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Water Services

About Legionnaires' Disease

Legionnaires' disease is a potentially fatal form of pneumonia which can affect anybody, but which principally affects those who are susceptible because of age, illness, immunosuppression or smoking.

It is caused by the bacterium Legionella pneumophila and related bacteria that can be found naturally in environmental water sources such as rivers, lakes and reservoirs, usually in low numbers. As they are commonly found in environmental sources they may also be found in purpose built water systems such as cooling towers, evaporative condensers and whirlpool spas.

If conditions are favourable the bacterium may grow creating conditions in which the risk from Legionnaires' disease is increased. It is therefore important to control the risks by introducing measures outlined in the Approved Code of Practice & guidance document Legionnaires' disease – the control of legionella bacteria in water systems (L8) [1].

Who is more likely to contract Legionella?

Anyone can be infected, but, the following groups are susceptible.

  • People ages 50 plus
  • Men are 3 times more likely to be infected
  • Those with existing respiratory infections
  • Smokers
  • People taking Immune Supressant drugs
  • Illnesses that weaken the body's natural defences (e.g. Diabetes, Cancer, Kidney diesease and Alcoholism)

Any equipment containing water likely to exceed 20 degrees Celsius and which release an aerosol or spray needs to be assessed. These include:

  • Hot and cold water systems
  • Laundry systems
  • Hydrotherapy pools
  • Birthing pools
  • Spa pools
  • Swimming pools, saunas, Jacuzzi's and hot tubs
  • Condensers and Air Handling units
  • Cooling Towers
  • Dust Suppression and Cooling systems
Case Study

The worst outbreak of Legionnaires' disease in the UK was recorded in
Barrow in Furness in 2002. Six women
and one man died with 172 others contracting Legionnaires' disease. The cause of the outbreak was traced back to a contaminated Cooling Tower at the town's Arts Centre. 
The Borough Council were charged (but cleared) with corporate manslaughter – however they were fined for breaches of Health and Safety Regulations along with Architect, Gillian Beckingham.

Legionella ACo P L8 Management

Legionnaires' disease occurs as a result of infections caused by the legionellaceae family of bacteria. This form of pneumonia results in around 250 identified cases a year and can prove fatal, especially to the elderly or those mentioned above.

Legionnaires' bacteria occurs naturally in surface water and soils etc. but can also proliferate within man made environments such as Cooling Towers, hot and cold distribution systems, water plants, humidifiers and air washers.

Proliferation of the bacteria typically occurs between 20∘C – 45∘C and is assisted by the presence of suitable nutrients present in dirt, sludge and scale as well as conditions of poor water flow, stagnation or where dead legs occur in water systems. Employers are required to control the risk of exposure to Legionella bacteria in accordance with control of Substances Hazardous to Health Regulations. This is achieved by following the Approved Code of Practice L8, The control of Legionella (Bacteria in Water Systems). In general these require the employer to conduct the following:

• Identification & assessment of risk
• Prevention or minimisation of risk from exposure to Legionella
• Systems for management and selection, training and competence of personnel
• Record keeping of maintenance, cleaning and disinfection

How can Wright Rain Environmental Water Services help you?

WRE Water Services staff will work with you and your organisation to ensure the risk from legionella is minimised whether it is reviewing and updating risk assessments, conduction routine testing and sampling or advising on appropriate control strategies, you can be rest assured that in choosing WRE Water Services the risk from legionella will be controlled giving you, the client, 'Peace of Mind'.

Legionella Risk Assessment

The aim of a Legionella Risk Assessment is to assess and record the extent, condition, design and management of all water systems within a property. It assesses and describes the risk of bacterial contamination by Legionella species, the potential for the bacteria to multiply and the potential for this to infect people with Legionnaires ' disease.

The assessment allows site management, in conjunction with WRE, to instigate the required remedial actions to reduce any perceived immediate risk and to implement a control regime to manage the risk long term.

The WRE Assessment is not filled with generic statements copied from guidance documents but is site specific in the individual site requirements. When presenting the report it is done in such a way as to make understanding of the requirements easy. At WRE Water Services we pride ourselves on providing a truly bespoke assessment which complies with BS8580 using suitable qualified and experienced personnel.

Our partners are audited members of the Legionella Control Association, along with being accredited by ISO9001 and Exor. This approval gives you the guarantee that not only do we carry the required Professional Indemnity insurance but that your report will be carried out by true professionals with years of experience.

Legionella Control Regimes

Where a risk from Legionella has been previously identified, usually from a technical survey and report, a regime of control is required. At WRE Water Services we believe that the level of frequency of the regime should reflect the risk level. We initially work with our client to establish an agreed programme and then provide suitably qualified and experience staff to undertake the required duties. We are also happy to work alongside the clients own personnel by providing audit services and required monitoring paperwork and log books.

Continuous Disinfection / Chlorine Dioxide

All commercial domestic water systems should have a continuous bacterial control regime in place. Traditionally most systems have used temperature as a control, hence the need to regularly monitor this aspect. Increasingly continuous injection of chemical disinfectants is used as an alternative. This must be completed under approval of DWI. The most common chemical disinfectant used for these purposes is Chlorine Dioxide normally generated at the point of injection by the controlled blending of two chemicals.

There are many benefits of this system which include 24/7 protection and potentially massive energy savings, there are many applications that would benefit from this system. For further details please contact us.

Where can I get further information?

More detailed guidance on your duties can be found in the Approved Code of Practice and Guidance Legionnaires' Disease@ The control of legionella bacteria in water systems. Approved Code of Practice and guidance L8 (third edition) HSE Books 2000 ISBN 978 0 7176 1772. Part 1 of this publication contains advice on your duties under the law. Part 2 contains guidance on technical aspects of the assessment and control of legionella risks.

You can also obtain advice from:

• HSE Info line:
• Environmental Health departments of local authorities:
• Professional bodies and organisations such as The Chartered Institution of Building Service Engineers (CIBSE). The Building Services Research and Information Association (BSRIA): and associations such as The Water Management Society (WMS) or The British Association for Chemical Specialities (BACS)

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