609.4.2 and 1609.4.3 and the exposure
resulting in the highest wind loads shall be used to
represent wind from that direction.
iBc 2009 (asce 7-05) code references
1608.1 Design snow loads shall be determined
in accordance with Chapter 7 of ASCE 7, but
the design roof load shall not be less than that
determined by Section 1607.
1603.1.4 Wind Design Data
1) Basic wind
2) Wind importance factor
3) Wind exposure
4) The applicable internal pressure coeficient
5) Components and cladding
1609.1.1 Wind loads on every building or structure
shall be determined in accordance with Chapter 6
of ASCE 7.
Table 1609.3.1, which converts from 3-second gusts
to fastest-mile wind speeds.
1609.4.1 Wind Directions and Sectors
1) Select wind direction for wind loads to be evaluated.
2) Two upwind sectors extending 45 degrees from either
side of the chosen wind direction are the markers.
3) Use Section 1609.4.2 and Section 1609.4.3 to
determine the exposure in those sectors.
4) The exposure with the highest wind loads is chosen
for that wind direction.
1609.4.2 Surface Roughness Categories
1) Surface roughness B: Urban, suburban, wooded,
closely spaced obstructions.
2) Surface roughness C: Open terrain with few
obstructions (generally less than 30 feet), lat open
country, grasslands, water surfaces in hurricane-
prone regions.
3) Surface roughness D: Flat areas and water surfaces
outside of hurricane prone regions, smooth mud
lats, salt lats, unbroken ice.
Below are the portions of the code that will be referenced in the sample calculations:

In this paper, examples explain step-by-step
procedures for calculating wind and snow loads
on PV systems with the following qualiications in
accordance with ASCE.
The recommended chapter references for ASCE 7-05 are:
■ Chapter 2 – Load Combinations
■ Chapter 6 – Wind Load Calculations
■ Chapter 7 – Snow Load Calculations
In ASCE 7 -10, the chapters have been re-organized
and provide more detailed guidance on certain
topics. The recommended chapter references are:
■ Chapter 2 – Load Combinations
■ Chapter 7 – Snow Load Calculations
■ Chapters 26 – 31 Wind Load Calculations
example calculations:
In the following examples, we outline how a designer
should calculate the effect of wind and snow loads
on a PV module for residential and commercial
buildings based on few assumptions and using the
Low-Rise Building Simpliied Procedure.
■ ASCE 7-05: Section 6.4
In the Simpliied Method the system must have the
following qualiications (see ASCE 7.05 section 6.4.1.2
or ASCE 7-10 section 30.5.1 for further explanation):
■ The modules shall be parallel to surface of the roof
with no more than 10 inches of space between
the roof surface and bottom of the PV module.
■ The building height must be less than 60 feet.
■ The building must be enclosed, not open or
partially enclosed structure like carport.
■ The building is regular shaped with no unusual
geometrical irregularity in spatial form, for
example a geodesic dome.
■ The building is not in an extreme geographic
location such as a narrow canyon a steep cliff.
■ The building has a lat or gable roof with a pitch
less than 45 degrees or a hip roof with a pitch less
than 27 degrees.
In case of designing more complicated projects the
following sections are recommended:
■ ASCE 7-05: Section 6.5.13.2
example 1 - residential structure in colorado:
system details:
■ Location: Colorado
■ Terrain: Urban, suburban, wooded, closely spaced
obstructions
■ Exposure: Class B
■ Building Type: Single-story residential (10- to 15-feet tall)
■ Mean height of roof: ~12.33 feet
■ Building Shape: Gable roof with 30° pitch (7:12)
■ System: Two Rail System; attached module at four
points along the long side between 1/8 to 1/4
points as described in the SolarWorld Sunmodule
User Instruction guide
■ Module area: 18.05 ft (Reference: Sunmodule
datasheet)
■ Module weight: 46.7 lbs (Reference: Sunmodule
datasheet)
■ Site ground snow load (Pg
): 20 psf

