Page "Standard conditions for temperature and pressure" Paragraph 0

Standard conditions for temperature and pressure are standard sets of conditions for experimental measurements established to allow comparisons to be made between different sets of data.

The most used standards are those of the International Union of Pure and Applied Chemistry ( IUPAC ) and the National Institute of Standards and Technology ( NIST ), although these are not universally accepted standards.

Other organizations have established a variety of alternative definitions for their standard reference conditions.