About the Wind Load (Rooftop)
Wind load is the design pressure the wind exerts on solar modules and their mounting structure. It is the governing load for most rooftop and ground-mount solar in India and sets member sizes, clamp spacing, and foundations — computed per IS 875 Part 3.
Formula
Design wind pressure pd = 0.6 × Vd² (N/m²)
- Vd
- Design wind speed = Vb × k1 × k2 × k3 × k4 (m/s)
- Vb
- Basic wind speed for the location (m/s)
- k1…k4
- Risk, terrain, topography and importance factors
How to calculate it
- 1Get the basic wind speed Vb for the site from IS 875 Part 3 (33–55 m/s across India).
- 2Apply the k1–k4 factors for risk, terrain/height, topography and importance.
- 3Compute the design wind pressure and multiply by the module area and force coefficients to get the load on the structure.
What you can calculate
- IS 875 Part 3
- Uplift & lateral
- Wind pressure
- 6 wind zones
Standards & references
Frequently asked questions
What wind speed are solar structures designed for in India?
Basic wind speeds in IS 875 Part 3 range from 33 m/s to 55 m/s depending on the region (coastal and cyclone-prone zones are highest). The mounting structure and foundations are designed for the resulting design wind pressure at the site.
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