sYmBols and notations
wind
■ I = Importance factor
■ Kzt
= Topographic factor
■ P = Design pressure to be used in determination of
wind loads for buildings
■ Pnet30
= Net design wind pressure for exposure B at
h = 30 feet and I = 1.0
■ V = Basic wind speed
■ λ = Adjustment factor for building height and
exposure
■ Zone 1 = Interiors of the roof (Middle)
■ Zone 2 = Ends of the roof (Edge)
■ Zone 3 = Corners of the roof
snow
■ Ce
= Exposure factor
■ Cs
= Slope factor
■ Ct
= Thermal factor
■ Pf
= Snow load on lat roof
■ Pg
= Ground snow load
■ Ps
= Sloped roof snow load
load combination
■ D* = Dead load
■ E = Earthquake load
■ F = Load due to luids with well-deined pressures
and maximum heights
■ H = Load due to lateral earth pressure, ground
water pressure or pressure of bulk materials
■ L = Live load
■ Lr
= Roof live load
■ R = Rain load
■ S* = Snow load
■ T = Self-straining load
■ W* = Wind load
* In this white paper we only use dead, snow and wind loads.
Gable Roof
Hip Roof
Interior Zones
Roofs - Zone 1
Interior Zones
Roofs - Zone 2
Interior Zones
Roofs - Zone 3

asce 7-10 (iBc 2012)
steps in wind design:
1. Determine risk category from Table 1.5-1
■ Risk category type II
2. Determine the basic wind speed, V, for applicable
risk category (see Figure 26.5-1 A, B, C)
■ Wind speed in Colorado is V = 115 mph
(excluding special wind regions)
3. Determine wind load parameters:
■ Exposure category B, C or D from Section 26.7
● Exposure B
■ Topographic factor, Kzt
, from Section 26.8 and
Figure 26.8-1
● Kzt
= 1.0
4. Determine wind pressure at h = 30 ft, Pnet30
, from
igure 30.5-1
5. Determine adjustment for building height and
exposure, λ, from Figure 30.5-1
■ Adjustment factor for Exposure B is λ = 1.00
6. Determine adjusted wind pressure, Pnet
, from
Equation 30.5-1
■ Pnet
= λKzt
Pnet30
Wind effective area is the pressure area on the
module that is distributed between four mounting
clamps. Each mid-clamp takes one-quarter of the
pressure and holds two modules which are equal to
one-half area of one module.
■ Area of module is 18.05 square feet.
■ Effective area is ~10 square feet.
Pnet
for wind speed of 115 mph and the wind
effective area of 10 ft2
:
asce 7-05 (iBc 2009)
2. Determine the basic wind speed, V, for
applicable risk category (see Figure 6-1 A, B, C)
■ Exposure category B, C or D from Section 6.5.6.3
● Exposure B
, from Section 6.5.7.2
● Kzt
= 1.0
4. Determine wind pressure at h = 30 ft, Pnet30
, from
Figure 6.3
5. Determine adjustment for building height and
exposure, λ, from Figure 6.3
■ Adjustment factor for Exposure B is λ = 1.00
6. Determine adjusted wind pressure, Pnet
, from
Equation 6-1
■ Pnet
= λKzt
Pnet30
Wind effective area is the pressure area on the
module that is distributed between four mounting
clamps. Each mid-clamp takes one-quarter of the
pressure and holds two modules which are equal to
one-half area of one module.
■ Area of module is 18.05 square feet.
■ Effective area is ~10 square feet.
Pnet
for wind speed of 90 mph and the wind effective
area of 10 ft2
:

