ASHRAE Standards 188 and 514: Requirements, Differences, and Compliance

The June 2015 release of ASHRAE Standard 188 – “Legionellosis: Risk Management for Building Water Systems” – was a giant step for Legionella prevention in the United States in part because it represented unprecedented agreement among government agencies and industry groups – not only about the need for Legionella prevention in building water systems—but also about the approach to it.

ASHRAE 514, which became an ANSI standard in July 2023, is an expansion of ASHRAE Standard 188.

Both ASHRAE standards, 188 and 514, outline requirements for the management of water systems in buildings (other than single-family homes) to reduce hazards to humans. “Management” includes design, construction, commissioning, operation, repair, maintenance, replacement, and expansion of the building water systems. “Building water systems” refers to domestic (potable) plumbing systems, cooling towers, evaporative condensers, whirlpool spas, ornamental fountains, misters, atomizers, air washers, humidifiers, or other devices that can pose a risk to humans.

ASHRAE 188 and 514 are the only regulation-ready ANSI standards in the United States for managing building water systems. States that base Legionella regulations on ASHRAE 188 or 514 can rely on ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) to do the work of updating procedures from time to time because the standards are in “continuous maintenance”—ASHRAE has a formal process for accepting comments and considering changes based on them. States that base regulations on 188 or 514 would thus need only to monitor compliance with specific performance metrics they deem imperative.

Differences Between ASHRAE Standard 514 and ASHRAE Standard 188

ASHRAE 514 actually requires compliance with ASHRAE 188.

The main difference between ASHRAE 188 and ASHRAE 514 is in the hazard(s) to be controlled (see table). The scope of ASHRAE 188 is specific and limited, to control one hazard: legionellosis (Legionella). ASHRAE 514 is broad, requiring control of all microbial, chemical, and physical hazards associated with building water systems.

Table: Differences Between ASHRAE 188 and 514

Requirements for a Water Management Program (WMP)

Buildings on the property must be surveyed to determine whether they have any of the above devices (e.g., cooling towers, whirlpool spas, ornamental fountains, etc.) requiring a water management program or any of the building factors that would require a water management program for the domestic (potable) and other water systems.

The framework of ASHRAE 188 and 514 is almost identical. Both standards require forming a program team to implement a water management program (WMP) that has the following:

1. Description of the building water systems, with flow diagrams
2. Analysis of the building water systems to determine where the hazards present a significant risk and can be controlled (control locations)
3. Control measures, each with a control limit (i.e., performance criterion), a monitoring procedure, and a corrective action to take if the limit is exceeded
4. Verification of program implementation
5. Validation that the program is sufficiently controlling the hazard(s)
6. Documentation
7. Communication procedures

Control measures must include procedures, as applicable, for:

• new construction
• equipment siting
• start-up and shutdown
• inspections
• maintenance
• cleaning
• disinfection
• monitoring (e.g., temperatures; disinfectant levels)
• water treatment

The team must also have a contingency plan – written steps for responding to disease should a case occur despite the prevention efforts.

Design and Construction

ASHRAE 188 outlines requirements for new construction or renovations involving water systems deemed to require Legionella control measures. Designers must provide documentation, diagrams, or instructions as needed for monitoring and control, code compliance, operation and maintenance, control system operation, calibration, installation and start-up, commissioning (including procedures for flushing and disinfection), filling and draining, equipment sizes, piping layout, system materials, pipe sizes, design flow rates, design temperatures, and the impact of heat loss or heat gain.

Designers must also note locations of equipment access (or note inadequate access), filling and draining, flushing, sampling, temperature monitoring, treatment, no flow and low flow areas, possible cross connections between potable and non-potable systems, and outside air intakes.

Proper balancing of plumbing systems must be documented in a report to the owner. Responsibility for balancing will begin with engineers, in specifying valves, and then pass to contractors for performing the work.

Disinfection of plumbing systems needs to be carried out no more than three weeks before “beneficial occupancy,” which in ASHRAE 188 is defined as the point when any part of the building is occupied for its intended purpose.

Adapting an ASHRAE 188 WMP for ASHRAE 514

Long before ASHRAE 514 was in the works, LAMPS water management plans already had control measures for pathogens other than Legionella and for the control of scalding and certain chemical hazards. LAMPS water management plans were thus simply reworded and slightly expanded for ASHRAE 514 around the time the standard was finalized. Therefore, if your water management plan was set up in LAMPS after July 2023, it already had the ASHRAE 514 content. If your water management plan was set up in LAMPS prior to July 2023, simply log in to LAMPS, review Training Note 3.003, and use the automated updating tools in LAMPS.

If you have not already expanded your ASHRAE 188 water management plan to cover the requirements in ASHRAE Standard 514, and if your water management plan was not set up in LAMPS, see “7 Keys to Smart Compliance with ASHRAE 514” in the article ASHRAE 514 Water Management Plans: Keys to Smart Compliance.