determining wind and snow loads for solar panels

5/20/2018 Determining Wind and Snow Loads for Solar Panels

DETERMINING WIND AND SNOWLOADS FOR SOLAR PANELS

Americas 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 SolarWorlds higher mechanical

load capacities to ensure that the Sunmodule sola

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 everystep 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

The design methodology in this document has been third party reviewed. Please see certied letter at the end of this document for more details.



U.S. model building codes have used ASCE 7-05 as thebasis 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 trst time, specically 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 ar

reected in the 2012 IBC and earlier versions.

Figure 1. A typical rooftop solar installation.



IBC 2012 (ASCE 7-10) Code References

1509.7.1Wind 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 coefcient

5) Component and cladding

1608.1Design 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.

1609.1.1Determination 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.

1609.4.1Wind 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

1608.1Design snow loads shall be determinedin 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 coefcient

5) Components and cladding

1609.1.1Wind 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 gust

to fastest-mile wind speeds.

1609.4.1Wind Directions and Sectors

1) Select wind direction for wind loads to be evaluat

2) Two upwind sectors extending 45 degrees from eit

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 cho

for that wind direction.

1609.4.2Surface 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), at op

country, grasslands, water surfaces in hurricane

prone regions.

3) Surface roughness D: Flat areas and water surfa

outside of hurricane prone regions, smooth mud

ats, salt ats, 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 qualications 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 Simplied Procedure.

ASCE 7-05: Section 6.4


In the Simplied Method the system must have the

following qualications (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 at or gable roof with a pitch

less than 45 degrees or a hip roof with a pitch le

than 27 degrees.

In case of designing more complicated projects th

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 spac

obstructions

Exposure: Class B

Building Type: Single-story residential (10- to 15-feet t

Mean height of roof: ~12.33 feet

Building Shape: Gable roof with 30 pitch (7:12)

System: Two Rail System; attached module at fo

points along the long side between 1/8 to 1/4

points as described in the SolarWorld Sunmodul

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

= 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 at roof

Pg= Ground snow load

Ps= Sloped roof snow load

Load Combination

D* = Dead load

E = Earthquake load

F = Load due to uids with well-dened pressure

and maximum heights

H = Load due to lateral earth pressure, groundwater 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 RoofHip 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

gure 30.5-1

5. Determine adjustment for building height and

exposure, , from Figure 30.5-1

Adjustment factor for Exposure B is = 1.00

6. Determine adjusted wind pressure, Pnet

, from

Equation 30.5-1

Pnet

= Kzt

Pnet30

Wind effective area is the pressure area on themodule 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.

Exposure B

Topographic factor, Kzt, 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, , from Figure 6.3

Adjustment factor for Exposure B is = 1.00

6. Determine adjusted wind pressure, Pnet

, from

Equation 6-1

Pnet

= Kzt

Pnet30

Wind effective area is the pressure area on themodule that is distributed between four mounting

clamps. Each mid-clamp takes one-quarter of the

pressure and holds two modules which are equal t

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 effecti

area of 10 ft2

:



ASCE 7-10 (IBC 2012) (Cont'd)

Zone 1

Downward: +21.8 psf

Upward: -23.8 psf

Pnet

= Kzt

Pnet30

PDown

= 1 * 1 * 21.8 = 21.8 psf

Pup

= 1 * 1 * -23.8 = -23.8 psf

Zone 2

Downward: +21.8 psf

Upward: -27.8 psf

Pnet

= Kzt

Pnet30

PDown

= 1 * 1 * 21.8 = 21.8 psf

Pup

= 1 * 1 * -27.8 = -27.8 psf

Zone 3

Downward: +21.8 psf

Upward: -27.8 psf

Pnet

= Kzt

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= C

sx P

f

2. Pfis calculated using Equation 7.3-1

Pf= 0.7 x C

ex C

tx I

sx P

g

3. When ground snow load is less than or equal to

20 psf then the minimum Pfvalue 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

