New ASHRAE Standard 188-2021 update and upward trending Legionnaires’ disease cases

By Hilary Nardone, Environmental Group Training Manager
Certified ASSE 12080 Legionella Water Safety and Management Specialist

In August 2021, ASHRAE released an updated version of Standard 188: Legionellosis Risk Management for Building Water Systems.  While a majority of the content remains the same, ASHRAE Standard 188-2021 now includes appendices that were released since its last update in 2018.

One critical addition to the building water systems commissioning section of ASHRAE Standard 188 is that disinfection and flushing of potable water systems shall be completed no more than three weeks before whole or partial beneficial occupancy.

As mentioned in a previous blog post, flushing and disinfecting building water systems to minimize the risk of Legionella bacteria amplification is vital as buildings re-open after reduced occupancy.  The release of the updated version of Standard 188 this summer serves as a timely reminder of the importance of Water Management Programs (WMPs) for domestic and cooling tower systems.  The CDC has long stated that cases of Legionnaires’ disease are more prevalent in the summer. This summer is no exception. In fact, the United States and Canada are currently experiencing several Legionnaires’ disease outbreaks.[1] Montreal, Quebec has seen ten cases of Legionnaires’ disease since mid-June, including two people over the age of 65 who have died from the disease.[2] The Michigan Department of Health and Human Services reported 107 cases between July 1 and July 14, 2021, which was a 569% increase in cases from the same time period in 2020.[3] Rhode Island has seen a similar increase in Legionnaires’ disease cases this year – up 300% – compared to last year (the state saw an average of 10 cases per year from 2014 – 2020).  Twenty-eight of the 30 cases the state has seen so far this year have resulted in hospitalization.[4],[5]  The New Jersey Department of Health is investigating a possible outbreak in Essex County, New Jersey, where there are currently eight suspected cases.[6] In the first three weeks of July, Chicago reported 49 cases of Legionnaires’ disease – three times more than the same period in 2020 and 2019.  Of the 49 cases, 15 were admitted to intensive care units and two died.[7]

While the exact cause of each of these outbreaks is currently unknown, they all emphasize the need for Water Management Programs for domestic and cooling tower systems.  Findings from a review of CDC-led Legionnaires’ disease outbreak investigations from 2015 to 2019 found that all deficiencies associated with outbreaks could have been prevented through the effective use of WMPs.  The review also found that most WMP deficiencies associated with outbreaks were due to a missing or improperly implemented WMP.[8],[9]

Developing a comprehensive and site-specific WMP that complies with ASHRAE Standard 188-2021 will help to control Legionella bacteria growth and spread in building and cooling tower water systems, which will minimize the risk of cases and outbreaks.

Barclay Water Management, Inc. is an industry leader in Legionella bacteria risk minimization and has created, implemented, and validated hundreds of WMPs in partnership with our customers. Barclay continually utilizes best practice recommendations from organizations included but not limited to ASHRAE, CIBSE, and the CDC to minimize waterborne pathogens in building water systems and is dedicated to ensuring its WMPs comply with national and local standards and guidelines including ASHRAE Standard 188-2021, The Joint Commission’s Water Management Program Standard EC.02.05.02, CMS, and local health departments.

Don’t miss this previous blog post which explains why Legionnaires’ disease cases are more common in the summer months.

[1] CDC.  Legionella (Legionnaires’ Disease and Pontiac Fever): History, Burden, and Trends.  CDC.  Updated March 25, 2021.  Accessed August 6, 2021.

[2] CBC.  Outbreak of Legionnaires’ disease in east-end Montreal responsible for 2 deaths.  CBC. August 4, 2021.  Accessed August 6, 2021.

[3] LeBlanc B.  Michigan reports big increase in Legionnaires’ disease across 25 counties.  The Detroit News.  Published July 19, 2021.  Accessed August 6, 2021.

[4] Schuler R.  Rising number of Rhode Island residents diagnosed with Legionnaires’ Disease.  Johnston Sunrise.,164060.  Published July 30, 2021.  Accessed August 6, 2021.

[5] AP.  Rhode Island sees rise in Legionnaires’ disease cases.  AP.  Published July 26, 2021.  Accessed August 6, 2021.

[6] Persichilli JM.  New Jersey Department of Health Investigating Possible Cluster of Legionnaires’ Disease Cases in Essex County.  State of New Jersey Department of Health.  Published July 30, 2021.  Accessed August 6, 2021.

[7] AP.  Chicago tracking July increase in Legionnaires’ disease.  AP.  Published July 25, 2021.  Accessed August 6, 2021.

[8] Environmental Health Services (EHS).  Water management gaps and Legionnaires’ disease outbreaks.  CDC.  Updated March 24, 2021.  Accessed August 6, 2021.

[9] Clopper BR, Kunz JM, Salandy SW, Smith JC, Hubbard BC, Sarisky JP.  A methodology for classifying root causes of outbreaks of Legionnaires’ disease: deficiencies in environmental control and water management.  Microorganisms,  2021.  9(1);89.  Doi: 10.3390/microorganisms9010089.

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