Global Design Wind Speeds for Solar Mounting Systems

Typhoons, hurricanes and cyclones are regional names for the same type of weather system: a tropical cyclone. However, a hurricane category cannot be used directly as the design wind speed for a solar mounting system.

For professional solar mounting wind design, it is not enough to know that the wind speed is “60 m/s” or “80 m/s.” Engineers must also know the averaging period, reference height, return period, terrain exposure, array geometry and complete structural load path.

• Is the value a 1-minute mean, 2-minute mean or 3-second gust?
• At what height is the wind speed defined?
• Does it represent a 50-year, 500-year or 700-year return period?
• Is the site in an urban, open-country or coastal exposure?
• What are the array tilt, height, row spacing and edge-zone conditions?
• Can the load be transferred safely from the modules to the clamps, rails, posts and foundations?

This guide examines Bangladesh’s BNBC wind zones, Nigeria’s wind design basis, the ASCE 7 system used in the United States, Australian cyclone regions and other global high-wind markets. It also explains how wind speed becomes structural pressure and how solar mounting suppliers should present wind resistance in international projects.

This article is intended for technical and commercial guidance. It does not replace project-specific calculations, approval by the authority having jurisdiction, or design by a qualified structural engineer.

Typhoon, Hurricane and Cyclone: What Is the Difference?

According to the World Meteorological Organization, the terminology mainly depends on the ocean basin in which the storm occurs.

All of these systems are tropical cyclones. The different names do not indicate different physical types of storms.

China’s Tropical Cyclone Classification

China’s current classification standard uses maximum sustained wind based on a 2-minute averaging period.

Source: China Meteorological Administration, GB/T 32935—2025.

The Japan Meteorological Agency generally reports tropical cyclone intensity using a 10-minute mean wind speed. Therefore, even data from agencies covering the same ocean basin may not be directly comparable without checking the averaging period. See the Japan Meteorological Agency RSMC Tokyo.

The Saffir–Simpson Hurricane Wind Scale

The United States National Hurricane Center classifies hurricanes using the maximum 1-minute sustained wind at approximately 10 metres above unobstructed ground.

Category 3 and above are classified as major hurricanes. The scale is based only on wind speed and does not account for storm surge, rainfall, flooding or tornadoes. Source: US National Hurricane Center.

Why an 80 m/s Design Wind Speed Is Not Automatically a Category 5 Hurricane

The comparison is misleading because the averaging periods may be different:

• The Saffir–Simpson scale uses a 1-minute sustained wind.
• China’s tropical cyclone classification uses a 2-minute mean.
• The Japan Meteorological Agency generally uses a 10-minute mean.
• BNBC and ASCE 7 design wind speeds are generally expressed as 3-second gusts.

A 3-second gust is normally higher than the corresponding 1-minute or 10-minute mean wind. However, there is no universal “add 10%” or “subtract 10%” conversion. The relationship depends on terrain roughness, atmospheric conditions, gust factors, reference height and the methodology used by the applicable code.

A professional wind-speed statement should identify the value, averaging period, reference height, terrain exposure, return period or risk category, and code edition. For example: V = 80 m/s, 3-second gust at 10 m height, Exposure B, 50-year return period, in accordance with BNBC 2020.

How Wind Speed Becomes Wind Pressure

At standard air density, the basic velocity pressure can be approximated by q₀ ≈ 0.000613V², where q₀ is in kPa and V is in m/s.

A 20% increase in wind speed produces approximately a 44% increase in velocity pressure. An 80 m/s wind produces approximately four times the basic velocity pressure of a 40 m/s wind.

This is not yet the final pressure acting on a module or mounting system. Structural codes also apply factors for height, terrain exposure, topographic speed-up, wind directionality, risk category, external pressure, underside pressure and array aerodynamics. For open ground-mounted arrays, carports and trackers, the applicable code may require net force coefficients developed for the relevant geometry.

Bangladesh: 80 m/s Exists, but It Is Not a Nationwide Value

Bangladesh is located at the northern end of the Bay of Bengal and is exposed to tropical cyclones, storm surge and extensive low-lying coastal terrain. BNBC 2020 was formally published through the Bangladesh Government Gazette and is the principal national reference for structural wind design.

The BNBC basic wind-speed basis is generally defined as a 3-second gust at 10 metres above ground, referenced to Exposure B and based on a 50-year return period. The value is selected from the applicable wind-speed map or location table.

Source: Bangladesh Public Works Department wind-hazard assessment.

1. Published basic wind speeds in Bangladesh range from approximately 41.4 to 80.0 m/s.
2. Dhaka does not have an 80 m/s basic wind speed; its listed value is 65.7 m/s.
3. Several southeastern coastal, port and island locations reach 80 m/s.
4. Not every coastal district automatically has an 80 m/s value.
5. Project coordinates, terrain, exposure, importance and local approval requirements must still be confirmed.

