Health and Safety Executive

Health and Safety Executive

Overview of Control of Legionella in Hot and Cold Water Systems & COSHH& Enforcement!

Martin BelcherSpecialist Inspector – Occupational HygieneHSE – Cardiff office

COSHH

COSHH Regulations:

• Introduced 1988

• Number of EC directives

• Amended in 2002

• ACoP

• Guidance

• 21 Regulations

• 9 Schedules

COSHH

Regulations:

• 6 – Assessment of the risk to health

• 7 – Prevention or control of exposure to substances hazardous to health

• 8 – Use of control measures

• 9 – Maintenance, examination and testing of control measures

• 10 - Monitoring exposure at the workplace

COSHH (cont.)

• 11 – Health surveillance

• 12 – Information, instruction and training for persons who may be exposed to substances hazardous to health

• 13 – Arrangements to deal with accidents, incidents and emergencies

• Also need to consider the Management Regs

Legionella bacteria: the organism

and disease

.

Description of organism

• Aquatic

• Aerobic

• Mobile, due to flagellum

• Respirable - 1-3µm long & 0.5-1µm wide

• Thin faintly-staining gram negative non-spore forming rod-shaped bacteria

Habitat

• Widespread in natural water sources• Rivers• Lakes• Streams• Sewage-polluted coastal waters• Mud and soil

• Also in many man-made water systems

Legionella

Conditions which favour growth:

• Legionella bacteria are present in both natural and artificial (man made) water systems

• The bacteria multiply when– Temperatures between 20-45oC– Nutrients (food) is available– Water is stagnant or slow moving– Formation of biofilms - important

Biofilm

A community of bacteria and other microorganisms embedded in a protective layer with entrained debris, attached to a surface

Biofilm can protect against chemical and thermal disinfectants

Biofilm

• Protozoa (e.g. amoeba) grazing on the biofilm can engulf bacteria which can then grow inside the protozoan cyst

• Some protozoa are thermo-resistant

Aetiology

• July 1976

• Bellevue-Stratford Hotel, Philadelphia

• 3 Day Pennsylvania State Convention of the American Legion

• Bicentennial celebration of the Declaration of Independence

• 2000+ ex-servicemen

‘Mystery’ disease

• 33 of 221 (15%) patients died

• 82% of cases were convention delegates

• Unknown cause

• 6 months later – a ‘new’ bacteria isolated (in water sample from air conditioning system cooling tower)

Laboratory culture

• BS7592: 2008

• Water samples (≥1 litre) collected from representative location

• Filtered to concentrate then re-suspended from filter

• Acid-treated to help remove non-Legionella competing bacteria

Other Legionella Detection Methods

• PCR (polymerase chain reaction)

• Detects legionella DNA and amplifies it to a measurable amount

• Acts like a genetic photocopier

Legionella

Legionnaires disease:

• Potentially fatal form of pneumonia– 90% of cases are caused by Legionella

Pneumophilia SG1 (SG2-14)– Onset of illness 2- 10 days– Can effect anyone but some people are at

higher risk• Age, sex, smokers, heavy drinkers, chronic

respiratory disease, suppressed immune system

Legionella

Infection route:

• People are infected with Legionella when they breath in tiny water droplets which contain the bacteria

• It is not passed from person to person

• It is not caught by drinking water containing the bacteria

Chain of Infection

Legionella Cases Sept

Legionella Cases

Legionella Cases

Health and Safety Executive

Health and Safety Executive

Legionella in Hot and Cold Water Systems

Risk Assessment and Control

Legionella

Types of Hot/Cold water Systems

1. The system does not have storage tanks

2. The system has hot water storage tanks but no cold water storage tanks

3. The system has cold water storage tanks but no hot water storage tanks

4. The system has both hot and cold water storage tanks

Gravity System WITHOUT Recirculation

Cold water stored in tanks

Feeds calorifier and cold water outlets to point of use

May be long runs of pipework to outlet, particularly in hot water

Gravity system WITH recirculation

Continuous circulation of Hot Water maintained by one or more pumps (NB standby pumps should be alternated or flushed)

Cold Water Storage Tanks

Pressurised systems

• Fed directly by a pressurised supply

• Expansion vessels

• Re-circulating and non-recirculating

Expansion vessels (hydraulic accumulators)

• Preferably be flow through design

• Have a drain valve– flush through and purge to drain

(HSG274 Pt2 Table 2.1)

• Minimise volume stored

• Should be sited– in cool areas– vertically on pipework

not horizontally

Thermostatic Mixing Valves (TMVs)

