Legionella Control in Building Systems Carl Schultz, PE National Healthcare Engineering Leader
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Legionella Control
in Building Systems
Carl Schultz, PE
National Healthcare Engineering Leader
Legionella Basics
• Bacterium that causes respiratory diseases such as Legionellosis and Pontiac Fever
• Present widely in water and soil
• The Philadelphia outbreak in 1976 attributed to hotel’s air conditioning system
– Sickened 200 and killed 34
• Transmission: aerosolized water droplets inhaled by a susceptible host
Favorable Conditions
• Temperature
– Grows and multiplies: 68 to 122 deg F
– Reproduces and thrives: 95 to 115 deg F
– @131 deg F takes 5 to 6 hours to die
– @140 deg F takes 32 minutes to die
– @151 deg F dies instantly
• Stagnation
• Scale, Sediment, Biofilms
• Presence of amoebae
Growth Influences
• Natural rubbers: washers,
hoses, spray attachments
• Some plastics
• Wood (think large water tanks)
• Carbon: think twice about providing carbon filtration at ice machines! Carbon also removes chlorine from the water!
Why is this topic important?
• Health of Building occupants
• New guidelines
• Preventable
• Increasing risk of litigation
Cases up 400% since 2000
Health of Building Occupants
• More than 20 outbreaks were reported in 2015 resulting almost 5,000 diagnosed
cases of Legionnaire’s disease
• 12% of population is susceptible
– Heavy cigarette smoking, chronic lung disease, weakened immune system from cancer, diabetes, kidney failure, organ transplantation
Wrongful Death Suit• 53 year old Allstate insurance employee
contracted Legionnaires Disease in Dec 2004
• Died in January 2005
• Used bathroom on ground floor of office building regularly
• Coworker testified that he saw him splash water on his face
• Defense said he drank alcohol and smoked cigarettes
• Summary judgement against plaintiff family
• Absence of statute, regulation, or industry standard
Barrow-in-Furness Case
• 2002 outbreak from cooling tower
• 7 deaths and 188 cases of illness
• A senior architect with the government council was charged with 7 counts of manslaughter
• Technical Manager for government was fired
• Architect was found not guilty but she and her employer paid significant fines
• Contractor settled for 1.5M British Pounds
Legionella Laws
• Bronx Legionnaires’ Outbreak summer 2015
• 12 deaths: Opera House Hotel cooling tower
• NYC Local Law 77: Registration, inspection, cleaning, disinfection, testing of all towers
• Owners: annually certify “in compliance” of law
• $25,000 fine, 1 year in prison for non-compliance
• New crisis = new laws, regulations
• Standards and guidelines used to craft laws and regulations
ASHRAE Standard 188
“Prevention of Legionellosis Associated with Building Water Systems”
• Much of this document is more useful to building owners and operators
• Gives insight on what O&M staff will need to be doing and how to design accordingly
• Presents opportunities for consultants: – Mapping water systems
– Designing remedies for proper system operation
– Writing risk mitigation plans
ASHRAE Standard 188
• Determining building Risk Characterization
• Conducting a hazard analysis
• Determining critical control points & limits
• System monitoring
• Establishing corrective actions
• Verification and documentation
Standard 188: Risk Characterization
• Multiple housing units with common water heater(s)
• Building with more than 10 stories
• Inpatient healthcare facility
• Occupants over 65 or receiving chemo or bone marrow transplant
• Whirlpool, spa, or aerosolizing water feature
• Less than 0.5 ppm Cl2 on incoming water supply
ASHRAE Guideline 12-2000
“Minimizing the Risk of Legionellosis
Associated with Building Water Systems”
• Should be updated soon and the information will be used to supplement Standard 188
• More practical guide for the building engineer
ASHRAE Guideline 12-2000
Recommended Treatment (Control Limits)
In healthcare facilities, nursing homes, and other high risk facilities:
• Cold water stored and distributed at temperatures below 68 deg F
• Hot water stored above 140 deg F
• HW circulated with a minimum return temperature of 124 deg F
• Washington DC office
• Updated primarily for Legionella Mitigation
• Impetus: 6 deaths at Pittsburgh VAMC in 2011
VA Plumbing Design Manual
VA Plumbing Design Manual
• Physical Security Manual: 4 day water supply
• Entering potable water monitored for:
• Pressure, temperature, pH, oxidant levels
• Temperature measured throughout hot & cold water systems
• Hot & cold water to be continuously re-circulated
VA Plumbing Design Manual
• Minimization of dead ends and fixture run-outs
• DHW must be available within 15 seconds
• Run-out volume and length - International Green Energy Code:
Limiting Pipe Volume In Patient Rooms
VA Plumbing Design Manual
• Taps for booster heater for thermal eradication and shock chlorination
• No PVC for sanitary due to thermal eradication
• 30 minutes at 160 to 170 deg F
• Water heaters to develop 180 deg F
• TMV to have bypass
New Hospital Case Study
VA Medical Center, Louisville, KY
- 1.1 million SF
- Mission critical design
Chill your Cold Water?
