Wind load calculation for solar mounting starts from the site’s design wind speed and ends in member sizing — rails, clamps, feet and foundations. The standards AS/NZS 1170.2 and ASCE 7-22 define that path. Solaracks has run this calculation per project since 2012 and returns an engineered design & quote within 24 hours, with published system ratings from 45 to 88 m/s.
Why a datasheet wind rating is not a site verdict
A line such as “wind speed up to 70 m/s” describes the tested envelope of a system family in a defined configuration. It does not say whether that system, at that clamp spacing, on that roof, in that town, is safe. Two buildings in the same postcode can see very different design pressures once height, terrain and roof-zone effects enter the arithmetic. That gap is exactly what a site-specific engineering calculation closes — and why Solaracks asks for site data before quoting, not just a model number.
The inputs that drive the number
Basic wind speed — Every calculation begins with a mapped regional wind speed for a defined return period. In AS/NZS 1170.2 this is the regional gust wind speed for the region and importance level; in ASCE 7-22 it is the basic wind speed V read from risk-category maps. If the value is unknown, the site address is enough — engineering reads it from the applicable map.
Terrain and height — Open farmland, suburbs and city centres roughen the wind differently. AS/NZS 1170.2 applies terrain-height multipliers by terrain category; ASCE 7-22 applies an exposure coefficient for exposures B, C or D. The same mast wind produces a higher design pressure over open ground than between sheltering buildings, and pressure grows with height above ground.
Topography and direction — Hills, ridges and escarpments accelerate wind locally, and both standards carry explicit multipliers for it — Mt in AS/NZS 1170.2, Kzt in ASCE 7-22 — alongside directional factors. A rooftop at the crest of a slope is not the same site as the same rooftop on flat ground.
Roof zones — Wind does not load a roof evenly. Both standards divide the surface into field, edge and corner zones, and the pressure coefficients rise sharply toward edges and corners. An array layout that respects zone boundaries can carry a materially lighter structure than one that ignores them.
From wind speed to design pressure
Both codes converge on the same physics — dynamic pressure grows with the square of wind speed. AS/NZS 1170.2 builds the site wind speed from the regional gust speed and its multipliers, then converts to pressure with shape and area factors for the structure. ASCE 7-22 computes a velocity pressure from V, exposure, topography and directionality, then applies external pressure coefficients per zone for components and cladding. The deliverable is identical in kind — design pressures in kN/m² for each zone of the array.
From pressure to members
Pressure times tributary area gives the force each part must hold. Uplift usually governs solar mounting, so the checks run from the module clamp downward — clamp capacity, rail bending over its span, the attachment or foot, and finally the foundation. Connection capacities come from physical testing, not tables alone. Solaracks documents clamp and foot capacities through SGS pull tests on the end clamp, mid clamp and L-foot, and ballasted systems get a per-bay load-spread check so the roof structure itself is never overloaded.
Published ratings across the Solaracks range
The table below lists the catalogue envelope per system. The engineering calculation decides the final configuration — spans, clamp spacing and ballast per site.
| System | Published wind rating | Calc basis |
|---|---|---|
| Metal-roof L-foot mount SR-R1 | Up to 70 m/s | AS/NZS 1170.2 / ASCE 7-22 |
| Metal-roof railless mount SR-R2 | Up to 60 m/s | AS/NZS 1170.2 / ASCE 7-22 |
| Standing-seam clamp mount SR-R3 | Up to 70 m/s | AS/NZS 1170.2 / ASCE 7-22 |
| Flat-roof tilt and ballast mounts | Up to 60 m/s | AS/NZS 1170.2 / ASCE 7-22 |
| Bitumen-roof flashing mount SR-R6 | Up to 88 m/s | AS/NZS 1170.2 / ASCE 7-22 |
| ZAM steel ground mount SR-G2 | Up to 88 m/s | AS/NZS 1170.2 / ASCE 7-22 |
| Agrivoltaic elevated mount SR-G6 | Up to 88 m/s | AS/NZS 1170.2 / ASCE 7-22 |
| Balcony bracket SR-R8 | Up to 45 m/s | AS/NZS 1170.2 / JIS C8955 |
What to send for an engineered design
- Site location, or the design wind speed in m/s if the project spec fixes it.
- Snow load in kN/m² or the snow zone — snow enters the same engineering calc.
- Roof or ground type — see the roof systems and ground systems for what each skin needs.
- A module layout drawing as PDF, DWG or photo.
Send it through the contact page and the engineered design and quotation return within 24 hours. The array gets sized for its own wind — not for a brochure’s.
FAQ
Who verifies the wind calculation? — Each project receives a site-specific engineered design to AS/NZS 1170.2 or ASCE 7-22, so the sizing carries an engineering signature, not a sales estimate. Is snow load part of the same calculation? — Yes — the regional snow zone enters the same engineering calc as wind, so one document covers both governing load cases. How long does a wind design take? — Solaracks returns the engineered design and quotation within 24 hours of receiving location, wind, snow and layout data.
Sized for the site’s wind, on paper. — Engineered design & quote within 24 hours.