Reducing the Risk of Legionnaires Disease: A New Standard of Care for Designers
Even if you’ve never heard of The American Legion, a U.S. veterans’ organization, chances are you’ve heard of Legionnaires’ disease. The affliction was named when more than two dozen people died, and more than 100 were hospitalized, after attending a Legion convention in Philadelphia in 1976. The source of the outbreak was determined to be bacteria, later named Legionella, that spread from the building’s cooling tower throughout the convention hotel via the air conditioning system.
According to the U.S. Centers for Disease Control and Prevention (CDC), some 8,000 to 10,000 persons are hospitalized with the disease, also referred to as “legionellosis,” in the U.S. each year. According to the Public Health Agency of Canada, the annual average number of cases reported in Canada is fewer than 100. However, in both countries, the actual number of cases is thought to be much higher, since someone suffering from the disease may be mistakenly diagnosed with common pneumonia.
When water contaminated with Legionella is released into the air in the form of droplets or mist, people may be exposed to the bacteria by breathing in the contaminated air. You can’t contract legionellosis from touching another person or drinking contaminated water.
In the U.S., the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recently released “ANSI/ASHRAE Standard 188-2015, Legionellosis: Risk Management for Building Water Systems.” According to ASHRAE, the standard is “intended for use by owners and managers of human-occupied buildings and those involved in the design, construction, installation, commissioning, operation, maintenance and service of centralized building water systems and components.” In effect, Standard 188 creates a new standard of care for architects, engineers and others involved in any aspect of centralized potable and non-potable water systems. The standard does not apply to single-family residential buildings.
ASHRAE released Standard 188 at the end of June 2015. To learn more about how it affects design professionals, Communiqué spoke to Jeff Boldt, Director of Engineering for KJWW, a consulting engineering firm headquartered in Rock Island, Illinois. Although Boldt was not involved in the creation of Standard 188, he regularly consults with ASHRAE on issues ranging from green building standards to duct leakage.
Communiqué: Jeff, can you give us a little background on ASHRAE’s Standard 188?
Jeff Boldt: ASHRAE has been working on this guideline for about 10 years. All ASHRAE standards are approved by ANSI [American National Standards Institute], meaning they’ve been reviewed by representatives of every profession involved in the issue. Typically, that includes building owners, equipment manufacturers, consulting engineers and others.
C: Let’s discuss the responsibilities of architects first, since only a couple of aspects of the new standard really apply to architects.
JB: The first is cooling tower siting. Sometimes an architect will want to locate a cooling tower in a particular place for aesthetic reasons, but it may be inadvisable from a legionellosis standpoint. For instance, the tower shouldn’t be sited in a location where the water drift might contaminate an air intake system, or in an area where discharged bacteria could come in contact with people. It should also be sited so there’s easy access to the tower for maintenance.
Architects should know that if they prevail and end up siting a cooling tower contrary to the standard’s recommendations, that could open the door to their liability to a legionellosis claim.
The other area that applies to architects relates to whirlpools and hot tubs. The standard requires posting the allowable bather load along with warnings about risks to immunocompromised bathers.
C: Can Legionnaires’ disease also be contracted from potable water supplies?
JB: Yes. The risk of contracting the disease from potable water, for example, showers and aerated hand-washing sinks, is comparable to, if not higher than, the risk from cooling towers. In fact, KJWW’s internal initiative is at least 50 percent related to potable water systems.
C: What are some of the standard’s highlights as it relates to the services of engineers, including HVAC designers?
JB: Section 8 contains “Requirements for Designing Building Water Systems.” Designers must document a number of items, including schematic diagrams, maintenance schedules and procedures—which are not traditionally the responsibility of the designer—and the impact of heat loss or gain in piping and components. Unfortunately, the standard does not define what it means to document these items. Section 8 also requires a survey of each new building’s water system designs.
As with all sections of the standard, these requirements have been developed to make everyone, particularly owners and their maintenance/operations teams, acutely aware of the conditions that can lead to the growth of legionella bacteria, from faulty maintenance to changing temperatures.
C: How can building owners and operators tell whether their water management system contains too much Legionella?
JB: There’s no magic number of Legionella bacteria that indicates you have a problem—the amount present has to be measured against a baseline, ideally the amount present during the water management system’s first year of operation. So if the owner can say, for example, “My first-year counts were X, Y and Z, and now they’re 3X, 3Y and 3Z,” then there’s a problem that needs to be solved.
C: How will the standard’s requirements regarding commissioning affect designers’ responsibilities?
JB: Section 8 also requires designers to provide detailed instructions for commissioning of all building water systems in their plans and specifications. These include instructions regarding disinfection and flushing and other procedures that designers normally don’t provide. It’s probably more appropriate to have the owners set that sort of stuff up than the designers. But we’ll still have to provide documentation for whatever system the owner sets up. And if the owner wants us to develop these procedures and schedules, then I believe that we should be paid extra for that and obtain some beneficial contract clause, such as a limitation of liability, waiver of consequential damages or indemnification, for taking on owner maintenance.
C: What can you tell us about the water management program team referred to in the standard?
JB: The program team is the group or individual that the building owner designates to develop, implement and maintain the water management program. I think owners are going to approach the architects and engineers about joining the program team. I think it’s fine for us to join as long as we don’t give them advice that’s beyond our knowledge. For example, I can give an owner advice about air flow or other matters an engineer understands, but I’m not going to give microbiology advice.
C: What’s the call to action for design professionals regarding Standard 188?
JB: The best thing designers can do is get a copy, read it and take out their highlighter to mark the sections relevant to their scope of services. Then they should insert those requirements into their master specifications.
At KJWW, we’ve created a set of action items to update our chemical treatment specs, plumbing specs, plumbing flow diagrams, HVAC cooling tower specs, HVAC flow diagrams, commissioning specs, and contracts with owners in order to comply with Standard 188.
To order a copy of “ANSI/ASHRAE Standard 188-2015, Legionellosis: Risk Management for Building Water Systems,” visit ASHRAE’s website.
As published in XL Catlin’s Design Professional Newsletter, Communique.
The information contained herein is intended for informational purposes only and does not constitute legal advice. For legal advice, seek the services of a competent attorney. Any descriptions of insurance provisions are general overviews only.
XL Catlin is the global brand used by XL Group Ltd’s insurance subsidiaries. In the US, the insurance companies of XL Group Ltd are: Catlin Indemnity Company, Catlin Insurance Company, Inc., Catlin Specialty Insurance Company, Greenwich Insurance Company, Indian Harbor Insurance Company, XL Insurance America, Inc., XL Insurance Company of New York, Inc., and XL Specialty Insurance Company. Not all of the insurers do business in all jurisdictions nor is coverage available in all jurisdictions. Information accurate as of August 2015.