4.3 Prevention and control of legionellosis

4.3 Prevention and Control of Legionellosis

This Document forms part of the University Health and Safety Policy

Contents

• 4.3.1 Introduction
• 4.3.2 Scope and Application
• 4.3.3 Assessment of Risk
• 4.3.3.1 Risk Assessment
• 4.3.3.2 Preliminary Assessment
• 4.3.3.3 Full Risk Assessment
• 4.3.4 Management Selection and Training of Personnel
• 4.3.5 Protection of Personnel
• 4.3.6 Record Keeping
• 4.3.7 Hot and Cold Services
• 4.3.7.1 Responsibilities
• 4.3.7.2 Areas of Risk
• 4.3.7.3 Routine Inspection and Maintenance
• 4.3.7.4 Cleaning and Disinfection
• 4.3.8 Air Conditioning and Industrial Cooling Systems
• 4.3.9 Responsibilities of Designers, Manufactures Suppliers and Installers

• Control of Substances Hazardous to Health Regulations 2002
• Control of Substances Hazardous to Health (Amendment) Regulations 2004
  
• Approved Code of Practise L8

4.3.1 Introduction

Legionnaires disease is a type of pneumonia caused by organisms found in water. Legionellosis is the term used for infections caused by Legionella pneumophila and other similar bacteria. Legionnaires' disease is a pneumonia that principally affects those who are susceptible due to age, illness, immunosuppression, smoking etc. and may be fatal. Legionellae can also cause less serious illnesses which are not fatal or permanently debilitating but which can affect all people. Infection is caused by inhaling air borne droplets or particles containing the organism. The disease can have an incubation period of between two and ten days and may produce symptoms of high fever, chills, headache, muscle pain, coughing, diarrhoea and vomiting

Although the organism is common in water the disease is relatively infrequent. Only about 300 cases are reported in England and Wales each year, whereas there are 180,000 estimated cases of pneumonia.

Infection is attributed to inhaling Legionellae, either in those water droplets which are small enough to penetrate deeply into the lung, or in droplet nuclei (the particles left after the water has evaporated). Legionellae are widespread in natural sources of water. They may enter man-made systems or water services, where they can multiply under certain conditions, and if there is a means of creating and transmitting water droplets, people in the vicinity may be at risk. Most cases and outbreaks of Legionellosis have been attributed to water services in buildings, cooling towers and whirlpool spas. Other sources have been identified in foreign outbreaks including a humidification system, industrial coolants and respiratory therapy equipment.

As Legionella are common in natural water sources random sampling of the water system and services for the bacterium will frequently yield positive results, while negative results will not guarantee that it is not present elsewhere in the system. For this reason HSE do not recommend random sampling for Legionella. As a consequence, and as positive results could have considerable impact on the operation of Faculties and Departments, sampling within the university shall only be with the agreement of the University Safety Advisor, and where appropriate, users of the system. Sampling for Legionella is separate and different from sampling to assess water quality. As indicated above such sampling will only be carried out under specific conditions and in particular circumstances such as to monitor the effectiveness of control systems or to trace the source of infection.

2 Scope and Application

This Policy applies to all parts of the university involving a work activity and/or premises where water is used or stored and where there is a means of creating and transmitting water droplets which may be inhaled, thereby causing a reasonably foreseeable risk of Legionellosis.

Experience shows that the following present a risk of Legionellosis:

a) Water systems incorporating a cooling tower.
b) Water systems incorporating an evaporative condenser.
c) Hot water services, except where the volume of hot water in the system does not exceed 300 litres.
d) Hot and cold water services, irrespective of size, in premises where occupants are particularly susceptible, e.g. healthcare.
e) Humidifiers, air washers and portable dehumidifiers which create a spray of water droplets and in which the water temperature is likely to exceed 20⁰C.
f) Spa baths and pools in which warm water is deliberately agitated and recirculated.

g) Other plant and systems containing water which is likely to exceed 20⁰C and which may release a spray or aerosol (i.e. a cloud of droplets and/or droplet nuclei) during operation or when being maintained, may also present a risk e.g. spray tapes or showers.

3 Identification and Assessment of Risk

The procedures contained in this document are designed to assist Heads to assess the risk of Legionella to users of the university, to provide measures to control that risk and to put systems in place to ensure, as far as is reasonably practical, that compliance with this policy causes minimum disruption to the activities of the university.

