Karl Stauss at AET Flexible Space discusses the changing face of commercial ventilation
Heating, ventilation, and air conditioning (HVAC) may seem almost incidental when designing commercial spaces. But with changing working trends and new regulations now in force, it is a background provision that is increasingly ‘front of mind.’
The changing landscape
Developers want buildings that will let quickly, with a low churn rate. Tenants want spaces that can adapt to today’s flexible working in which two to four days a week are spent in the office, spaces that help them deliver on their ESG (environmental, social and corporate governance) policy, and office spaces that are sustainable and cost-efficient to run. Grade B space is becoming less attractive. Grade A – especially offices with new HVAC systems – are increasingly popular.
Further, as of April 2023, commercial property has to have an EPC certificate, with an E rating being the lowest acceptable; consultations are in hand for that to increase to a B rating by 2030.
By nature, architects look beyond the conventional, and embrace new technologies.
Instead of using the accepted overhead space to provide the air conditioning/ventilation, underfloor air conditioning (UfAC) uses the floor void. In this simple way it delivers the ultimate design freedom for architects, developers and tenants.
The concept is not new in the global scheme of things. Indeed, in other temperate climates – Australia, the Far East and Europe – it has been widely used for 30 years, so is proven technology. The drive towards sustainable, low carbon, energy-efficient solutions alongside our changing weather is seeing the concept being more widely adopted in the UK.
UfAC focuses around a conditioned air module (CAM) unit, that handles the air supply and exhaust. Air is drawn into the unit from outside the space and uses the floor void as a plenum to reach strategically located ‘plug and play’ floor grilles to ventilate the space above. The used air is directed back to the CAM unit at low or high level for reconditioning.
Design freedom
From a design perspective, it eliminates the space required for the ceiling-mounted building services.
In new builds, that can reduce overall build height by up to 10% with all its benefits in easing the planning approval process and savings on construction costs, while maintaining the compliant headroom within. The reduction in overall height also accelerates the build process; we know of schemes whereby the building is complete and let three months earlier than a block with the same floor space using conventional high level building services. It overcomes the constraints of unusual layouts and configurations, and enables the full potential of historic architectural features to be exposed in renovation projects.
The ‘plug and play’ design of UfAC also means that as needs change, the air conditioning can easily evolve alongside. The floor grilles can be moved as required, giving complete freedom as to how the occupant utilises the space. Tenants are not constrained by the positioning of ceiling grilles with their potential for draughts, nor of radiators around the walls.
UfAC’s relocatability also ensures happy workers – no-one is subjected to cold ‘dumping’ or draughts. Even as the workspace is reconfigured, the floor grilles can be moved across the floor plate to maintain occupant comfort. A happy workforce is 15% more productive, and employees are also more likely to take fewer days sick leave.
The floor grilles can also play a part of the design with the option to have them powder coated to complement and enhance the design palette.
Sustainable by design
Because it is prefabricated and modular in design with no ductwork, each UfAC zone operates independently, at very low pressure. Air temperature sensors monitoring the office temperature and underfloor temperature adjust airflow to modulate dampers to operate at optimum efficiency.
The combination can achieve up to 30% savings on energy and almost the same on CO2 emissions compared with conventional, ceiling-based systems. The temperature for each zone can be individually set, thereby ensuring energy wastage is minimised.
What’s more, its design and construction – with its utilisation of aluminium and lack of ductwork – has a positive impact on embodied carbon too, building in circularity and resilience. UfAC systems have been proven to contribute towards BREEAM, LEED and WELL accreditation; UfAC has been employed at the Sky Central Campus, which achieved the highest possible BREEAM rating of Outstanding.
The changing office environment requires a change in thinking. The building services can play a pivotal role in creating a flexible, quality and sustainable environment. Certainly our experience is that once architects have ventured from the norm, and specified UfAC, it becomes their ‘go to’ option for commercial environments.
Karl Stauss is UK head of sales at AET Flexible Space