LEGIONELLA IN THE REAL WORLD. May 2017

Transcription

1 1 LEGIONELLA IN THE REAL WORLD May 2017

2 LEGIONELLA IN THE REAL WORLD Better L8 than Never 2

3 3 LEGIONELLA IN THE REAL WORLD

4 Legionnaires Disease Bellevue - Stratford Hotel, Philadelphia July 1976 American Legion Department of Pennsylvania hosted their 58 th state convention people contracted disease - 29 died Disease was called Legionnaires Disease Causative organism was a bacteria Legionella pneumophila 4

5 Legionnaires Disease Legionellosis what is it? It is the collective name for diseases caused by the bacteria Legionella. There 2 types of infection: Bacterial infection - Legionnaires disease. Symptoms include fever, tiredness, pleurisy, cough, pneumonia, effects the function of the lungs, liver and kidneys, and causes neurological damage. Mortality rate is 10-12% but increases with susceptible people. Not contagious Allergic reaction - Pontiac Fever An allergic reaction, mild illness like a cold, 95% have had it. No deaths recorded. 5

6 Legionnaires Disease Risk Profile Men Women >70 N/S Everyone can catch Legionnaires Disease but certain people are more susceptible Men years old Smokers Alcoholics Diabetics Respiratory problems Immunosuppressed people Children rarely infected 6

7 Legionella Legionella bacteria what do we know? A naturally occurring aquatic organism found in all water systems and is present in your mains cold water supply Pathogenic bacteria approx 50% are disease causing bacteria Legionella pneumophila sero group 1 the most commonly associated with Legionnaires Disease and account for approx 95% cases Multiplies exponentially Can colonise a water system within a few weeks 7

8 Legionella The route of infection is the inhalation of a contaminated aerosol Aerosols <5μ can enter your alveoli, deep in your lungs The smaller the water droplets, the deeper the inhalation, the greater the potential of infection 8

9 Legal requirements Legionella management and control What does the law require us to do? 9

10 Legal requirements ACoP L8 The Approved Code of Practice and guidance on regulations is aimed at duty holders, employers and those in control of premises with H&S responsibilities, to help them comply with their legal duties in relation to legionella. The 4 th edition is now separate from the Technical Guidance Documents. 10

11 Legal requirements ACoP L8 The Code has a special legal status. If you are prosecuted for breach of health and safety law, and it is proved that you did not follow the relevant provisions of the Code, you will need to show that you have complied with the law in some other way or a Court will find you at fault. 11

12 Legal requirements Legionnaires Disease Technical Guidance: HSG274 Parts 1-3 Part 1 provides Technical Guidance on the Operation and management of Evaporative Cooling system Part 2 provides Technical Guidance on the Operation and management of Domestic Hot and Cold Water Systems Part 3 provides Technical Guidance on the Operation and management of Other Risk Systems, including vehicle wash systems, emergency showers, spa baths and process water. 12

13 Legal requirements 1. Requirement to identify and assess sources of risk for all water systems regardless of size or volume. The risk assessment is a legal requirement. 2. Requirement to prepare a Written Scheme (or course of action) for preventing or controlling the risk Policy and Procedures. 3. Appoint a responsible / competent person with sufficient authority and knowledge to comply with the law. 4. Requirement to implement, manage and monitor precautions planned maintenance, auditing, sampling etc. 5. Requirement to keep records and check that what has been done is effective. 13

14 What are the common issues in legionella control? Poor management processes 14

15 What are the common issues in legionella control? Poor system conditions. Infrequently used outlets Dead legs Stagnation, Foreign objects in tanks Poor control measures 15

16 Legionnaires Disease CAUSAL CHAIN Property with water system Virulent strain of Legionella enter the water system Legionella Bacteria multiply Aerosol production Inhalation by susceptible person 16

17 Legionnaires Disease RISK SYSTEMS Any system that contains water which is likely to exceed 20 o C and which may release a spray or aerosol. Cooling Towers Evaporative Condensers Hot & cold water systems CWST, calorifiers, showers Spa baths Humidifiers Fire hose reels / sprinkler systems Water features Jet washers 17

18 Legionella Living environment Water body - Natural or Man made 25 C 47 C (37 C optimum) Biofilm ph Sessile bacteria loves stagnant water and will not multiply in moving water. Scale, sludge or sediment, wood, rubber and dissolved iron 18

19 Control Measures Legionella Control is simple! Keep it Clean Moving At correct temperature 19

20 Control Measures How is Legionella growth controlled in water systems? Using temperature - e.g. >60 C and >50 C HWS and <20 C CWS Using flushing e.g. maximisation of water movement Using regular cleaning techniques Using chemicals e.g. Chlorine dioxide Using physical processes e.g. ionisation, filtration, ozone 20

21 Control Measures Effect of Temperature 70 o C 60 o C 50 o C 37 o C 20 o C At 70 o C killed virtually instantaneously At 60 o C killed in 5 minutes At 50 o C can survive for a matter of hours Above 46 o C Growth ceases 37 o C Optimum growth rate Below 37 o C Multiplication decreases Below 20 o C Growth is insignificant 21

