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Managing Risks of Legionella in Building Water Distribution Systems
UF TREEO 2018 Presentation Agenda
• Legionella Management• Legionella Basics
• Regulations/Guidelines Legionella Control
• Legionella Field Survey – VA Medical Site
• Suggested Best Management Practices
30+ Years in Business
250+ Municipal and Industrial/Commercial Clients
• Cross Connection Programs/Surveys
• Legionella Water Management
• Water Distribution Quality Studies
• Sampling Programs
• Pipe Labeling Studies
• System Drafting (Chilled Water, Waste Water, etc.)
One Goal We visit some neat places…
And not so neat…
Legionella Basics
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Recent Legionnaires Disease Cases
• City of Flint (2014-2015)
• VA Hospitals/Properties
• Playboy Mansion?!?!
• Hotels
• Hospitals
The Happiest Place on Earth?!?!
No, Florida is not Exempt… Oh No, Do not mess with our BEER!!!!
“Whether or not the Warsteiner brewery is
found to be the breeding ground for
the Legionella bacteria, officials have been making it clear
that the beer is completely safe to
drink.”
Legionella Basics• Bacteria which thrives in aquatic environments -
groundwater, biofilms, surface waters, soils, etc.
• Found in man made/engineered systems:
• Domestic water supplies, cooling towers, domestic hot water supplies, showers, spas, misters, decorative fountains, etc.
• Categorized in 1976 (at least 50 species today):
• Legionnaires convention
• Cooling Tower-cause of illness/death
“Legionellosis”
• Many cases of pneumonia type illnesses throughout USA – caused by Legionella bacteria (LB)• Estimated 8000 to 18,000 cases per year-likely many more1
• Legionnaire’s Disease/Pontiac Fever – caused by inhaling/aspirating Legionella bacteria
• US standard/guidelines for control, management of LB:
• Few states have guidelines (MD, TX, and PA)
• PA has highest rate of reporting disease likely due to increased vigilance/monitoring
1. Marston BJ, Plouffe JF, File TM Jr, Hackman BA, Salstrom SJ, Lipman HB, et al. Incidence of community-acquired pneumonia requiring hospitalization. Results of a population-based active surveillance Study in Ohio. The Community-Based Pneumonia Incidence Study Group. Arch Intern Med. 1997;157(15):1709–18.
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Legionellosis-Data (CDC)
• 87% of Legionellosis cases reported ages >40
• Men twice as likely to become ill vs. women
• Children < 15 years of age rarely become ill
• Most cases reported are “sporadic” – not associated with outbreak
• Age, gender, smoking, alcoholism, immunosuppression, autoimmune diseases – risk factors
Legionellosis
• Preventable, and treatable with antibiotics
• NOT “communicable”
• 90% of cases have incubation period of 3 to 14 days
• At Risk Water Systems: Hot water systems, cooling towers, high pressure wash systems, Spas, decorative fountains, irrigation systems
Legionella Bacteria Growth Requirements
1. Water pH 5 to 9
2. Growth range = 68 to 122°F (98 optimal) – Significance?
3. Moist environments
4. Oxygen
5. Iron, sediment, scale, biofilm
City Water Suppliers
• PWS must meet EPA National Primary Drinking Water Standards, BUT……
• No enforceable MCL for Legionella! Only Maximum Contaminant Level Goal (MCLG)…
• Is Legionella controlled 100% of the time in city water distribution systems? What level is safe or dangerous?
• City can mitigate legionella by:
• Chlorinating effectively
• Flushing programs/eliminate terminal end mains
• Cross Connection Control Program
• Water quality monitoring/treatment
Private Water Systems
• Private Water Users must adhere to OSHA 1910.141, Plumbing Code, Health Department for drinking water quality
OSHA General Duty Clause
• Hotels, Offices, Hospitals, Factories, Grocery Stores, etc. have had reported Legionella related illnesses
• New standard for Legionella mitigation/risk management…….
General Water Management Plan Development
1. Develop Water Process Flow Diagrams (Potable and Non-Potable Water Systems)
2. Perform Hazard Identification, Analysis and Risk Characterization
3. Identify/establish “Critical Control Points”
4. Establish control measures/limits for critical control points
5. Plan Validation (i.e., Sampling) and Verification (Program Management)
ASHRAE 188 Standard
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Legionella Field Survey – Medical Site
Project Scope
1) Developed detailed domestic hot and cold plumbing drawings -12 buildings• ID all plumbing equipment, evaluate
cross connection measures, dead legs, operating inefficiencies
2) Assist in developing LegionellaWater Management Plan for each building
3) Recommendations/Corrective Actions/Report
Basic Concept-Water Safety Plan Development
Evaluate Water Systems and ID Hazards – Biological,
Physical, Aerosol, Chemical, Radiological
Can this water system allow for Legionella bacteria to
amplify, become aerosolized and exposed to people?
