A Sunday forum at the ASHRAE Winter Meeting here examined the topic, along with the use of Guideline 12-2000: Minimizing the Risk of Legionellosis Associated with Building Water Systems. The Technical Committee for Water Treatment wanted to know how people were using the guideline — or whether they are using it at all.

The guideline (an easily digestible 12 pages) contains information on drinking fountains and spas, as well as optimum temperatures with which water can kill the bacteria (usually 140 degrees F and up). Most spas and other building water systems keep water at a temperature that is ideal for legionella — 77 to 108 degrees.