Acoustic ambitions for a better built environment – part 4.


Future possibilities.

In parts 1 and 2 we outlined the instanced where acoustics should remain silent or, conversely, shout loudly, plus, in part 3, planet-conscious design.

While still highly relevant, the previous examples discussed in part 3 assume a business-as-usual approach to delivering beneficial acoustic outcomes. However, the world we live in today is anything but ‘usual’. Rapid advances are occurring across a whole range of building technologies, including digital enablement, materials, manufacturing and approaches to both off-site and on-site construction. Research is simultaneously leading to advances in our underlying scientific understanding of both physical acoustics (in particular the acoustic properties of materials) and human response to sound, while technology is enabling ever-more sophisticated numerical modelling to be performed.

If ever there was a time to step back from the norm and take a more holistic, outcomes-focused approach to delivering truly sustainable buildings, then surely that time is now.

Building construction hasn’t fundamentally changed for decades. To this day, buildings rely primarily on the delivery of materials to site, where construction workers craft a basic shell, with multiple trades subsequently attending site to fit out and modify that shell to deliver the building to its required, typically compliance-driven, specification. However, the emergence of design tools integrated with factory-based modern methods of construction (MMC) means this traditional approach no longer needs to remain the status quo. In this transformation, the more radical the thinking, and the greater the emphasis placed on achieving truly holistic outcomes across both human-centric and planet-conscious spheres of influence, the better.

Looking outwards
Take the window as an example of how taking a more outcomes-focused, systems-based approach to design, and making use of modern technologies, could provide far-reaching benefits. The aforementioned outcomes-focused approach needs to start with the most fundamental of questions: what basic functions does a window serve?

First and foremost, windows provide a connection between a building’s occupants and their natural habitat of the outside world. Whether open or closed, clear glass allows for daylight and warmth in and views out. When open, windows provide an even greater connection, offering a conduit into buildings for fresh air to enable ventilation and cooling, and for the sounds of nature. It is hard to argue that any of these attributes can deliver anything other than beneficial human outcomes.

However, such a connection with the external environment isn’t always desirable. At night, for example, we often wish to shut out artificial light from road traffic or streetlights, as well as prevent views from outside to in. We address these issues by adding opaque coverings to windows in the form of internal curtains, or blinds and shutters, internal or external. During the day, solar gain through windows may also result in internal spaces overheating. Again, this is addressed using blinds, curtains, or shutters, or possibly via external solar shading.

Also, what if the act of opening a window doesn’t allow in fresh air or the sounds of nature, but instead opens a conduit to poor external environmental conditions such as the low air quality and excessive noise that frequently exists close to roads?

The ‘solution’ in such cases is to keep windows closed, or to provide permanently sealed windows which ensure that poor external environmental conditions are kept out. But this action introduces the need to provide a means of ventilating the internal space; the introduction of some form of forced system. Whether such systems are local or central, they come with attendant energy requirements, potentially leading to improved human-centric outcomes at the cost of poorer planet-conscious outcomes. The need to additionally provide some form of cooling to the internal space, again with attendant energy requirements, is also becoming an increasingly critical issue. This is due to a combination of the increased occurrence of climate change-induced temperature extremes and the need to provide better insulated buildings to accommodate new thermal technologies such as heat pumps.

Taking control
The complex balance between human-centric and planet-conscious outcomes is further complicated by the traditionally perceived human benefit of affording building users some degree of control over their internal environment, including their ability to open and close windows and/or their associated coverings. This must now be considered in the context of the energy and emissions associated with such control, including impacts on the effectiveness of the ever-increasing complexity of ventilation, cooling and heating strategies.

Based on the above, even the humble window has a host of (often competing) outcomes to deliver on behalf of building occupants. Not least, windows need to variously connect occupants with, and isolate them from, the building’s external environment. Specific considerations have thus far included: daylight; views; light pollution; privacy; sound; ventilation; air quality, heating; cooling. Other design considerations include security, fire safety, façade access, etc.

In part 5, we focus on the question the acoustics community is presently asking itself: whether the design of the high-performance building of the future could benefit from acoustic designers taking a step back to look at the issues from a systems perspective, and not just in isolation but in tandem with engineers and designers from other technical disciplines.

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