Three big changes to the British Standard on Legionella risk assessment for safer water systems

Although still rare, cases of Legionnaire’s diseases are rising in the UK and represent a life-threatening risk. Building services expert, Dr. Richard Beattie sets out the three key changes to the BSI’s recently updated Legionella guidance that responsible persons and occupiers need to know to manage this threat effectively.

Contaminated domestic water poses a serious threat to health, in particular for those with weakened or impaired immune systems, and recent studies show an increase in infections in healthcare facilities. For example, in 2018, a hospital was fined £300,000 and a private care home £3 million in the UK for health and safety breaches that resulted in patients’ deaths due to Legionnaire’s disease.

Employers, occupiers and others responsible for the control of hospitals and premises across sectors need to ensure that the quality of water they provide is safe, and actively work to reduce the risks of exposure to infection.

To help with this, the BSI recently published BS8580-1-1:2019 Water quality. Risk assessments for Legionella control. Code of practice. The new guidance updates the original British Standard — reflecting the revisions made since its release in 2010, and incorporating supplementary materials previously published separately.

Drawing on our specialised expertise and experience in this area, these are the three biggest changes to the British Standard that employers and people in control of premises (the Duty Holder or Appointed Person) need to know to identify and manage the risks associated with Legionella more effectively and perform risk assessments to the standard required.

1/ Defining and ensuring the right level of competence

The term ‘competence’ is often used in water guides, but rarely defined in detail. And, prior to the 2019 guidance, no minimum level of qualification or experience has been required to undertake risk assessments.

BS 8580-1 seeks to rectify this, setting out the essential criteria that a Responsible Person should consider when appointing their risk assessor, and the standards of detail, clarity and quality that their final risk assessment report should meet.

Primarily, this involves ensuring that the assessor demonstrates the appropriate specialist knowledge, experience and understanding of the factors that contribute to legionella colonization, as well as the water systems and equipment to be assessed.

To assist with this, the guidance provides a list of questions for building owners to ask when sub-contracting their risk assessments to make sure they appoint the appropriate risk assessor for their organisation’s needs.

This includes, for example, consideration of the assessor’s previous work: How previously has the assessor evaluated a risk? How has the risk assessor undertaken prior surveys? And measured the issues? Does the risk assessor understand how to mitigate a risk? Such as in maintenance regimes?

Also, as water systems vary in complexity depending on the nature of the building and their usage, what is the depth of the risk assessor’s understanding of the facility’s water system and its associated equipment? Is the hot water calorifier reaching temperature? And are the water services’ flow temperatures in compliance?

For the BSI, comprehensive answers to these questions and others covered in the guidance are essential to ensure an assessor’s competence, help reduce harmful bacterial growth in water systems and reinforce compliance.

2/ Highlighting the biggest points of risk

Building on this, the revised British Standard provides additional details to the elements of inspection. These 11 points are designed to inform more comprehensive assessments — again emphasising the levels of competence and standard of risk assessment required to help manage water systems safely.

The 11 points to risk cover:

  • Dead ends — no flow points, capped ends, etc.
  • Little-used outlets.
  • Imbalances in water flow.
  • Routes for potential contamination.
  • Cool areas at the base of calorifiers.
  • Cross flow of hot and cold water systems.
  • Locations for potential incubating temperatures
  • Sources of heat transfer.
  • Materials of construction.
  • Sources of nutrients for bacterial growth.
  • Any changes to the system that might cause stagnant areas.

3/ Looking at the bigger picture

The BSI has also updated the Annexes to BS 8580-1, with extensive revisions made to Annex B (informative) — hot and cold water systems. This includes, in section B.8, advising that the assessor should inspect the whole system and not just the tanks and calorifiers; and that, during the inspection, the assessor should look for any elements of the design, construction or operation of the water system that could lead to conditions for Legionella growth.

More information has been provided on spa pools, humidifiers, vehicle wash systems, and thermal processing in the food industry (pasteurizers), to elaborate on the limited information given in previous documents relating to these risks.

Finally, one of the most obvious updates to the guidance is that its name has changed from BS 8580 to BS 8580-1. This is in preparation for the later planned release of a risk assessment standard for Pseudomonas, a common bacterium found in soil and water that can cause infections in humans — usually with weakened immune systems or long-term lung conditions.

For full reference, the BS 8580-1 2019 can be obtained with track changes, helping readers to see more clearly the updates made to BS 8580:2010.

Dr. Richard Beattie is the CIBSE, Society of Public Health Engineers representative for Scotland.

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