What does "Produced by Air Liquefaction" indicate?

The phrase "Produced by Air Liquefaction" specifically refers to the process of separating gases found in the atmosphere, primarily oxygen and nitrogen, by cooling air until it becomes liquid and then distilling the resulting liquid air to isolate the different gases. This process does not exempt certain analyses; rather, it indicates the method of production for these gases. In contexts like medical gases, understanding how a gas is produced is essential for ensuring proper handling, storage, and safety standards are met.

The correct interpretation of the phrase is that it relates to the type of gas produced from the air, with emphasis on the production method rather than regulatory or safety aspects. This indicates a connection to the identity of the gas—specifically, gases such as oxygen and nitrogen that can be separated and liquefied in this manner. Thus, recognizing that this method is not about exemption from analysis, but the specific source and production method of medicinal gases, clarifies why this understanding is essential in medical and safety practices.