Modern Building Services

MODERN BUILDING SERVICES APRIL 2023 31 FEATURE INDOOR AIR QUALITY T he new post pandemic world with new and different ways of working has set new requirements on building services. Not only to ensure the continuing safety of building users, but also to provide comfortable flexible workspaces to encourage workers to return to the workplace and to aid productivity when they are there. These are in addition to the ever growing need to address climate change through energy efficiency and reduced CO 2 outputs. This has been further exacerbated by spiralling energy costs brought on by the Russian invasion of Ukraine. All these new requirements are perhaps contradictory in some respects and the solution is a balance between these conflicting parameters; the need for good ventilation and comfort for building users whilst minimising carbon output and energy costs. It is a significant challenge to get the balance right, but without accurate data it is near impossible. Airflow needs to be measured accurately and consistently. Looking more closely General office and retail applications have never needed to have these higher specifications; they have usually been reserved for clean rooms, healthcare / life science applications and data centres. The push for energy efficiency has improved performance and specification to a significant degree in recent years, but it has been the reviewing of airborne risk following the pandemic which has led to greater changes. Designers, facilities managers and end users are looking more closely at existing and planned building services installations to see what can be done to provide the required ventilation rates to mitigate future infection risks whilst balancing the energy consumption of the ventilation system. The growth of hybrid working practices has accelerated demand for Variable Air Volume / Demand Controlled Ventilation systems which, while offering energy saving potential, leave the door open for Indoor Air Quality (IAQ) issues if not measured and monitored accurately. A key issue is being able to demonstrate air flow and ventilation to reassure occupants, staff and visitors so they can feel safe. Measurement is key, but most building systems have levels of uncertainty of measurement as much as ±20%of volume flow, which is too wide amargin for this purpose. Higher specificationmeasurement is required, such asWilson Flowgrids (WFG) which provide levels of uncertainty to ±2%across multiple points. More andmore clients are conscious of climate change and have been looking to significantly reduce energy consumption and carbon waste by installing such systems in both new buildings and refurbishment projects, and at the same time enjoying the added life cycle and IAQ benefits. This type of measurement device can provide differential pressure signals which directly relate to volume flowwithin the duct and, when used with a pressure transmitter produce an instrument with ‘real time’ flow measurement accuracy usually associated with clean rooms and data centres. In general HVAC applications, apart from demonstrating required levels of ventilation, it can greatly improve the effectiveness of building management systems and enhancing energy efficiency and IAQ. ➜ By Andrew Hamshere , Managing Director, Sensing Precision Measurement is the key