(And how to avoid them)
By Andy Clews, Senior Consultant – Water Hygiene Centre
In this blog we share some experiences of situations that can increase the risk of Legionella bacteria growth and what could have been done to prevent them.
Introduction – Why controlling Legionella bacteria in education matters.
Has you or your organisation ever been subject to an HSE investigation due to a Legionella outbreak? It can be a daunting experience that triggers a lot of internal Q&A’s where many ‘hope that it’s not us’ and ‘have we done all of the things we should have?’ The process moves very quickly causing some to panic. The actual need to control Legionella bacteria is to prevent people from coming to harm and not just to limit reputational damage.
If you have reached the position of investigation, it is probably too late to affect any of the outcomes. However, even if your facility is not the actual source of the outbreak you could still be prosecuted for not fulfilling your legal responsibilities.
A case we recall was one of a cricket team, a mixed age group, who played at various locations. Two of the team reported illness to their separate GP’s who registered the symptoms as possible ’legionnaires’ disease’ (which is a notifiable disease). Public Health England investigated and established that the two individuals were known to each other via the cricket team. The cricket club shared the locations of where both had played which triggered the Local Authorities to take Legionella samples. One location being an educational sports facility, not the source of the outbreak, but there were some anomalies which the HSE investigated anyway.
Common Mistakes and How to Avoid Them.
Schools, Colleges and Universities bring a diverse mixture of water-based systems which can be subject to seasonal changes that bring changing risks. Whether it be a water feature, a staff kitchenette, an outside tap, a hall of residence, a complex laboratory building or sports facility, there is a legal responsibility to operate and manage each water system so that the in-built hazards are controlled to a safe level.
Inadequate / outdated Legionella risk assessments (LRA): Each water system requires a LRA that informs on the true level of risk. The LRA should be reviewed on a regular basis which is dependent on the risk. Take a small office block that has mains cold water and point of use water heaters serving just toilet and kitchenette facilities, this could be reviewed every 3 years say. However, this is subject to other factors such as user susceptibility, regular continued use and an implemented Legionella written scheme of control e.g. maintenance, cleaning, temperature checks, usage evaluation.
If there is a significant change, say a shower being added or hybrid working implemented, the LRA must be updated to reflect the changes and inform of any changes that amend the written scheme.
Your Legionella risk assessment should be to a standard that reflects the complexity of your water system with BS8580 being the minimum standard. Further accreditations such as UKAS ISO/IEC 17020 are available that reassure that the British Standard has at least been met.
Inadequate design risk assessments: for any new project design review should be conducted to inform on the selection of component, fixtures and fittings. Collaborative working between the Architect, Mechanical Designer, Client and the Operations Team should ensure that designs are rational and reflect the true risk and not the perceived risk.
All too often future proofing and poor practices pass from one project to the next. Often thermostatic control of hot outlets on wash hand basins is installed without considering the actual risk. A scald risk assessment could negate the need for thermostatic control reducing the Legionella risk and saving Cap Ex and Op Ex. Equally, installing outlets or connections for the ‘just in case’ scenario should be avoided.
A specific Project Water Safety Group should be formed and a Project Water Safety Plan developed. BS8680:2020, advises on the requirements.
Operating and Maintenance Manuals / Legionella Written Scheme of Control: Designers and Contractors have the responsibility to provide Operating and Maintenance (O&M) manuals to advise how the facility, including water systems, should be operated and maintained.
Architectural, mechanical services and building management / control systems information should be consolidated and compiled within a specific domestic water services section that provides relevant information for the Legionella written control scheme. Asset information should be concise and inclusive so that the asset management teams can transfer the relevant information into their PPM planners.
Training / Competence: All too often it can be assumed that ‘it’s someone else’s job’ to deliver the various tasks. The management and control of water systems could require a multi-disciplined team with the correct level of competence for the roles that they are to perform. A few experiences that need to be addressed are:
- A project team for a multi-million-pound laboratory building, apart from the Mechanical Designer, were from an electrical background and this included the Clerk of Works. Whilst there was some familiarisation of water systems nobody had attended at least a Legionella awareness training
- I was told that ‘CAT5 (laboratory) water systems do not matter as they have backflow protection’. Legionella bacteria do not know what type of water system they are in. If the conditions are such that the bacteria can proliferate and water be discharged through an outlet you are legally required to control the hazard. ACoP L8 supports you with this.
- BMS teams making decisions without realising the consequences. One being the hot water return sensor to the HWS generator was omitted / removed to reduce alarms i.e. if the water temperature dropped below 50oC!! The other was automated pasteurisation, raising the HWS temperature to 70oC, was included in the control logic for new student accommodation, that took place at 0100 hours for one hour. Pasteurisation is a disinfection method, optional if failed sample results have been returned, and must be a controlled process otherwise the scald risk is significantly increased to a dangerous level.
Operational Management: Often the simple tasks are the most effective control of Legionella but equally they could be weakest link which requires auditing to check that the teams / individuals assigned to the task are fulfilling their obligations. Before staff are engaged, they should have training for the task and follow a standard operating procedure.
- Usage evaluation. Theoretically most outlets should be used through usual occupancy patterns e.g. Monday to Friday, leaving just a few outlets that require dedicated flushing. Individuals should be assigned to this task (responsible person) on a weekly basis and periods of low / no use, that requires increased flushing activity, should be noted. Also, there is the need to appointment a deputy for the task should there be any absence.
- Prevention of scale build up is significant and should be a routine task.
- Temperature monitoring monthly, focussing on sentinel points (advised in your LRA) and a selection of other outlets, is required and must be recorded in the logbook.
Record keeping: I’ll refer you back to the start of this blog, the HSE investigation. To demonstrate that your obligations have been fulfilled it is very important to keep signed and dated records for any activity that is part of operating, maintaining and changing your water systems. This includes staff records and their training records. If there is ever a need to demonstrate that you have taken your responsibility seriously these records will be crucial in the process.
