Why are safety glasses required when handling R12 refrigerant?

When handling R12 refrigerant, safety glasses are required primarily to prevent eye tissue damage from freezing. Refrigerants like R12 can exist in extremely low-temperature states and can cause severe frostbite if they come into contact with skin or eyes. The propellant is stored under pressure, and if released, it can rapidly convert to gas, resulting in temperatures that can damage sensitive eye tissues. Wearing safety glasses acts as a protective barrier, reducing the risk of such injuries from unexpected exposure to the refrigerant.

While enhancing visibility, blocking UV rays, or improving thermal insulation might be relevant in other contexts, the critical concern with refrigerants is their potential to inflict physical harm due to their extreme cold properties, making eye protection essential.