This document places duties on the Director of Facilities and Estates who is responsible for the water systems within the University and the Heads of Faculties/Support Departments using their own equipment, e.g. filters, humidifiers and dehumidifiers.

This policy is based upon the Control of Substances Hazardous to Health Regulations, the Control of Legionellosis, (HSE HS(6)70) and the HSC Approved Code of Practice for the Prevention or Control of Legionellosis.

3.1 Risk Assessment

A suitable risk assessment must be carried out to identify the risk of Legionella from work activities, water sources and the necessary precautionary measures The need for a risk assessment applies whenever water is stored or used in such a way which may create a reasonably foreseeable risk of Legionellosis and in particular:

a) Water systems including a cooling tower.
b) Water systems including an evaporative condenser.
c) Hot water systems containers over 300 litres.
d) Humidifiers, air washers etc. and all other items of equipment which may create a spray of water droplets in which the water temperature may be over 20°C, e.g. showers.

e) Spa baths and pools in which warm water is deliberately agitated and recirculated.

The Director of Facilities and Estates (in the case of building water systems etc.) or the Dean of Faculty/ Head Support Department responsible for specific items of equipment must:

a) Identify and assess the sources of risk.
b) Prepare a scheme for controlling the risk.
c) Implement and manage controls.
d) Monitor the effectiveness of controls by means of temperature recording and examination of the system.
e) Supply the Health and Safety Management and Training Unit with information and copies of the risk assessments and records.

3.2 Preliminary Assessment

Where the preliminary assessment demonstrates that there is only a trivial risk no further assessment or measures are necessary.

The assessment should be reviewed regularly and in any case whenever there is reason to believe that the original assessment may no longer be valid. This may be because of changes to the use of the building, plant or water system or the availability of new information about risks or control measures or having obtained results after monitoring of temperatures or bacterial examination indicating that control measures may be no longer effective.

3.3 Full Risk Assessment

Where the Preliminary Assessment shows that there is other than a trivial risk, a full risk assessment should be undertaken. The assessment should be supplemented by such information about the plant or system as is necessary to reduce or contain the risk to acceptable levels. This information will include an up-to-date plan or schematic showing layout of the plant or system (including parts temporarily out of use ) a description of the correct and safe operation and the controls necessary to:

a) Minimise the release of water spray.
b) To avoid water temperatures and conditions that favour the proliferation of Legionella.
c) To avoid water stagnation and the use of materials that harbour or support the growth of micro-organisms.
d) To maintain the cleanliness of the system and water and the use of water treatment techniques.

The assessment should specify measures to be taken to ensure that the controls remain effective, including any checks to be carried out on water temperatures, conditions of tanks etc. and their frequency.

4 Management and the Selection and Training of Personnel

Heads have a delegated duty to ensure that those persons who carry out the risk assessment and who draw up and implement precautionary measures should have such ability, experience, instruction, information, training and resources as to allow them to carry out their tasks competently and safely. In particular, they should:

a) Be aware of the potential hazards and the risks they present.
b) Understand the control measures to be adopted, including precautions to be taken for the protection of people concerned and their significance.
c) Be competent in the use of the University of Bedfordshire risk assessment system.
d) Be aware of the potential effects of their actions on other staff and cost centres within the university and of the management and communication procedures necessary to minimise difficulties and losses to University of Bedfordshire.

5 Protection of Personnel

Maintenance, cleaning, testing and operating procedures should be designed to protect works personnel and users of the building. Specific Risk Assessments should be completed for any processes involving the use of cleaning reagents covered by COSHH or where any procedure might, if adequate precautions were not taken, expose staff to infection.

Appropriate protective clothing and respiratory protection must be provided.

All affected water outlets must be labelled during chemical disinfection and notices displayed at the entrance to buildings. Appropriate precautions and notices should be provided during thermal disinfection.

If procedures will involve the interruption of drinking water or the supply of water to sanitary facilities etc. provision should be made for the staff working in the area.

6 Record keeping

The Director of Facilities and Facilities and Estates shall ensure that appropriate records are kept, including:

a) A description and plan of the system in each building identifying storage and header tanks, calorifiers, softeners, filters, strainers, pumps etc.
b) The risk assessment and supplementary information detailed above.
c) Records showing when the system or plant is in use and if not in use, whether it is drained down.
d) Details of the implementation of control measures and monitoring. These should be in sufficient detail to show that they were carried out correctly and the dates on which they were carried out, the results of any inspection, test or check carried out and the dates, remedial work required and carried out and the date of completion.

