Which toxicity classification applies to refrigerants with an occupational exposure limit of 400 ppm or greater?

The classification that applies to refrigerants with an occupational exposure limit of 400 ppm or greater is Class A. This classification indicates that the refrigerant has a low toxicity level, meaning that it is generally safe for workers when exposure is within the set limits. Specifically, refrigerants in Class A are not expected to pose a significant health risk at the specified exposure levels.

This standard helps ensure that materials used in mechanical systems align with safety protocols and guidelines, particularly concerning worker safety. It's essential for professionals in the field to understand these classifications for proper handling, usage, and compliance with safety regulations. Recognizing that refrigerants in Class A can be handled safely under controlled exposure limitations allows technicians to perform their work without undue risk to health.