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The Power of Steel in Green Buildings

(originally published 30 June 2016)

The dynamics associated with the built environment have shifted deeply into the area of sustainability. With a rise in urban renewal projects, the influence of Green Star certification has grown. However, some might not realise just how rewarding the use of reusable and recyclable products like steel are to a project and points accrual.

Sustainability and green were major buzzwords for many years. While some of the contentiousness of the term ‘green buildings’ seems to have worn off, the importance of creating greener buildings and spaces remains. In fact, sustainability and best practice buildings are synonymous, says OneSteel Business Development Manager David Bell.

“Being ‘green’ considers the Indoor Environment Quality of its inhabitants, is sensitive to the broader environment, is resilient to the ebbs and flows of the modern city, is efficient during its use and the asset attracts a premium in the market,” Bell said. 

Moreover, it has practical and significant paybacks when it comes to accruing the Green Star points necessary for a building to be awarded a Green Star rating.

Sustainable steel

Steel is infinitely recyclable, and even the processes of manufacturing steel are increasingly environmentally-conscious, with Polymer Injection Technology improving the method of making steel via the Electric Arc Furnace (EAF) process. 

“Steel is one of the most sustainable building materials in the world – due in part to the nature of its recyclability as well as its ability to be adapted and reused,” Bell said. 

The GBCA rating tool

In 2014, the Green Building Council of Australia (GBCA) replaced its legacy rating tools with the ‘Design & As Built Rating Tool’. Rather than apply a points system according to the type of building being assessed, the new tool updated the benchmarks and covered all building types.

This tool rates buildings across nine categories: management, indoor environment quality, energy, transport, water, materials, land use and ecology, emissions, and innovation.

Design & As Built delivers benefits for steel users. Not only does steel have sustainability benefits, it contributes to a building’s Green Star rating.  

Green Star - Design & As Built ratings tool using steel

The Green Star points available through the use of structural and reinforcing steels are recognised in several areas of the Design & As Built V1.1 tool, Bell explained, adding that there remain some misconceptions around steel’s place in the ratings tool.

“The Design & As Built tool no longer halves the points earned in the Material Category. One point earned is a full point towards the Green Star rating,” Bell said.  

He notes that the higher strength steels required in the Material Category are available from local steel manufacturers, including the Grade 350 hot rolled sections that are manufactured by OneSteel in Whyalla, the Grade 450 square (SHS) and rectangular hollow sections (RHS) available from Austube Mills.

“Also, the three Green Star points for concrete available in the Materials Category are available to structural steel framed buildings.”

Two credit points are available for steel, whether the building frame is steel or concrete. One point sits in the ‘Life Cycle Impacts - Steel’ section and one point comes from the ‘Responsible Building Material – Steel’ section. An alternative pathway to ‘Life Cycle Impact’ is available using life cycle assessment methodology. 

Point for Lifecycle Impact

Point for Responsible Building Material  

The Life Cycle Impact Point rewards projects for reducing the amount of steel used when compared to standard practice. 

In a steel framed building this can be demonstrated by either using higher grade steels or by reducing the mass of steel framing by 5% compared to a suitable reference building. 

The first option is the same as it was for the legacy tools, where 95% of Category A steel products and 25% of Category B steel products used in a project must meet the minimum strength grades specified in Table 1 and Table 2 here

The permanent marking of the higher strength grade, which was a requirement of the legacy tools, is not a requirement of the Design & As Built tool. 

In a concrete framed building a point is awarded for reducing the mass of steel reinforcing by 5% compared to a suitable reference case.

 A point is awarded for steel products that are responsibly sourced or have a sustainable supply chain. The compliance requirements for this point are the same as for the legacy tools, specifically that:

• The steel making facility shall have an ISO 14001 Environmental Management System in place; and

• The steel maker supplying the steel is a member of the World Steel Association’s (WSA) Climate Action Programme (CAP).
For steel framed buildings, at least 60% of the fabricated steelwork must be from a steel fabricator/contractor accredited to the Environmental Sustainability Charter of the Australian Steel Institute.

For concrete framed buildings, at least 60% of all reinforcing bar and mesh must be produced using an energy reducing process in its manufacture, such as Polymer Injection Technology.

Building knowledge

A project can achieve up to three Green Star points by using materials and products with valid EPDs – recognised in the Sustainable Products section of the Design & As Built tool.

OneSteel is developing Environmental Product Declarations (EPDs) that cover its structural, rail and reinforcing steel products. 

Bell points to the value in a simple conversation with experienced people. A major focus with clients is highlighting how steel can deliver an economic advantage, in addition to delivering a sustainability outcome. 

“With our clients, we explain how using our structural and reinforcing steel can help their projects to easily and economically achieve Green Star points. Soon we will also provide our EPDs and explain the intricacies not readily known – that is, your project can accrue Green Star points through the Materials and Sustainable Products criteria.”

Reuse reaps rewards

The evidence lies in real-life examples. Bell notes that there are many examples of clever reuse of steel in projects, delivering not only a positive impact to construction by reducing waste, but also boosting the project’s green credentials.

“There have been numerous multi-storey structural steel framed projects across Australia that have been delivered with strong economic, social and sustainability outcomes,” Bell said.

“One recent example is the 480 Queen Street project in Brisbane. This landmark building was delivered four months ahead of its original program and had a fantastic safety outcome with nil Loss Time Injury (LTI) or Medical Treatment Injury (MTI) for the steel trades onsite."

480 Queen St utilised a significant proportion of OneSteel’s Grade 350 Universal Beams, which contributed to the project meeting the Green Star (higher strength steel) requirement, and also reduced the amount of steel used. This delivered a favourable structural, economic and sustainability outcome for the floor structure.

“The steel contractor was also a member of the Australian Steel Institute Environmental Sustainability Charter, which offered the builder, Grocon, the opportunity to also achieve the Green Star point for using a Responsible Building Material.”

In Sydney, 20 Martin Place is another project that proved highly sustainable, with the team behind its extensive refurbishment retaining the original OneSteel-supplied structural steel frame from the 1970s and providing a renewed building that will continue to deliver in the coming decades.