asce 7-10 (iBc 2012) (cont'd)
Zone 1
■ Downward: +21.8 psf
■ Upward: -23.8 psf
Pnet
= λKzt
Pnet30
PDown
= 1 * 1 * 21.8 = 21.8 psf
Pup
= 1 * 1 * -23.8 = -23.8 psf
Zone 2
Pnet
= λKzt
Pnet30
PDown
= 1 * 1 * 21.8 = 21.8 psf
Pup
= 1 * 1 * -27.8 = -27.8 psf
Zone 3
Pnet
= λKzt
Pnet30
PDown
= 1 * 1 * 21.8 = 21.8 psf
Pup
= 1 * 1 * -27.8 = -27.8 psf
steps in snow design:
1. For sloped roof snow loads Ps
= Cs
x Pf
2. Pf
is calculated using Equation 7.3-1
■ Pf
= 0.7 x Ce
x Ct
x Is
x Pg
3. When ground snow load is less than or equal to
20 psf then the minimum Pf
value is I * 20 psf. (7.3.4)
4. Find exposure factor from Table 7-2, in category B
and fully exposed roof
■ Ce
= 0.9
Zone 1
Pnet
= λKzt
Pnet30
PDown
= 1 * 1 * 13.3 = 13.3 psf
Pup
= 1 * 1 * -14.6 = -14.6 psf
Zone 2
■ Upward: -17psf
Pnet
= λKzt
Pnet30
PDown
= 1 * 1 * 13.3 = 13.3 psf
Pup
= 1 * 1 * -17 = -17 psf
Zone 3
■ Upward: -17psf
Pnet
= λKzt
Pnet30
PDown
= 1 * 1 * 13.3 = 13.3 psf
Pup
= 1 * 1 * -17 = -17 psf
= Cs
x Pf
2. Pf
■ Pf
= 0.7 x Ce
x Ct
x Is
x Pg
3. When ground snow load is less than or equal to
20 psf then the minimum Pf
value is I * 20 psf. (7.3.4)
■ Ce
= 0.9

5. Determine thermal factor using Table 7-3, for
unheated and open air structures
■ Ct
= 1.2
6. Find the importance factory from Table 1.5-2
■ Is
= 1.00 (7-10)
7. Using Section 7.4 determine Cs
. Using above
values and θ = 30°
■ Cs
= 0.73
Pf
= 0.7 x Ce
x Ct
x Is
x Pg
Pg
≤ 20 lbs
Pg
is the ground snow load and cannot be used
instead of the inal snow load Pf
for the sloped roof
in our load combinations' equations. We need to
calculate the sloped roof snow load as follows:
Pf
= 0.7 * 0.9 * 1.2 * 1 * 20 = 15.12 psf or 1 * 20
Ps
= Cs
x Pf
Ps
= 0.73 * 20 = 14.6 psf
load combinations: (lrfd)
Basic combinations Section 2.3.2, according to ASCE
7-10 structures, components and foundations shall
be designed so that their design strength equals
or exceeds the effects of the factored loads in the
following combinations:
1) 1.4D
2) 1.2D + 1.6L + 0.5 (Lr
or S or R)
3) 1.2D + 1.6 (Lr
or S or R) + (L or 0.5W)
4) 1.2D + 1.0W + L + 0.5 (Lr or S or R)
5) 1.2D + 1.0E + L + 0.2S
6) 0.9D + 1.0W
7) 0.9D + 1.0E
5. Determine thermal factor using Table 7-3, for
■ Ct
= 1.2
6. Find the importance factory from Table 7-4
■ Is
= 1.0 (7-05)
. Using above
values and θ = 30°
■ Cs
= 0.73
Pf
= 0.7 x Ce
x Ct
x Is
x Pg
Pg
≤ 20 lbs
Pg
instead of the inal snow load Pf
for the sloped roof
in our load combinations’ equations. We need to
Pf
= 0.7 * 0.9 * 1.2 * 1 * 20 = 15.12 psf or 1 * 20
Ps
= Cs
x Pf
Ps
= 0.73 * 20 = 14.6 psf
load combinations: (asd)
Basic combinations Section 2.3, according to ASCE
7-05 loads listed herein shall be considered to act in
the following combinations; whichever produces the
most unfavorable effect in the building, foundation
or structural member being considered. Effects of
one or more loads on acting shall be considered.
1) D + F
2) D + H + F + L + T
3) D + H + F + (Lr
or S or R)
4) D + H + F + 0.75 (L + T) + 0.75 (Lr
or S or R)
5) D + H + F + (W or 0.7 E)
6) D + H + F + 0.75 (W or 0.7 E) + .75L + .75 (Lr
or S or R)
7) 0.6D + W + H
8) 0.6D + 0.7E + H

