Certification of steel support for solar photovoltaic systems

Core Certification Content

The certification of steel supports for solar photovoltaic systems focuses on the structural safety and durability of steel supports, with core evaluations covering the following dimensions:

Product Classification and Marking: Steel supports are classified into fixed supports and adjustable supports based on installation type, into steel supports and aluminum alloy supports based on the material of the main load-bearing members, and into six load grades from Grade I to Grade VI.

General Requirements: The support design must meet the requirements for the ultimate limit state and the serviceability limit state, with sufficient stiffness, strength, and stability in the structure. Anti-corrosion gaskets should be placed between dissimilar metal materials to prevent galvanic corrosion.

Technical Requirements: This includes indicators such as appearance quality, dimensional tolerances, material wall thickness, mechanical properties, and corrosion resistance. The surface of steel materials should be free from defects such as cracks, bubbles, scabs, rust, inclusions, and folds. Welds should have a smooth and uniform appearance, free from defects such as porosity, slag inclusions, cracks, incomplete fusion, incomplete penetration, and weld beads. The wall thickness of steel plates for main load-bearing members should be no less than 2.0 mm, and that for connecting members should be no less than 3.0 mm.

Mechanical Performance Requirements: The slenderness ratio limits for tension and compression members of the support are clearly specified. For steel supports, the slenderness ratio of main compression members should not exceed 180, and for bracing members, it should not exceed 220. For tension members, the main load-bearing members should not exceed 350, and bracing members should not exceed 300. For the allowable deflection of flexural members, the deflection of main beams in steel supports should not exceed L/250, and that of secondary beams should not exceed L/180.

Corrosion Resistance Requirements: Carbon structural steel and low-alloy high-strength structural steel should be treated with effective anti-corrosion measures. When hot-dip galvanizing is used for corrosion protection, it should comply with the provisions of GB/T 13912. When fluorocarbon paint or polyurethane paint is applied, the average film thickness should be no less than 35 micrometers; in areas with severe air pollution or coastal areas, the average film thickness should be no less than 45 micrometers.

Test Methods: Appendix A of the standard specifies the test method for deformation performance of main load-bearing members of photovoltaic system supports. Static load tests are used to verify the load-bearing capacity of the support and to check whether the maximum deformation is less than L/250.

Inspection Rules: This includes factory inspection and type inspection. Type inspection should test all technical requirements specified in the standard and should be conducted under the following circumstances: during trial production and type identification of new products or products transferred to a new factory; when significant changes in structural design, materials, or processes occur after formal production that may affect product performance; when production has been suspended for more than half a year and is resumed; and when factory inspection results differ significantly from the previous type inspection.

Certification Process

The certification of steel supports for solar photovoltaic systems typically involves the following stages:

Application and Document Submission: Select a third-party testing institution with CNAS and CMA qualifications, and submit materials such as the company's business license, product design drawings, material composition descriptions, and production process descriptions. The certification body conducts a preliminary compliance review of the application materials.

Product Sampling Inspection: The certification body sends personnel to the production site or finished product warehouse to collect samples, which are then sent to a qualified laboratory for testing. Test items include appearance quality inspection, cross-sectional dimension measurement, static load deformation test, salt spray corrosion test, material composition analysis, and welding procedure qualification.

Structural Strength Testing: According to the deformation performance test method specified in Appendix A of JG/T 490-2016, static load tests are conducted to verify the load-bearing capacity of the support and to check whether the maximum deformation is less than L/250.

Corrosion Resistance Testing: Accelerated corrosion tests are performed using a salt spray test chamber. Neutral salt spray tests are conducted in accordance with relevant standards to evaluate coating thickness, adhesion, and rust grade.

Certification Decision and Issuance: After passing all tests, the certification body issues a formal test report. The report clearly states the conclusion "Complies with the requirements of JG/T 490-2016 'General Technical Requirements for Solar Photovoltaic System Supports'" and is stamped with the CNAS or CMA mark.

Post-Certification Surveillance: Some certification bodies provide annual surveillance audit services to ensure that products continue to meet certification requirements. Enterprises should establish an internal quality control mechanism and regularly test raw materials and batch-produced products.

Value of Certification

Ensuring Structural Safety of Photovoltaic Power Stations: As the core supporting structure of photovoltaic power generation systems, the safety and reliability of photovoltaic supports directly affect the long-term stable operation of the entire photovoltaic power station. Type inspections can effectively reduce the early failure rate of photovoltaic supports and extend their service life to over 25 years.

Meeting Project Bidding Access Requirements: In the bidding processes for EPC contracts and equipment procurement of photovoltaic power stations, steel support product certification is a core access qualification. The certification certificate is an important credential for entering the supplier list of major projects.

Standardizing Production and Improving Quality: The certification process drives enterprises to establish standardized production process systems and quality control systems, covering aspects such as material selection, welding processes, galvanizing thickness control, and dimensional accuracy inspection, thereby enhancing overall technical management capabilities.

Reducing Lifecycle Costs: Anti-corrosion solutions that have passed certification can significantly reduce the costs of replacement and repair caused by corrosion of supports. An average hot-dip galvanized coating thickness of no less than 85 micrometers ensures structural safety of the support throughout its 25-year design service life.