What is the maximum water concentration allowed in Ammonia for it to be classified as anhydrous or refrigeration grade?

The classification of ammonia as anhydrous or refrigeration grade is contingent upon its water concentration. For ammonia to meet the criteria of being anhydrous or refrigeration grade, the maximum allowable concentration of water is 500 parts per million (PPM). At this concentration, ammonia can function effectively in refrigeration systems without the detrimental effects that higher water levels would introduce, such as increased corrosion or reduced efficiency. The specification for 500 PPM is a standard that ensures the chemical properties necessary for refrigeration applications are maintained, safeguarding both the performance of the system and the longevity of the equipment utilized.