May 2017

LEGIONELLA IN THE REAL WORLD

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LEGIONELLA IN THE REAL WORLD

Better L8 than Never

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LEGIONELLA IN THE REAL WORLD

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• Bellevue - Stratford Hotel, Philadelphia

• 21-24 July 1976

• American Legion Department of Pennsylvania hosted their 58th state convention - 211 people contracted disease - 29 died Disease was called Legionnaires Disease Causative organism was a bacteria Legionella pneumophila

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.

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Legionnaires Disease

Risk Profile

0

50

100

150

200

250

0-9 10- 20- 30- 40- 50- 60- >70 N/S

Men

Women

Men

40 - 70 years old

Smokers

Alcoholics

Diabetics Respiratory problems

Immunosuppressed people Children rarely infected

Everyone can catch

Legionnaires Disease but certain

people are more susceptible

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Legionnaires Disease

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

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Legionella

The route of infection is the inhalation of a contaminated aerosol

The smaller the water droplets, the deeper the inhalation, the greater the potential of infection

Aerosols <5μ can enter your alveoli, deep in your lungs

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Legionella

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

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Legal requirements

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 4th edition is now separate from the Technical Guidance Documents.

ACoP L8

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Legal requirements

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.

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Legal requirements

ACoP L8

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.

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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.

Legal requirements

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What are the common issues in legionella control?

Poor management

processes

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• Poor system

conditions.

• Infrequently used

outlets

• Dead legs

• Stagnation,

• Foreign objects in

tanks

• Poor control

measures

What are the common issues in legionella control?

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CAUSAL CHAIN

Property with water system

Virulent strain of Legionella enter the water system

Legionella Bacteria multiply

Aerosol production

Inhalation by susceptible

person

Legionnaires Disease

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RISK SYSTEMS

Any system that contains water which is likely to exceed 20o 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

Legionnaires Disease

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Living environment

• Water body - Natural or Man made • 25°C – 47°C (37°C optimum) • Biofilm • pH 6.5 - 7.5 • Sessile bacteria – loves stagnant water and will

not multiply in moving water. • Scale, sludge or sediment, wood, rubber and

dissolved iron

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Legionella

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Control Measures

Legionella Control is simple!

Keep it…

• Clean

• Moving

• At correct temperature

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

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Control Measures

Effect of Temperature

20oC

37oC

50oC

60oC

Below 20oC Growth is insignificant

37oC Optimum growth rate

Below 37oC Multiplication decreases

Above 46oC Growth ceases

At 50oC can survive for a matter of hours

At 70oC killed virtually instantaneously

At 60oC killed in 5 minutes

70oC

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Control Measures

Effect of Temperature Nos. of Legionella

Temperature

20 25 30 35 40 45 50 55 60 65 70

37 27 47

Legionella

Control

Legionella

Control

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Control Measures

Flow @ ≥60°C within 1 minute

Return @ ≥50°C* within 1 minute

Distribution @ ≥50°C* in 1 minute

Temperature Requirements

Storage @ <20°C*

Distribution @ <20°C* in 2 mins <25oC in high ambient condition environments

HWS

CWS

*55°C in healthcare

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Control Measures

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Control Measures

Legionella Control is simple!

Keep it…

• At correct temperature

Scale on Tap

Infrequently used outlet

Avoid conditions that will encourage growth

Deadleg

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Control Measures

Keep it moving Keep it clean

Effect of Stagnation

Removes effect of temperature control

Removes effect of chemical control

Removes effect of planktonic bacteria

removal

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Benefit of flushing Legionella

Start flushing

Stop flushing

Time

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Numbers of bacteria are often higher once flushing / usage has stopped

Control Measures

Frequent use or flushing will -

1. Prevent and remove localised bacterial contamination

2. Reduces the potential of systemic bacterial contamination

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Reduce the risk – flush the outlet!

Control Measures

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!

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What do you need to do?

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

Removal

If you are flushing the same outlet every week it should be considered for removal

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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

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Control Measures

Legionella Control is simple!

Keep it…

• Clean

• Moving

• At correct temperature

Biofilm

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• 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.

• Live in amoeba

Biofilm

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Biofilms

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• CWST – tide-marks around water line

• Outlets, sinks, sink traps, pipework • Ice-machines • Hydrotherapy pools

Biofilms

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• 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

Use of chemicals

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Control Measures

• Point of use filters, • UV on pipework & UV taps • 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

Control Measures

Physical Methods

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Control Measures

Legionella Control is simple!

Keep it…

• Clean

• Moving

• At correct temperature

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Problem: Extensive legionella issues in domestic hot water system of a school

Risk Assessment Identified

Single calorifier - flow temperature was at 55oC and the return temperature was at 44oC

Buffer vessel flushing – no records

Thermostatic mixer valve servicing – no records

Flushing regimes outside term time – no records

Calorifier inspections – no records

Case Study

LOW TEMPERATURES, UNDERUSED OUTETS, DEAD-LEGS

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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

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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

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

Risk Assessments

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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

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

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Conclusion

“Risks of Legionnaires’ Disease are significant

and deadly, hence costly preventative measures are justified”

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HSE Statements…

“There has never been a known case of Legionnaires Disease in a well managed system”

Conclusion

Legionella control does work in the “real world”

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Better L8 than Never!

Conclusion

Any questions?

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Thank You