The objectives were to provide a forum in which information and data could be exchanged, and the representation of refrigerant fluids could be standardized through the publication of comprehensive, internationally accepted property formulations. NIST, representing the United States, acted as the coordinator for the eight countries that participated in the activities of Annex 18 while Japan assisted in coordinating two phases of the work. Annex 18 has completed its work, which resulted in the adoption of international standards for the thermodynamic properties for the refrigerants R134a, R123, R32, R125, and R143a. Evaluations of property models for mixtures of these fluids facilitated the adoption of a new approach for computing the thermodynamic properties of mixtures. The evaluations, and the underlying data surveys and compilations, have contributed to many national and international property compilations.
Further work remains because new fluids and mixtures are being proposed continually.
Refrigerant mixtures, especially, present needs for additional data and comprehensive models. Ask for paper no. On assignment from her position as senior policy advisor in the Commerce Department's National Telecommunications and Information Administration , Sene monitors standards-related activities in the European Union, this nation's largest trading partner. She also helps U.S. exporters resolve questions and issues as they work to demonstrate compliance with EU regulations and standards. Posted at U.S. embassies or co-located with national standards bodies in host countries, NIST's five standards attach s have been credited with helping U.S. companies and government officials to reduce regulatory and other technical obstacles to the sale of U.S. goods and services in foreign markets.