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Legionella Bacteria and Microorganisms in Data Center HVAC Systems

Rob Rottersman, MS, CIHPrincipalRamboll

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1) Introductions and Interests2) History of Legionnaires’ Disease3) Illness and Outbreaks4) Legionella Growth Requirements5) Current Standards and Guidelines6) Evaluation7) Controls

OUTLINE


• July 1976: Philadelphia Bi-centennial• Strains of flu with similar to the 1918 flu pandemic recently found in pigs

• Heightened fear of another global pandemic• Michael Crichton’s book Andromeda Strain to the best seller list

• > 4000 WWII Vets in the city for American Legion’s Convention• Approximately 600 staying at the Bellevue Stratford Hotel

• participants started getting ill – fever, cough, difficulty breathing• As days passed, more got ill and some died• 221 people were infected and 29-34 died

HISTORY – SETTING THE STAGE


• Philadelphia inundated with investigators – cause of disease elusive• Theories of communists trying to take out veterans.• A doctor claimed the only real consensus to develop among scientists was that this

was not a bacterial disease!

• The cause would not be known until early 1977• Dr. Joseph McDade working to investigate another potential

pathogen responsible for the disease• Observed “insignificant” bacteria contaminating his samples• Bored at a party, went to the lab and looked at the bacteria – strange things were happening• New experiments were done on the bacteria – Legionella discovered

INVESTIGATION AND DISCOVERY


• Will not grow under typical conditions. • Specific requirements to culture in lab• Likes high temperatures

• Where did it come from?• 221 people got sick but 72 were not involved with the convention• BUT….those 72 all walked by the Bellevue Stratford Hotel• Bacteria was found in the cooling tower

• The bacteria was traced back and found to be responsible for many unsolved outbreaks

• Some as early as the 1950s.

WHY WAS IT HARD TO FIND?


• Legionella the bacteria that causes legionellosis • Legionella pneumophila serogroup 1– the type of Legionella most likely to

cause disease • Legionellosis – one of two types of illnesses caused by Legionella

• Legionnaire's disease• A type of pneumonia. Mortality rate about 10% but much higher in

immune compromised• Tends to affect older population

• Pontiac fever• Flu like symptoms. Resolves untreated. Not believed to be fatal• Tends to affect younger people

Terminology


1. Legionella bacteria must be present• In sufficient quantity and• Pathogenic species

2. Water containing bacteria must be aerosolized into a fine mist• Respirable size droplets

3. The mist must be inhaled by a susceptible person• Risk factors: advanced age, suppressed immune system, smoking, cancer,

male, diabetes

Requirements for Disease


• Legionella Bacteria is common – low levels found in rivers, lakes, ponds, etc.

• Some survive water treatment and enter the potable water system• Find a niche in building systems and multiply

• Biofilm, biofilm, biofilm• Can live within amoeba or other protozoa

• Temperature important factor in growth • 77 to 113 degrees F growth range – rapid growth can occur between 90 and

108 degrees• Starts to die at 122 degrees (slow death). Rapid disinfection above 150

degrees F

Legionella – Where and How does it Grow


6,100 reported cases of Legionnaires’ disease in the United States in 2016.

8,000 – 18,000 estimated


• Water tanks • Aerators • Infrequently used equipment

• Water heaters • Faucet flow restrictors • Ice machines

• Water hammer arrestors • Showerheads/hoses • Hot tubs

• Expansion tanks • Pipes/valves/fittings (dead end legs) • Decorative fountains

• Water filters • Evaporative coolers • Cooling towers/Evaporative condensors

• Faucets • Aerosol (non steam) humidifiers • Medical devices (CPAP, bronchoscopes, etc.)

Where Legionella Grows in Buildings


• World Health Organization “Legionella and the prevention of legionellosis” 2007

• ASHRAE 188 - 2018 – “Legionellosis: Risk Management for Building Water Systems” first published in 2015

• New York State Sanitary Code ”Part 4 – Protection Against Legionella”, July 2016

• CDC “ Developing a Water Management Program to Reduce Legionella Growth & Spread in Buildings” June, 2017

• Center for Medicare and Medicaid Services - June, 2017• OSHA e-Tool and Technical Manual Section III Chapter 7

Standards & Guidelines


• Evolved from ASHRAE Guideline 12-2000• Took over 10 years to reach consensus • Compliance is voluntary

• Unless jurisdiction makes compliance mandatory

• Written in “mandatory” and “code intended language” for easy adoption into codes and regulations

ASHRAE - 188


• Cooling Towers or Evaporative Condensers • Building is more than 10 stories high (include below grade)

• Whirlpools or Spas • Health care facility with >24 hour stays

• Ornamental fountains, misters, atomizers, air washes, humidifiers or other aerosol source

• Treatment of burns, cancer (chemo), organ or bone marrow transplant

• Other nonpotable water systems or devices that release water aerosols in the building or on the site.