Develop Water Management Plan - Establish Hazard Control Measures for “Critical Control
Points” High Risk Systems
“Validate” controls are working (Legionella
sampling, etc.)
Process Flow Diagram Sample
Pod A (POEA)
Pod B (POEB)
Pod D (POED)
Community Water Supply (CWS1)
Pod E (POEE)
Pod C (POEC)
“Heat Exchanger #2”
Central Hot Water Supply
(Pod E Mech. Room) (DHW2)
“Heat Exchanger #1”
Central Hot Water Supply
(Pod E Mech. Room) (DHW1)
Thermostatic Mixing
Valve
Personal Rooms, Bath
Rooms,
Laundry Room (POUA)
Personal Rooms, Bath
Rooms, Laundry Room
(POUB)
Personal Rooms, Bath
Rooms, Laundry Room
(POUC)
Personal Rooms, Bath
Rooms, Laundry Room
(POUD)
Personal Rooms, Bath
Rooms, Public Restroom
(POUE)
Kitchen and Cafeteria
(POUE)
Domestic Hot Water Return →
1. RECEIVING
2. COLD WATER
POINT OF ENTRYCRITICAL CONTROL POINT
6. DOMESTIC HOT
WATER MAKEUPCRITICAL CONTROL POINT
7. DOMESTIC HOT WATER
DISTRIBUTION SYSTEMCRITICAL CONTROL POINT
8. WASTE
← Domestic Hot Water Supply
Sanitary Sewer
Domestic hot water system supplies kitchen operations, bathing showers, sinks and
commercial clothes washing with no zone mixing/anti-scald valves.
Potable cold water system generally supplies bathing showers and sinks, toilets, urinals, ice machines, drinking fountains, laundry equipment, hose bibbs, utility sinks in
Pods A through D. Pod E also has makeup to heating system, eyewash, kitchen equipment, hose bibbs, and utility
sinks.
Decorative Fountain
(DEF1)
Hot Water
Heating Makeup
3. DECORATIVE
FOUNTAINCRITICAL CONTROL POINT
PROCESS STEPS
5. COLD WATER
POINT OF USECRITICAL CONTROL POINT
Domestic Hot Water
Distribution System (DHWS1)
Softened Hot Water
Supply from Building 500 (DHW3)
Domestic Soft Hot Water Supply and Return from
Building 500 to Pod E Kitchen only - not in use
Refer to “Building 100 Process Flow Diagram”
Domestic Soft Hot ←
Water Supply
Domestic Soft Hot
Water Return →
4. HOT WATER HEATING
• Building domestic cold water supply• Cross connections, dead legs, low turnover areas
• Domestic Hot Water Tanks/Plumbing Systems
• Cooling water systems
• Ice machines, eyewashes, baths/pools
• Building humidification, decorative fountains
Building Field Survey-Potential Areas of Risk for Legionella Plumbing System Risks – Legionella Growth!!!
• Dead legs/low use water lines (hot and cold)
• Low chlorine
• Heaters below 140°F and hot water piping systems below 124°F
• Recirculating/return pumps not working effectively
• Oversized tanks/vessels or piping in relation to water demand (residence time > 24 hours)
• Cross connections with sanitary sewer, irrigation, etc.
