ANSI/ASHRAE Standard 55 (Thermal Environmental Conditions for Human Occupancy) is a standard that provides minimum requirements for acceptable thermal indoor environments. It establishes the ranges of indoor environmental conditions that are acceptable to achieve thermal comfort for occupants. It was first published in 1966, and since 2004 has been updated periodically by an ASHRAE technical committee composed of industry experts. The most recent version of the standard was published in 2013.