• Building designed to house occupants over 65 years old

• Building has multiple housing units with centralized water heater

ASHRAE 188 – Building Survey


https://www.cdc.gov/legionella/maintenance/wmp-risk.html

Asks 8 yes or no questions about your building.

Click “see results” and will tell you if the program applies

CDC Toolkit

https://www.cdc.gov/legionella/maintenance/wmp-risk.html


1. Assign a program team2. Describe building water systems3. Evaluate water systems for hazard risk4. Identify where control measures must be applied or maintained within limits5. Establish monitoring plan and corrective actions6. Confirm that the program is being implemented (verify and validate)7. Document and communicate

Legionella Management Program


Assign a team leader with to own and oversee the programTeam members based on skills and type of building. May include:- Building owner- Building manager- Maintenance & Engineering- Risk management - Equipment contractors/vendors- Industrial hygienists/Microbiologist/Safety- Local health officials

Step 1 – Program Team


Step 2 – Describe the Building Water System


“Identify Areas Where Legionella 3 Could Grow & Spread” from CDC Toolkit

• Areas for potential bacterial growth• Sources where water could be aerosolized• Locations with higher risk populations

Step – Identify Water System Risks


“Control Measures & Corrective Actions: The Basics” from CDC Toolkit

• Identify how bacteria will be controlled• Based on risks identified in step 3

• What are ways to control bacteria in building water systems?

Step 4 – Controls and Corrective Actions


See “Decide How to Monitor Your Control Measures” from CDC Toolkit

• Visual inspection• Temperature

• Keep hot water distribution above ideal growth but beware of scalding

• Residual disinfectant• Surrogate microbial (dip slides, plate counts, ATP)Air sampling for Legionella almost never recommended

Step 5 – Implement Monitoring and Corrective Actions


Once established in a system controlling Legionella can be• Time consuming• Expensive• Frustrating

Select the best control for the source. Some common options:- Clean - Eliminate source of mist- Maintain temps - Separate mist from people (barriers/contain)- Disinfect - Remove dead end legs

Controls


Supplements primary controls (some examples)

Secondary Treatment Options

• Chlorine • Ozone

• Chlorine dioxide • Heat and flush

• Monochloramine • Point of Use

• UV • Hyperchlorination

• Copper/Silver Ionization


• Verification: are we doing what we said we were gonna do? • Audit

• Validation: is what we are doing effective• May include periodic water testing for Legionella bacteria• Air sampling for Legionella bacteria is almost never recommended

Step 6 – Verify and Validate


From ASHRAE 188 – 2018

“The Program Team shall determine whether testing for Legionella shall be performed and, if so, how test results will be used to validate the Program. If the Program Team determines that testing is to be performed, the testing approach, including sampling frequency, number of samples, locations, sampling methods, and test methods, shall be specified and documented.”

“The Program Team shall include the following as part of the determination of whether to test for Legionella:

a. Program control limits are not maintained in building water systems, including in water systems with supplemental

disinfection.

b. A health care facility provides in-patient services to at risk or immunocompromised populations.

c. A prior history of legionellosis is associated with the building water system.”

Legionella Bacteria – to Test or not to Test


Table 1. Colony forming units (CFU) of LDB per milliliter

Action Cooling tower/Evaporative Condenser Potable water Humidifiers and Misters

12

1001,000

10100

110

•The levels requiring action vary for the source of exposure, based on the assumption that some routes of exposure result in a greater dose to the lung. For this reason humidifiers and similar devices (such as misters and evaporative condensers) produce aerosol mists and, therefore, need to be controlled to lower levels than cooling towers and domestic water supplies to minimize the risk of inhalation. Levels of LDB equal to or greater than the values in the table constitute a need for action, as described below:

Action 1 Cleaning followed by biocide treatment of the system, if appropriate.•Action 2 Cleaning and or biocide treatment.

•Take immediate steps to prevent employee exposure.

Guidelines for Data Interpretation and Response(example is from OSHA’s e-tool)


Tables 3.1 & 3.2 in the AIHA Bookprovides additional guidance on interpretation from Culture Samples


Document (Pulls in steps 1-6)• Program team members: names, roles, responsibilities• Building description (age, use, etc)• Water system description, flow diagrams, description of risks• Control measures including what to monitor, where to monitor, frequency and

acceptable/unacceptable results• Confirmation. How will the program be verified? How will it be validated?• Document collection and maintenance. Who will do the testing? How will lab

reports be managed?Communicate – let them know before they ask.

Step 7 – Document and Communicate

DISCUSSION

Documents

Legionella Bacteria and Microorganisms in Data Center HVAC ...files.informatandm.com/uploads/2019/3/126ABC_-_W... · • Some survive water treatment and enter the potable water system