It is a legal requirement to assess the risk posed by legionella bacteria in all commercial properties. The risk assessment must be “suitable” and “sufficient”. As the complexity of water systems increases, along with the number of outlets, components, and systems, the need for expert external assistance tends to rise
HC Legionella can provide independent and impartial Legionella Risk Assessments (LRAs) that scale up based on the systems you have; we have experience in producing large-scale, multi-building risk assessments for healthcare providers as well as commercial entities across the South and East of England.
What makes a good risk assessment?
There is clear guidance on what a good LRA should contain; this is provided by the British Standard (BS8580-1) and the Legionella Control Association (LCA) Service Delivery Standard. HC Legionella is a registered member of the LCA and offers registered services of LRAs in both hot and cold-water systems, as well as healthcare systems.
Both the LCA and BS8580-1 make it clear that your risk assessment needs to identify any risks present – both the Inherent and Residual risks – as well as identify what is low as reasonably practicable (ALARP) would look like. Inherent risk, the risk posed if no controls are present; residual risk, the risk level present on the day of the assessment; and ALARP, the lowest achievable level of risk, should all be stated for each water system present.
To conclude, the risk scores of both BS8580-1 and LCA require the inclusion of CATES risk scoring.
| CATES Acronym | Description |
| Contamination | Does contamination already exist in the system? Do we have any known or previous legionella-positive results that indicate the system has been, or is currently, contaminated? |
| Amplification | Do the conditions exist to allow any legionella bacteria in the system to grow and multiply in number? This is impacted by allowing growth temperatures to persist, the presence of nutrients in the system, stagnant systems, and low-use outlets. |
| Transmission | Do conditions exist within the system that allow for the aerosolization of water from the system? This is often driven by splashes and processes that create a misting effect, typically from domestic systems, which is often the result of using toilets and showers. In commercial kitchens, pot washes can be a major transmission route; the same can be said for decorative water features in shopping centres. In industrial settings, washer tunnels can pose a significant risk, with cooling towers posing the highest risk of transmission. |
| Exposure | Does an infection pathway exist between the transmission route and those who are most at risk of acquiring Legionnaires’ disease? The infection pathways examine transmission routes and identify who is most likely to be affected by the operation of these outlets and the aerosols they generate. |
| Susceptibility | Do people at increased risk of infection come into contact with the system or the aerosols generated? The level of susceptibility increases with the age of the system user. Other factors that influence susceptibility include ongoing health issues, immunocompromised, males over 45, ex-smokers, and females over 50. Due to these risk factors, healthcare settings and care home facilities house some of the most susceptible individuals; careful management and risk mitigation within these systems is of paramount importance. |
Once the CATES risks are identified and the system has been fully assessed, the risk assessor should be able to provide detailed schematics that accurately reflect the system on site, including all major plant, valve configurations, and all assets within the site/system, in line with BS8580-1 guidance.
Who is responsible for arranging a risk assessment?
The legal responsibility for commissioning an LRA lies with the duty holder, who is normally the business owner or head of the organisation. The duty holder (DH) can, and normally does, appoint a responsible person (RP), who takes responsibility for certain day-to-day tasks for Legionella control on behalf of the duty holder. It is worth noting that the RP must be appointed in writing, listing the tasks that are their responsibility, and they must accept this role in writing, formally confirming that both parties understand the role they are taking on. Although responsibility can be delegated to the RP, the legal accountability remains with the duty holder.
In large, more complex sites, a Water Safety Group (WSG) may be formed; BS8680 can govern these and may include more than a DH and RP. In healthcare settings, for example, it is common for estates, domestic cleaning services, infection control, clinical leads, contractors, and an external authorising engineer (Water) (AE(W)) to be involved in the WSG. Ultimately, the makeup of any WSG is down to the DH and their understanding of the guidance in BS8680. If you have a complex site, you may want to establish an operational water management team that meets more frequently and addresses challenges on a daily basis; this team would inform WSG meetings. If you require external AE (W) support, then HC Legionella can provide this service. WSGs are productive and effective in a range of industries that manage extensive portfolios of multiple or complex buildings or water systems.
Allocation of responsibilities
One of the key outcomes of a comprehensive LRA is the identification of tasks that need to be completed to effectively manage the risk posed by legionella moving forward; this ensures that every necessary task is considered.
Both HSG 274 Part 2, Table 2.1, and HTM04-01, Table 1, list all the main tasks that need to be allocated to a hot and cold-water system in domestic and healthcare environments, respectively. A well-defined allocation of responsibilities will serve as a baseline for monitoring tasks and evolve based on your site-specific needs. For instance, it is common for sites to undertake their own weekly flushing of little-used outlets. Still, a third-party provider, such as HC Legionella, usually performs the annual tank inspection and potential subsequent cleaning.
Executive summary
The start of the LRA should be the last thing written, the executive summary. This should provide the reader with a brief synopsis of the report, highlighting any key risks identified and the necessary mitigation measures to reduce these risks. The executive summary is the part of the document that gives the assessor free rein to comment on your specific system, risks, and challenges, as well as clearly articulate their thoughts, concerns, and suggested remediation.
If a significant issue has been identified, the risk assessor should debrief the site and ensure that they understand the risk and its implications before leaving on the day of assessment. This should not be left until the final written report is issued.
What is suitable & sufficient?
HC Legionella has the knowledge, skill, and competence to undertake a bespoke legionella risk assessment for your site; we work in line with the LCA service standards, BS 8580-1 and BS 8680 guidance, which enables us to truly understand what is suitable and sufficient for your setting whilst being independent and impartial.
For clients working within the healthcare sector or adhering to healthcare standards, our experience extends even further, as HC Legionella is a company affiliate member of the Institute of Healthcare Engineering and Estate Management (IHEEM). We have a wealth of experience and knowledge, meaning that if required, after any Legionella or other waterborne pathogen risk assessment, our proficient plumbers working alongside our in-house AE (W) are able to provide a range of remediation solutions to resolve any issues or elevated risk scenarios identified. This means that we can live by our motto of managing through to resolution.
