ASHRAE-514: Addressing Legionella and Other Waterborne Pathogens in Building Water Systems

ASHRAE LogoWith the increasing awareness of the dangers posed by waterborne pathogens, there is a heightened focus on mitigation. Among these pathogens, Legionella is particularly well known, as it can lead to a severe form of pneumonia known as Legionnaires’ disease (legionellosis) and even death. Recognizing these risks, ASHRAE Standard 514 provides guidance and best practices for managing and controlling these waterborne hazards. However, guidance from an independent waterborne pathogen expert is important for the proper implementation of this standard as part of a water management program.

The Threat of Legionella and Other Waterborne Pathogens

Legionella and other waterborne pathogens thrive in stagnant or poorly maintained water systems. These microorganisms can grow and multiply in plumbing systems, cooling towers, and other building water systems. When these systems produce water aerosols, such as from a shower or a cooling tower, there is a potential for individuals to inhale these water droplets and become infected. Legionnaires’ disease, while treatable with remediation, can be fatal, particularly in older adults, smokers, or those with compromised immune systems.

Disinfection and Chemical Hazards

One of the most common methods to manage waterborne pathogens is the use of disinfectants. While these chemicals can effectively reduce or eliminate pathogens, they come with their own set of challenges.

  1. Chemical Residue: Over time, residual chemicals and by-products can accumulate in the water system that individuals consume or come into contact with.
  2. Chemical Interactions: Some disinfectants can react with other substances present in the water system. These reactions might produce harmful by-products.
  3. Corrosion: Certain disinfectants can corrode plumbing systems, leading to leaks or even system failures. They may also damage piping systems and increase the potential for biofilm, which harbors Legionella and other pathogens.

So while disinfectants play a crucial role in managing the risk of pathogens, it’s imperative to select the right kind and use them judiciously.

High Water Temperature Hazards

Raising the temperature of water systems is another method employed to combat the growth of waterborne pathogens. Legionella, for instance, cannot survive in temperatures above 140°F. However, this presents a scalding risk to building occupants. Water at a temperature of 140°F can cause third-degree burns in just five seconds.

ASHRAE-514 balances the need to maintain elevated water temperatures to mitigate the growth of Legionella while implementing safeguards to ensure occupants are not exposed to scalding water. These might include:

  1. Point-of-use Thermostatic Mixing Valves: These can be installed to blend hot water with cold water, ensuring that the delivered water is at a safe temperature.
  2. Regular Monitoring: Implementing a regular monitoring schedule to ensure that the delivered water temperature remains within safe limits.
  3. Education: Informing building occupants about the potential risks associated with elevated water temperatures.

Implementing ASHRAE-514 Best Practices

ASHRAE Standard 514

While ASHRAE-514 serves as a guide, its successful implementation depends largely on the commitment of building managers and maintenance personnel under the guidance of waterborne pathogen and Legionella experts. Some recommended practices include:

  1. Water Management Programs: Establishing a water management program that assesses risks, implements control measures, and conducts regular evaluations.
  2. Regular Testing of Waterborne Pathogens and Legionella: Conducting periodic water tests  to detect the presence of Legionella and other pathogens, ensuring that control measures are effective.
  3. System Maintenance: Regularly flushing stagnant sections of the water system, cleaning and disinfecting cooling towers, and maintaining water heaters at recommended temperatures.
  4. Training: Providing ongoing training to maintenance staff and other relevant personnel to ensure that they are aware of the risks and the measures to mitigate them. This should naturally flow from the water management plan or program.

Connect with the Experts in Waterborne Pathogens and Legionella Control

Facility water systems, when improperly maintained, can become reservoirs for waterborne pathogens such as Legionella. While ASHRAE-514 provides an essential roadmap for building professionals to navigate the challenges associated with managing these risks, expert guidance is needed. Contact Legionella Control Systems to better understand the potential hazards, select appropriate disinfectants, balance the need for elevated water temperatures with scalding risks, and commit to best practices through your water management plan.