The highest values for upward and downward
pressures will govern the design.
Load Case 3)
1.2 * 2.59 + 1.6 (14.6) + 0.5 (21.8) = 37.4 psf
Load Case 6)
0.9 * 2.59 + 1.0 (-27.8) = -25.7 psf
The next step is to check that the module can
withstand the design loads for this two-rail mounting
coniguration. The designer should refer to the
module installation instructions where the design
loads for different mounting conigurations are
provided.
When two rails are supporting the module with top-
down clamps, the module design capacity is:
■ Downward: +113 psf
■ Upward: -64 psf
These values are well above the governing design
loads of:
To distribute the combined loads on the module
that are transferring to the rails, please refer to the
Mounting User Instruction guide and ASCE 7-10
section 30.4.
Load Case 6)
2.59 + 0.75 (14.6) + 0.75 (13.3) = 23.5 psf
Load Case 7)
0.6 (2.59) + 1.0 (-17.0) = -15.45 psf
provided.
When two rails are supporting the module with top-
down clamps, the module design capacity is:
■ Upward: 33 psf
These values are well above the governing design
loads of:
To distribute the combined loads on the module
that are transferring to the rails, please refer to the
Mounting User Instruction guide and ASCE 7-05
section 6.5.12.2.
fmin, max fmin, max

example calculations
In the following example we outline how a designer
should calculate the effect of wind and snow on a
PV module for commercial buildings based on few
assumptions and using Main Wind-force Resisting
Systems design.
■ ASCE 7-05: Section 6.5.12.4.1
example 2- commercial structure in colorado:
■ Location: Colorado
■ Terrain: Urban, suburban, wooded, closely
spaced obstructions
■ Exposure: Class B
■ Building Type: Two-story Commercial (25 feet
tall)
■ Mean height of roof: ~25.33 feet
■ Building Shape: Gable roof with 5° pitch (1:12)
■ System: Two Rail System; attached module at
four points along the long side between 1/8
to 1/4 points as described in the SolarWorld
Sunmodule User Instruction guide
■ Module area: 18.05 ft. (Reference: Sunmodule
Datasheet)
■ Module weight: 46.7 lbs (Reference:
Sunmodule Datasheet)
■ Site ground snow load (Pg
): 20 psf
sYmBols and notations
wind
■ Cn
= New pressure coeficient to be used in
determination of wind loads
■ G = Gust effect factor
■ Kd
= Wind directionality factor
■ Kz = Velocity pressure exposure coeficient
evaluated at height z
■ Kzt
= Topographic factor
■ P = Design pressure to be used in determination of
wind loads for buildings
■ qh = Velocity pressure evaluated at height z = h
■ θ = Tilt angle of the module
snow
■ Ce
= Exposure factor
■ Cs
= Slope factor
■ Ct
= Thermal factor
■ Pf
= Snow load on lat roof
■ Pg
= Ground snow load
■ Ps
= Sloped roof snow load
load combination
■ D* = Dead load
■ E = Earthquake load
■ F = Load due to luids with well-deined pressures
and maximum heights
■ H = Load due to lateral earth pressure, ground
water pressure or pressure of bulk materials
■ L = Live load
■ Lr
= Roof live load
■ R = Rain load
■ S* = Snow load
■ T = Self-straining load
■ W* = Wind load
* In this white paper we only use dead, snow and wind loads.

asce 7-10 (iBc 2012)
risk category (see Figure 26.5-1 A, B, C)
■ Wind Directionality factor, Kd
, see Section 26.6
● Main wind-force resisting system
components and cladding, Kd
= 0.85
■ Exposure category B, C or D from Section 26.7
● Exposure B
, from Section 26.8 and
Figure 26.8-1
● Kzt
= 1.0
4. Determine velocity pressure exposure coeficient,
Kz
of Kh
, see Table 30.3-1
● For exposure B and height of 25 ft, Kz
= 0.7
5. Determine velocity pressure, qh
, Eq. 30.3-1
■ qh
= 0.00256 x Kz
x Kzt
x Kd
x V2
6. Determine net pressure coeficient, GCp
■ See Fig. 30.4-2A
■ Downward: GCp
= 0.3
■ Upward: GCp
= -1.0 (zone 1)
-1.8 (zone 2)
-2.8 (zone 3)
asce 7-05 (iBc 2009)
risk category (see Figure 6.1 A, B, C)
■ Wind Directionality factor, Kd
, see Section 6.5.4.4
● Main wind-force resisting system
components and cladding, Kd
= 0.85
■ Exposure category B, C or D from Section 6.5.6.3
● Exposure B
, from Section 6.5.7.2
● Kzt
= 1.0
4. Determine velocity pressure exposure coeficient,
Kz
of Kh
, see Table 6-3
● For exposure B and height of 25 ft, Kz
= 0.7
5. Determine velocity pressure, qh
, Eq. 6-15
■ qh
= 0.00256 x Kz
x Kzt
x Kd
x V2
x 1
6. Determine net pressure coeficient, GCp
■ See Fig. 6-11B
■ Downward: GCp
= 0.3
■ Upward: GCp
= -1.0 (zone 1)
-1.8 (zone 2)
-2.8 (zone 3)

