Scientists investigated using inert refrigerant fluids mixed with hydrocarbons and hydrofluorocarbons to reduce fire risk. These mixtures can replace harmful chemicals like hydrochlorofluorocarbons. They found that the ratio of flammable to nonflammable components in these blends is crucial for safety. By testing different blends, they identified a Critical Flammability Ratio that distinguishes safe and risky mixtures. The researchers developed methods to calculate and evaluate these ratios, helping to predict if a blend is fire-prone. The study provides steps to assess the flammability of these mixtures accurately, ensuring safer use of refrigerants in various applications.