A Look at the Impact of Proposed Water Standard to Prevent Legionnaires` Disease

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Courtesy of Phigenics, LLC

From the standpoint of water treatment industry experts, failure to prevent legionellosis (or Legionnaires’ Disease) is the most significant water treatment problem today. Essentially every case of the disease is the result of exposure to inadequately managed building watersystems, and both utility and potable water systems can be the source of the hazard (i.e., Legionella bacteria). In order to prevent future cases of disease, a consensus of industry experts came together to move the current ASHRAE Legionella Guideline (12-2000) to a full ASHRAE Standard. After several years of work, Standard Project Committee (SPC) 188 has completed the Standard document and released it for public review.

ASHRAE Standard 188, entitled Prevention of Legionellosis Associated with Building Water Systems, is a risk management standard that establishes absolute requirements for prevention of legionellosis associated with building water systems. Standard 188 applies to the owners/managers of most commercial, industrial and institutional buildings in the United States, and states that all health care facilities must comply with its requirements.

What does this mean for health care facilities?

  • Standard 188 requires a risk management process called Hazard Analysis Critical Control Point (HACCP, pronounced “Hassip”), therefore all health care facilities will be required to have a HACCP Program.
  • HACCP requires the facility form a team, sometimes referred to as a “Water Management Team”(WMT), to facilitate the completion of the HACCP plan and drive the ongoing validation and verification of the water system.
  • HACCP is the most widely used risk management process (both U.S. and internationally) to prevent environmental-source diseases from harming people. The process systematically answers and documents answers to three questions: 1) What are the hazards in the facility? 2) How are the hazards being controlled in the facility, and 3) How do we know that the hazards have been controlled in the facility?
  • The last question is answered by validation and verification, requirements of the HACCP process.Validation is defined as evidence that a hazard has been controlled or eliminated. The most defensible way to validate performance is through water testing for the hazard (i.e., Legionella), known as environmental surveillance. Verification is defined as evidence that the HACCP program is correctly implemented. HACCP emphasizes that validation and verification should be independent from suppliers of water treatment products and equipment.

As was the case with ASHRAE Standard 62 for indoor air quality, the industry expects ASHRAE Standard188 to become part of local and state building codes, as many regions and states currently reference the ASHRAE Guideline 12-2000 for Legionella. Changes to code take time, but ASHRAE Standard 188 will soon be the measure of industry best practice and used to determine legal due diligence should a case(s) be suspected from the healthcare facility water system.

The review period began on Oct. 1, 2010 and closed on Nov. 14, 2010. An estimated timeline from ASHRAE is that the standard will be published in the second quarter of 2011. Based on these time estimates, it is recommended that health care facilities review this standard and determine the best path to address its requirements.

Putting it into Perspective

With this increased focus around the safety of building water systems, how can facilities address the new ASHRAE requirements within existing operating budgets? The good news is the standard has defined the process by which facilities can prevent waterborne pathogen disease, and the purchase of capital equipment or treatment systems is not a requirement and in many cases, may not be necessary. Furthermore, a “byproduct” of this process often finds ways to continually improve the operational efficiency and sustainability of potable and utility water systems.

Water-related inefficiencies and treatment program costs are often highest when water safety is poorest. This is especially true if water and energy waste is due to microbial fouling in the system, often a 10 percent to 15 percent loss in heat transfer efficiency, which can significantly increase your energy costs. The best first step to improve water system safety is to reduce any inefficiency in the system. Practice to reduce inefficiencies in the water system and in the water treatment program can be achieved through better use of water pre-conditioning, more economical and more effective water treatment practice, and closer attention to water/energy conservation. Savings from better water management can then be used to improve the safety of the water system through the HACCP process.

Typically, more than 50 percent of a health care facility’s total water usage can be attributed to the operationof the heating and cooling systems, with numbers being as high as 75 percent to 80 percent during the warmest summer months. Along with high water usage and the potential for waterborne pathogens to growin utility water systems, reviewing the utility water systems is very worthwhile during the HACCP analysis phase. Important points for review include:

  • Maximizing cooling tower cycles through management of TDS/conductivity levels. Reducing the amount of makeup and blow-down water will also result in reduced chemical usage, which also helps lower environmental impact.
  • Taking advantage of evaporation credits for cooling towers.
  • Elimination of leaks in heating/cooling closed loop systems, notably steam/condensate lines. Returning the maximum possible amount of condensate will significantly reduce the amount of water that needs to be converted to steam.
  • Utilizing water meters across the utility systems to not only identify leaks but also verify water costs.
  • Use of reverse osmosis (RO) for boiler water pre-treatment may allow the boiler to run significantly higher cycles compared to a standard softener approach. This equipment solution can provide asignificant ROI, depending on the percent condensate return of the steam system. In addition towater/energy savings, chemical usage also can be reduced. RO reject water can then be re-used ascooling tower makeup water.

For potable water, current estimates reflect that 20 percent to 30 percent of a health care facility’s water usage is from the potable water system (i.e., sinks, showers, toilets, kitchen), therefore the efficiency and sustainability of these water streams cannot be ignored. There are many new solutions on the market tosave potable water, but it is critical that these solutions, when implemented, do not cause the water quality and/or safety levels to deteriorate. Low-flow devices that are installed often reduce the usage in hot water circulating loops, leaving a significantly under-utilized loop that becomes almost a “storage” location for water without significant levels of disinfectant.

Some potable water solutions that can be effectively and safely implemented when managed as part of a HACCP program are:

  • As with utility water streams, utilize water metering to help direct the WMT to areas that present the biggest pay off from a sustainability or safety perspective.
  • Identify any water streams that can be centrally piped back for reuse in cooling tower makeup water(RO systems for hemodialysis or other high-purity systems, equipment cleaning/processors, etc.).
  • Utilize devices that reduce the flow rate for kitchen sprayers, improving their cleaning ability and reducing water usage.
  • Consider energy-efficient dishwashers and cleaning systems as well as any cooking systems that require significant amounts of steam, determining ROI payback for replacements.
  • Consider hands-free controls only for those hospital water systems where usage is highest in orderto prevent issues from stagnant/low flow areas. Be sure to consider the operational resources needed to maintain the hands-free controls (IR, foot pedals, etc).
  • Consider low-flow or waterless toilet fixtures, again only when maintenance resources can support the systems.


The requirements of ASHRAE Standard 188 will not only help facilities prevent disease from waterborne pathogens such as Legionella, but give teams an opportunity to review their current water systems and treatment programs, looking for ways to reduce their water-related operating costs and improve their water/energy efficiency. Improving water safety and sustainability contributes to the health care facility’s green/sustainability goals.

Melissa Cain is Regional Manager, Phigenics, LLC


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