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The first British Standard on assessing the risk of Legionella was published in 2010. Now a significant revision to the standard has been released. This blog post explains why and outlines what’s changed.

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

Outbreaks of Legionnaires’ disease regularly attract media coverage. For example at the time of writing an apartment building in New York City has generated local headlines as a result of 59 people falling ill and two fatalities.[1] Closer to home, would you be surprised to learn that the most recent UK Government statistics, from December 2018, report that 469 cases of Legionnaires’ – a notifiable disease – were recorded in England and Wales last year?[2]. Clearly Legionnaires’ disease isn’t going away.  

Consequently, employers or people in control of premises are responsible, under the Management of Health and Safety at Work Regulations 1999 and the Control of Substances Hazardous to Health Regulations 2002, for understanding the associated health risks and for carrying out Legionella risk assessments. To help them do so, in 2010, BSI published the first edition of a British Standard, BS 8580, designed to help those performing and commissioning Legionella risk assessments.

In 2014, the UK’s Health and Safety Executive (HSE) made changes to its Approved Code of Practice and guidance on controlling legionella bacteria in water systems, otherwise known as ACoP L8. It separated ACoP L8 from its technical guidance. Then the guidance was further developed by industry groups into three distinct parts as follows:

• 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

In addition, in 2017 the HSE published HSG 282 The control of legionella and other infectious agents in spa pool systems.

The principles of Legionella risk assessment have not changed but the introduction of these new HSE documents meant that updates had to be made to the related British Standard. This has now been published as Water quality. Risk assessments for Legionella control. Code of practice and the changes are outlined in more detail below.

What the changes entail

The most significant changes relate to the competence of risk assessors (section 5.1) and the preparation of the risk assessment report (section 9). If followed the guidance should lead to the production by competent individuals of brief, clear, user-friendly reports lacking superfluous information. Section 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.

Finally, close observers will notice that the standard’s name has changed from “BS 8580” to “BS 8580-1”. This has happened because the drafting panel felt that it’s going to be 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. The plan is that in due course this will be published as “BS 8580-2”.

In the meantime, anyone involved in the safe management of water systems can turn to the revised version of BS 8580-1. It supplies recommendations and guidance on conducting Legionella risk assessments, both a legal requirement and a way to keep people in your building safe from Legionnaires’ disease.

Tracked-changes versions of Revised Standards

This year, BSI is offering tracked-changes versions of key standards that have been revised, to help users see clearly what's changed and what's stayed the same. BSI is pleased to say that 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.