Why Galvanized Steel for PV Mounting Structures
At the core of every reliable solar power system is the mounting structure. Hot-dip galvanized steel photovoltaic brackets combine the load-bearing strength of carbon steel with the corrosion protection of a zinc coating. The hot-dip process forms a metallurgical bond between steel and zinc, and the zinc corrodes preferentially at cut edges, scratches, and fastening points, protecting the base steel by sacrificial action. A typical coating of 60-80 µm gives decades of protection in normal atmospheric environments; the actual life depends on coating thickness and the atmospheric corrosivity class of the site, so coastal salt-spray and aggressive industrial locations may require thicker coatings or supplementary protection.
Technical Specification
| Parameter | Specification |
|---|---|
| Principal material | Carbon steel, commonly Q235B or Q355B |
| Surface treatment | Hot-dip galvanizing, 60-80 µm zinc coating typical |
| Foundation options | C-section steel pile, H-section steel pile, screw pile, concrete pile |
| Installation angle | Adjustable, 0-60° standard range |
| Module arrangement | Portrait or landscape |
| Compatible modules | Framed or frameless crystalline silicon, thin film, standard commercial sizes |
| Design wind load | Up to about 60 m/s, verified per project |
| Design snow load | Up to about 2.0 kN/m², verified per project |
| Fire resistance | Class A1, non-combustible |
Wind and snow design values must be confirmed per project by structural calculation against the local building code. The designer should verify the 50-year extreme wind and snow events for the specific site rather than assuming a fixed figure, because array geometry, terrain, and exposure class all change the loads.
Applications
Ground-mounted solar farms use multiple foundation types, allowing rapid deployment on desert, grassland, gravel, and uneven terrain without costly site modification. Rooftop projects use adjustable heights and angles to maximise solar exposure while respecting building load limits; on flat roofs, ballasted mounts with concrete weights avoid roof penetration, and a structural survey is mandatory. Agrivoltaic systems elevate the array so that farming can continue beneath it. Coastal and industrial sites rely on the galvanized coating to mitigate salt-spray and chemical exposure, and the coating specification should be checked against the site corrosivity class.
Service Life
A galvanized steel mounting system in a suitable environment typically serves more than 25 years, which is an industry experience figure rather than a guarantee. The actual life depends on coating thickness, the corrosivity of the environment, drainage details, and installation quality. In coastal areas, specify a heavier coating or a zinc-aluminium coating. In any environment, design joints and fasteners so that water drains rather than pooling, and use corrosion-resistant fasteners to avoid galvanic effects between dissimilar metals.
Selection Points
When specifying a photovoltaic bracket, confirm four things. First, the coating: zinc mass and thickness should be matched to the site corrosivity category defined in ISO 9223, with heavier coatings for coastal or industrial exposure. Second, the loads: wind and snow values must come from a structural calculation for the actual site and array geometry. Third, module compatibility: frame type, dimensions, and clamping method must match the module data sheet. Fourth, the foundation: soil conditions and ground water level determine whether piles or concrete foundations are suitable.
FAQ
What wind and snow loads can a solar mounting system withstand?
Designs are calculated to the local building code, commonly covering wind up to about 60 m/s and snow loads up to about 2.0 kN/m², with the 50-year extreme events used for safety. The actual values depend on the site and array configuration.
Can solar panels be mounted on a flat roof without penetrating it?
Yes. Ballasted mounts use concrete weights instead of roof penetrations. A structural survey is essential to confirm that the roof can carry the added weight.
How long do galvanized steel mounting brackets last?
With a suitable coating thickness for the environment, galvanized steel PV brackets typically serve more than 25 years. Coastal exposure shortens life unless a heavier or alloyed coating is specified.
Why is hot-dip galvanizing preferred for PV structures?
It is the most economical way to give carbon steel long-term outdoor corrosion protection, it covers cut edges and drilled holes sacrificially, and it requires no maintenance for decades in most climates.
How much load does a rooftop solar system add?
Modules typically add about 18-22 kg/m² and the mounting structure about 10-15 kg/m², a total of roughly 25-45 kg/m². Ballasted systems add significantly more, typically 80-120 kg/m², so a structural check is mandatory.
What coating thickness should be specified for a coastal PV project?
For coastal sites, specify a heavier zinc coating, typically above 85 µm, or a zinc-aluminium-magnesium coating, and confirm the choice against the site corrosivity category per ISO 9223.
