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The Effects Of Wind On Solar PV Panels: How To Protect Your Solar Panel System From The Wind Load?

What is a wind load and how important is it to ensure a successful installation of your solar PV system? How to calculate wind load for your solar panel system? In this article, you will find answers to these questions.

1. Why should you consider the wind load when installing solar panel system?

Another factor, which must certainly be taken into account when installing solar PV panels, is the wind load.

This plays a central role for two reasons: The wind subjects the solar PV modules, and the PV mounting system to excessive force and the wind load influences how close the solar PV panels must be mounted to the edges of the roof. The higher the wind load, the larger the distance to the roof edge should be chosen.

2. What is wind load and how does it affect on the solar PV modules?

The wind load is defined as the exerted loading which flows on the building (or even the solar PV modules).

This effect is divided into the loading via the wind pressure and wind suction. The first, influences the wind-facing side of the building and the second on the side opposite to the wind.

3. Wind load map: Wind load zones

Wind load map of the USA is divided into four wind load zones. An average wind speed is assigned to each wind load zone.

The highest average wind speed is in the zone 4 with 250 Miles per hour (111.76 m/s), and the lowest wind speed is in zone 1 with 130 Miles per hour (58.1m/s).

The following chart shows the wind speeds and the pressure loads in the four wind load zones:

Wind load zones	Wind speeds	Pressure load
I	130 Miles per hour	7.80 kN/m2
II	160 Miles per hour	5 kN/m2
III	200 Miles per hour	3.19 kN/m2
IV	250 Miles per hour	2.10 kN/m2

Notice:

One kilo Newton per square meter corresponds to the loading of 100 kg per square meter.
Pressure load = Wind speed (at 10 meter high) / 1600

4. The loading of solar PV panels by the wind load

The wind load can be hazardous for solar PV modules. If the solar PV panels are torn from their anchorage, severe damage can be caused.

This applies not only to the solar PV modules, which are elevated on flat roofs or to the ground-mounted systems but also solar PV panels on pitched roofs. They can be strongly influenced by the wind load. Here, the wind suction effect appears as an additional loading.

In the case of wind suction effect, the distances between the solar PV modules and the roof surface as well as how close the solar modules are mounted on the edges of the roof play a central role.

The wind forces can be extensive especially in the gables and at the roof ridge.

Tip: When choosing the right distances of solar PV panels, a compromise must be found between the best possible rear ventilation and the lowest possible loading by the wind suction effect.

The mounting guidelines of the manufacturer must always be respected.

5. The resistance of the solar PV panels and PV mounting system

The wind loading can be enormous, but there are particularly robust solar PV panels, which are designed for large wind and snow load and adverse weather conditions.

In this connection, the frame and cover are decidedly constructed, and of course, the used PV mounting system should withstand high stress.

6. Wind load calculations

The standard ASCE 7-10 (Chapter 26 to 31 – Wind Load Calculations) includes the methods of calculation for the wind load. Also, the calculation formulas for the wind load on pitched roofs are found in this standard.

7. Online wind load calculator for solar PV system

Despite the lower wind load zone, the wind load can be in individual cases by topographic conditions or other location effects very significant. On the web, you can find wind load calculator to determine the wind load.