7. Calculate wind pressure, p, Eq. 30.8-1
■ p = qh
GCp
qh
= 0.00256 x kz
x kzt
x kd
x V2
qh
= 0.00256 * 0.7 * 1 * 0.85 * 1152
= 20.14 psf
pdown
= 20.14 * 0.3 = 6.04 psf
pup
= 20.14 * (-2.8) = 56 psf
= Cs
x Pf
2. Pf
■ Pf
= 0.7 x Ce
x Ct
x Is
x Pg
3. When ground snow load is less than or equal 20
psf then the minimum Pf
value is I * 20 psf (7.3.4)
■ Ce
= 0.9
5. Determine Thermal factor using Table 7-3, for
■ Ct
= 1.2
6. Find the importance factory from Table 1.5-2
■ Is
= 1.00 (7-10)
. Using above
values and θ = 5°
■ Cs
=1.0
Pf
= 0.7 x Ce
x Ct
x Is
x Pg
7. Calculate wind pressure, p, Eq. 6-26
■ p = qh
GCp
qh
= 0.00256 x kz
x kzt
x kd
x V2
qh
= 0.00256 * 0.7 * 1 * 0.85 *902
= 12.34 psf
pd
= 12.34 * 0.3 = 3.7 psf psf
pu
= 12.34 * (-2.8) = 34.6 psf
= Cs
x Pf
2. Pf
■ Pf = 0.7 x Ce
x Ct
x Is
x Pg
3. When ground snow load is less than or equal 20
psf then the minimum Pf
value is I * 20 psf (7.3.4)
■ Ce
= 0.9
5. Determine Thermal factor using Table 7-3, for
■ Ct
= 1.2
6. Find the importance factory from Table 7-4
■ Is
= 1.0 (7-05)
7. Using section 7.4 determine Cs
. Using above
values and θ = 5°
■ Cs
=1.0
Pf
= 0.7 × Ce
× Ct
× Is
× Pg

Determining wind and snow loads for solar panels | 13
Pg
≤ 20 lbs
Pg
instead of the inal snow load for the sloped roof
Pf
= 0.7 * 0.9 * 1.2 * 1 * 20 = 15.12 psf or 1 * 20
Ps
= Cs
x Pf
To ind out the effect of snow load perpendicular to the
plane of module we multiply the Ps
value by COS (θ).
Ps
= 1 * 20 * COS (5°) = 19.9 psf
load combinations: (lrfd)
Basic combinations section 2.3.2, according to ASCE
7-10 structures, components and foundations shall
be designed so that their design strength equals or
exceeds the effects of the factored loads in following
combinations:
1) 1.4D
2) 1.2D + 1.6L + 0.5 (Lr
or S or R)
3) 1.2D + 1.6 (Lr
or S or R) + (L or 0.5W)
4) 1.2D + 1.0W + L + 0.5 (Lr
or S or R)
5) 1.2D + 1.0E + L + 0.2S
6) 0.9D + 1.0W
7) 0.9D + 1.0E
Pg
≤ 20 lbs
Pg
instead of the inal snow load for the sloped roof
Pf
= 0.7 * 0.9 * 1.2 * 1 * 20 = 15.12 psf or 1 * 20
Ps
= Cs
x Pf
To ind out the effect of snow load perpendicular to the
plane of module we multiply the Ps
value by COS (θ).
Ps
= 1 * 20 * COS (5°) = 19.9 psf
load combinations: (asd)
Basic combinations section 2.3.2, according to ASCE
7-05 loads listed herein shall be considered to act in
the following combinations; whichever produces the
most unfavorable effect in the building, foundation
or structural member being considered. Effects of
one or more loads on acting shall be considered.
1) D + F
2) D + H + F + L + T
3) D + H + F + (Lr
or S or R)
4) D + H + F + 0.75 (L + T) + 0.75 (Lr
or S or R)
5) D + H + F + (W or 0.7E)
6) D + H + F + 0.75 (W OR 0.7E) + .75L + .75 (Lr
or S or R)
7) 0.6D + W + H
8) 0.6D + 0.7E + H

