What is the recommended maximum fill percentage for a cylinder when transferring refrigerant?

The recommended maximum fill percentage for a cylinder when transferring refrigerant is 80%. This guideline is established to ensure safety during the storage and handling of refrigerants. Maintaining this fill percentage provides adequate space for vapor expansion within the cylinder, which is crucial, especially given that refrigerants can change phases between liquid and gas. This space helps to prevent over-pressurization of the cylinder due to temperature changes, which can occur during handling or transportation. When the cylinder is filled to 80%, it is less likely to encounter dangerous conditions that could lead to leaks or ruptures. This practice is a standard safety precaution in the HVAC industry to protect both the equipment and the individuals handling refrigerants.