For many years, educators taught about the Fire Triangle, showing that for something to burn, it needed fuel, heat, and oxygen. Now the Fire Triangle has been replaced. What replaced it?

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The Fire Triangle has been replaced by the Fire Diamond, also called the Fire Tetrahedron. The fourth requirement for combustion is chemical reactions. This was added because by using flame retardant chemicals, it is possible to have plenty of fuel, plenty of heat, and plenty of oxygen, and still not have combustion. Flame retardants interfere with chemical reactions to stop the fire.

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