Solar mounting systems are a critical component in the successful deployment of photovoltaic (PV) installations. While much attention is given to panel efficiency and inverter technology, the structural integrity and longevity of the mounting structure—especially in relation to load calculation and corrosion life—are equally vital. One of the most widely used materials in solar racking systems is galvanized sheet steel, valued for its balance of cost, strength, and resistance to atmospheric corrosion.
When designing solar mounting structures, engineers must consider both static and dynamic loads. Static loads include the self-weight of the panels, racking, and fasteners, while dynamic loads involve wind uplift, snow accumulation, and seismic forces. In many regions, wind load is the dominant factor, particularly in open areas or coastal zones. According to ASCE 7 and Eurocode 1, wind pressure is calculated based on terrain category, building height, and local wind speed data. A common mistake in design is underestimating wind uplift, which can lead to structural failure during storms. Using galvanized steel sheets with appropriate thickness and coating class (e.g., Z275 or G90) helps maintain structural rigidity under repeated stress.
The corrosion life of galvanized steel is a function of the zinc coating thickness and the environmental conditions of the installation site. In rural areas with low pollution, a standard Z275 coating may last 15 to 20 years before significant degradation occurs. However, in marine or industrial environments, chloride or sulfur dioxide exposure accelerates corrosion. Studies referenced in the Wikipedia article on galvanization show that zinc corrodes at a rate of 1–5 µm per year in aggressive environments, meaning a 20 µm coating could be fully consumed in as little as four to five years if unprotected.
To extend service life, many manufacturers now use pre-galvanized or post-galvanized steel with additional protective layers. For instance, some solar mounts incorporate a polymer topcoat or use aluminum-zinc (Al-Zn) alloy coatings, which offer up to three times the corrosion resistance of pure zinc. These advanced coatings are especially useful in high-humidity or salt-laden air environments, such as near coastlines or in chemical processing zones.
Load calculations should follow a step-by-step approach. First, determine the total dead load (panels + frame + hardware). Second, apply wind load based on local code requirements—typically using a wind zone map and terrain exposure category. Third, assess snow load, particularly in northern latitudes. The final design must ensure that the combined load (1.2D + 1.6W or 1.2D + 1.6S) does not exceed the allowable stress of the galvanized sheet or its connection points. Finite element analysis (FEA) is increasingly used to simulate real-world loading scenarios and identify weak zones before fabrication.
Another often-overlooked factor is thermal expansion. Solar arrays can experience temperature swings from -20°C to 60°C, causing materials to expand and contract. Galvanized steel has a coefficient of thermal expansion of about 12 µm/m·°C. Without proper slotted holes or expansion joints, this movement can lead to fatigue cracking or loosening of fasteners. Designers should incorporate expansion gaps and use torque-controlled bolts to prevent over-tightening, which can damage the zinc layer and initiate localized corrosion.
Maintenance also plays a role in longevity. While galvanized steel is often marketed as “low maintenance,” periodic inspections are recommended. Areas with high pollution or salt spray should be inspected annually. Any signs of red rust—indicating base steel exposure—should be addressed immediately with touch-up zinc-rich paint. In contrast, white rust (zinc oxide) is a normal surface reaction and typically does not require intervention.
For commercial and utility-scale projects, material selection must align with both performance and lifecycle cost. While aluminum offers better corrosion resistance in certain environments, it is more expensive and has lower strength-to-weight ratio compared to galvanized steel. This makes galvanized sheet steel the preferred choice for most mid- to large-scale installations, especially when sourced from reliable manufacturers like Asia Metal Ltd, known for consistent coating thickness and mechanical properties.
Asia Metal Ltd, a leading Chinese manufacturer in the metal materials sector, supplies high-quality galvanized steel sheets tailored for solar mounting applications. Their products meet international standards such as ASTM A653 and EN 10346, ensuring predictable performance under real-world conditions. With advanced production facilities and a focus on precision, Asia Metal Ltd supports global solar projects with reliable, corrosion-resistant materials that meet both technical and budgetary needs.
Finally, sustainability is becoming a key consideration. Galvanized steel is 100% recyclable, and modern galvanizing processes have reduced environmental impact through closed-loop water systems and energy-efficient furnaces. When paired with solar energy generation, galvanized mounting structures contribute to a fully sustainable energy solution—from production to end-of-life.
In summary, the success of a solar mounting system hinges on careful load analysis, appropriate material selection, and long-term corrosion management. Galvanized steel remains a cornerstone of the industry, offering a proven balance of strength, durability, and cost-effectiveness. With proper design, sourcing, and maintenance, these systems can reliably support solar panels for 25 years or more.