ASHRAE Standard 188 - 2018

Since 2018, ASHRAE (the American Society of Heating, Refrigerating, and Air Conditioning Engineers) has updated the Standard to prevent the growth and spread of legionella.  With this Standard, new and existing buildings will be able to apply a number of practices for analyzing, monitoring and minimizing the risk of legionella in their water systems. 

Hereafter you can find a summary of what is required to comply with the new ASHRAE 188 Standard:

1. Program Team

Identify persons responsible for Program development and implementation.


2. Describe Water Systems/Flow Diagrams

Describe the potable and non-potable water systems, within the building and on the building site, and develop water-system schematics.


3. Analysis of Building Water Systems

Evaluate where hazardous conditions may occur in the water systems and determine where control measures can be applied.


4. Control Measures

Determine locations where control measures must be applied and maintained in order to stay within established control limits.


5. Monitoring/Corrective Actions

Establish procedures for monitoring whether control measures are operating within established limits, and, if not, take corrective actions.


6. Confirmation

Establish procedures to confirm that the Program is being implemented as designed and the Program effectively controls the hazardous conditions throughout the building's water systems.


7. Documentation

Establish documentation and communication procedures for all activities of the Program.


If you want to know more about how Magnus can help you comply with the new Ashrae 188-2018 Standard, call or email us now!


Questions and Answers

What is the new ANSI / ASHRAE 188 standard?

This standard is a directive that establishes legionella risk management requirements for building water systems.

Why a new standard even though an ASHRAE guideline was already published?

This standard answers the need for specific requirements in order to reduce the risks of legionella infection whose incidence continues to increase.

Which systems are covered by the 188 standard?

All water systems, including drinking and sanitary water, HVAC systems, decorative fountains, spas, etc. within commercial, institutional and industrial buildings.

  • Cooling towers
  • Closed loop systems
  • Evaporative condensers
  • Jacuzzis
  • Decorative fountains
  • Spas
  • Atomizers
  • Misters
  • Air washers
  • Humidifiers
  • Ice machines
  • Other earosol dispensers

What is the responsibility of the designer / installer?

During all phases of design, installation and commissioning of a new installation, a renovation or a replacement, water systems' information must be documented according to the standard.

What is the responsibility of the owner / manager ?

The building owner must monitor water systems in order to identify and analyze hazardous conditions, identify preventive and corrective measures as well as to ensure efficient implementation.

What is the legal impact of this directive?

The Standard 188 becomes the reference for best practices in legionella prevention and force of law where the standard is adopted in the building code.

What is not covered by Ashrae 188 ?

ASHRAE 188 does not provide guidance on target water parameters, such as temperature and disinfectant levels. It also does not describe how to perform emergency remediation or give guidance about what to do if cases of disease are associated with the facility.

Is your establishment one of the following ?

  • Residence with centralized hot water system.

  • More than 10 floors (including the basement).

  • A health care center with more than 24hrs residence time for patients.

  • Building with an area dedicated to hosting and/or treating patients with burns, chemotherapy, organ transplant(s), bone marrow transplant.

  • Building with an area dedicated to hosting and or treating immuno-compromized patients, those at risk, those taking medication which weaken the immune system, those suffering from kidney disease, diabetes or lung disease.

  • Building dedicated to the accommodation of persons over 65 years.

  • Health care establishment, accredited by a regional, national or international agency, having jurisdiction on activities that are responsible for the prevention and control of infections.

  • Health care facility Infecton Prevention and Control program has an infection preventionist that is certified in infection prevention control and epidemiology by the Certification Board of Infection Control and Epidemiology (CBIC) or other regional, national, or international certifying body, or the health care facility has an epidemiologist with a minimum of a master's degree or equivalent.

For more information about the official ASHRAE Standard 188-2018, please visit Ashrae's official website.

You may also want to consult the following document : IM15161-2013. This is a standard published by Public Works and Government Services Canada  destined for building owners, design professionals and maintenance personnel.