This paper describes the process used to revise the design weather data tables in the 1997 ASHRAE Handbook- Fundamentals. Design conditions were determined for 509 U.S., 134 Canadian, 339 European, 293 Asian, and 169 other worldwide locations. Thirty-three years of hourly weather data were used for approximately half of the U.S. and all of the Canadian locations. Twelve years of data were used for the other locations. The data went through quality checking and short-term linear interpolation filling processes. Months that had sufficient data were then used in the analysis. The data were analyzed to produce annual frequency-of-occurrence design dry-bulb (DB), wet-bulb (WB), and dew-point (DP) temperatures with mean coincident values at the design conditions. A comparison with the previous design values indicated that the new dry-bulb and wet-bulb design conditions are slightly less extreme than the values previously published. However, the new design dew-point values indicate the potential for significantly more extreme dehumidification design conditions than would be found by using the old extreme dry-bulb temperature with mean coincident wet-bulb temperature. Software was also developed so users could extract the design values, cumulative frequencies, and DB/DP, DB/WB, DB/H, and DB/WS coincident matrices for 1444 locations from a CD-ROM.

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