Determining wind and snow loads for solar panels | 14
Load Case 3)
1.2 * 2.59 + 1.6 (19.9) + 0.5 (6.04) = 38 psf
Load Case 6)
0.9 * 2.59 + 1.0 (-56) = -53.7 psf
provided.
For the case of two rails simply supporting the module
with top-down clamps, the module design capacity is:
■ Upward: -64 psf
These values are above the governing design loads
of:
To distribute the combined loads which are
transferring to the rails please refer to the Mounting
User Instruction and ASCE 7-10 section 30.4.
Load Case 6)
2.59 + 0.75 (19.9) + 0.75 (3.7) = 20.3 psf
Load Case 7)
0.6 (2.59) + 1.0 (-34.6) = -33 psf
provided.
For the case of two rails simply supporting the module
with top-down clamps, the module design capacity is:
■ Upward: -33 psf
These values are above the governing design loads
of:
■ Upward: -33 psf
To distribute the combined loads which are
transferring to the rails please refer to the Mounting
User Instruction and ASCE 7.05 section 6.5.12.2.
fmin, max
fmin, max

Determining wind and snow loads for solar panels SW-02-5156US-MEC 04-2013 | 15
As this white paper illustrates, SolarWorld Sunmodules easily meet many high wind and snow load requirements
within the United States and therefore are ideal for installation in most climates. The ability to meet these
requirements is essential when designing solar systems that are expected to perform in various weather
conditions for at least 25 years. As America’s solar leader for over 35 years, SolarWorld’s quality standards are
unmatched in the industry. Unlike most other solar manufacturers in the market today, our systems have proven
performance in real world conditions for over 25 years.
references
1. Minimum design loads for buildings and other structures. Reston, VA: American Society of Civil Engineers/
Structural Engineering Institute, 2006. Print.
2. Minimum design loads for buildings and other structures. Reston, Va.: American Society of Civil Engineers :,
2010. Print.
3. International building code 2009. Country Club Hills, Ill.: International Code Council, 2009. Print.
4. International building code 2006. New Jersey ed. Country Club Hills, IL: The Council, 2007. Print.

