Making a BEMS a liquid asset
Legionella bacteria and the threat of Legionnaires’ Disease are ever-present threats to hospitals and other healthcare estates. Peter Moore of Trend Control Systems looks at how a BEMS can help monitor and control water supply, storage and distribution systems.
Primarily because of their large and often complex water supply systems, hospitals and healthcare estates are potential breeding grounds for the bacteria that can cause Legionnaires’ Disease. It is therefore no surprise that they have to take the issue very seriously to maintain the highest levels of protection for patients, staff and visitors.
One way that innovative organisations are achieving this objective is through the use of a BEMS. When configured to provide an automatic early-warning system, it can monitor, control and inform about a range of conditions relating to the status of the water system, and alert designated personnel via email and text messages if quality conditions fall outside pre-defined levels.
Legionella pneumophila bacteria are common in natural water sources such as rivers, lakes and reservoirs, but usually in low numbers. They may also be found in purpose-built water system infrastructures, and unless conditions are kept within certain parameters they can thrive in cooling towers, evaporative condensers, hot- and cold-water systems and spa pools. Once the bacteria proliferate, Legionnaires’ Disease becomes a distinct possibility and can cause a potentially fatal form of pneumonia.
It is therefore important to control and reduce the risk of this happening by introducing appropriate measures. ‘Health Technical Memorandum 04-01 (HTM-04)’ and the UK Health & Safety Commission’s ‘Approved Code of Practice (ACoP) L8’ provide guidelines for legionella control and offer guidance on how best to prevent it.
Utilising a BEMS for the management and control of water-supply systems requires a number of key considerations; perhaps the most important concerns temperature.
Domestic cold water (DCW) storage tanks should be monitored and alarmed to check that the water temperature stays below 24°C, as above this level legionella bacteria can grow. Furthermore, DHW (domestic-hot-water) flow and return temperatures can be monitored; if they fall below 50°C for a prolonged period an alert can be sent and the problem resolved before there is any risk.
In addition, compliance with HTM-04 means that water stored in tanks must be adequately ‘turned over’ to prevent stagnation. This process can be monitored and alarmed so that if an individual tank does not reach the correct turnover levels required based on the size of the tank, an alert is issued.
HTM-04 also specifies the requirement for purified water. Chlorine dioxide is added in tightly controlled amounts to the water, and levels are closely monitored and controlled to make sure they comply with the Water Supply (Water Quality) Regulations 2000. Monitoring and alarming the areas where water-dosing equipment is located and the process carried out is also vital, as if a high level of chlorine dioxide is present, as a result of a spillage or leak, the resultant gas could prove harmful to the health and safety of operatives.
One of the main ways to prohibit the growth and spread of legionella bacteria is to carry out regular flushing of DHW and DCW systems. A BEMS can be configured to carry out this task automatically, using outputs connected to solenoid valves to ensure sections of pipework are flushed for a pre-determined duration.
Central to the ability of a BEMS to communicate water-quality data from the devices is a graphical, real-time user interface that enables users to monitor specific activities and make any necessary changes. This should also feature security settings to ensure that an individual is only presented with information and functions that are relevant to their authority or task, ensuring that consistent standards of operation are maintained.
Health and safety is of paramount importance to all hospitals and healthcare estates. The data produced by a BEMS, along with a comprehensive alarm system, will make a water supply infrastructure more resilient and drastically reduce the risk of Legionnaires’ Disease. This not only means that these organisations can work smarter, they will also achieve complete compliance with HTM-04 and ACoP L8.
Peter Moore is a key account manager with Trend Controls Systems
