Prevention of Legionellosis for Facility Managers

Legionella_Risk_Management_by_CESNew Standard to Help Minimize the Risk of Legionellosis

This summer, the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. released ASHRAE Standard 188: Prevention of Legionellosis Associated with Building Water Systems – a new standard requiring that facility owners and managers implement stronger safeguards via proactive risk assessment and risk management practices aimed at preventing Legionellosis from being contracted in commercial, institutional and industrial buildings.

CES provides Legionella Risk Assessments for building and process water systems.  Our assessments include a review of facility design, operation, maintenance and treatment programs to help facilities minimize the risk of problems related to waterborne pathogens and insure compliance with applicable guidelines and regulations.

Locally, here in Orlando, Florida Hospital Orlando recently hit the news for having to flush their after system after positive Legionella tests.  (Orlando Sentinel, January 21, 2016).

Schedule a Legionella Consultation with CES

It is important to understand that ASHRAE does not police the implementation of any of its standards. Instead, compliance is under the purview of agencies that are directly involved with assuring the safety of building occupants. These agencies are commonly known as AHJ’s (Authority Having Jurisdiction) and include OSHA for commercial buildings and The Joint Commission for healthcare facilities. 

In short, the proposed standard calls for an annual survey of all human-occupied non-single family buildings to determine building and occupant risk characteristics for Legionella. When any of these risk characteristics apply, owners and facility managers will be required to form a risk management team, and conduct a hazard risk analysis of their water system for Legionella using Hazard Analysis and Critical Control Point (HACCP) principles.


ASHRAE Standard 188 was finalized and officially became an ANSI standard on June 26, 2015.

A legionella risk assessment is recommended by many of guidelines as a first step in managing the risk of legionnaires’ disease.  An assessment does not guarantee the prevention of problems related to legionella but it does have a significant impact on risk reduction.  Because a risk assessment is a recommended “standard of care” it will also have a significant impact on liability reduction should any problems occur. 

Building shall be surveyed to determine whether it has one or more:

  1. Open- and closed-circuit cooling towers or evaporative condensers that provide cooling and/or refrigeration for the HVAC&R system or other systems or devices in the building;
  2. Whirlpools or spas, either in the building or on the site; or
  3. Ornamental fountains, misters, atomizers, air washes, humidifiers, or other nonpotable water systems or devices that release water aerosols in the building or on the site.

The building shall be surveyed to determine whether it is characterized by one or more of the following factors that relate to legionellosis:

  1. It includes multiple housing units with one or more centralized potable water-heater systems.
  2. It is more than 10 stories high (including any levels that are below grade).
  3. It is a health care facility where patient stays exceed 24 hours.
  4. It is a building containing one or more areas for the purpose of housing or treating occupants receiving treatment for burns, chemotherapy for cancer, or solid organ transplantation or bone marrow transplantation.
  5. It is a building containing one or more areas for the purpose of housing or treating occupants that are immunocompromised, at-risk, are taking drugs that weaken the immune system, have renal disease, have diabetes, or have chronic lung disease.
  6. It is a building identified by the owner or designee as being for the purpose of housing occupants over the age of 65 years.

Present US Guidelines related to legionella control include:

  • Occupational Safety and Health Administration (OSHA)
  • American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE)
  • Cooling Technology Institute (CTI)
  • Centers for Disease Control (CDC)
  • Joint Commission on Accreditation of Healthcare Organizations (JCAHO)
  • Applicable State and Local Guidelines

Fast Facts from the CDC (

  • Legionella bacteria can cause Legionnaires’ disease or Pontiac fever, collectively known as legionellosis.
  • The bacterium was named after an outbreak in 1976, when many people who went to a Philadelphia convention of the American Legion suffered from this disease.
  • An estimated 8,000 to 18,000 people are hospitalized with Legionnaires' disease each year in the U.S.
  • Legionella bacteria are found naturally in the environment, usually in warm water.
  • Legionella bacteria are not transmitted from person to person.
  • People get Legionnaires' disease or Pontiac fever when they breathe in a mist or vapor (small droplets of water in the air) that has been contaminated with Legionella bacteria.
  • Keeping Legionella bacteria out of water is the key to preventing infection.
  • Most people with Legionnaires' disease will have pneumonia (lung infection) since the Legionella bacteria grow and thrive in the lungs.

Schedule a Legionella Consultation with CES


Posted by Comprehensive Energy Services

Comprehensive Energy Services, Inc. is an award-winning, self performing provider and recognized leader in Design Build and Maintain Mechanical Contracting and Plumbing; providing a full range of advanced HVAC commercial, healthcare, and industrial services, including mechanical engineering design, mechanical construction, plumbing, IAQ, preventative maintenance and system maintenance throughout Florida.

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