Downward: +13.3 psf

Upward: -14.6 psf

Pnet

= Kzt

Pnet30

PDown

= 1 * 1 * 13.3 = 13.3 psf

Pup

= 1 * 1 * -14.6 = -14.6 psf

Zone 2

Downward: +13.3 psf

Upward: -17psf

Pnet

= Kzt

Pnet30

PDown

= 1 * 1 * 13.3 = 13.3 psf

Pup

= 1 * 1 * -17 = -17 psf

Zone 3

Downward: +13.3 psf

Upward: -17psf

Pnet

= Kzt

Pnet30

PDown= 1 * 1 * 13.3 = 13.3 psf

Pup

= 1 * 1 * -17 = -17 psf

Steps in snow design:


sx P

f


Pf= 0.7 x C

ex C

tx I

sx P

g

3. When ground snow load is less than or equal to

20 psf then the minimum Pfvalue is I * 20 psf. (7.3.4

4. Find exposure factor from Table 7-2, in categor


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 = 30

Cs= 0.73

Pf

= 0.7 x Ce

x Ct

x Is

x Pg

Pg 20 lbs

Pgis the ground snow load and cannot be used

instead of the nal snow load Pffor 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= C

sx P

f

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 (Lror S or R)

3) 1.2D+ 1.6 (Lror S or R) + (L or 0.5W)

4) 1.2D+ 1.0W+ L+ 0.5 (LRor 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)


values and = 30

Cs= 0.73

Pf

= 0.7 x Ce

x Ct

x Is

x Pg

Pg 20 lbs

Pgis the ground snow load and cannot be used

instead of the nal snow load Pffor the sloped roo

in our load combinations equations. We need to


Pf= 0.7 * 0.9 * 1.2 * 1 * 20 = 15.12 psf or 1 * 20

Ps= C

sx P

f

Ps

= 0.73 * 20 = 14.6 psf

Load Combinations: (ASD)

Basic combinations Section 2.3, according to ASC

7-05 loads listed herein shall be considered to act i

the following combinations; whichever produces t

most unfavorable effect in the building, foundatio

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 + (Lror S or R)

4) D + H + F + 0.75 (L + T) + 0.75 (Lror 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 ( Lror S or

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

conguration. The designer should refer to themodule installation instructions where the design

loads for different mounting congurations 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:

Downward: +37.4 psf

Upward: -25.7 psf

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


withstand the design loads for this two-rail mountin

conguration. The designer should refer to themodule installation instructions where the design


provided.

When two rails are supporting the module with top

down clamps, the module design capacity is:

Downward: +55 psf

Upward: 33 psf

These values are well above the governing design

loads of:

Downward: +23.5 psf

Upward: -15.45 psf

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 fewassumptions 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 fee

tall)

Mean height of roof: ~25.33 feet Building Shape: Gable roof with 5 pitch (1:

System: Two Rail System; attached module

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: Sunmod

Datasheet)

Module weight: 46.7 lbs (Reference:

Sunmodule Datasheet) Site ground snow load (P

g): 20 psf

SYMBOLS AND NOTATIONS

Wind

Cn= New pressure coefcient to be used in

determination of wind loads

G = Gust effect factor


Kd= Wind directionality factor

Kz = Velocity pressure exposure coefcient

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 = Tilt angle of the module

Snow

Ce= Exposure factor

Cs= Slope factor

Ct= Thermal factor


Pf= Snow load on at roof

Pg= Ground snow load

Ps= Sloped roof snow load

Load Combination

D* = Dead load

E = Earthquake load

F = Load due to uids with well-dened pressure

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)




2. Determine the basic wind speed, V, for applicable

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

Topographic factor, Kzt, from Section 26.8 and

Figure 26.8-1

Kzt= 1.0

4. Determine velocity pressure exposure coefcient,

Kzof K

h, 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= 0.00256x K

zx K

ztx K

dx V2

6. Determine net pressure coefcient, 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)




2. Determine the basic wind speed, V, for applica

risk category (see Figure 6.1 A, B, C)




Wind Directionality factor, Kd, see Section 6.5.

