The National Institute of Standards and Technology (NIST, released an expanded and upgraded version of its “Reference Fluid Thermodynamic and Transport Properties Database,” a computer package for calculating the properties and modeling the behavior of fluids, which is now available in Version 8.0. Data on key components of alternative fuels, such as ethanol and hydrogen, are among the new additions to the latest version. The database provides critically evaluated property values needed to evaluate fluids and optimize related equipment and processes.

Widely used by industrial, academic, and government scientists, the database originally was called Refrigerant Properties and was limited to thermophysical properties of alternative refrigerants. When the previous version was issued in 2002, the name was changed to Reference Properties, denoting a broader range of fluids, including some natural gas components. The latest version has been expanded further in response to user requests and NIST efforts to include more of the most widely used fluids.

Among its new features, Version 8.0 provides properties of ethanol, cryogenic fluids, and additional natural gas components. It also includes many new equations, which enable users to plug in variables such as temperature and pressure and find out how a fluid’s other properties, such as density and viscosity, stack up. In addition, many other aspects of the program have been enhanced, including the graphical interface.

NIST has distributed more than 4,000 copies of REFPROP since 1990. Thousands of additional copies are made available every year through commercial packages produced by companies that have distribution agreements with NIST. REFPROP has been the de facto standard in the refrigeration industry for years and is credited with helping industry find replacements for ozone-depleting chlorofluorocarbons (CFCs). Timely delivery of reliable data on the properties of alternative refrigerants made the search for CFC replacements more efficient, according to an economic impact study commissioned by NIST in the late 1990s.

More information about REFPROP, the NIST Reference Fluid Thermodynamic and Transport Properties Database (SRD 23), is available at