International Temperature Scale of 1990
A comprehensive resource for temperature metrology
Launched by Isotech in 1999, ITS-90.com published text of the International Temperature Scale of 1990. For 25 years, this site has been a foundational internet resource, providing the global metrology community with early access to the official text and critical information about ITS-90.
Essential Resources
Definitions & Principles
Complete definitions of the International Temperature Scale of 1990, including fundamental principles and mathematical formulations.
Explore Definitions →Fixed Points
Comprehensive reference data for all ITS-90 fixed points, including phase transition temperatures and uncertainties.
View Fixed Points →Realisation Guides
Practical guidance for implementing ITS-90 in laboratory settings, including apparatus requirements and procedures.
Access Guides →Resources & References
Links to official publications, BIPM documents, national laboratory resources, and current research.
Browse Resources →Serving the Global Metrology Community
Today, ITS-90.com continues its legacy by serving as a trusted gateway to the most current and authoritative ITS-90 resources. While we no longer host the official text, our mission is to expertly guide researchers, calibration professionals, and national measurement institutes directly to the definitive publications and essential information from the Bureau International des Poids et Mesures (BIPM) and other leading metrology organizations.
- ✓ Official ITS-90 definitions and equations
- ✓ Complete fixed point reference data
- ✓ Practical realisation guidance
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Whether you're new to temperature metrology or an experienced professional, our comprehensive resources will help you understand and implement ITS-90.
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