• No insulation on piping
• Cold water piping becoming heated
• Significant water hammer/ pressure fluctuations
• Old piping/tanks
• Rubber materials, plastics vs. copper pipe
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Domestic Water Heaters – StudyAlary, et. al
40% of homes with an electric water heater reported the detection of legionella in tank
0% of homes with gas heaters reported legionella in tank
Homes in older areas of community more susceptible to detection of legionella
Type, age and size – main factors
At 151° F, Legionella dies within 2 minutes
At 140 °F, Legionella dies within 32 minutes
At 122° F, Legionella can survive but do not multiply
82.2° C
76.7° C
71.1° C
65.5° C
60.0° C
54.4° C
48.9° C
43.3° C
37.8° C
32.2° C
26.7° C
21.1° C
15.6° C
10.0° C
Water Temperature and Legionella
• Water heaters need capability of
heating water to 158° F for disinfection
• Commercial water heaters have a 180° F T-stat limit
• Residential water heaters have a 160° F T-stat limit
• Instantaneous heaters typically are not capable of heating water to disinfection temperature ranges
Water Temperature effects on Legionella Bacteria
ASHRAE Guideline
1. HW Min Storage Temp = 130° F for circulated tanks
2. HW Min Storage Temp = 140° F for uncirculated tanks
3. HWR Min Temp before return to HW tank = 124° F
Ideal Growth Range 95° F -115° F
Tempered Water 85° F -110° F
Legionella Growth Range 68° F -122°F
Below 68° F, Legionella can survive, but are dormant. Cold water in storage tanks, piping, decorative fountains and other equipment, ideally, should be kept below 68° F
Disinfection Range 158° F- 176° F
180° F
170° F
160° F
150° F
140° F
130° F
120° F
110° F
100° F
90° F
80° F
70° F
60° F
50° F
Scalding Considerations
Temperature Amount of Time to Cause Serious Burn
120°F More than 5 Minutes
125°F 1.5 to 2 Minutes
130°F 30 Seconds
135°F 10 Seconds
140°F 5 Seconds
145°F <5 Seconds
150°F 1.5 Seconds
155°F 1 Second
Maintain tank temperature at >140°F
Maintain hot water piping at >124°F
Routine tank/system pasteurization
Routine system draining
Inspect/test master mixing valves
Domestic Hot Water Tank and Hot Water System Control Measures
Return pump on at all times
At least daily turnover of tank
Ensure freshest water possible supplies tank (high Cl2)
Inspect expansion tanks regularly
Install antiscald valves where required
Maintain/disinfect shower heads and hoses
Insulate hot water piping
Flush stagnant/low flow areas
Copper piping-hot water
Domestic Hot Water Tank and Hot Water System Control Measures
Mixing valves-install as close to end use as possible (i.e., sink, etc.)
Use point of use/instantaneous water heaters where possible
Cross connections (i.e., janitor sink soap dispensers)
Domestic Hot Water Systems
Domestic Hot Water Source
DHW Return Pump
Sinks, Showers, etc.
Sinks, Showers, etc.
124°F→ Hot Water Supply
←124°F Hot Water Return
Antiscald Protection Required 110°F required at outlets ASSE
1017, ASSE 1062, etc.
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Cross-ConnectionImproper BackflowPreventerHot Water Source
Inspection Items
Pipe supply material Pipe labeling Piping leaks Expansion Tanks Hot Water Vessel Temperature
Settings Hot Water Outlet Temperature Hot Water Return Temperature Check Valve Installations
Cross-ConnectionImproper BackflowPreventerHot Water Source
Inspection Items
Master Mixing Valves Hot Water Return Pumps Hot Water Vessel Recirculation Pumps Number of outlets served Types of outlets served
Showers, sinks, kitchen operations Water Supply
Soft Water, City Water Quality
Might be time for a new tank?System Leaks
• May be indicative that equipment needs maintenance or replacement
• Impacts heating capacity
Case Study- Insufficient Heat in System
Target Domestic Hot Water Piping System Temperature = 124°F
• Semi-instantaneous heat exchanger set 130-136°F (Typ. 2)
• 5 Wing - Community Living Center• Highest temperature in piping
system is 112°F, recorded 15 feet from heat source
• Why?
Case Study-Insufficient Heat in System
Target Domestic Hot Water Piping System Temperature = 124°F
• Semi-instantaneous heat discharge 130-136°F
• Recirculating and return pumps working
• Highest use is immediately downstream = Kitchen Operations = high hot water use
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Case Study-Insufficient Heat in System
Master Thermostatic Mixing Valve Downstream Heating
• Tempered water temperature gauge = 124°F
Domestic Cold Water
Domestic Tempered Hot Water
Domestic Hot Water
124°F
Case Study-Insufficient Heat in System
15 Feet Downstream of Mixing Valve Gauge = 108°F
• Mixing valve and temperature gauge malfunctioned!
