No Mandatory Wind Load Permit Required
Arizona is one of 40 states where building departments do NOT require PE-sealed wind load calculations by law to obtain a building permit. However, you may still need wind load calculations for insurance requirements, manufacturer warranties, utility interconnection standards, or engineering best practices.
Arizona: America's Solar Capital
Arizona leads the nation in solar potential with over 300 days of sunshine annually and some of the highest solar irradiance values in the United States. This makes wind load engineering for solar installations particularly critical, as the state's vast solar farms and residential rooftop systems must withstand both everyday desert winds and extreme monsoon events.
Why Solar Wind Loads Matter in Arizona
- Utility-Scale Solar: Arizona hosts massive solar farms requiring precise wind load calculations for ground-mounted tracker systems
- Residential Rooftop: Over 300,000 homes with solar panels need proper Component & Cladding (C&C) design
- Extreme Weather: Monsoon season brings microbursts and dust storms (haboobs) with localized high winds
- Insurance Requirements: Many insurers require wind load documentation for solar installations
Arizona Code Adoption - Local Jurisdiction State
Arizona does not have a mandatory statewide building code. Building codes are adopted at the local jurisdiction level, with the exception of the state-wide adoption of the International Fire Code 2018 with amendments. Each city, county, and municipality determines which edition of the International Building Code (IBC) to adopt.
Important: Always Verify Local Requirements
Because Arizona lacks statewide code adoption, you must verify the adopted code edition with the local building department before beginning any solar project. Code editions can vary significantly between neighboring jurisdictions.
Key Jurisdiction Code Adoption
Phoenix
Current Code: 2024 IBC
Wind Standard: ASCE 7-22
Effective: August 1, 2025
ASCE 7-22 2024 CodeTucson / Pima County
Current Code: 2024 IRC
Wind Speed: 110 mph design
Status: Updated 2024
ASCE 7-22Scottsdale
Current Code: 2021 IBC
Wind Standard: ASCE 7-16
Exposure: B (with conditions)
ASCE 7-16Prescott
Residential: 115 mph (Exp C)
Commercial: 95-115 mph
Status: Varies by Risk Cat
ASCE 7-16Phoenix Engineering Design Criteria
The City of Phoenix provides specific engineering design criteria for wind load calculations:
| Parameter | Value |
|---|---|
| Basic Wind Speed (Risk Cat I) | 95 mph |
| Basic Wind Speed (Risk Cat II) | 105 mph |
| Basic Wind Speed (Risk Cat III) | 110 mph |
| Basic Wind Speed (Risk Cat IV) | 115 mph |
| Default Exposure Category | C (typical for solar) |
| Ultimate Design Wind Speed (Max) | 180 mph (2024 code) |
Solar PV Wind Load Requirements (ASCE 7-16/7-22)
ASCE 7 provides specific provisions for calculating wind loads on solar photovoltaic (PV) systems. These provisions are critical for Arizona's extensive solar industry.
ASCE 7-16 Solar Panel Sections
| Section | Application | Description |
|---|---|---|
| 29.4.3 | Low-Slope Roofs (≤ 7°) | Rooftop solar on flat or nearly flat roofs |
| 29.4.4 | Parallel to Roof Surface | Flush-mounted panels on any roof slope |
| Chapter 27 | Ground-Mounted (≤ 45°) | Treated as open building with monoslope roof |
| Chapter 27 | Ground-Mounted (> 45°) | Treated as solid sign |
ASCE 7-22 Solar Panel Updates
New in ASCE 7-22 for Solar
- Section 29.4.5: New comprehensive provisions for fixed-tilt ground-mount systems
- Updated Pressure Coefficients: Refined coefficients based on wind tunnel testing
- Effective Wind Area: Clarified calculations for panel arrays
- Panel Loading Statement: "Solar panels shall not be considered as part of the load path that resists the interconnection force unless evaluated or tested for such loading"
ASCE 7-22 Solar Wind Pressure Formula
Typical Arizona Solar Wind Pressures
For Phoenix area projects using ASCE 7-16 provisions with Exposure C:
| Zone | LRFD Pressure (psf) | Application |
|---|---|---|
| Interior | 25-35 psf | Field of roof away from edges |
| Edge | 35-45 psf | Within 10% of roof dimension from edge |
| Corner | 45-55 psf | Corner zones of roof |
Monsoon Season Considerations
Arizona Monsoon Season: June - September
The Arizona monsoon brings unique challenges for solar installations including high winds, dust storms (haboobs), and intense microbursts. Building codes specify wind load requirements that account for these severe weather events.
Monsoon Wind Characteristics
- Microbursts: Localized downdrafts producing wind gusts exceeding 80+ mph in concentrated areas
- Haboobs (Dust Storms): Walls of dust preceding thunderstorms with sustained winds of 40-60 mph
- Rapid Onset: Storms develop quickly, often with little warning
- Debris Loading: Wind-carried debris can impact solar panels and mounting systems
Design Considerations for Monsoon Winds
| Consideration | Recommendation |
|---|---|
| Exposure Category | Use Exposure C unless detailed analysis justifies otherwise |
| Safety Factors | Consider additional safety factors for ground-mounted systems in open desert |
| Mounting Hardware | Stainless steel or hot-dip galvanized for corrosion resistance |
| Panel Gaps | Maintain proper spacing per manufacturer specifications |
| Rapid Shutdown | Utility interconnection standards include provisions for severe weather |
Arizona Exposure Categories
Exposure category selection is critical in Arizona due to the prevalence of open desert terrain and "open patches" even in developed areas.
Arizona Building Official Preference
Previous projects in Phoenix have required engineers to use Exposure C per local amendments/building officials, unless the Engineer of Record provides calculations proving Exposure B is acceptable. This is difficult due to "open patches" common throughout Arizona.
| Category | Description | Arizona Application |
|---|---|---|
| Exposure B | Urban/suburban, wooded areas | Dense urban cores (Phoenix downtown) |
| Exposure C | Open terrain, grasslands | Default for most Arizona projects |
| Exposure D | Flat, unobstructed coastal areas | Not applicable in Arizona |
Scottsdale Exposure B Conditions
The City of Scottsdale permits Exposure B for buildings meeting these conditions:
- Mean roof height of less than or equal to 30 feet
- Located within specific boundary conditions defined by the city
- Engineer of Record must document compliance
Rooftop Solar Structural Requirements
Per the IBC and local Arizona codes, rooftop-mounted photovoltaic systems must be designed to resist wind loads while not overloading the existing roof structure.
Structural Loading Requirements
Load Cases for Roof Structures with PV
Portions of roof structures covered with photovoltaic panel systems shall be designed for:
- Load Case 1: Dead load (including PV panel weight) plus snow load
- Load Case 2: Dead load (excluding PV panel weight) plus roof live load or snow load, whichever is greater
| Requirement | Specification |
|---|---|
| Max Additional Truss Loading | 5 psf for all rooftop units |
| Point Load Maximum | 50 pounds |
| Engineering Report | May be required for roof capacity verification |
| Mounting Data Required | Fastener sizes, dead load, wind uplift calculations |
Ground-Mounted Solar Foundations
Foundations for ground-mounted solar arrays must be engineered to:
- Support the weight of the system (dead load)
- Resist wind uplift forces calculated per ASCE 7
- Account for soil conditions (Arizona soite/expansive soils in some areas)
- Consider scour potential from monsoon runoff
Need Arizona Solar Wind Load Calculations?
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