Blended water to hot tap

Supply to cold water tap

TMV

Cold water into TMV

Hot water into TMV

Assisted Baths

• Separate cleaning shower head system

• Hydro-massage function

• Flexible hoses

• Expansion vessels

• Filters

Risk Assessment

Risk assessment:

• Duty holders should assess the risk from their water system

• Where there is an identified risk, the duty holder should draw up a written scheme identifying the measures to control Legionella

• This should include a schematic diagram of the water system

Risk assessment

Legionella risk assessment should include:

• Management responsibilities

• Description of the water system

• Susceptibility of persons

• Potential sources of risk

The written scheme should include details of:

– Controls in place– Monitoring, inspection and

maintenance procedures– Records

Written Control Scheme

• Temperature monitoring arrangements– temperature profiling– location of sentinel points

• Other control regime checks e.g. Chlorine dioxide• Legionella monitoring arrangements (if required)

• healthcare premises, patients at increased risk.• doubt about the efficacy of the control regime. • where recommended temperatures, disinfectant

concentrations or other precautions are not being consistently achieved.

• Up to date Schematic

• Flushing regime

• Inspection and cleaning regime

• Action to take in the event of a suspected case of LD

Written Control Scheme

Legionella – schematic

Legionella - schematic

Up to date schematics may help to identify dead-legs

• Dead-ends are typically sections of pipe where no water flows

• May encourage biofilm formation

• Biofilm - Bacteria and other micro-organisms embedded in a protective layer

• Dead-legs should be removed

Legionella - controls

Legionella control Methods

• The principle control method is temperature control

• Other control measures include the use of:– Biocide treatment (e.g. chlorine

dioxide)– Copper/silver ionisation

• These can be used as an alternative or as an additional control to temperature

Temperature Control

• <20°C remains dormant (but viable)

• >50°C 90% kill in 2 hours

• >60°C 90% kill in 2 mins

• >70°C 100% immediate kill

Temperature Control

• Temperature Control Regime (see Table 2.1 HSG274 Part 2– Cold water storage <20°C – Cold water outlet <20°C after 2 minutes of

running– Hot water storage 60°C – Hot water outlets >50°C within 1 minute of

running (Healthcare >55°C)– Hot water should return to calorifier not less than

50oC

Legionella - monitoring

Monitoring:

• Hot and cold water systems need to be monitored to ensure:– The temperatures needed to control

legionella are being achieved– The system and the water in it are kept

clean– The system is in good condition

• The results of any monitoring should be recorded

Legionella - monitoring

Frequency of Monitoring Temperatures

• Guidance on the frequency of checking is published in the ACoP “L8”, and supporting guidance

• Additional guidance for health care premises is published in Health Technical Memorandum (HTM’s)– HTM 04 Part A – design, installation,

testing– HTM 04 Part B – operational

management

Legionella - monitoring

Frequency of monitoring temperatures:

• Monthly– Temperature of hot water tank outlet and

return (if recirculating)– Temperatures at “sentinel” cold and hot water

outlets

• 6 monthly– Temperature of the cold water tank

• Annually – Check temperature of a representative

number of hot and cold outlets on a rotational basis

Legionella – sentinels

Sentinel outlets – first and last outlets (for a recirculating system)

Legionella – other checks

• Frequency of other checks:

• At least weekly– Flush little used outlets

• At least 3 monthly– Clean/de-scale or replace shower heads and

hoses

• Annually– Visually inspect hot and cold water tanks– Check the schematic is up to date & accurate

Infrequently used outlet flushing records – look for gaps or evidence of not being completed/recorded

Legionella - monitoring

Microbiological monitoring:

• Routine biological monitoring of hot & cold water systems is not necessary

• However monitoring is recommended:– Where storage and distribution temps are

reduced– Where control levels are not constantly

achieved– When an outbreak is suspected– In hospital wards with at risk patients

• Results require careful interpretation

Common failings 1

• No Legionella risk assessment and occupiers are ignorant of the control and monitoring requirements (lack of competence)

• Assessment findings not being implemented

• No schematics or not comprehensive

• Sentinel outlets not identified

• Not measuring hot water temperatures at inlet to TMVs where fitted

• Homes only measure and record hot water temps after tmv’s for scald risk

• Tmv’s fitted too far from outlet

• Not measuring hot water storage temperatures

• Hot water storage thermostats set below 50 degrees C

Common failings 2

• No temperature gauges fitted to hot water outlets and returns (and no one measuring with surface probe)

