Shaping the future of legionella control
Legionnaires’ disease or Legionellosis is a potentially fatal form of pneumonia. People may get infected when they breathe in tiny water droplets (aerosols) or droplet nuclei (particles left after the water has evaporated) contaminated with elevated concentrations of Legionella bacteria.
Legionella bacteria grow best between temperatures of 20°C – 45°C, with optimum growth temperature being 35°C – 40°C. High temperatures (minimum 60°C) usually kill the bacteria.
Legionella bacteria are found in low numbers in natural aquatic environments, for instance, lakes, rivers and ground water. As a result, it is virtually impossible to prevent Legionella bacteria entering man-made water systems.
In low numbers the bacteria are generally considered harmless. With the correct conditions, for example, warm water, the presence of micro-organisms and nutrients in the water or materials such as rust, these bacteria can grow and multiply to high levels which increase the risk of exposure.
The bacteria tend to grow in biofilms (slime). Biofilms are likely to form on surfaces where there is low water flow or water is allowed to stagnate. However the growth of Legionella bacteria can be controlled.
As a buildings/facilities manager or Responsible Person, you have clear responsibilities around the control of Legionella bacteria in your water systems. Specifically, you MUST:
Legionella Control Services
HBE is audited by and a certified member of the Legionella Control Association across the UK and Ireland. We provide the following services to help the building manager to discharge their duties and obligations relating to the control of legionella bacteria in water systems:
Ask us about the future of Legionella Monitoring & Flushing:
The Legislation & Guidelines for Legionella Control
We adhere to and utilise the following documents, when devising legionella control programmes:
- Health & Safety at Work etc Act 1974
- The Management of Health & Safety at Work Regulations 1999 as amended 2003 & 2006
- The Control of Substances Hazardous to Health Regulations 2002 as amended 2003 & 2004
- The Notification of Cooling Towers and Evaporative Condensers Regulations 1992
- TM 13:2013 CIBSE Technical Memorandum – Minimising the risk of Legionnaires’ Disease
- HSE document L8 – Legionnaires’ Disease, The control of Legionella bacteria in water systems: Approved Code of Practice (ACoP) and Guidance (Version 4)
- HSG274 Part 1 – The control of legionella bacteria in evaporative cooling systems
- HSG274 Part 2 – The control of legionella bacteria in hot and cold water systems
- HSG274 Part 3 – The control of legionella bacteria in other risk systems.
- HSG220 – Health & Safety in Care Homes (June 2014)
- HSG 282 The control of legionella and other infectious agents in spa-pool systems
- HTM 04-01 – The control of Legionella, hygiene, “safe” hot water, cold water and drinking water systems
- Scottish Health Technical Memorandum SHTM 04-01: Water safety for healthcare premises Part A Design, installation and testing, Part B Operational management.
- The Water Supply (Water Quality) Regulations 2010
- The Water Supplies (Water Quality) (Scotland) Regulations 2011
- The Water Supply (Water Fittings) Regulations 1999
- BS 8580:2010 Water quality. Risk assessments for legionella control. Code of Practice
- BS 8558:2015 – Guide to the design, installation, testing and maintenance of services supplying water for domestic use within buildings and their curtilages.
- BS 8554:2015 – Code of practice for the sampling and monitoring of hot and cold water services in buildings
- BS 7592:2008 Sampling for legionella bacteria in water systems – code of practice
- BS PD 855468:2015 – Guide to the flushing and disinfection of services supplying water for domestic use within buildings and their curtilages
- WMSoc Guidance Documents.
- Safety, Health and Welfare at Work Act 2005 (S.I. No. 10 of 2005)
- Safety, Health and Welfare at Work (General Application) Regulations 2007 (S.I. No. 299 of 2007)
- Safety, Health and Welfare at Work (Biological Agents) Regulations 2013 (S.I. No. 572 of 2013)
- Safety, Health and Welfare at Work (Chemical Agents) Regulations 2001, as amended in 1998 (S.I. No. 619 of 2001)
- The Safety, Health and Welfare at Work (Reporting of Accidents and Dangerous Occurrences) Regulations 2016 (S.I. No. 370 of 2016)
- National Guidelines for the Control of Legionellosis in Ireland. Published by Health Protection Surveillance Centre (HPSC), 2009.
- Health & Safety at Work Order (NI) 1978 (as amended 2000)
- Management of Health & Safety at Work Regulations (NI) 2000 as amended 2003 & 2006
- Control of Substances Hazardous to Health Regulations (NI) 2003 as amended 2005
- The Notification of Cooling Towers and Evaporative Condensers Regulations 1992.
Legionella is not a sector-specific risk. However, the HSE consider key sectors being manufacturing, health and social care, and leisure and, within these, there is a range of systems and premises which give rise to varying levels of risk. These include Cooling towers, air conditioners, spa equipment, fountains, humidifiers and showers, hot and cold water systems, oil/water emulsions used for lubricating lathes, misting devices, decorative fountains and water features, dentistry tools and TMVs (thermostatic mixing valves).
The HSE have used the following criteria, to determine risk groupings:
- Numbers and scale of outbreaks arising from the system
- Levels of compliance associated with the system/sector
- Complexity of the systems involved
- Profile of the industry and the key players
The risk grouping is based upon an analysis of both the risks posed and the likely impact that would arise from an outbreak.
The HSE’s groupings are as follows:
Risk level 1 – Cooling towers and evaporative condensers
These systems operate at optimum temperatures for the growth of bacteria. They are re-circulating systems that can allow bacteria to build up within the system and generate large quantities of aerosol that, if uncontrolled and dispersed, can spread into the general environment, potentially affecting the general public.
Such systems are generally associated with a larger number of exposures during individual outbreaks, and can be described as low frequency/high impact occurrences.
Risk level 2
Hot and cold water systems
These ubiquitous systems operate at optimum temperatures for the growth of legionella bacteria and they may be connected to outlets and showers that can generate an aerosol when in use. In some premises, the water system can be extremely complex e.g. hospitals, but the majority of premises have much simpler systems (such as in care homes, hotels etc).
Hot and cold water systems are associated with low numbers being exposed and little or no off-site impact. However, outbreaks in hospitals are characterised by an increased likelihood of major ill health effects or death following infection because the exposed population is more vulnerable.
These systems generally operate at optimum temperatures for growth of bacteria, including legionella. They are re-circulating systems that, when not properly controlled, allow bacteria to build up within the system and the mode of operation generates an aerosol in the vicinity of the breathing zone of the user/s.
The HSL review of outbreak data indicates that, in GB, the ill health outcomes from exposures in spa pools are sometimes less serious, e.g. Pontiac fever. However, they are associated with large numbers of exposures during individual outbreaks.
Risk level 3
These systems include fire sprinkler units, pressure washers, spray humidifiers, fogging and water misting systems, emergency showers, train/car and bus washers, outdoor and indoor fountains and water features, composting facilities and irrigation systems.
In fact, any industry that uses water for processes such as washing, misting and cooling may pose a legionella risk as such systems commonly allow water to stagnate and generate aerosols that can potentially be spread into the environment. They are variable in nature and scale and are less likely to affect large numbers of people.