Fire Department combats large fire in Itaquaquecetuba, in SP A large fire hit a chemical industry in Itaquaquecetuba, in Greater São Paulo, on Tuesday afternoon (4). Until the last update of this report, there were no records of victims. The affected company produces and sells solvents and polyester resins. According to preliminary information, the unit has 24 solvent tanks, but it is not yet known which substances are burning or whether any of these tanks were hit. But why can fires in places that store solvents and resins reach large proportions? ?Download the g1 app to see news in real time and for free Many of these products release flammable vapors, capable of forming a mixture that catches fire when in contact with a spark or other heat source. The risk, however, depends on the material involved, the quantity stored and the conditions of the accident. Understand more below. Aerial images show the site of the fire in Itaquaquecetuba Cristina Mayumi / Rede Globo Why do solvents catch fire easily? Solvents are substances used to dissolve, dilute or mix other materials. Many release vapors even at temperatures close to those found in the environment. In general, it is not the liquid itself that starts to burn, but the vapors released by it. When these gases mix with oxygen and find an ignition source, flames can emerge and spread quickly. ?? FLASH POINT - A measure used to assess this risk is the so-called flash point: the lowest temperature at which a liquid releases enough vapor to form a flammable mixture with air. The lower this value, the greater the ease of ignition. MORE United States bodies, such as the National Institute for Occupational Safety and Health (Niosh), also maintain technical sheets with information on flammability and vapor concentration limits of different solvents. And are polyester resins also flammable? Unsaturated polyester resins may contain styrene, a liquid, volatile substance that helps keep the resin in a form suitable for application and participates in its transformation into a rigid material. ?? According to the chemical emergency database of the United States National Oceanic and Atmospheric Administration (Noaa), styrene releases flammable vapors, which are heavier than air and can travel until they reach an ignition source. Heat can also speed up chemical reactions within certain products or containers. In the case of resins, this can happen during hardening, a stage in which the material stops being liquid or pasty and turns into a solid piece. This process releases heat. In large quantities or without adequate temperature control, the mixture can heat up quickly and further accelerate the reaction itself, increasing the risk of overheating and fire, according to studies available at the United States National Library of Medicine. This behavior, however, depends on the composition of each resin, the additives used, the temperature and the form of storage. ? gif home 2 - Large fire hits chemical industry in Itaquaquecetuba Cristina Mayumi / Rede Globo And why can these fires be difficult to fight? Fires involving flammable liquids require product identification so firefighters can choose the safest strategy. Water can be used to cool nearby tanks, structures and containers, but a jet launched directly onto certain liquids may not put out the flames and may even spread the material. In some cases, special foams are used that cover the surface, reduce the release of vapors and make it difficult for the fuel to come into contact with oxygen. Technical standards from the Fire Departments of Paraná and Minas Gerais explain that the type of foam must be compatible with the product involved, because different solvents may require different agents. Noaa also recommends that large fires involving certain flammable liquids be fought from as far away as possible, with the cooling of containers exposed to the heat. In Brazil, the storage and handling of these materials are regulated by NR-20 and fire safety standards for flammable and combustible liquids. VIDEO: Why is the James Webb a super telescope? Compare photos of the James Webb super telescope with its predecessor