Specifier Review
water systems

Testing the water

Water hygiene within large buildings is of paramount importance. Bob Blincowe, strategic account manager UK healthcare at Trend Control Systems, explains how a Building Energy Management System (BEMS) can prevent the outbreak of water borne diseases by monitoring and controlling supply, storage, and distribution systems.

Legionella pneumophila bacteria are common in natural water sources such as rivers, lakes, and reservoirs, but usually in low numbers. However they can 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, achieving optimal growth at temperatures of 25-42°C. Proliferation can be encouraged by water stagnation and sediment build-up in water systems including fittings, pipework and materials and, once the bacteria proliferate, Legionnaires’ disease becomes a distinct possibility and can cause a potentially fatal form of pneumonia.

Water systems are notoriously complex and it is vital, therefore, to control this risk by introducing and continually adhering to appropriate measures. One way of achieving better management and infection control is through the use of a BEMS, which can monitor and manage up to 84 per cent of a building’s energy consuming devices. In addition, the ability to monitor and control many different inputs/outputs (I/O) into the main plant area of the water system can be achieved by utilising unused capacity already on-site.

A properly specified, installed and maintained BEMS will ensure that plant is operating correctly and will provide an alert if attention is required. Furthermore, the key to maximising the effectiveness of a BEMS is information – the more connected devices in a single building, multi-building site or multi-location estate, the more information is gathered and can be acted upon.

Prevention is better than cure

Utilising a BEMS for the management and control of water supply systems requires a number of key considerations and, perhaps, the most important concerns temperature. 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.

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, domestic hot water (DHW) flow and return temperatures should be monitored, and 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 water stored in DHW and DCW tanks must be ‘turned over’ every 12 hours to guarantee a fresh supply. This process can be monitored and alarmed so that if an individual tank does not reach the correct turnover in 12 hours, an alert is issued. 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.

Drilling down

By monitoring systems such as metering, tank level and temperature, backflow prevention valves, filters and pumps, not only does a BEMS provide a clearer picture of the system, but also avoids costly wastage of water either through leakage or – if the tanks have gone over-temperature – through ‘dumping’. In the event that this does happen, in a well-managed system this water can be transferred into a ‘recovered’ tank for use in toilet flushing/laundry etc., rather than simply being dumped to drain.

Identifying problems early can also minimise expense and hassle in the long-term. For example, in a complex flow and return system, if one room reports no hot water this is obviously not just an issue at the point of use, but also indicates that stagnation points exist in the system. Traditionally, this would result in an engineer tracing the cause of a ‘cold spot’ by trying to balance the system. However, by using temperature and flow sensors that are linked to a BEMS in each room, as well as the sentinel points at the inlet to each wing/building/facility on the flow and return ring main, the problem can quickly be identified. The system can then be balanced, ensuring all rooms get hot water and, just as importantly, avoid stagnation in the system.

BEMS can also facilitate highly sophisticated configurations and the addition of solenoid valves on the hot and cold inlets and mixed outlet can allow the testing and shut down of TMVs automatically, with control and reporting. Furthermore, through the adoption of ‘smart’ outlets such as infrared taps and mixers, and touch-free and electronically controlled devices for flushing and showering etc., the overall ‘connected’ result can be maximised. Apart from the time saved, there are other issues that are subsequently addressed such as unnecessary time taken to fault find, and disruption/access to patient rooms, consistency of result, automated logging of data and reports and alarms generated before an infection control incident.

Seeing is believing

Through easy monitoring and management, a BEMS gives building managers the ability to identify issues quickly and easily and to optimise their systems. The more inputs into the system, the greater range of reports available and the greater control offered by the available outputs. The status of connected devices into a common graphical, real-time user interface or wider monitoring system can help integrate systems together, monitor specific activities and initiate any necessary changes.

Cutting edge systems are now available that integrate controllers, third-party smart devices and internet protocols into a centralised software platform that offers the ability to highlight and investigate plant status, as well as energy use, and a building’s comfort conditions. They enable a diverse range of useful functions such as centralised data logging, archiving, alarming, trending, master scheduling, system-wide database management, and integration with enterprise software applications.

The introduction of the GDPR it is also important to use systems with the highest possible level of security and state-of-the-art ‘head end’ systems, and which have in-built authentication that requires users to choose strong Lightweight Directory Access Protocol passwords that are then encrypted. To further enhance security, a comprehensive audit trail of database changes, database storage and back-up, global time functions, calendars, central scheduling, control and energy management routines can be configured.

Make the connection

The three desired benchmarks of BEMS implementation are:

• Compliance

Conformity to guidelines, standards and organisational goals and objectives.

• Sustainability

Placing emphasis on economic and environmental sustainability, and the efficient use of all resources.

• Resiliency

Minimising instances and the impact of non-compliance, and managing risk, people and undertakings. When these elements work together they can provide a high-quality environment that is safe, hygienic and poses no unacceptable risk

Final word

The data produced by a BEMS will make a water supply infrastructure more resilient and drastically reduce the risk of Legionnaires’ disease. This shouldn’t be a ‘fit and forget’ process though – it is advisable to regularly reassess any objectives and key performance

indicators to make sure compliance is ‘joined up’ and not counterintuitive, and use of all the functions and systems that are in place to use information in the smartest ways possible.

For further information please call Trend Marketing on 01403 211888 or email marketing@trendcontrols.com.


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About Trend Control Systems:

With a worldwide distribution and support network covering over 50 countries, Trend Control Systems is a major international supplier of building energy management solutions (BEMS).
The vast majority of Trend’s control systems are supplied, engineered and commissioned by approved systems integrators.

Trend Control Systems is part of Honeywell Home and Building Technologies.

About Honeywell Home and Building Technologies:

Honeywell Home and Building Technologies (HBT) is a global business with more than 38,000 employees worldwide. HBT creates products, software and technologies found in more than 150 million homes and 10 million buildings worldwide. We help homeowners stay connected and in control of their comfort, security and energy use. Commercial building owners and occupants use our technologies to ensure their facilities are safe, energy efficient, sustainable and productive. Our advanced metering hardware and software solutions help electricity, gas and water providers supply customers and communities more efficiently. For more news and information on Honeywell Home and Building Technologies, please visit: http://www.honeywell.com/newsroom.

Honeywell is a Fortune 100 diversified technology and manufacturing leader, serving customers worldwide with aerospace products and services; control technologies for buildings, homes, and industry; turbochargers; and performance materials.