How to Describe an 80 m/s Bangladesh Design Correctly

Avoid an unqualified claim such as “hurricane-proof mounting system for Bangladesh, up to 80 m/s.” A more defensible statement is:

Designed for a BNBC 2020 basic wind speed of 80 m/s, defined as a 3-second gust at 10 m height, Exposure B and a 50-year return period, subject to the specified array geometry, module configuration, foundation conditions and project location.

Nigeria: There Is No Single National 35–45 m/s Design Value

Nigeria is not exposed to landfalling tropical cyclones in the same way as Bangladesh. Its principal strong-wind hazards include thunderstorm downbursts and microbursts, squall lines, the West African monsoon, Harmattan-season winds, and open-country or coastal exposure.

The Nigerian Meteorological Agency and the Nigeria Civil Aviation Authority regularly warn of severe thunderstorms, squally winds, microbursts and low-level wind shear.

Nigerian Code Basis

The wind-loading section of Nigeria’s National Building Code 2006 requires the basic wind speed to be selected from the code’s wind map. Its pressure tables include basic wind-speed columns of 31, 36, 40, 45 and 49 m/s, with further consideration of urban, open-country and coastal exposure. See the Federal Ministry of Housing and Urban Development National Building Code.

According to the Ministry’s 2025 code-review information, the 2006 edition remains the existing national text while a revision is in progress. Actual enforcement and code adoption must also be checked with the relevant state and local authority.

Why Do Some Nigerian Projects Specify 35 or 40 m/s?

These values may come from individual procurement documents rather than a nationwide rule. For example, one Nigerian Rural Electrification Agency solar street-light specification required structural design for a 35 m/s, 3-second gust. This proves that the specific project adopted 35 m/s; it does not establish a national Nigerian design wind speed.

For a Nigerian solar mounting quotation, the supplier should obtain the project coordinates, elevation, applicable code and edition, state or local approval basis, wind-map value, averaging period, terrain exposure, topography, risk classification, design life and any additional EPC specification.

United States: ASCE 7 Wind Speeds Depend on Location and Risk Category

US projects commonly use ASCE 7. The design wind speed is not selected from the hurricane category. It is obtained using the project coordinates, applicable ASCE edition and structural risk category.

The ASCE Hazard Tool reports wind speeds as 3-second gusts at 10 metres above ground in Exposure C reference terrain. The return period depends on the applicable risk category.

Source: ASCE Hazard Tool API Documentation.

Florida Example

Under the 2023 Florida Building Code, the ultimate design wind speed for an ordinary Risk Category II project can reach 175 mph, or approximately 78.2 m/s, in Miami-Dade County and 170 mph, or approximately 76.0 m/s, in Broward County. These are 3-second design gusts, not 1-minute sustained hurricane wind speeds.

ASCE 7-22 includes provisions for tilted panels on low-slope roofs, roof-parallel panels, fixed-tilt ground arrays, support posts and foundations. Systems outside the permitted geometry may require wind-tunnel testing. US enquiries should therefore include the project’s ASCE Hazard Tool report rather than only a state name or a general description such as “Florida hurricane zone.” See ASCE 7-22 and SEAOC PV2.

Comparing Global High-Wind Regions

Australian Regions C and D are among the world’s most demanding code-defined cyclone regions. Official values include Region C at V500=66 m/s, V1000=70 m/s and V2000=73 m/s, and Region D at V500=80 m/s, V1000=85 m/s and V2000=90 m/s. Source: Australian NCC/ABCB high-wind guidance.

In 1996, Tropical Cyclone Olivia produced a measured 3-second gust of 113.2 m/s at Barrow Island, Australia. The World Meteorological Organization recognises this as the world record for the highest surface wind gust. This record demonstrates natural severity but should not be substituted for a code-defined project wind speed.

Markets requiring particular attention include the Bay of Bengal, southeastern China, the Philippines, Taiwan, southern Japan, Florida, the Gulf of Mexico, the Caribbean, northern and northwestern Australia, South Pacific islands, exposed ridges and coastal cliffs, and inland regions affected by downbursts or tornadoes.

How High Wind Affects Solar Mounting Design

The complete structural load path is: wind pressure → module glass and frame → clamps → rails or purlins → posts or roof attachments → building structure or pile foundation → ground.

A system cannot legitimately claim an 80 m/s rating if any part of this load path has not been verified.

Edge and Corner Zones

Roof corners, array perimeter rows, first rows and last rows frequently experience the highest suction. Internal-row shielding should not be assumed unless permitted by the applicable code or supported by wind-tunnel testing.