• Staff assumed hot water was at 124°F
Case Study-Insufficient Heat in System
Domestic Hot Water Return Piping System Temperature = 104°F
• Temperature difference of 4 to 8°F piping system from supply to return
• May possibly need supplemental return pump – 2 separate return line systems, 1 pump
• Consider dedicated heater for kitchen operations
Maintain temperatures <67°F
Rotate booster pumps weekly
Eliminate any dead legs in cold water piping system
Flush known low use areas
Test backflow prevention assemblies
Manage expansion tanks, hammer arrestors
Domestic Cold Water System Control Measures
Flush strainers
Insulate cold water piping, run cold water pipe below hot
Maximize chlorine levels through flushing, strategic plumbing
Eliminate cross connections
New Construction – utilize backflow preventer to isolate area, chlorinate new mains (AWWA C651-14)
Cross-ConnectionImproper BackflowPreventerInspection Items
Ice Machines
Water supply - backflow prevention Filters (type, change frequency) Hands free, manual scoop Water cooled vs. air cooled condenser Population Served (high risk
population vs. general public) Ice Machines may require routine
cleaning/disinfection/inspection
Inspection Items Eye Washes
Water supply – cold vs. tempered Shared supplies Pipe supply material Shower vs. eyewash only Weekly Flushing Schedule
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Inspection ItemsDead Legs
• Pressurized sections of water piping – no use/flow
• Bacteria proliferation (i.e., Legionella) and corrosion issues
• May introduce water of poor water quality into active mains
• Dead legs should be eliminated/removed, or disconnected and capped in place
Dead Legs
Pipes Pressurized w/ Water and Capped
Dead Legs?
Pipes Pressurized w/ Water and Capped
Dead Legs
Pipe Pressurized w/ Water and Capped
Operational Dead Leg-Backup Soft Water
Domestic Soft Hot Water Backup
Domestic Hot Water Supply
X
Backflow Prevention Assemblies
• Test annually or as required• Flush strainers at least annually • Failed assemblies may allow for
contaminated water to enter distribution system (i.e., bacteria such as Legionella), thus posing hazard
• Fire Systems – take precautions during fire flow tests/assembly testing
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Chemically treated pressurized
cooling water may contain Legionella
–backflow into potable water supply
Potable water supply with
no backflow protection
Cross-Connection Subject to Backpressure Processes and Kitchen Share Supply- Hospital Domestic Water System Exposed to Process Soft Water.
What’s wrong here?
Case Study – Process Cold Soft Water
Double Check Valve Assembly (Backflow
Preventer)
Kitchen Operations
Domestic Hot Water Heat Exchanger
Water Softeners (2)
Automated Endoscope
Reprocessors
Reverse Osmosis Systems/Process Heat Exchangers Humidification
Hospital Domestic Hot Water Supply –
Backup Line
Hospital Domestic Cold Water Supply
Backup Line/Dead Leg
Ice Machine
Ice Machine Supply….look closely…….what is this?
?
Cross-ConnectionImproper BackflowPreventer
Inspection Items Cooling Towers
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Cross-ConnectionImproper BackflowPreventer
Inspection Items Cooling Towers
Water supply - backflow prevention Biofilm/growth Location of tower, relation to air intakes Chemical treatment program Dead legs/seasonal usage considerations Side stream devices Number of chillers/absorbers Free cooling
Case Study - Capacity vs. Usage
- Holding Tank – Tank supply to Cooling Tower bypassed direct, highly chlorinated city water feed- Low turnover in tank – frequent Legionella bacteria detected in samples
Decorative Fountains
Inspection Items Decorative Fountains
Water supply - backflow prevention Biofilm/growth Location of fountain Chemical treatment program, aeration Water turnover Proximity of seating Requires routine cleaning, water
turnover, biocide evaluation, etc.
Building Humidification
Softening Steam Generation
Humidification
Building Humidification
Inspection Items Building Humidification Water supply - backflow prevention Steam vs. water Water treatment (RO and chlorine
depletion, softening, etc.) Water quality (turnover, temperature,
quality, etc.) Pipe supply material Areas served
Other Systems
Systems to Evaluate/ Inspect…..
Dialysis Systems Dental Chairs/Lines Nebulizers/humidifiers Pharmacy/compounding Softeners Hydrotherapy/Baths And more……..
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FACILITY BEST MANAGEMENT PRACTICES
Best Management Practices
1. Perform an in-field assessment of building water systems for
Legionella risk to include
evaluating water equipment,
cross connections, dead legs,
plumbing materials, etc.
2. Develop a Legionella Water
Management Plan
3. Maintain accurate data management/records, training,
system drawings/information
Benefits of Water System Program Management
• Minimize Risk
• Improved Safety
• Reduced Operational Costs (accurate documentation, mapping)
• Improved efficiencies
• Regulatory & internal guideline compliance
Secondary Disinfection Methods
• Thermal Shock Treatment (Pasteurize)
• Shock Chlorination(>10mg/L residual)May require water tanks to be 20 to 50 mg/L
• Continuous Supplemental Chlorination (2-4 mg/L)
• Copper- Silver Ionization (continuous)
• Monochloramine
Point-of-use Filtration
Further Information
HydroCorp
5700 Crooks Road, Suite 100
Troy, MI 48098800.690.6651 | hydrocorpinc.com
Steve Fox
301-741-7093