On July 21, 1976, the 58^th Annual American Legion Convention was held in Philadelphia. More than 600 Legionnaires stayed at the luxurious Bellevue-Stratford Hotel, where a day after the convention, several of the Legionnaires came down with what appeared to be pneumonia-like symptoms.

By the time the outbreak was over, 221 of them contracted the unknown disease, and 34 of them died.

It took six months before the CDC could identify the type of bacteria that caused the outbreak, which they found out was spread through the air-conditioning cooling towers.

A little known fact is that when the scientists worked backward to determine if similar outbreaks had been caused by the same strain of bacterium, they discovered that 78 people who worked at the Hormel Foods meat packing plant in Austin, Minnesota were affected 19 years earlier. There were several other cases uncovered as well, including one in 1965 when 81 people contracted Legionella (L-pneumophila) and 14 people died.  

Later in 1968 in Pontiac, Michigan, 144 people contracted a mild illness that was eventually called “Pontiac Fever;” it was later traced back to the air-conditioning system. Pontiac Fever is primarily caused by Legionella pneumophila. There was another outbreak in 1974, at the very same Bellevue-Stratford hotel that brought attention to this serious issue. The list goes on, and continues to occur around the world today.

What these outbreaks all have had in common were the air-conditioning cooling towers, showers, spas and domestic water systems were in varying degrees. Through the years, ASHRAE and ASPE have continued to develop ways of controlling or mitigating the bacterium that causes Legionella (L-pneumophila), which is commonly found in a facility’s domestic water supply and eventually the mechanical systems’ make-up water. The most common way of contracting Legionella is by inhalation or aspiration of contaminated water. The CDC and WHO organization say it usually takes between two and ten days to incubate, and that it’s not transmitted from person to person, although there has been a recent claim of being transmitted person to person.

One of the most important ways to control Legionella is through maintenance. If a facility fails to maintain its control measures that are in place, the risk of having an outbreak increases daily. Monitoring and recording required data will lead to early detection and mitigation efforts.

So how do we achieve a collaborative health care design when it comes to Legionella? For starters, it requires educating ourselves by reading articles like this one and discussing it with our colleagues. In this article, I have identified the design guides and directives for use; the systems effected; design considerations; documenting; and mitigation. In the next two articles, I will provide a side-by-side comparison listing pros and cons of each to consider.

Design guides:

“ASHRAE 188 Legionellosis: Risk Management for Building Water Systems” discusses environmental conditions that promote the growth of Legionella and ways to control it. Also look at “ASHRAE 12-2000: Minimizing the Risks of Legionellosis Associated with Building Water Systems.”

ASPE handbook 2010-2011 chapter 6 on domestic hot water design, and chapter 11 discuss growth ranges and mitigation methods for controlling Legionella.

The VA Directive 1061 provides a means and methods approach to controlling Legionella.

As of June 2, 2017, CMS issued a Legionella reduction memo. This memorandum directs general hospitals, critical access hospitals and long-term care facilities to develop and adhere to policies and procedures that inhibit microbial growth in building water systems.

The CDC still requires facilities to only test water systems during an outbreak of two or more cases or after one case in a transplant unit. The CDC states on its website that: “There is no evidence-based consensus recommendation regarding routine testing for Legionella for the prevention of Legionellosis; as many research gaps exist. However, if testing is performed and Legionella is found, a plan should be in place regarding the actions needed to eliminate Legionella from the water system.”

Hospitals in the UK test quarterly for Legionella by culturing water systems. This is considered a proactive approach, whereas the CDC has taken a reactive approach. The CDC is expected to fall in line with the rest of the guidelines, and recommend that ASHRAE 188 be used in upcoming updates.

The following 21 areas and systems are where Legionella has been found to cause outbreaks each year.

Areas and systems:

1. Hot- and cold-water storage tanks
2. Water heaters
3. Water-hammer arrestors
4. Pipes, valves and fittings
5. Expansion tanks
6. Water filters
7. Electronic and manual faucets
8. Aerators
9. Faucet flow restrictors
10. Shower heads and hoses
11. Centrally installed misters, atomizers, air-washers and humidifiers
12. Non-steam aerosol-generating humidifiers
13. Eyewash stations
14. Ice machines
15. Hot tubs/saunas
16. Decorative fountains
17. Cooling towers
18. Medical devices (such as CPAP machines, hydrotherapy equipment, bronchoscopes and heater-cooler units)
19. Incoming cold water with temperatures over 67 degrees Fahrenheit
20. Hot water recirculation systems
21. Stagnation in distribution and branch lines to areas that see little use

The design considerations listed below are the most common mitigation and protection systems being used around the world today to control Legionella. I will cover this more in depth in part two of this three-part series.

DESIGN CONSIDERATIONS:

1. Protect incoming water using various approved methods:
   1. Copper silver ionization
   2. Chlorine dioxide
   3. Hyperchlorination
   4. Super heating system
   5. Ozone
   6. Monochloramine
2. Water heating and return temperatures
3. Cold water return viability
4. Fixture distance from recirculating or active main

Recording and mitigation sections are an important part of the new CMS requirements and ASHRAE documentation process. Everything I am covering in this series will be submitted to the CMS, VA, DNV or JCAHO.

Recording:

1. Source water quality readings
2. Heating source temperature readings
3. Floor levels
4. Furthest point readings.
5. BMS / BACNET
6. Wireless to BMS
7. Portable recording unit

Mitigation:

1. Copper silver ionization
2. Chlorine dioxide
3. Hyper-chlorination
4. Super heating
5. Ultra violet light
6. Monochloramine
7. Ozone

Remember to challenge your colleagues and challenge me. But most of all, challenge yourself when it comes to learning all you can about this issue. It is, unfortunately, on the rise (see chart below).

Take a look at Legionella Prevention/Mitigation – Part 2.