Tilt Angle

It is an oversimplification to say that a larger tilt angle always produces a higher wind load. Tilt changes positive pressure, suction, torque and the aerodynamic response to different wind directions. The result also depends on array height, row spacing, module gaps, parapets and ground clearance.

Foundations

Foundation safety is not determined only by foundation weight. High-wind foundations may need to resist uplift, horizontal shear, overturning moment, cyclic loading, erosion and long-term corrosion. The mounting-system engineer should provide maximum compression, tension, shear and moment reactions for every support.

Construction Conditions

An incomplete array may be more vulnerable than the finished structure. High-wind construction plans should define temporary bracing, installation sequencing, wind-related stop-work limits and pre-storm inspection procedures.

What Real Hurricane Damage Has Taught the Solar Industry

The US Department of Energy investigated five federal PV systems in the Caribbean after Hurricanes Irma and Maria. Damage ranged from minimal to complete system loss. Some systems appeared to comply with the applicable code but still performed very differently because of variations in frame stiffness, fastener capacity, installation quality and structural detailing.

Source: US Department of Energy — Learning from Hurricane Loss and Rebuilding Better.

• Inadequate capacity at critical connections;
• Inconsistent bolt preload or installation quality;
• Fastener loosening caused by vibration;
• Progressive module release after the failure of one mid-clamp;
• Insufficient lateral or torsional frame stiffness;
• Corrosion reducing long-term structural capacity;
• Tracker systems failing to enter a safe stow position.

Wind resilience therefore depends on more than a calculation report. It requires coordinated material selection, connection design, installation quality control, inspection and maintenance. See the DOE severe-weather PV design guidance.

Product Certification Does Not Replace Project-Specific Design

IEC 61215

IEC 61215 addresses PV module design qualification, including mechanical-load and dynamic mechanical-load testing. A module test result does not automatically prove that the module is safe at a particular site wind speed, clamp position or mounting configuration.

UL 2703

UL 2703 addresses functions including mounting, clamping, retention, grounding and certain fire-related characteristics. A listing does not by itself complete the structural design of the mounting system, roof structure or foundation for a specific project.

Project engineering must still address site-specific wind speed and exposure, net array pressure, module and clamp compatibility, rail and connection capacity, roof or foundation capacity, and local approval requirements.

How Solar Mounting Suppliers Should Apply This Information

Do Not Classify Products by Wind Speed Alone

Labels such as “Standard 40 m/s,” “High Wind 60 m/s” and “Cyclone 80 m/s” may help with preliminary internal screening. They should not become unconditional external performance claims.

A more defensible product matrix should define allowable positive and negative pressure, permitted array geometry, module dimensions and clamping arrangement, rail span and post spacing, roof or foundation conditions, governing code and conditions requiring project-specific analysis.

Create a Wind Design Data Sheet

1. Project address, coordinates and elevation;
2. Governing code, edition and authority having jurisdiction;
3. Basic wind speed, unit, averaging period and reference height;
4. Return period or risk category;
5. Terrain exposure and topographic conditions;
6. Roof, ground-mount, carport or tracker configuration;
7. Tilt, clearance, row spacing, gaps and array dimensions;
8. Module model, dimensions, frame and permitted clamp zones;
9. Roof substrate information or geotechnical parameters;
10. Corrosion environment, design life and material requirements;
11. Deflection limits and special load combinations;
12. Local engineering, product-approval or wind-tunnel requirements.

Sell a Verifiable Load Path, Not Only Material Weight

Professional deliverables for an EPC contractor, developer or engineering consultant should include a structural calculation summary, the complete design-wind definition, positive and negative pressures, component capacities, reactions transferred to the roof or foundations, installation torque requirements, corrosion specification and rules requiring recalculation when project parameters change.

Conclusion

Meteorological categories answer the question, “How intense is the storm?” Structural codes answer a different question: “What design conditions must the structure resist?” The two are related, but they are not interchangeable.

Bangladesh’s 80 m/s locations, Florida’s approximately 76–78 m/s design regions and Australia’s Region D values of 80–90 m/s are based on different codes, exposures and return periods. Comparing these figures without their design conditions can lead to incorrect conclusions.

In the global high-wind solar market, the strongest supplier is not the one that prints the largest wind-speed number. It is the supplier that provides the clearest, most complete and most verifiable engineering evidence.

Solaracks provides engineered rooftop, ground-mount and solar carport structures for international projects. Our team can support project-specific wind-load input review, structural configuration and documentation. Visit the Solaracks Engineering Center or contact us for a project assessment.

Update, 2026: the step-by-step calculation method is now published as Wind load calculation for solar mounting, explained — this page keeps the global design wind-speed reference tables.