EN 
PT_BR 
With the rapid expansion of photovoltaic systems, manufacturers and consumers are increasingly concerned about the mechanical safety of installations. Whether on a roof or on the ground, structures and fixing systems must be correctly sized and designed to withstand the operating conditions.
According to Reinaldo Burcon, industrial development engineer at Romagnole, aerodynamic drag coefficients – which make it possible to measure the force of resistance to air or another fluid across a given area/surface – are extremely important in this environment, as their inaccuracy can lead to both to an undersized structure and to an oversized one.
Given this scenario, the current Brazilian standard that governs wind loads, NBR-6123, is undergoing a review process. This new version will include alteration of the wind isopleths, with a refinement that will allow greater precision of calculations.
Aerodynamic coefficients will also be revised to include modern constructions. This standard, taken as a basis for sizing structures for photovoltaic modules, will become more precise and, therefore, the review is extremely important to achieve greater reliability. and more accurate costs at facilities, said the expert.
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“But despite so many advances, a gap will still be left with regard to photovoltaic installations. In principle, there will be no specific tables for solar structures, as is the case with international standards, such as the ASCE (American Society of Civil Engineers)”, he said.
“In the Brazilian case, it is necessary to relate to similar structures. On the other hand, ASCE set up a specific committee to discuss photovoltaic installations, including those on the ground, garage and roof, with the objective of defining procedures that lead to the optimization of sizing”, reported Burcon.
Still regarding international development, some engineering associations (Structural Engineers Association of California and Solar America Board for Codes and Standards, for example) have published guidance articles, based on best scientific and engineering practices, on how to carry out photovoltaic module installations.
“We also have universities and research centers (Western University, in Canada) that publish what they have as research sources, and are still far ahead of any standard (this university participates in the review of the ASCE standard), including tests and simulations by CFD (computational fluid dynamics) software”, he explained.
Therefore, according to the Romagnole engineer, it is up to the industry to take these efforts as a basis and carry out a “tropicalization of results” of these tests and procedures, taking into account the national environment – redoing these simulations – in order to safely advance in these developments.
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“It is worth remembering that these structures are of civil construction, therefore they must comply with current standards, such as NBR-8800. And considering that they must have a useful life similar to fixed systems, they must comply with what the NBR-14643 and ISO 9223 standards classify and estimate about atmospheric environments with regard to corrosion”, he pointed out.
Finally, Reinaldo Burcon highlighted that there are corrosion and mechanical tests, the latter being essential for carrying out tensile and compression tests on structures, both to certify the mechanical properties of the components and to carry out the testing the assembly rigidity of the assemblies, considering the static load equivalent to the wind load.
“Salt-spray tests must be carried out – a simulation of the effects of a maritime atmosphere on different metals with or without protective layers – to confirm the corrosion resistance of the components used”, he concluded.
