What is Legionella?A naturally occurring

bacteriumFound in most water

systemsOften present in mains

water Easily colonises most

domestic water systems – hot and cold

Requirements for Growth?

Optimum temperature range of 20 - 45 ⁰C

Food source (other bacteria & sediments)

Prefers stagnant conditions

Route of Infection?Primarily through inhalation of

aerosols, fine droplets & mistsCan be contracted by choking

on contaminated water Statistically most susceptible

- 50 to 70 year olds- Males- Smokers

How big a risk?

Legionnaire’s DiseasePotentially fatal form of pneumonia –

5-30% fatality rate

200-300 cases of infection in England & Wales annually

Incubation period 2-10 days - typically 3-6days

Legionella pneumophila – 23 sub typesHSE view Legionnaire's Disease as

“preventable” assuming management failure!

LegislationThe Health and Safety at

Work etc Act 1974Management of Health

& Safety at Work Regulations 1999

COSHH 2002 ACOP L8 (see front

cover)

L8 Guide to Successful ControlRequires: Management regime in placeRisk AssessmentsControl regimeMaintenance and upgradeReview

Risk Assessments should:Identify & quantify relevant wet systems plus

equipment holding / circulating waterAssess potential for Legionella growthIdentify who is at riskAssess the potential for bacterial transferQuantify and prioritise the risksDetermine suitable means of control

UoS Responsibilities 1Statutory Duty Holder who is ultimately

responsible – Registrar & SecretaryAppointed Responsible Person for day to day

management – Director of EstatesDeputy Responsible Person to cover holidays

and illness – Head of Engineering OperationsResponsibility cannot be delegated

UoS Responsibilities 2Policy for the Control of Legionella bacteriaManagement structure in place with

Contractors charged with carrying out: -Legionella Risk assessments of all buildingsTreatment of water assets where requiredSampling and analysis of water systemsRemedial works incl. removing “dead-legs”

5 Zones - Engineers managing Contractors

Current PositionCurrent regime in place for > 2 years95% buildings assessed (some low risk o/s)Current costs ~ £250,000 paMonitoring of sample results on-line Legionella Procedures Manual in placeLegionella Control Steering Group – 3 meetings

per year chaired by Prof R F JacksonPolicy and Procedures on Safety Services website

Typical Systems at RiskCooling TowersDomestic hot & cold water systemsWater features incl. ornamental fountainsEquipment producing aerosols, mists or

droplets from stored water sources including showers & humidifiers

Equipment holding / circulating water at 20 - 45⁰ C

Examples of lab & workshop equipmentWater tanks & bathsSpray tapsWater recirculation systems for coolingRarely used taps & showers (even at home)Misting equipmentDentistry toolsOil / water emulsions for lubricating lathesMobile AC equipment with water

Controlling Legionella bacteriaTemperature monitoringControlled release of water sprayAvoid temp. conditions 20 - 45⁰ CAvoid water stagnation - empty & clean regularlyAvoid materials which harbour bacteriaMaintain cleanliness of spray outletsWater treatment where necessaryEnsure correct & safe operation of systemFlushing regime for rarely-used outlets

What Departments need to do - 1Identify a Nominated Person to help you

manage Legionella risks in your DepartmentIdentify & record all : -

water-containing equipment which operates in the temperature range 20-45⁰C

all rarely-used taps & showersall equipment supplied from stored water

sources producing sprays, mists or aerosolsAssess the risk of Legionella growth in each

What Departments need to do - 2Check Legionella Procedures Manual for

information of the management of specific items of laboratory equipment

If your equipment is not listed, determine the best means of reducing Legionella risks – if needed, contact Department of Estates for help

Consider which treatment options are the most appropriate from the next slide

Treatment / remedial optionsMonitor temperatures; 20-45⁰C = risk rangeEvery 2 weeks - heat water to 60⁰C for 5 minsAdd disinfectants / Chloros as advisedEmpty out the water system, thoroughly clean

& refill with fresh water every monthClean & disinfect spray heads every monthFlush rarely-used outlets weeklyArrange with Estates for removal of “dead-legs” Arrange with Estates for samples to be taken if

risk exists (sampling is NOT a control measure – it takes 10 days for results to be sent through – it monitors whether your controls work)

Next stepRecord all actions taken and

results received.Review the efficacy of the

treatment regime by checking the results of analyses received

Re-assess the risk assessment if there are any changes to the operating parameters or the system layout

Drinking water coolers2 types generally available:

Using large bottles of mineral waterPlumbed-in units

Legionella is not reported to be a problem with water bottle coolers, usually work outside “critical temperature range”,

1 reported instance of Legionella bacteria being isolated from Activated Carbon filters in a plumbed-in unit in New Zealand – replace as recommended by manufacturer.

We hope you found this information useful!