What is a defining requirement for a refrigerant to be classified as Class 1?

What is a defining requirement for a refrigerant to be classified as Class 1?

• A. flames propagate readily in air
• B. low flammability by definition
• C. no flame propagation in air at 140 °F and 14.7 psia
• D. must be non-toxic

Answer: (B)

Nonflammability is the defining trait of Class 1 refrigerants. They are categorized this way because they have low flammability by definition, meaning they do not support flame propagation in air under typical conditions. This safety criterion helps separate them from refrigerants that can ignite and burn. Some standards use a specific test condition to verify nonflammability (such as no flame propagation in air at a certain temperature and pressure), but the essential idea is that the refrigerant’s flammability is effectively negligible.

Nonflammability is the defining trait of Class 1 refrigerants. They are categorized this way because they have low flammability by definition, meaning they do not support flame propagation in air under typical conditions. This safety criterion helps separate them from refrigerants that can ignite and burn. Some standards use a specific test condition to verify nonflammability (such as no flame propagation in air at a certain temperature and pressure), but the essential idea is that the refrigerant’s flammability is effectively negligible.