First published in 2003, Standard 41.10 is designed to help users select a suitable flowmeter for measuring volatile refrigerant mass flow rates and perform the test measurement.

Selecting an appropriate refrigerant mass flowmeter can be a daunting task given the wide variety of operating principles, measurement precision, and costs of commercial products. Some meters can be used for either liquids or gases, while others can be used only for liquids or only for gases. Considerable pressure losses are inherent in some approaches, but the pressure losses in some other types of meters are very small and often negligible. Useful basic information can be found in the 2005 ASHRAE Handbook—Fundamentals, Chapter 14, "Measurements and Instruments," and in various textbooks that focus on measurement technology. Once a meter has been selected, the user may need to consult with the meter manufacturer regarding installation specifics, operations, range limits, calibration limits, and other similar performance specifics in order to obtain the expected measurement accuracy.

Changes to the 2013 edition include the following:

• Changes to Section 3, "Definitions"
• Equations 7-1, 7-2, and 7-12 were separated into distinct I-P and SI versions. Equations were renumbered and text was modified to reflect the change.
• Section 11, "References" was revised.
• Informative Annex A, "Bibliography" was added, and other annexes were renumbered.
• Substantive modifications to the text to provide additional clarity or instruction
• Minor editorial changes