What’s changed in the Legionella risk assessment standard?

Published on 04/26/2019 | by Waterline Admin
As featured in waterline Spring 2019

What’s changed in the Legionella risk assessment standard?

By David Fatscher, Head of Sustainability at BSI. Additional technical content by John V Lee, Leegionella Ltd

Outbreaks of Legionnaires’ disease continue to happen today. Recently, an apartment building in New York City saw 50 casualties and 2 fatalities, while in England and Wales, Government statistics reported 469 cases in 2018.

Legionellosis is a collective term for diseases caused by bacteria of the genus Legionella, an opportunist pathogen which normally inhabits warm, moist or aquatic environments. The most serious and potentially fatal is Legionnaires’ disease.

The first British Standard on assessing the risk of Legionella was published in 2010. Now a significant revision to the standard, in line with changes to the HSE’s Code of Practice, has been released.

BS 8580-1:2019 Water quality. Risk assessments for Legionella control. Code of practice applies to risk assessments undertaken on premises, plant and systems and where control measures may have been implemented. This revision now aligns the standard with HSE ACoP L8 and its associated guidance documents.

Legionella risk assessment is a legal requirement, making this standard invaluable to anyone responsible for the safe management of water systems, especially within hospitals, the wider healthcare industry, leisure centres and schools.

The regulations
Under the Management of Health and Safety at Work Regulations 1999, and the Control of Substances Hazardous to Health Regulations 2002, employers or those people in control of premises are responsible for understanding the associated health risks, and for carrying out Legionella risk assessments.

Why the need for a new standard?
In 2014, the UK’s Health and Safety Executive (HSE) updated its Approved Code of Practice and guidance for controlling Legionella bacteria in water systems, known as ACoP L8. It separated ACoP L8 from its technical guidance, this was further developed by industry groups into three distinct parts:

  • HSG 274 Part 1 is concerned with cooling towers
  • HSG 274 Part 2 is concerned with hot and cold-water services
  • HSG 274 Part 3 is concerned with “other” systems

The revised standard has been updated to bring it in line with the revised HSE documents and guidance. BS 8580 is referenced in, and is an important supplement to, the HSE documents. This revision of the original British Standard published in 2010, takes into account:

  • the separation of the ACoP L8 and HSG documentation
  • the shift from a single description of the risk assessment process and outputs, to the recommendations for the frequency of inspection in each of the individual industry groups (HSG 274 Parts 1, 2 and 3)
  • new information published in 2017 as HSG 282 – control of Legionella and other infectious agents in spa pools.

“BS 8580-1:2019 is a significant revision of the existing British standard BS 8580 published in 2010. BS 8580:2010, on the assessment of the risk of legionellosis presented by artificial water systems, was a widely applied and recognized standard throughout the industry. The revision, BS 8580-1:2019, now reflects current practice and should enhance standards even further.”

Water Management Society

Why is the incidence of Legionnaires’ Disease increasing?
Globally, there are increasing reports of Legionnaires’ disease; the reasons for this, perhaps, are a complex combination of improved medical science, demographics, technological advances and climatic change. Some argue the following factors may be relevant.

  • Improved ascertainment by clinicians and improved diagnostics.
  • An increasing proportion of the population that is susceptible – including increasing numbers of people who are older, have chronic illnesses and are surviving longer, are treated with immunosuppressants, or have chronic diseases, such as diabetes.
  • Increased travel – particularly in northern Europe, significant numbers of cases are associated with travel, where modern hotels have complex water systems with bathroom facilities for each room, along with spa pools, hot tubs, irrigation systems and cooling towers.
  • Increasing complexity of our artificial water systems – greater tendency for us to be exposed to colonised systems.
  • The drive for energy and water conservation – some argue this can lead to an increased likelihood of the colonisation of systems with Legionella.
  • Application of anti-scalding measures – some suggest they can increase the risk of systems becoming colonised with Legionella and causing Legionnaires’ disease.
  • Increased average ambient temperatures – some believe the effects of global warming can lead to the more frequent contamination of our water supplies and man-made water systems, eg if cold water supplies are warmer, these support the growth and survival of legionellae, the cause of Legionnaires’ disease.

“Legionnaires’ disease is an example of a consequence of humans adapting their environment to suit themselves and, coincidentally, creating conditions conducive to the growth of other organisms that may cause disease to humans.”

John V Lee BSc, PhD, FRSPH, FWMSoc, FPWTAG, independent consultant, public health microbiologist and Chair of BSI’s Legionella Risk Assessment panel

What’s changed in the standard?
The most significant changes relate to the competence of risk assessors (Section 5.1) and the preparation of the risk assessment report (Section 9).
Sections 8 ‘Evaluation of the Risk’ and section 10 ‘Risk Review and Reassessment’ have also had some reorganisation and modification to improve clarity.
The annexes have been updated in particular:

  • annex B on hot and cold-water systems has been extensively revised;
  • annex D, Spa Pools, has been updated to encompass the nomenclatural and other changes within HSG 282; and
  • annex E, Other Systems, includes more information on humidifiers, vehicle wash systems, and thermal processing of food.

Benefits of using the new BS 8580-1 standard
If followed, the guidance should lead to the production by competent individuals of brief, clear, user-friendly reports lacking superfluous information.
Dr John Lee, Chairman of the expert panel that revised the standard commented:

“The new standard should be essential reading for all those who commission and undertake Legionella risk assessments, as well as those teaching others to carry out these assessments. This standard will enable the commissioning and production of much more effective Legionella risk assessment reports.”

Why parts 1 and 2?
The standard’s name has changed from “BS 8580” to “BS 8580-1” because the drafting panel believed it necessary to develop a similar risk assessment standard for Pseudomonas – another pathogen, widely found in soil, water and plants, which can cause infections in humans. This will be published as “BS 8580-2”.

“We shouldn’t underestimate the risk Legionnaires’ disease poses today, and up-to-date guidance and recommendations for its prevention is as important as ever. The substantial revisions in this standard aim to enable anyone with responsibility for the health and safety of others in public premises, to take responsibility and adopt adequate prevention measures. Legionella risk assessment is a legal requirement, making the standard invaluable to anyone responsible for the safe management of water systems.”

David Fatscher, Head of Sustainability at BSI

New for 2019: Tracked-changes versions of Revised Standards
BS 8580-1 can be bought as a simple standard or as a ‘Tracked-changes package’ where customers receive both the new standard and a tracked-changes version.

BS 8580-1:2019
The standard gives recommendations and guidance on the assessment of the risk of Legionnaires’ disease, which is a legal requirement, presented by artificial water systems.

Available in PDF or Hard Copy. Price: £246 (BSI Members 50% off)

BS 8580-1:2019 + Tracked Changes
This package includes a copy of the new standard, along with a track-changed version which shows clearly what has changed from the 2010 standard, and what has remained the same. Available in PDF or Hard Copy. Price: £320 (BSI Members 50% off)

About BSI
BSI is the business improvement company that enables organizations to turn standards of best practice into habits of excellence. For over a century, BSI has championed what good looks like and driven best practice in organizations around the world. Working with over 86,000 clients across 193 countries, it is a truly international business with skills and experience across a number of sectors including aerospace, automotive, built environment, food, and healthcare. Through its expertise in Standards Development and Knowledge Solutions, Assurance and Professional Services, BSI improves business performance to help clients grow sustainably, manage risk and ultimately be more resilient.

BS 8580-1:2019

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WMSoc. Training


Specialist training for all aspects of legionella & water treatment.


Product Spotlight

PrimeLab Photometer

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