22 Control Measures Nos. of Legionella Effect of Temperature Legionella Control Legionella Control Temperature

23 Control Measures Temperature Requirements 60 C within 1 minute HWS 50 C* within 1 minute 50 C* in 1 minute *55 C in healthcare CWS <20 C* <20 C* in 2 mins <25 o C in high ambient condition environments 23

24 Control Measures Legionella Control is simple! Keep it At correct temperature 24

25 Control Measures Avoid conditions that will encourage growth Infrequently used outlet Deadleg Scale on Tap Keep it moving Keep it clean 25

26 Effect of Stagnation Removes effect of temperature control Removes effect of chemical control Removes effect of planktonic bacteria removal 26

27 Control Measures Legionella Benefit of flushing Start flushing Numbers of bacteria are often higher once flushing / usage has stopped Stop flushing Time 27

28 Control Measures Frequent use or flushing will - 1. Prevent and remove localised bacterial contamination 2. Reduces the potential of systemic bacterial contamination Reduce the risk flush the outlet! 28

29 What do you need to do? Usage evaluation Check that all water facilities such as basins, sinks, fume cupboards, bench taps, emergency showers / eye washes, WCs, urinals etc. are used regularly. If it has not been used log it and flush it! Flushing Flush all identified infrequently used outlets at least weekly Flush the outlets for at least 3 minutes or until the temperature has stabilised at the correct temperature 29

30 What do you need to do? Keep records You must keep records of all flushing undertaken Complete record sheet / log book sign and date the task as done Don t just flush outlets identified in risk assessment make sure you do usage evaluation of all outlets every week Removal If you are flushing the same outlet every week it should be considered for removal 30

31 Control Measures Legionella Control is simple! Keep it Clean Moving At correct temperature 31

32 32 Biofilm

33 Biofilm The typical living environment of legionella bacteria is biofilm Biofilm is present on the internal surfaces of tanks, pipes, taps etc. It does not swim freely in the water it only does this when released from the biofilm. Will not multiply if planktonic. 33 Live in amoeba

34 34 Biofilms

35 Biofilms CWST tide-marks around water line Outlets, sinks, sink traps, pipework Ice-machines Hydrotherapy pools 35

36 Control Measures Use of chemicals Temperature and flushing has little or no effect on biofilms (it will remove the planktonic cells but not most of the sessile cells) It requires, therefore, an alternative method of disinfection: Chemical: Chlorine (and other halogens) Chlorine derivatives (Chlorine dioxide) Ozone 36

37 Control Measures Point of use filters, UV on pipework & UV taps Physical Methods Cleaning / descaling CWST, calorifiers, showers, taps Removable taps and spouts to allow cleaning Remove TMVs and TMV taps, the more parts/surface area the greater the colonisation Replace non WRAS approved flexible hoses 37

38 Control Measures Legionella Control is simple! Keep it Clean Moving At correct temperature 38

39 Case Study Problem: Extensive legionella issues in domestic hot water system of a school Risk Assessment Identified Single calorifier - flow temperature was at 55 o C and the return temperature was at 44 o C Buffer vessel flushing no records Thermostatic mixer valve servicing no records Flushing regimes outside term time no records Calorifier inspections no records LOW TEMPERATURES, UNDERUSED OUTETS, DEAD-LEGS 39

40 Case Study Problem: Local legionella issues in domestic hot water system Office Block Investigation identified Single calorifier - good flow and return temperatures but low HWS temperatures at the effected area - low flow issues to this area (design problem) - TMV s isolated / by-passed to improve flow LOW TEMPERATURES & DEADLEGS 40

41 Case Study Problem: Legionella issues in recently refurbished ward in hospital Investigation identified - good temperatures to the effected areas - refurbished rooms had sinks and separate shower rooms which were not used - pipework connected to TMV s with flexible hoses to the taps DEADLEGS & FLEXIBLE HOSES 41

42 Risk Assessments When should my risk assessment be reviewed? The assessment should be a LIVING DOCUMENT and must be reviewed regularly. It must also be reviewed whenever there is reason to believe that the original assessment may no longer be valid. This may be because of, for example: 1. changes to the plant or water or its use; 2. changes to the use of the building in which it is installed; 3. the availability of new information about risks or control measures; 4. the results of checks indicating that the control measures are no longer effective; 5. changes to management/key personnel 6. a case of legionnaires disease associated with the system 42

43 The Management Loop Risk Assessment to IDENTIFY SIGNIFICANT RISKS Written Scheme to CONTROL those Risks Periodic AUDIT of performance against the Written Scheme ACTION PLAN to correct non-compliances Periodic REVIEW of Risk Assessment 43

44 Conclusion Legionella Management and Control is the responsibility of everyone We are all accountable We all must play our part and NOT leave it to others 44

45 Conclusion HSE Statements Risks of Legionnaires Disease are significant and deadly, hence costly preventative measures are justified There has never been a known case of Legionnaires Disease in a well managed system 45

46 Conclusion Legionella control does work in the real world Better L8 than Never! 46

47 Thank You Any questions? 47