Incêndios de Classe K / Classe F: Mídias de Cozinha
Essa classe de incêndio, conhecida como Classe K nos EUA e Classe F na Europa e Austrália, envolve meios combustíveis de cozinha, como óleos vegetais, gorduras animais e graxa. Esses incêndios queimam a temperaturas muito altas, e a aplicação de água é extremamente perigosa, pois pode causar uma explosão de vapor (transbordamento) que espalha a gordura em chamas. Extintores químicos úmidos especializados são o principal método de extinção.
The creation of a separate class for cooking media fires was driven by changes in the food service industry. Modern, highly efficient deep-fat fryers heat cooking oils to sustained temperatures at or above their autoignition point. It was discovered that traditional dry chemical (Class B) extinguishers could extinguish the flame, but the oil would often re-ignite because it remained above its autoignition temperature. A new approach was needed.
The solution was the wet chemical agent, typically an aqueous solution of potassium acetate, potassium carbonate, or potassium citrate. When applied to burning cooking oil, this agent performs two functions. First, the water content has a cooling effect, lowering the temperature of the oil below its autoignition point. Second, the potassium salts react with the hot grease in a process called saponification. This chemical reaction creates a thick, soapy foam layer on the surface of the oil. This foam blanket effectively smothers the fire by cutting off the oxygen supply and prevents flammable vapors from escaping, thus preventing re-ignition.
The danger of using water on a grease fire is a key aspect of this class. Because oil is hotter than water’s boiling point, any water introduced instantly flashes to steam, expanding in volume by a factor of about 1,700. This rapid expansion ejects the burning oil from the pan, creating a large fireball and spreading the fire dramatically.
UNESCO Nomenclature: 3305
Engenharia química
Precursores
- the proliferation of high-efficiency deep-fat fryers in commercial kitchens
- an observed high rate of re-ignition in cooking fires when using traditional class b extinguishers
- a scientific understanding of the saponification chemical reaction
- high incidence of severe fires and injuries in the restaurant industry
Aplicações
- automatic fire suppression systems installed in commercial kitchen ventilation hoods
- design of wet chemical portable fire extinguishers for restaurants and food processing plants
- fire safety education for culinary students and home cooks
- building code requirements for commercial cooking operations
- development of cooking oils with higher smoke points and reduced flammability
Ideias de Inovação Potencial
Devido ao tráfego de bots de coleta de dados, atualmente superior a 40 mil por dia, este conteúdo é reservado aos membros da comunidade.
> Login < ou > Registrar < (100% gratuito) para acessar isso, assim como todo o restante do conteúdo e das ferramentas restritas.
Related to: class K fire, class F fire, grease fire, cooking oil, wet chemical extinguisher, saponification, kitchen safety, boilover, deep fryer, NFPA.