The 2017 edition of ASHRAE’s thermal comfort standard has been published to incorporate seven published addenda to the 2013 edition. ANSI/ASHRAE Standard 55-2017, Thermal Environmental Conditions for Human Occupancy, simplifies the language of the 2013 standard and clarifies the three comfort calculation approaches in Section 5.3.3. The 2017 edition includes a new requirement to calculate the change in occupants’ thermal comfort from direct solar radiation. The three comfort calculations methods provided in the 2017 edition are:
• a graphic method for simple situations,
• an analytical method for more general cases, and
• a method that uses elevated air speed to provide comfort.
Other additions include simplification of Appendix A to a single procedure for calculating operative temperature; clearly stated requirements and calculation procedures appearing sequentially; an update to the scope to ensure the standard is not used to override health, safety, critical process requirements, and removal of permissive language.

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