1. New Rules on Legionella Prevention N. Bangert TS Workshop 2005, Archamps

2. Table of Contents Diseases caused by Legionella Diseases caused by Legionella Living environment / Installations with risk Living environment / Installations with risk Cooling towers at CERN Cooling towers at CERN –Analysis and limits –Preventive chemical treatment –Corrective chemical treatment –Annual preventive maintenance –Personnel protection –Conception and Follow up of Cooling Towers Conclusions Conclusions

3. Legionnaires’ Disease Legionnaires’ Disease –Pneumonia (collapse of respiratory function) –Incubation time: up to 10 days –Mortality rate 5% to 30% Diseases caused by Legionella = Legionellosis Pontiac Fever Pontiac Fever –Flue-like illness (fever and muscle aches) –Incubation time: few hours to 3 days

4. Living Environment Warm stagnant water Warm stagnant water

5. Showers Installations with risks Cooling towers Whirlpool spas Evaporative condensers

6. Cooling Towers at CERN 23 Power: 1.25 MW to 70 MW Volume: 5 m 3 to 4000 m 3

7. LHC and SPS Cooling Towers Cooling Tower

8. Cooling Towers at the Meyrin Site Cooling Tower French / Swiss Border

9. Analysis and Limits Frequency now on a monthly basis (In the past 2-4 times per year) Preventive chemical treatment 100 000 UFC/l Stop, disinfection, cleaning, purge Corrective chemical treatment 1 000 UFC/l 1 000 UFC/l 0 UFC/l 0 UFC/l Stop

10. Preventive Chemical Treatment Continuous treatment Continuous treatment –Anti-scaling reduces formation of bio-films Weekly treatment Weekly treatment –Biocide targeted on general bio- contamination (algae, fungi, bacteria)

11. Corrective Chemical Treatment Amount of chemical depending on level of contamination and volume of circuit Amount of chemical depending on level of contamination and volume of circuit –Bactericide targets Legionella bacteria –Bio detergent detaches slime off the surfaces Slime Surface

12. Annual Preventive Maintenance Mechanical cleaning Mechanical cleaning –Basins, structures, … Purge of circuit Purge of circuit –not always practicable –time consuming Disinfection of circuit Disinfection of circuit –Similar to corrective chemical treatment

13. Personnel Protection All personnel performing work in or close to cooling towers need to be properly trained regarding risks All personnel performing work in or close to cooling towers need to be properly trained regarding risks Zones to be signaled Zones to be signaled Respiratory protective equipment need to be carried in case of exposure to aerosols or in cooling towers Respiratory protective equipment need to be carried in case of exposure to aerosols or in cooling towers

14. Conception and Follow up of Cooling Towers –Free of dead end pipes –Drop separators installed –Good quality of supply water (Problems: SPS, STP18) –Accessibility for inspection and cleaning given –Technical documentation up to date –Installation logbook put in place –Follow up of water consumption and purges Methodical Risk Analysis

15. Conclusion I: In Place –Respect of frequencies and type of analyses (100%) –Preventive and corrective chemical treatment defined (and applied if necessary) (100%) –Annual preventive maintenance (70%) –Completion and review of existing procedures about preventive and corrective activities (60%)

16. Conclusion II: To-Do-List –Carry out a methodical risk analysis on all cooling tower circuits –Put warning signs in place –Implementation of a cooling tower Logbook –Training of personnel intervening on and operating the cooling towers –Update of hydraulic plans –…–…–…–…

17. Conclusion III: Evaluation –Hydraulic disconnection of north area cooling towers to SPS ring –Hydraulic disconnection of STP18 from SPS –Put purge counters in place Budget evaluation / Schedule : ?

18. Questions ?