As your building reopens, check out ASHRAE’s water system guidelines to help prevent legionellosis

by Brianna Crandall — July 22, 2020 — Global building technology society ASHRAE has published an updated guideline that gives specific directions on how to prevent the growth and spread of Legionella bacteria in building water systems, which can cause a respiratory disease known as legionellosis, either in the form of Pontiac fever or the more serious Legionnaires’ disease.

The guidance is particularly relevant as facilities reopen after pandemic shutdowns, especially in cases where buildings were unoccupied for long periods of time.

ASHRAE Guideline 12-2020, Managing the Risk of Legionellosis Associated with Building Water Systems, provides guidance useful in the implementation of ANSI/ASHRAE Standard 188, Legionellosis: Risk Management for Building Water Systems.

The guideline is intended for use by owners of human-occupied buildings and those involved in the design, construction, installation, commissioning, management, operation, maintenance and service of centralized building water systems and components.

Paul Lindahl, committee chair for ASHRAE Standing Standard Project Committee (SSPC) 188, the committee responsible for writing Guideline 12-2020, explained:

ASHRAE Standard 188 gives direction regarding what to do to control the spread of legionellosis, such as to follow a risk management process, but does not necessarily explain how to do it in a prescriptive way. Guideline 12 complements Standard 188 by providing detailed guidance for water management program teams to develop the necessary elements of an effective water management plan. This can be a particularly important aspect of plans to reopen buildings following the COVID-19 pandemic.

Guideline 12 applies to spaces such as hotels, office buildings, hospitals and other healthcare facilities, assisted living facilities, schools, universities, commercial buildings, industrial buildings and centralized systems in multifamily residential buildings. Buildings with noncentralized water systems, and single-family residential buildings, though not included, may also benefit.

Three presentations on Guideline 12-2020 took place during the 2020 ASHRAE Virtual Conference in June:

  • History of Standard 188, Guideline 12 and Other Guidelines
  • ASHRAE Guideline 12 and the Facts about Legionella Growth in Building Water Systems
  • Guideline 12 Is a Tool Designed to Support the Preparation of a Water Management Plan Using ANSI/ASHRAE Standard 188

The presentations are available along with all 96 technical sessions and PDHs and more by registering for the ASHRAE 2020 Virtual Conference, and are accessible until December 2021.

While Legionnaire’s Disease has been known for many years, recent outbreaks have increased awareness of the disease, its causes, and prevention strategies, points out ASHRAE. According to the World Health Organization (WHO), because many countries lack appropriate methods of diagnosing the infection or sufficient surveillance systems, the rate of occurrence is unknown.

ASHRAE Guideline 12-2020, Managing the Risk of Legionellosis Associated with Building Water Systems, is available to purchase from the ASHRAE Bookstore.