Major revisions for the design and measurement of comfortable spaces are included in a newly published 2013 standard from ASHRAE.
ANSI/ASHRAE Standard 55-2013, Thermal Environmental Conditions for Human Occupancy, combines the 2010 standard and 18 published addenda into a consolidated standard.
Major changes include:
- Requirements are more clearly stated.
- The cooling effect of air movement now applies to naturally conditioned spaces as well as mechanically conditioned spaces, and in each case correction factors are given that adjust the comfort boundaries when air movement is present.
- A new alternate procedure for estimating occupant clothing insulation based on outdoor weather was added. This procedure is based on extensive field research and can be used for design calculations, annual simulations, and control of occupied spaces.
- Major revisions to Section 7 procedures for measuring comfort in existing spaces including survey and physical measurement methods and a new section on evaluating and reporting results.
- The standard now requires that two of the key comfort parameters, air speed, and air temperature, must be calculated as an average that the occupant experiences at three heights across the body and over a period of time.
The full standard is available for purchase at the ASHRAE Bookstore.