Which refrigerants can be vented

• A. It can be vented for all refrigerants
• B. It can be vented for R717 ammonia, R744 carbon dioxide, and R28 nitrogen
• C. It cannot be vented for any refrigerants
• D. It can be vented only during system charging

Answer: (B)

When it comes to venting refrigerants, rules distinguish between those that are halogenated (which require recovery) and certain exempt refrigerants. Ammonia (R-717), carbon dioxide (R-744), and nitrogen (R-28) are not halogenated refrigerants, so they’re exempt from the general venting prohibition. That means, under the applicable regulations, releasing these specific substances to the atmosphere is allowed in certain circumstances (such as decommissioning or system shutdowns), whereas most other refrigerants must be recovered rather than vented. This is why these three can be vented, while the vast majority of other refrigerants cannot. Always follow safety practices, since ammonia is toxic and proper venting procedures and protections are essential.