On June 26, 2015, ASHRAE issued ANSI/ASHRAE Standard 188-2015, Legionellosis: Risk Management for Building Water Systems. Ten years in the making, ASHRAE 188 is the first industry standard in the United States to address Legionnaires’ disease prevention. It provides minimum risk management requirements for Legionella found in building utility and potable water systems. This consensus document prepared by the leading experts in the industry ushers in a new era of responsibility for building owners regarding water safety.
Prior to ASHRAE 188, there was no uniform approach or mandatory requirement, for Legionella control and prevention, only guidance documents. The United States has lagged behind such countries as the United Kingdom, France, the Netherlands, Italy, Spain, and Australia that implemented standards years ago. The very first Legionella prevention guideline, introduced by the Allegheny County Health Department (ACHD) in Pennsylvania, came 20 years after the 1976 Legionnaires’ disease outbreak in Philadelphia. Soon after, professional organizations, as well as local and state governments, developed their own guidelines as an attempt to control Legionnaires’ disease. However, this lack of a standard approach created confusion regarding best practices, and no matter how effective the guideline, implementation was voluntary. Many building owners and facility managers applied Legionella control measures only when necessary, such as in response to publicized cases or when legal action was involved. In spite of these efforts, Legionnaires’ disease cases continued to occur. According to the Centers for Disease Control and Prevention, there has been a 200 percent increase in reported cases from 2001 to 2009.
The ASHRAE Standard 188 is the first step in a unified approach to prevention. Its “you shall” and “you must” language raises the specter of legal liability for those who choose not to comply.
REQUIREMENTS OVERVIEW
ASHRAE 188 provides the minimum risk management requirements intended to control the amplification and transmission of Legionella bacteria in building water systems, especially Legionella pneumophila serogroup 1, the most pathogenic strain responsible for the majority of cases. In short, the standard requires building owners to convene a water management team, survey their buildings, implement control measures, validate and verify the risk management program is working and document, document, document. It applies to human-occupied buildings with certain characteristics and potable and utility water systems and components associated with the building. It includes requirements for construction, commissioning, operation, maintenance, repair and renovations.
The core of the ASHRAE standard is the development and implementation of a Water Management Program, which must be reviewed and updated annually.
To comply, building owners are required to conduct a survey of each existing building, new building, and any renovation, addition or modification to an existing building. The objective is to determine whether a building has one or more water systems including: cooling towers, evaporative condensers, whirlpools, spas, ornamental fountains, misters, humidifiers or other non-potable devices that release water aerosols in the building or on the site.
Additionally, the survey determines whether a building possesses one or more of the following characteristics historically associated with cases of Legionnaire’s disease:
a) multiple housing units with one or more centralized potable water systems
b) more than 10 stories high (including levels below grade)
c) Health care facility where stays exceed 24 hours
d) Occupants that are immunocompromised or at risk including elderly, smokers, transplant
recipients, etc.
e) Buildings designated to house occupants more than 65 years old.
If a building survey reveals the presence of one or more of the building water systems (listed in Section 5.1), but none of the above factors identified in Section 5.2, the standard requires building owners to implement a Water Management Program to manage the risk of Legionellosis for those specific building water systems or devices. For example, if a building has a cooling tower, ASHRAE 188 requires a Program to manage risk. The requirements for the Water Management Program are described in sections 6 and 7.
When a building survey indicates the presence of one or more of the factors listed in Section 5.2, building owners must implement a Water Management Program to manage the risk of Legionellosis for potable building water systems in addition to the building water systems listed in Section 5.1. 
From ANSI / ASHRAE Standard 188-2015. Copyright 2015 ASHRAE. Reprinted by permission. ASHRAE 188-2015 may be purchased from the ASHRAE website or from ASHRAE Customer Service at orders@ashrae.org.
If a building meets the above requirements, building owners must take the following actions:
1. Survey the facility for characteristics that have been associated with outbreaks in the past. If these factors are present, then the water management program team must develop a water management program for the device (cooling towers, evaporative condensers, fountains, spa/hot tubs, misters, etc.) or the building water distribution system (potable hot and cold systems and the processes affecting them) or both.
2. To convene a water management program team you must identify persons responsible for water management program development and implementation. Members should include: building owner, facility manager, infection control (if hospital), someone with knowledge of building water system design and water management as it relates to Legionellosis.
3. Describe the potable and non-potable water systems within the building and on the building site and develop water system schematics (flow diagrams).
4. Evaluate where hazardous conditions may occur in the water systems and determine where control measures can be applied.
5. Determine locations where control measures must be applied and maintained in order to stay within established control limits.
6. Establish procedures for monitoring whether control measures are operating within established limits and if not, take corrective actions.
7. Establish procedures to confirm that the program is being implemented as designed and effectively controls the hazardous conditions throughout the building water systems.
8. Establish documentation and communication procedures for all activities of the program.
Section 8 of the standard sets out requirements for those designing and commissioning building water systems. Annex A provides an alternative path to compliance for certain healthcare facilities.
ASHRAE Standard 188 Requires Risk Management to Prevent Legionnaires' Disease
Standard 188: A Good Start to Preventing Legionnaires' Disease
