1. WHAT’S in the PIPELINE? Tobias van Reenen CSIR
Building Design and Engineering Approaches to Airborne Infection Control
WHAT’S in the PIPELINE?
Tobias van Reenen
CSIR

2. OVERVIEW
BACKGROUND
STANDARDS & LEGISLATION
DESIGN
MANAGEMENT 2

3. BACKGROUND LEGIONELLA:-
Mesophilic Bacteria naturally occurring in low numbers in aquatic environments
Thrives in man-made water distribution and storage systems (20-50°C)
~ Half of the species cause Legionellosis
Legionella Pneumophila is responsible for 90% of cases
Within endemic regions, about 4% to 5% of pneumonia are caused by L. pneumophila
-Robert-Koch-Institut
Legionella Pneumophila can also be divided into sub groups. These sub groups are referred to as Sero-Groups. There are 16 different Sero-groups of Legionella Pneumophila, and Serogroup 1 is associated with most cases of Legionnaires Disease (it is also associated with the majority of fatalities from Legionnaires Disease, but not all).

4. BACKGROUND LEGIONELLA PNEUMOPHILA:- >70 °C : Disinfection range
At 66 °C  : Legionellae die within 2 minutes
At 60 °C  : They die within 32 minutes
At 55 °C  : They die within 5 to 6 hours
50 °C  : They can survive but do not multiply
35 to 46 °C : Ideal growth range
20 to 50 °C : Growth range
Below 20 °C : They can survive but are dormant

5. BACKGROUND LEGIONELLA PNEUMOPHILA:- 35 to 46 °C : Ideal growth range
20 to 50 °C : Growth range
Legionella coincidently likes water at the same temperatures that we do.

6. BACKGROUND LEGIONELLA RISK ENVIRONMENTS
Cooling towers and evaporative condensers
Hot and Cold water systems especially showers
Spa baths
Water Features / Fountains
Machinery Spray-Cooling Systems
Water misting systems
HVAC Systems
Emergency Showers & Fire Hoses
Sprinkler systems and hose reels
Portable room humidifiers
In other words “do nothing”

7. BACKGROUND
BACKGROUND
Biofilm:- a thin layer of microorganisms adhering to the surface of a structure, which may be organic or inorganic, together with the polymers that they secrete –
Biofilm development can result in cyclical system contamination, complicating trouble-shooting

8. BACKGROUND 4 EASY STEPS TO CONTRACTING LEGIONELLOSIS
Contamination & Colonisation of Water Systems
Growth & Proliferation
Aerosolisation
Inhalation Exposure (Duration x Susceptibility)
In other words “do nothing”

9. STANDARDS & LEGISLATION STANDARDS & LEGISLATION
SOUTH AFRICA:-
Occupational Health and Safety Act, 1993 Regulations For Hazardous Biological Agents – pg24
SANS 11731: - Detection and enumeration of Legionella
Act No. 36, 1998 National Water Act
Act No. 108, 1997 Water Services Act
SANS 893 (1&2) Risk Management and Control of Legionella in Water Systems (Committee Draft for Comment)

10. DESIGN Biofilm colonises stagnant or low-flow water in piping.
Legionella risk increases with over-supply of Hand Wash Basins
Over-use of alcohol based hand sanitizers = stagnation in unused basins (Dead Legs)
DESIGN
Avoid stagnation of water at the wrong temperatures!

11. DESIGN Avoid “dead legs” in distribution piping and fittings.
A “dead leg” is a leg length >2x the diameter of the piping.
DESIGN
WHO Supplementary Training Modules: Validation, Water, Air Handling Systems - Water for Pharmaceutical Use (Part 2): Water Purification Engineering

12. DESIGN Point-of-use “RO filters” ?
Filters eradicate concentrate organisms
Point-of-use carbon filters?
Breading grounds for Bio-film
Aerosolizing/ Low flow faucets?
Increase inhalation risk
Pillar taps?
Open standing dead-legs
Automatic Faucets?
Internal bio-film
Maintenance burden
DESIGN

13. DESIGN Avoid warm water circulation or storage
Keep COLD loops <20°C
Keep HOT loops >55°C
Avoid storing too much water
Use of many smaller cisterns reduces stagnation
Avoid long pipe runs
Longer runs =
Greater heat gain in cold water systems
Greater heat loss in hot water systems
Cisterns should be insulated from heat sources
DESIGN

14. DESIGN Mixing devices should provide 55°C at upper limit of range
A geyser is the “gatekeeper” to your distribution system.
>55°C prevents colonisation of HW systems.
Geysers should be set to 60°C
Solar geysers can fail to maintain >45°C year round.
DESIGN

15. MANAGEMENT 1. Risk Assessment and Management Plan Identify Risks
Hygiene risks
Safety risks (>55°C water)
Operational protocols
Thermostatic mixing
Define competency and responsibility (Hygiene & Safety)
Planners,
Designers &
Operators
Implement program
MANAGEMENT

16. MANAGEMENT 2. Disinfection Poor Water Supply Quality?
Dispersive Disinfection
Chlorination
Free Chlorine
Chloromines
Chlorine Dioxide
Silver & Copper ionisation
Thermal Pasteurisation
Site Disinfection
Ozone & UV
Not effective with downstream colonies
MANAGEMENT
Free chlorine may be associated with the formation of carcenogens in the presence of natural organic residues
Ionisation can result in pitting corrosion

17. MANAGEMENT 3. Maintenance and Cleaning
Develop and Implement Cleaning program
Maintenance Policy
Record keeping
4. Training, Monitoring and Review
Training & Skills Matrix
Develop monitoring program
Updated asset register
Effective logbook
Engineering Change Control
Safety and Hygiene Risks
MANAGEMENT

18. REFERENCES & FURTHER READING
Water Systems: HTM The control of Legionella , hygiene, “safe” hot water, cold water and drinking water. Part A & B
ASHRAE White Paper : Position Paper on Legionellosis, 1995
World Health Organization – Legionella and the Control of Legionellosis – 2007 – ISBN
SANS 893 (1&2) Risk Management and Control of Legionella in Water Systems (Committee Draft for Comment)
REFERENCES