ASHRAE Standing Standard Project Committee 55 (SSPC 55)
Thermal Environmental Conditions for Human Occupancy


Welcome to the Homepage of SSPC 55!

This project committee is responsible for maintaining ASHRAE Standard 55,
Thermal Environmental Conditions for Human Occupancy (ANSI Approved)

This standard specifies the combinations of indoor space environment and personal factors that will produce thermal environmental conditions acceptable to 80% or more of the occupants within a space. The environmental factors addressed are temperature, thermal radiation, humidity, and air speed; the personal factors are those of activity and clothing.

ANSI/ASHRAE Standard 55 is under continuous maintenance by SSPC 55 for which the Standards Committee has established a documented program for regular publication of addenda or revisions.

ANSI/ASHRAE Standard 55-2013 is the latest edition of Standard 55. The 2013 edition combines Standard 55-2010 and the eighteen approved and published addenda to the 2010 edition into one easy-to-use, consolidated standard. The standard outlines conditions in which a specified fraction of the occupants will find the environment thermally acceptable. The standard is intended for use in design, commissioning, and testing of buildings and other occupied spaces and their HVAC systems and for the evaluation of thermal environments. Because it is not possible to prescribe the metabolic rate of occupants, and because of variations in occupant clothing levels, operating set points for buildings cannot practically be mandated by this standard.


Standard 55 was first published in 1966 and republished in 1974, 1981, and 1992. Beginning in 2004, it is now updated on a regular basis using ASHRAE’s continuous maintenance procedures. According to these procedures, Standard 55 is continuously revised by addenda that are publicly reviewed, approved by ASHRAE and ANSI, and published and posted for free on the ASHRAE Web site.


  • For more information on submitting a proposed change to this or any other ASHRAE Standard that is under continuous maintenance.  Click Here

  • To download the latest published addenda to ASHRAE Standards  Click Here


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    Revised Date:
    June 20, 2016

  • ANSI/ASHRAE Standard 55-2013              

    Now Available