ASHRAE is working to create a standard that would help prevent the growth of the Legionella bacteria responsible for infecting an estimated 10,000 to 18,000 people in the U.S. each year. According to, Legionnaires’ disease is a severe, often lethal, form of pneumonia caused by the bacterium Legionella pneumophila and is found in both potable and nonpotable water systems. The most popular theory for contacting the disease is that the organism is aerosolized in water and people inhale the droplets containing Legionella.

Proposed by ASHRAE, Standard 188P will be the first set of standardized requirements specific to the building industry for management of the risks associated with the amplified growth of and exposure to Legionella. In a May 2014 press release posted on the ASHRAE website, 188P Standard Committee Chair, Tom Watson, commented that the standard, Legionellosis: Risk Management for Building Water Systems, will identify risk factors for growth and exposure of the Legionella bacteria along with measures to mitigate that risk. “The standard will help facility managers/owners understand how to evaluate the design and operation of their building water systems to reduce the risk of Legionellosis.”

The standard was submitted for a fourth public review in October. After the close of that public review period in November, ASHRAE made changes to the proposed standard and will once again present a revised version to the 188P Standard Committee this month. Watson is optimistic the standard will be approved and made available during the summer.

If the committee accepts the most recent round of revisions, ASHRAE will submit the proposed standard for another round of public comments. Before the standard becomes an official ASHRAE/ANSI standard, the public will have the opportunity to submit appeal letters, according to Stephanie Reiniche, Senior Manager of Standards for ASHRAE. The standard also will be a continuous maintenance standard so addendums can be published as needed and will be published with a timeline for compliance.

Watson cautioned, “As the committee moves forward the provisions in the current draft are subject to change and use of the technical details of the proposed standard could lead to actions and expenditures that may not fall under the final requirements of the published standard.”

Currently, because the standard is under development, it is not available for use by anyone and proposed language is made available during public review for the purpose of commenting only. To learn more about the proposed standard and stay current on developments, subscribe to the Standards 188P list serve. Membership in ASHRAE is not required for joining the list serve or making public comment.