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  • Josh Shkrab

New Standards To Be Issued For Prevention Of Legionella

Updated: Aug 30, 2023

The American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., (ASHRAE) published the first draft document entitled, “: Prevention of Legionellosis Associated with Building Water Systems”, on October 1, 2010. The new standard 188P differs from the “Guideline 12, Minimizing the Risk of Legionellosis Associated with Building Water Systems”. Standard 188P was written by some of the leading experts in the microbiology, engineering, and epidemiological fields.

Legionellosis or Legionnaires’ disease is the severe form of the disease that can potentially result in death. A significant percentage of cases are attributed to Legionella pneumophila, which is an aquatic organism that survives in water temperatures ranging between 77˚ and 113˚ F. The most common sources of contamination include water cooling towers, large central air-conditioning units, evaporative coolers, spas, misters, and even architectural fountains.

As a result of the multitude of sources that Legionella can be found in, ASHRAE determined that it was necessary to address the situation with a set of standardized practices for preventing the spread of this potentially pernicious disease. The new standards will mandate that all “human occupied dwellings” must be surveyed on an annual basis to determine if it meets a set of criteria designating it a risk factor. The criteria includes multiple housing units with several central water heaters (i.e. apartment complex), buildings that are greater than 10 stories in height, the presence of a cooling tower, multiple spas or whirlpool, and in-patient healthcare facilities.

The standard requires that a written Hazard Analysis and Critical Control Point (HACCP) risk management plan be created to address the issues that involve the installation of new cooling towers or evaporation systems and maintenance procedures for every potable water device in the facility. Standard 188P provides the facility manager or owner with the appropriate tools to effectively prevent the outbreak of Legionella.

The Standard 188P has undergone a second review for public comments, which closed on July 25 of this year. After the comment period was closed, a few sections of the standard were rewritten to provide clarity, such as section 8, which deals with potable water systems. The ASHRAE has created a Standard 188P committee that has been working diligently on revisions and updates based on comments submitted from the public during the review period. Additionally, a preparedness course offered by a Legionella consulting firm in San Diego educated engineers, water treatment specialists, industrial hygienists, and other professionals on how to perform assessments based on requirements outlined in the standard. There is currently no definitive date set on when the standard will be issued, or if and when individual states will codify it through state legislation. Interested parties will have to monitor the release of the document by checking the website for ASHRAE and here.

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