Earlier this week, the roof of a steakhouse collapsed, leaving at least 20 customers and employees injured in the city of Serra Branca (PB). The collapse occurred during the afternoon of Monday (6). In an interview with the press, Mário Gomes, captain of the city's Fire Department, reported that the cause may have been the lack of support of the structure. “It was probably a weight issue because the structure is made of wood and has the weight of the plaster, the roof and the solar panels,” he said.
However, Gomes stated that the cause is being investigated by the city government and that a report on the cause of the fall should be issued soon by an engineer from the Municipal Administration. The firefighter also commented that the rain that fell in the region may also have contributed to the accident. The photovoltaic system installed on the roof of the steakhouse had 22 panels.
In the midst of this scenario, the question that remains is: was a structural analysis of the building and roof carried out before installing the plant?
Raphael Vaz, product engineer at 2P Accessories, said that there are numerous problems that can be found, but the only way to work safely is to hire qualified companies to perform this analysis. “The wooden structure, for example, can suffer degradation by fungi, the steel can be corroded and poorly welded, the concrete fractured. It is our duty to expand solar energy in Brazil in a safe and efficient way”, he highlighted.
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Vaz also commented that almost every week at 2P they receive the following question: after how many modules is it necessary to prepare a technical report on the roof? “The answer is always the same, always.” “Most roofs are not designed to withstand overloading on the roof, and photovoltaic modules have been getting bigger and heavier over the years. Five years ago we were working with 5 kg panels, and now, more powerful panels that reach 18 kg,” he reported.
In Brazil, according to him, there are very different roofs in structure and raw material design: “a roof covered with ceramic tiles has a totally different structure than one with a fiber cement roof, and both can be built with beams made of wood, steel, or even concrete.”
Therefore, in the engineer's view, there is no design pattern or case that is 100% safe without a technical feasibility study. This is what Marcelo Villalva, a specialist in photovoltaic systems, also thinks, who emphasized that installing panels on roofs without structural analysis is a criminal offense.
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“It is recommended that the structural engineer visit the space to survey the characteristics of the structure and roof. In many cases, however, due to the distance, the assessment can be carried out by another professional, using sketches and photos, as occurs in some cases,” he explained.
For Villalva, wind and rain must be anticipated in projects. “We cannot simply install systems without any concern for security. Did the roof collapse after a gale of rain? We cannot place the blame on ourselves,” she concluded.
Answers of 5
There are many people working in the area of solar energy without any training. I see that many companies present budgets with low prices, using lower quality materials and with professionals who are, in fact, curious… are not qualified to carry out the installations. There must be an inspection of these companies, checking whether there are qualified professionals and whether they actually work in the company or merely sign the ART. There are distributors that even want to exempt the consumer from presenting ART in the project, which is an absurd mistake. There are many engineers who sign projects for any money and don't even visit the consumer units. There is a lot of incompetence, amateurism and irresponsibility in the area of solar energy. Our country is a general mess and there is no supervision. If it remains like this, we will have these situations repeating themselves across the country. And look, we still have many consumer units (the vast majority of them) that do not have a solar energy generation system installed.
We have been in the market since 2015. I strongly believe in solar photovoltaic energy. However, with this exponential expansion that we are seeing in the market, in addition to alerting new integrators and consumers about the implicit and explicit responsibilities of implementing a photovoltaic system, there is an urgent need for greater oversight by the Confea/Crea and CFT/CRT professional associations regarding integrating companies and those executing installations to verify their real technical capabilities. I leave here for reflection a question that a client asked us when we proposed a photovoltaic system: (Do you install or place panels on roofs????) Each person must answer this question for themselves, but it is not right to leave this bill to the consumer or society to pay. Let us reflect on this.
Hugs to all.
The colonial tile used in the steakhouse as shown in the photo is very heavy and old-fashioned. Typically, it weighs 66kg per m2! Fiber cement tiles weigh 3x less, around 15kg/m2.
The solar panel adds around 20kg per m2. Wind loads, for the slope of this type of roof, can add up to 45kgf/m2 of down-force (winds of 120km/h or 34m/s), which results in total at around 120kgf per m2.
If it were fiber tiles, it would be approx. 70kgf/m2 under the same conditions.
Precisely for these and other reasons, you should never, ever hire any company to carry out this type of installation.
Always, without exception, what is cheap is very expensive.
Only engineering companies are able to carry out photovoltaic solar energy generation services.
You shouldn’t hire “stone masons” just because of the price.
This is likely to be work done without technical expertise and being well executed at the installation site.
I have worked in construction for over 20 years and have stopped performing several services due to the client's insistence on disrespecting technical standards. Unfortunately, this only makes our work even more difficult with the installation of solar energy.
I value everyone's safety in any type of work and especially in the electrical area, whether alternating or direct current. If you are not sure, do not perform the services.
Hugs to all.