ASHRAE-Standard-55 - Page 027

Extracted Content

(This is a normative appendix and is part of this standard.)

NORMATIVE APPENDIX A OPERATIVE TEMPERATURE AND PROCEDURE FOR SECTION 5.3

A1. METHODS FOR DETERMINING OPERATIVE TEMPERATURE

Determine operative temperature to using the following method or ASHRAE Handbook—Fundamentals [ 1], Chapter 9. Informative Note: Average air speed and average air temperature have precise definitions in this standard.

See Section 3 for all defined terms. Operative temperature to is permitted to be calculated per the following formula:

to = Ata +  1 - A  tr

where to = operative temperature ta = average air temperature

tr = mean radiant temperature ( Informative Note: For detailed calculation procedures, see the “Thermal

Comfort” chapter of the most current edition of ASHRAE Handbook—Fundamentals .)

A can be selected from the following values as a function of the average air speed Va .

A2. PROCEDURE FOR DETERMINING SATISFACTORY THERMAL ENVIRONMENT IN  OCCUPIED SPACES PER SECTION 5.3

The predicted mean vote model with adjustments for solar radiation and elevated air speed is used to determine the boundaries of the comfort zone per the calculation methods described in Normative Appendix B through Normative Appendix D. These calculation methods are incorporated in the Thermal Comfort Tool [3] . The flowchart in Figure A-1 provides the procedure for how these calculation methods should be applied.

Figure A-1 Flowchart describing process of calculation methods used in Section 5.3.

ANSI/ASHRAE Standard 55-2023 25