National Physical Laboratory

What is the reference temperature for dimensional metrology? (FAQ - Length)

The internationally agreed temperature is 20°C. It is defined in ISO 1:2002 Geometrical Product Specifications (GPS) -- Standard reference temperature for geometrical product specification and verification. This standard can be obtained from the ISO web site at Follow the catalogue link. Search for ISO 1 and then click on the hyperlink.
Last Updated: 25 Mar 2010
Created: 18 Jul 2007


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