7 Hot and Cold Services

7.1 Responsibilities

While overall responsibility for hot and cold services rests with the Facilities and Estates Department, in certain areas specific duties may be delegated to others, e.g. Facilities or Halls staff, by agreement. Deans and Heads of Support Departments are responsible for:

a) Tanks, calorifiers, dead legs, shower heads, intermittently ceased services which form part of their current equipment and complete items of 'departmental' equipment such as portable humidifiers and water softeners.
b) Recording temperatures and their running systems where this is required monthly.

7.2 Areas of Risk

The higher risk parts of the system are:

a) Water storage tanks and plant, such as water softeners, where the water system is allowed to become warm, e.g. in poorly insulated pipes in roof spaces or pipes in a warm part of a building where use is intermittent if water temperature exceeds 20⁰C, e.g. showers in halls during vacation.

b) Calorifiers where water is at between 20-45⁰C, possibly as the result of intermittent use.
c) Deadlegs, e.g. pipes leading to emergency eye wash stations.

Water services should operate at the following temperatures:

a) Hot water storage (calorifiers) 60°C - measured at the equipment or the nearest tap.
b) Hot water distribution. At least 50 °C attainable at all taps within one minute of running.
c) Cold water distribution and storage 20 °C or below.

Where the above temperatures cannot be maintained Facilities and Estates will be responsible for implementing additional controls, identified as part of the risk assessment, to reduce the risk to an acceptable level, e.g. treatment by thermal disinfection, on-line pasteurisation or continuous chlorination at 3 mg chlorine per litre at intervals identified as part of the assessment control measures.

7.3 Routine Inspection and Maintenance

The water system should be inspected and maintained as follows:

a) Water temperatures at calorifiers - monthly.
b) Water temperatures at taps after one minute running - at least once a year, with a representative number near calorifiers monthly.
c) Condition of tanks and calorifiers, accessible pipework and insulation - annually.
d) Water softeners, filters, strainers, portable humidifiers, dehumidifiers etc. should be checked as advised by the manufacturers or monthly if the manufacturer's recommendations are not available.

Where the system is not in stable operation more frequent inspections may be necessary.

If inspection reveals contamination, damage or malfunction remedial action should be instigated.

Details of the inspection programme will form part of the Facilities and Estates Department’s ‘safety plan’.

7.4 Cleaning and Disinfection

Water services must be disinfected before being brought into use and if:

a) Routine inspection shows it to be necessary.
b) The system has been substantially altered or entered for maintenance purposes in a manner which may lead to contamination.
c) Following the isolation, or an outbreak of, Legionellosis.
d) Following annual cleaning.

Facilities and Estates will normally be responsible for the above except in the case of Faculty/ Departmental equipment, where the Head will be responsible by prior agreement for such equipment. Heads should notify Facilities and Estates of the type and location of equipment so that details may be entered on the plan of the building.

8 Air Conditioning and Industrial Cooling Systems

Cooling towers and evaporative condensers present particular risks and the standards of design given in the HSE document ‘Control of Legionellosis’ should be applied to all uses and modified systems.

Facilities and Estates are responsible for notifying the local authority and the University Safety Advisor of any buildings containing cooling towers or evaporative condensers and of any subsequent changes.

The risk assessment and control systems required for such systems are set out in HS(G)70

9 Responsibilities of Designers, Manufacturers, Importers, Suppliers and Installers

Whoever designs, manufactures or supplies plant or water systems that may create a risk of Legionellosis should, so far as is reasonably practicable:

a) Ensure that the risk is avoided or, where this is not reasonably practicable.
b) Ensure that the plant or water system is so designed and constructed that it will be safe and without risks to health when used at work.

Designers, manufacturers, or suppliers of plant or water systems should be required by the Head to provide adequate information to the user on the risk and about conditions necessary to ensure that the plant or water systems will be safe and without risks to health during operation and maintenance. Where appropriate they should carry out testing, or arrange for testing to be carried out to ensure that the plant and systems will be safe when used at work. Such testing will be by arrangement with the user of the plant or service so as to minimise the risk/losses to the university.

Suppliers of products and services, including consultancy and water treatment services, aimed at preventing or controlling the risk of Legionellosis, should.

a) Comply with University of Bedfordshire requirements in respect of contractors.
b) Provide adequate information on the correct and safe use of products and their use.
c) Ensure that all plant and water services are properly installed and commissioned, where appropriate, before use.