Domestic Water System
Upgrades
• Hand-over-hand pipe
investigation
• Mapped the entire
domestic hot and cold
water systems: 450,000 sf
• Identified dead legs and
abandoned piping
• Designed remedies
• Legionella management
program
Renovation Case Study
VA Medical Center Clarksburg, WV
Field Investigation
• HEPA Containment Cart
• Infection Control Risk Assessment (ICRA)
• Work with Infection Control Staff
Piping Details
Building Automation System
Domestic hot water supply and return systems
• Graphic displays
• Temperature sensors
• Trending
• Alarm
Water Balancing
• Plumbing professionals need to craft a detailed water balancing specification similar to the HVAC colleagues
• Contractor needs to have credentials and provide a report at the end of the balancing exercise
• This will ensure that hot water is circulating properly throughout the facility
Commissioning
• Water heating equipment: 140 Deg F or above
• ASSE 1017 Master Mixing Valve
• Point-of-use ASSE 1070 mixing valves at lavatories
• Shower temperature limit stops
• Recirculation systems:
– System temps above 124 deg F
Energy Codes
• 120 deg F storage temperature
• Cycling of circulation pumps and heat trace based on occupancy schedule or demand
• Don’t have to comply if it affects health/safety
• International Energy Conservation Code
– Maximum allowable pipe length method
– Maximum allowable pipe volume method
• Veterans Administration has adopted similar pipe volume restrictions
International Energy Conservation Code
Maximum allowable pipe length method
• 2 foot maximum runout to a public lavatory faucet with 1/2” HW (from the nearest source of heated water)
Maximum allowable pipe volume method
• Volume from the nearest source of heated water to a public lavatory faucet is 2 ounces. A 3/8” pipe has 0.75 ounces/ft.
2015 IECC Compliant
Take Aways
There is going to come a day when people and organizations will be held to a higher level of accountability for:
• Designing
• Constructing
• Operating
• Maintaining
Domestic hot water systems
Take Away for Critical Facilities
• DHW distribution: 130 deg F minimum
• Generation and storage: 140 deg F minimum
• DHW return: 124 deg F minimum
• Use of TMVs throughout
• Extend return lines DEEP into system
• Minimize dead legs & stagnant area
Other Considerations
• Create schematics of water systems
• Include temperature and chlorine monitoring
• Access to water hammer arrestors, trap primers
• Building Automation System
• Water balancing
• Commissioning
Other Approaches
• Copper-Silver Ionization
– Optimal concentration of ions is not know (ASHRAE Guideline 12-2000)
– Was used at Pittsburgh VAMC where 6 died of LD
• Chlorine Dioxide
– Used by municipal water providers
– Secondary treatment in buildings requires EPA approval
– Has been used in UK and continental Europe
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