20 Degrees as Reference Temperature

Since all matter changes size with temperature, in order to define the size of something we must also say at what temperature it is the stated size. The international standard temperature for dimensional measurements is standardized in ISO 1 as 20 degrees Celsius (°C). The statement above is from the US tolerancing standard, and shows that all drawings that have dimension marked on them, by default, refer the to dimensions at 20 °C.

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Date Created: Monday, October 15, 2001
Last Updated: Tuesday, November 09, 2004