American National Standards Institute

The American National Standards Institute, or ANSI, is a private nonprofit organization, founded in 1918, that oversees the development of voluntary standards in the United States. It does not write most standards itself. It accredits the groups that do and approves their work as American National Standards.

The square footage standard for houses carries its name: ANSI Z765. Home Innovation Research Labs is the secretariat that develops and sells it, and editions have come out in 1996, 2003, 2013, and 2021.

ANSI also approves measuring standards for other kinds of buildings, including the office standard developed with BOMA. The ANSI name on a standard means it went through that consensus process, not that the institute wrote the rules.

Further reading: American National Standards Institute on Wikipedia.