When you expect fifty people at a ‘lunch and learn’, you naturally order around 25 pizzas.
Such was the case for Adam Jones, now a structural engineer at WoodSolutions and recognised by the Green Building Council of Australia as a Future Green Leader of the Year.
Jones was at his first job at a structural engineering firm. The lunch and learn was about reducing embodied greenhouse gas emissions in cement, which accounts for around eight percent of global greenhouse gas emissions. When invitations went out, acceptances were received from ten out of ten sustainability consultants and 40 out of around 100 structural engineers.
At one for every two people, twenty-five pizzas were ordered to cover the 50 expected attendees.
The day came. All ten sustainability consultants rocked up keen, ready and hungry. Not one structural engineer showed. With 25 pizzas between them, the ten who showed were well fed.
Relating the above story at Green Building Day in Melbourne on June 6th, Jones said this was one of two experiences at his first job as a graduate structural engineer which demonstrated that not all engineers are on board when it comes to sustainability.
The other happened in the first week. One partner did not want any documents sent to him by electronic means. Everything which came across his desk had to be paper.
Such experiences, Jones said, underscore that a number of engineers are yet to embrace environmentally friendly construction to the same extent as others such as sustainability consultants.
He says there are two reasons for this.
With safety rightfully being the top priority, many engineers are understandably conservative in their designs and adopt caution on matters such as the amount of material specified.
Jones says the extent of this should not be underestimated. He points to a European study which looked at utilisation ratios for a range of mostly steel construction projects and the percentage to which structural members are working. Whilst a utilisation rate of 100 percent would mean that the materials are working to capacity, the average utilisation ratio across all projects studied was only 50 percent. This, Jones says, means a lot of material being used is not necessary.
Second, costs and profit margin considerations mean that engineering firms often wish to complete designs as quickly as possible. Time or effort spent adding sustainability features over and above design brief requirements eats into margins achieved on the job.
Because of this, Jones says many engineers are not yet as engaged in sustainable construction as would ideally be the case.
This matters, he says. As operational energy use becomes more efficient and less carbon intensive, the proportion of overall energy consumption and greenhouse gas emissions which are wound up in embodied energy used during construction of buildings will rise. As this happens the need to reduce embodied energy consumption will become more important and the role of engineers – particularly structural engineers – will be critical.
“I don’t want to bag them but I just think they are not engaged at the moment for some standard opportunities to make meaningful change,” Jones said.
“Engineers have many tricks up their sleeve to pull out in respect of sustainable design to take down emissions. We don’t always pull them up. We are a bit more on the pragmatic and conservative side of things.”
Jones says engineers can promote sustainable outcomes in five ways.
Without compromising safety, they can specify only the amount of material needed.
Next, there a concrete solutions that do not use Portland cement, which is energy intensive during manufacturing. One example is geopolymer cement. This is made using geopolymers – a type of inorganic polymer that can be formed at room temperature by using industrial waste or by-products as source materials to form a solid binder that looks like and performs a similar function to Portland Cement. Using materials such as this, Jones says carbon savings in the realm of 50 to 60 percent in terms of the concrete used can be achieved compared with using Portland cement.
In high-framed steel, technologies which use hydrogen rather than carbon are emerging.
Beyond concrete and steel, the emergence of glulam and CLT mean that timber is increasingly being used multi-storey construction and offers environmental benefits in a range of areas including carbon sequestration.
Finally, designs can facilitate deconstruction and material reuse at the end of a building’s life. This be done by minimising welds and (with timber) avoiding gluing elements together unless necessary.
Of course, there are challenges and limitations. The ability to use substitutes to Portland cement is subject to supply limitations for materials such as fly ash and oil slag. With steel, the aforementioned hydrogen technology remains speculative for now. Despite timber’s advantages, Jones cautions that wood is beneficial only when sustainably sourced through a transparent supply chain. Even specifying only material which is needed – arguably the best solution of the above – has a ceiling in how much improvement it can deliver and will not in itself get the entire job done.
Accordingly, Jones says a long view is needed and that we must start now if we are to reach net zero carbon emissions by 2050.
He says the importance of engineers having a sustainability focus should not be underestimated.
“Operational energy is going down and the proportion of embodied energy is increasing,” he said.
“We as structural engineers need to get on board as much as we can. “