Main wind-force resisting system

components and cladding, Kd= 0.85

Exposure category B, C or D from Section 6.5.

Exposure B

Topographic factor, Kzt, from Section 6.5.7.2

Kzt= 1.0

4. Determine velocity pressure exposure coefcie

Kzof K

h, see Table 6-3

For exposure B and height of 25 ft, Kz= 0.

5. Determine velocity pressure, qh, Eq. 6-15

qh= 0.00256x K

zx K

ztx K

dx V2x 1

6. Determine net pressure coefcient, 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 = qhGCp

qh= 0.00256xk

zx k

ztx k

dx 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

Steps in Snow design:


sx P

f


Pf= 0.7x C

ex C

tx I

sx P

g

3. When ground snow load is less than or equal 20

psf then the minimum Pfvalue is I * 20 psf (7.3.4)

4. Find exposure factor from Table 7-2, in category B


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)


values and = 5

Cs=1.0

Pf= 0.7 x C

ex C

tx I

sx P

g

ASCE 7-05 (IBC 2009)(Cont'd)

7. Calculate wind pressure, p, Eq. 6-26

p = qhGCp

qh= 0.00256 x k

zx k

ztx k

dx 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

Steps in Snow design:


sx P

f


Pf= 0.7 x Cex C

tx I

sx P

g

3. When ground snow load is less than or equal 20

psf then the minimum Pfvalue is I * 20 psf (7.3.4)

4. Find exposure factor from Table 7-2, in categor


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 = 5

Cs=1.0

Pf= 0.7 C

e C

t I

s P

g


Determining wind and snow loads for solar panels |


Pg 20 lbs

Pgis the ground snow load and cannot be usedinstead of the nal snow load for the sloped roof



Pf= 0.7 * 0.9 * 1.2 * 1 * 20 = 15.12 psf or 1 * 20

Ps= C

sx P

f

To nd out the effect of snow load perpendicular to the

plane of module we multiply the Ps

value by COS ().

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 (Lror S or R)

3) 1.2D + 1.6 (Lror S or R) + (Lor 0.5W)

4) 1.2D + 1.0W+ L+ 0.5 (Lror S or R)

5) 1.2D + 1.0E+ L+ 0.2S

6) 0.9D + 1.0W

7) 0.9D + 1.0E




Pg 20 lbs

Pgis the ground snow load and cannot be usedinstead of the nal snow load for the sloped roof



Pf= 0.7 * 0.9 * 1.2 * 1 * 20 = 15.12 psf or 1 * 20

Ps= C

sx P

f

To nd out the effect of snow load perpendicular to

plane of module we multiply the Ps

value by COS ()

Ps= 1 * 20 * COS (5) = 19.9 psf

Load Combinations: (ASD)

Basic combinations section 2.3.2, according to ASC

7-05 loads listed herein shall be considered to act i

the following combinations; whichever produces t

most unfavorable effect in the building, foundatio

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

7) 0.6D + W + H

8) 0.6D + 0.7E + H




Determining wind and snow loads for solar panels |


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


withstand the design loads for this two-rail mounting

conguration. The designer should refer to the

module installation instructions where the design


provided.

For the case of two rails simply supporting the module

with top-down clamps, the module design capacity is:

Downward: +113 psf

Upward: -64 psf

These values are above the governing design loads

of:

Downward: +38 psf

Upward: -53.7 psf

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


withstand the design loads for this two-rail mountin

conguration. The designer should refer to the

module installation instructions where the design


provided.

For the case of two rails simply supporting the mod

with top-down clamps, the module design capacity

Downward: +55 psf

Upward: -33 psf

These values are above the governing design load

of:

Downward: +20.3 psf

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, maxFmin, max


Determining wind and snow loads for solar panels SW-02-5156US-MEC 04-2013 |

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 Americas solar leader for over 35 years, SolarWorlds quality standards are

unmatched in the industry. Unlike most other solar manufacturers in the market today, our systems have prov

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.


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wind resistance

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