Which of the following additions of refrigerant triggers the requirement to calculate a leak rate when added to an appliance that contains 50 or more pounds of an ozone depleting refrigerant?
1) Any addition of refrigerant
2) An addition of 10 or more pounds of refrigerant
3) An addition of 20 or more pounds of refrigerant
4) An addition of 30 or more pounds of refrigerant
