Shipments of refrigerating machines transported by air or ocean transport in some cases may be exempt from requirements under IATA DGR and IMDG code.
According to IATA dangerous goods regulations 59th edition there is a listed special provision that allows for some refrigerating machines to be shipped without the issuance of a dangerous goods declaration. This exemption also negates the need to mark and label as would a fully regulated shipment would be required.
Section 4.4 Special Provisions
A26 (119) Refrigerating machines include air conditioning units and machines or other appliances which have been designed for the specific purpose of keeping food or other items at low temperature in an internal compartment. Refrigerating machines and refrigerating machine components are considered not subject to these Regulations if containing less than 12 kg of a gas in Division 2.2 or if containing less than 12 L ammonia solution (UN 2672).
For IMDG code there is a similar exemption that can be applied
Chapter 3.3 Special Provisions
119 Refrigerating machines and refrigerating-machinery components including machines or other appliances which have been designed for the specific purpose of keeping food or other items at a low temperature in an internal compartment, and air-conditioning units. Refrigerating machines and refrigerating machine components are not subject to the provisions of this Code if they contain less than 12 kg of gas in class 2.2 or less than 12 L of ammonia solution (UN 2672).