• Hot water vent pipe overflowing to cold water tank

• Cold water stored above 200C (e.g. un-insulated cold water tanks located on roofs)

• Cold water tank lids not tight fitting or broken

• Insects screens not fitted to cold water over flows and vents

• Dead legs / ends present

• Infrequently used outlets not flushed weekly

• No cleaning of shower heads

• Evidence that some Water treatment company reports do not reflect the inadequate management, treatment and control of legionella at the homes

Health and Safety Executive

Health and Safety Executive

Regulatory Approach

L8 APPROVED CODE OF PRACTICEHSG274 TECHNICAL GUIDANCE

Regulatory Approach

• Established from Case Law - R v Board of Trustees of the Science Museum

• Pivotal in support of approach taken in L8 ACOP

Science Museum Prosecution 1993

• Charge: S3(1) HSWA that for their air conditioning system they failed to:

• clean and disinfect• operate a water treatment system• monitor

• thereby exposing the general public to risks to their health from exposure to legionella

Science Museum Case

• Defence submitted that no actual risk to public health had been proved

• Trial judge directed that the prosecution:• Did not need to prove that a Member of

the Public had inhaled legionella bacteria• Did not need to prove that the legionella

bacterium was present within the building• It was sufficient to prove that there had

been a risk of it being there

Enforcement

• The thrust of any H & S enforcement action pertaining to legionella should be on proving that:-• Water temperature in the right range• Supply of nutrients available • Presence of aerosol• Potential for exposure to that aerosol

• NOT the presence of the legionella bacteria itself

– L8 ACOP (4th edition)– HSG274

• Part 1 – Evaporative Cooling Systems• Part 2 – Hot and cold water systems• Part 3 – Other risk systems• HSG282 – Spa pool systems

– INDG458 – Brief Guide for Employers– HSE Website

•L8 ACOP & HSG274

L8 and HSG274 Compliance with the law

…..Those who create the risks are responsible for managing the risks….

• L8– To help dutyholders understand what is

necessary to comply with their legal duties in relation to legionella

– To give practical guidance on how to assess and control the risks from exposure to legionella

• HSG274 – To help dutyholders understand how to effectively manage and

control the risk of proliferation of legionella in water systems

L8 Approved Code of Practice

Main elements• Risk assessment

– System as a whole, up-to-date schematic diagram

• Specific role of the appointed competent person– Responsible person

• Written control scheme– What it should include

• Review of control measures– Monitoring and routine inspection

• Responsibilities of designers, manufacturers, importers, suppliers and installers (including consultants)– Design and construction of water systems

The Responsible Person should…

• Have sufficient authority and access to funds.

• Be competent and have sufficient knowledge of the installation to ensure that all:– operational procedures, – responses to adverse results, and– remedial worksare carried out in a timely and effective manner.

The Responsible Person should…

• Be familiar with the systems under their management.

• Have a clear understanding of their duties and the overall health and safety management structure, governance arrangements and policy in the organisation.

• HSE-owned but produced in partnership with Industry Group

• WMSoc, LCA, BACS

HSG274Legionella Technical Guidance

www.hse.gov.uk/legionnaires/

HSE’s Legionella webpages

• Legal duties

• Specific risk systems – cooling towers, H&CWS, etc.

• Frequently asked questions – Risk Assessment, Competence, Landlords…

• Links and signposts to HSE and other external guidance

• Regular updates and news events (eBulletins, RS Feeds)

Enforcement

HSE Inspectors apply:

• Enforcement Policy Statement

• Enforcement Management Model– Determine the risk gap

• Operational circulars

• Operation guidance– OG00095 – control of Legionella: inspection of

cooling systems & investigation of outbreaks, clusters, and single cases of Legionnaires disease

– Initial Enforcement Expectations

Operational guidance

Operational guidance

Operational guidance

Operational guidance

CASE Study - BUPA

2015

• Mr Kenneth Ibbetson – 86 years old

• Admitted to BUPA care home in Essex – Hutton Village

• 12 weeks later contracted Legionnaires disease – resulted in his death

• Inquest - 2016

• Court case – 2018

• BUPA pleaded guilty – fine £3 million

Case study (cont.)

Key failings included:

• Poor temperature control,

• Inadequate standards of cleanliness,

• Fouled thermostatic mixer valves (TMVs),

• Presence of multiple dead legs,

• Poor record keeping,

• Responsible persons not trained

• Concerns were raised in 2012