Letter of Approval
Dat
Proj
EPS
To:
From:
A
pres
(Version 7)
pres
acco
2005
Engin
design
each
This l
as dis
the
methodo
are pub
ensur
P
Since
Matth
Engin
Letter of Approval
Date:
Project:
EPS Job Num
To:
From:
At the reque
presented in
(Version 7)
prescribed wind
accordance
2005 Minim
Engineers (A
design me
each said building
This letter is in
as discussed in t
the site spec
methodology
are publishe
ensure it ma
Please feel fr
Sincerely,
Matthew B. Gilliss,
Engineered P
Letter of Approval
EPS Job Number:
t the request of Sola
presented in SolarWorld
(Version 7). The pap
prescribed wind and snow lo
accordance with eithe
Minimum Design
Engineers (ASCE 7
methodology
each said building cod
This letter is in approv
as discussed in the re
site specific loading
methodology for roof
are published. Becaus
ensure it matches with th
lease feel free to cont
Sincerely,
Matthew B. Gilliss, P
Engineered Power Solutions
Letter of Approval – SolarWorld
Decemb
Solar
Number: 12-SWD003
Amir Sh
SolarW
4650 Adohr L
Camarillo,
Matthew
Enginee
equest of SolarWorld,
SolarWorld’s
paper presen
ed wind and snow loa
either the
um Design Loads
rs (ASCE 7-05), or
thodology and exam
id building code.
er is in approval of th
ussed in the referenced
specific loading condi
for roof mounte
ished. Because of this, E
it matches with the mo
eel free to contact me
B. Gilliss, P.E., LEE
red Power Solutions
STRUCT
SolarWorld Design Loads Methodology Review
ecember 30
Solar Module
SWD003
Amir Sheikh
SolarWorld Ame
4650 Adohr Lane
Camarillo, CA 93012
Matthew Gilliss
Engineered Pow
st of SolarWorld, Enginee
s “White Pap
paper presents the re
and snow loads for sol
either the 2009 (and 2
ign Loads for Buil
or the 2012 IBC
and examples
pproval of the general
e referenced paper
oading conditions for
for roof mounted solar syst
ecause of this, EPS rec
s with the most current
to contact me with any
B. Gilliss, P.E., LEED AP
er Solutions
STRUCTURAL L
Design Loads Methodology Review
30, 2012
odule Design Lo
arWorld Americas
4650 Adohr Lane
CA 93012
tthew Gilliss
Engineered Powe
White Paper” title
esents the recommend
for solar modul
009 (and 2006)
oads for Buildings and
2012 IBC – whi
examples presented in t
general design m
nced paper. It is the re
onditions for each proj
ounted solar systems
of this, EPS recommends
rrent code re
me with any questions.
.E., LEED AP
UCTURAL LETTER
Design Loads Methodo
(SolarWorld)
Power Solutions (EPS)
titled: Determ
e recommended design
for solar modules mount
nd 2006) Internation
ldings and Other S
which refere
presented in this pap
design methodology
. It is the responsibility
each project.
d solar systems has continu
PS recommends period
code requirements
any questions. Thank y
ENGIN
MATT
URAL LETTER OF APP
Methodology R
(SolarWorld)
olutions (EPS)
ower Solutions (EPS
Determining Wi
ed design methodolog
odules mounted on a
ternational Buildi
and Other Structures
references AS
ed in this paper are
sign methodology for flush
s the responsibility of th
Please note
continually cha
periodically re
e requirements and
stions. Thank you.
ENGINEERED
MATTHEW B. G
879 SYCAMORE
PASO R
ETTER OF APPROVAL
ethodology Review
olutions (EPS) has revi
ining Wind and S
esign methodology for d
on and flush to
al Building Code
Structures by the A
eferences ASCE 7-
are consistent with t
for flush roof
onsibility of the project
lease note that the
ontinually changed ove
eriodically reviewing th
ements and industry
Thank you.
NGINEERED POWE
TTHEW B. GILLISS, PRO
879 SYCAMORE
PASO ROBLES
(805) 423
APPROVAL
logy Review
EPS) has reviewed the
ind and Snow Loads
ethodology for determ
flush to a roof
ing Code (IBC)
by the American
-10. EPS
ent with the d
roof mounte
of the project enginee
the industry
changed over recent y
lly reviewing the state
industry recommend
RED POWER SOL
ILLISS, PROFESSIONA
YCAMORE CANYO
SO ROBLES, CA 93446
(805) 423-1326
12/31/14
s reviewed the design
Loads for So
thodology for determining th
a roof surface
(IBC) - which refe
by the American Society
EPS has found
ent with the design int
mounted solar m
engineer of reco
industry recomm
d over recent years as
wing the stated method
recommendations.
POWER SOLUTIONS
OFESSIONAL ENGINEER
AMORE CANYON RD.
BLES, CA 93446
1326
12/31/14
d the design methodo
ads for Solar Panels
termining the code
roof surface in
which reference
rican Society of Civil
has found that the
nt with the design intentions
solar modules on
ngineer of record to addr
recommended de
cent years as new studi
stated methodology to
mendations.
SOLUTIONS
ENGINEER
CANYON RD.
Page 1
odology
Solar Panels
ining the code
h references the
iety of Civil
the
ions of
solar modules only
r of record to address
ended design
rs as new studies
thodology to

determining_wind_and_snow_loads_for_solaR PANELS EXAPMPLE USA-1-1.pdf

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to determining_wind_and_snow_loads_for_solaR PANELS EXAPMPLE USA-1-1.pdf

Similar to determining_wind_and_snow_loads_for_solaR PANELS EXAPMPLE USA-1-1.pdf (20)

Recently uploaded

Recently uploaded (20)

determining_wind_and_snow_loads_for_solaR PANELS EXAPMPLE USA-1-1.pdf