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Tuesday, 08 December 2015 08:19

Designing green buildings for the future

A building’s sustainability is influenced by many factors and product decisions, much of which is prescribed by building regulations. However, to get the optimal mix takes more than just a Coke and a smile.

Jacques Laubscher, associate professor in the Department of Architecture at the Tshwane University of Technology, is part of a working group focused on building regulations in the face of climate change. Together with the other members on the steering committee, Henk Visscher from the Delft University of Technology and Edwin Chan from the Hong Kong Polytechnic University, they involve built environment specialists from around the world and present their research with the aim to affect legislation in various countries.

“Building regulations’ primary focus is on protecting people and their possessions, but these usually come into effect after something went wrong, such as an accident or a structure collapsing,” Laubscher states. “However, climate change predictions implicate future global threats. So instead of focusing on the past, building regulations should take a different approach and rather focus on preparing for the future of climate change,” he explains.

One of the variants connected to climate change in terms of dwindling resources, is energy consumption, and although the current regulations make suggestions and recommendations in this regard, Laubscher doesn’t believe that these are stringent enough.

Design for a ventilated climate
“In South Africa, my research has shown that we are not looking at passive environmental design enough, which entails cost-effective ways of reducing energy consumption within buildings,” he says.

“One aspect not included in current regulations is that South Africa does not have an insulated building climate. In fact, it has a ventilated building climate, which requires different kinds of solutions than the European and even American products that are simply reused locally.

“An apt building solution for South Africa is something that has thermal mass and thermal inertia. Actual measurements taken in two buildings within a similar context, with similar users, indicate that the Part XA and glazing requirements that everyone is implementing at the moment are not applicable in South African climatic conditions,” Laubscher states.

Low-cost implications
In response to the local climate, Laubscher names cross-ventilation, building overhangs, the correct orientation and the appropriate selection of materials as low-cost implications of building sustainably.

High-cost interventions
Higher cost alternatives include advanced construction methods and alternative materials, specifically those that respond directly to daily temperature changes.

“At the moment the regulations basically suggest a choice between single and double glazing insulated glass units, but imagine a facade reacting to the light with apertures opening and closing or blinds going up and down in response to light changes. Even though this technology requires energy and regular maintenance, it is available, but not yet included in the building regulations,” Laubscher explains.

Consider the micro climate
In addition, Laubscher suggests doing a climatic simulation during the planning stage of any project. This would involve modelling the building’s design according to a weather file for the building site to determine the building’s actual performance and to change materials accordingly to find the best performance.

“The solution needs to be site-specific. If you respond appropriately to the micro climate with the materials, the orientation, and passive and active design, the result will be an optimal building,” he states.

The good and bad of ecolabels
When it comes to selecting materials and products for sustainable construction, ecolabels are supposed to simplify the selection process for architects and specifiers, but this isn’t a silver bullet.

“There is a lot of greenwashing going on,” says Marloes Reinink, sustainable building consultant at Solid Green Consulting. “Manufacturers will claim that their product is very green and even has an ecolabel, but it might not even be applicable to the type of product or wouldn’t say the right thing about that product – instead it just misleads people,” she points out.

A UL whitepaper on green product labels states that “there are an estimated 440 different ecolabels in use by 25 industry sectors in 197 countries around the world. And this doesn’t include the growing number of fake ecolabels that are readily available for sale on the Internet”.

Another study on green product claims, conducted by the Shelton Group and published by UL Environment, indicates that even though these certifications matter to business audiences, professionals are sceptical about green claims in general, especially if they aren’t backed by third parties, and have a more sophisticated understanding of problematic or false claims than ordinary consumers.

While valid certifications can help them to save time, unclear or unreliable certifications might lead to these products being disregarded as specifiers just don’t have the time to research the background of every product’s green claims.

“It is important that architects and specifiers understand what a label stands for, what the standard is measuring and if that is what they need. For example, looking at virgin timber, you should be looking for a FSC label; looking at paints, you want to look for a VOC label. I always double-check what the ecolabel is measuring before I trust it,” she says.

Making sense of green
“Selecting green materials is a very confusing area of building because there isn’t one set of criteria that you can apply across the board. When you look at timber, you need to look at different criteria than when you look at concrete. Or when you look at a chair, you consider different aspects than when you look at a table, so you have to understand each product’s different sustainability criteria and know which metrics to compare,” Reinink explains.

And while one product’s embodied energy might be lower than another, its manufacturing process might not be as clean or it might contain more harmful chemicals. “In the end it isn’t an easy quantifiable choice, but rather up to the person specifying to decide which metric weighs more in each case,” adds Warren Gray, mechanical engineer at Solid Green Consulting.

As an example, compare PVC and aluminium window frames: Where PVC has a relatively low embodied energy, the harmful emissions related to the manufacturing PVC are not great. Aluminium has a much higher embodied energy, but the product can be recycled at its end of life. It is up to the buyer to make a decision according to what he finds more important.

Focus to make the biggest impact
In trying to get the best bang for your buck, Gray suggests that when working on a refurbishment or new building that isn’t necessarily going through a Green Star rating process, it makes sense to focus on a few big items that will make a significant impact rather than trying to scrutinise the confusing differences in embodied energy, manufacturing processes and waste of every single product.

One way might be to bring in reused or recycled furniture, or leasing certain items instead of buying everything new.

Energy-related products such as lights or HVAC systems are also easy to compare since the energy is measured in the same currency of kWh, and doing lighting retrofits or adding lighting control can result in a big payback.

In revamping a building with existing systems though, one doesn’t get the easier payback that you might get on new buildings, according to Gray. “When comparing two different systems for a new building, it is easy to compare price and energy savings to select the best fit, but as soon as you change systems in an existing building, the energy savings don’t always justify the replacement. Therefore it makes sense to try and coincide the greening of an existing building with the end of the life of some of the major equipment,” he advises.

Building for the future
Laubscher highlights the importance of maintaining a holistic view when specifying products. He explains that even though product decisions taken in isolation might be appropriate, if no one takes responsibility to manage and look after these products, they might need to be replaced before their end-of-life, wasting both operational and embodied energy.

“In my view, the professional team and its many role-players should focus on the building itself and ultimately prioritise the role of the building to house people and possessions. Within that focus, they need to determine how to use as little as possible resources and when having to use a resource, how to use it as efficiently as possible,” he states.

SASBE 2015 Conference
Laubscher, together with Visscher and Chan, will present their research at the Smart and Sustainable Built Environments (SASBE) 2015 Conference taking place in Pretoria, South Africa, from 9 to 11 December 2015, in a special session focusing on the impact of climate change on the future direction of building regulation and control.

Full thanks and acknowledgement are given to Solid Green Consulting and Jacques Laubscher for the information given to write this article.

In a nutshell:
-    Should building regulations focus on the future to gear up buildings for the implications of climate change?
-    South Africa has a ventilated, not an insulated, building climate.
-    Passive design is underutilised in South Africa.
-    Ecolabels play a role, but specifiers should know what they stand for and what they measure.
-    Focus on making the biggest impact with the least effort.
-    Remain cognisant of the building’s primary function to house people and possessions safely.