The ASHRAE 188 Standard – Key Information for Facility & Property Managers


Facilities Net has provided and excellent four part series on the New ASHARE standard 188 to help prevent Legionnaires Disease. It is expected that this new standard will become a mandatory compliance issue in the near future. Apart from the health benefits of adopting this standard it is a given that once it becomes a compliance regulation it will have to be factored into every public buildings annual budget.

ASHRAE 188, written by engineering, microbiology, disease prevention and water treatment experts, provides a comprehensive set of practices that facility & property managers can follow to help prevent Legionellosis.

We would like to thank the contributing authors, Janet E. Stout and Garry R. Boehlert, for providing this valuable information in such an effect and concise manner.

The first post, “New ASHRAE Standard 188 To Prevent Legionnaires’ Disease” begins with:

“Two dreaded words no facility manager wants to hear: Legionnaires’ disease. The mere mention evokes haunting images of the 1976 American Legion Convention in Philadelphia at which 220 became ill and 30 died.” This certainly draws one into the post which provides a clear background on the history and prevention of Legionella.

The complete post is available at: ASHRAE 188 – PART 1

The second post, “Facility Managers’ Responsibilities For Legionella Prevention Under ASHRAE 188”, provides information on how to conduct an annual survey to determine risk characteristics. Under the new standard, facility managers are charged with conducting an annual survey to determine what risk is present in their buildings. Specific risk factors called out in the standard are:

  • multiple housing units with one or more centralized water heaters
  • more than 10 stories (including levels below grade)
  • cooling tower or evaporative condenser
  • one or more whirlpools or spas within or adjacent to building
  • devices that release aerosols (e.g., ornamental fountains, misters, air washers or humidifiers)
  • incoming potable water containing less than 0.5 ppm residual halogen such as chlorine
  • inpatient health care facility
  • occupants primarily older than age 65

The complete post is available at: ASHRAE 188 – PART 2

The third post: “What Facility Managers Should Know About HACCP Plans And ASHRAE 188”, clearly explains how the ASHRAE 188 standard is modeled after HACCP, a widely used method to prevent disease from infectious organisms transmitted from food and water.

ASHRAE specifically requires that for every critical control point (i.e., where the presence of Legionella bacteria is of most concern), the team must address four issues about the hazard control method being applied:

(1)  critical control limit of Legionella bacteria,

(2)  hazard control monitoring method,

(3)  frequency of monitoring hazard control, and

(4)  corrective actions to be taken if the critical control limit is exceeded.

The complete post is available at: ASHRAE 188 – PART 3

The fourth post: “ASHRAE Legionella Standard: Monitoring, Disinfection, Legal Considerations”, provides valuable information how monitoring for Legionella is the key to prevention. However, we think that the most important component to consider in this post is the summary on the Impact of Standard 188 on Legal Liability. Simply put, where it is adopted within building codes, it will have the force of law and be a very real compliance issue that can’t be ignored.

The complete post is available at: ASHRAE 188 – PART 4

Paragon Engineering Services would be happy to provide more information on how to effectively manage the new compliance regulations required by ASHRAE 188. If we can be of assistance please contact

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