Modern Building Services

28 MODERN BUILDING SERVICES MARCH 2023 R eal-time monitoring of closed water systems leads to savings at every stage of a system’s life; from reducing the need for chemicals, sampling and consultants, to preventing the disruption and cost associated catastrophic failures. The phrase ‘prevention is better than cure’ is often attributed to Dutch philosopher, Desiderius Erasmus, around the turn of the 16th Century and is a concept that remains to this day a pillar of modern healthcare. By identifying the precursors to ill health, early interventions can bemade that delay the onset of severe conditions or even prevent them fromoccurring. The same concept can be applied to commercial building management. Think of HVAC systems and pipework as the heart and veins of a building and if they get clogged up or fail due to lack of monitoring or mismanagement, it can affect the efficiency and operation of the entire building. The ‘health’ of our buildings is under threat Data from Hevasure’s real- time HVAC monitoring systems show that more than 50% of commercial buildings are under threat from pipework corrosion. The data was collected frommore than 85 commercial buildings nationwide over an eight-year period, including some of London’s most iconic commercial spaces, such as the Leadenhall Building and Scalpel. Other installations include hospitals, data centres and residential blocks connected to district heating schemes. Systems at risk of corrosion are more likely to breakdown, which could end up costing into the millions, depending on the level of damage and the knock-on effect it has on reliant plant and building operations, failed cooling for a data centre with consequential outage, for example, could run into even higher figures. Themajority of alarms triggered on our monitoring systems relate to high levels of dissolved oxygen, something that is not detected by sampling and corrosion coupons, and prior to the invention of real-time corrosionmonitoring technology, went largely unchecked. Why is oxygen such a problem? Water-based HVAC systems are key to the operation and efficiency of commercial buildings, transferring heat energy around a building by pumpingwater through pipework and valves to a range of heat emitters or fromchillers. Systems are either open to the air; cooling towers for example, or closed; such as sealed pressurised systems including low-temperature hot water (LTHW) heating systems, chilledwater (CHW) systems and heat pumps. Closed systems must remain sealed and pressurised environments. Any oxygen ingress can quickly lead to pipework corrosion, wreaking havoc on overall building performance and increasing the risk of breakdown and expensive repairs. Oxygen ingress is common in closed systems; it can be caused by the entry of fresh aerated water due to leaks or routine maintenance activities such as flushing, or, as our data shows, sudden loss of pressure. What is key is that dissolved oxygen in the system is identified immediately, allowing building maintenance engineers and FMs to make targeted interventions, therefore preventing any further problems. Following updates in 2021, dissolved oxygen (DO) is now identified as themain cause of closed system corrosion in BSRIA guides BG50/2021 Water Treatment for Closed Heating & Cooling Systems and BG29/2021 for Precommission Cleaning of Pipework. Real- time monitoring technology is recommended as ‘best practice’ for mitigating against the effects of DO. Steve Munn , Managing Director at Hevasure, explores some of the common problems picked up by real-time monitoring technology and explains why early detection of problems and timely intervention can save huge amounts of money and hassle. Behind the scenes of pipework corrosion FEATURE PIPED SERVICES, PUMPS ANDWATER