Sustainable Steel Framing

Design-professionals, and particularly architects, strive to specify materials that minimise harm to the environment. They are among the leaders in the drive for buildings that are as friendly towards the environment as possible. Independent bodies (and some steel producers) around the world have performed life-cycle analyses on the environmental impacts of using steel. Based on the results, well-informed architects freely specify steel products in their various forms for projects of all sizes, including single and multiple dwellings.

Major foundations for a sustainable world

For reasons of strength, durability, versatility and economy steel is a universal building material. The superstructures of skyscrapers, bridges, high-rise apartments, commercial buildings and offices are built with steel. The proven performance and quality of steel have also caused it to dominate commercial interior wall framing applications for many years now. Today an increasing number of builders have discovered lightweight steel framing to construct homes and are doing so with great success. Steel is lightweight, cost effective, easy to use, recycled and 100% recyclable.

The steel framing industry in New Zealand is committed to sustainable development aimed at improving the quality of life for everyone, now and for generations to come. The benefits of steel framing include environmental, social and economic factors which are all linked.

In New Zealand much of house framing in steel is manufactured from iron sand originating from volcanic activity in the Taranaki region and washed up by the action of the ocean on west coast beaches.

New Zealand has been a world leader in applying fine ore materials to the development of high strength and formable steel materials for building products.

Research and development in the use of precision, lighter weight steel materials has resulted in steel framing now holding a significant share in residential applications in Australia and a growing share in New Zealand.

Life Cycle Assessment

It is generally accepted practice in the building industry today that Life Cycle Assessment (LCA) is the appropriate method to be used in the assessment of sustainability in building. LCA has the advantage of taking into account the whole life energy use of a building including materials.

Estimates of sustainability need to be made with care and integrity, especially as the area is relatively new and developing as a science.

For low rise buildings, the difference between steel framing and timber framing as regards life cycle energy has been found to be very small. This has resulted in greater emphasis on how materials are used in a building in a way that requires less energy during the occupancy of the building.

The steel framing industry has been very careful to protect the value of LCA - both in the undertaking of studies and in the publication and interpretation of data and results.

The industry supports efforts to develop a consistent, rigorous and transparent methodology for LCA. This enables society to make informed choices on the environmental impact of products and processes.

Biodiversity and Ecosystem Disruption

Life-cycle stress-effects assessment (LCSEA) has been developed to consider the whole context of sustainable development and thus land use effects of material production on habitats and biodiversity.

Ecosystem disruption of steel production for residential steel framing has been found to be less than one percent of equivalent wood framing production. This demonstrates steel’s contribution to sustainable building for future generations.

Recycling and Efficient use of Natural Resources

Steel has made a large commitment to recycling and is now the world leader in recycled material. In New Zealand over 250,000 tonnes of steel are recycled into new steel products every year.

Every new steel framed house contains recycled steel. Steel framed housing is 100% recyclable and the framing can be recycled over and over indefinitely.

The use of recycled steel reduces the energy required for steel making significantly. The industry has made numerous improvements to energy efficiency. A recent centrepiece is the second co-generation plant at Glenbrook steelworks which helps generate 60 percent of the plant’s required electricity from waste heat and gas from ironmaking.

Steel framing is easy to use on-site. It is lightweight because steel has the highest strength to weight ratio of any construction material, resulting is less framing material compared to wood for an equal size structure. Steel framing is cost effective. It can be purchased in specific lengths and assembled or panelised, minimising job site scrap. Steel does not twist warp or split so there is no need to sort poor quality product which saves time and money. Builders reduce their disposal costs and divert material from local landfills.

Wastage for landfill can be next to nothing as all steel components can be recycled through a scrap metal recycler.

Structural performance

Increased performance of steel framing arises from the benefits of some of its unique properties such as having the highest strength to weight ratio of any construction material. House framing in steel does not twist or warp so there is no need to sort out poor quality with resulting cost benefits for manufacturers, builders and homeowners. Consistent quality and dimensional stability contribute to better drywall and exterior appearance and performance. Quality of fit for doors, windows and cupboards is enhanced.

Housing costs and material usage are expected to fall in New Zealand as steel framing costs reduce by some 15% over the next three years. Consequent reductions in use of time, materials and capital will significantly benefit sustainability.

Framing with steel as a material consumes only 6.5% of the total life-cycle energy used by a home; the balance is consumed by heating and cooling, food refrigeration and lighting. Thermal barrier insulating materials provide exceptional heat and cooling loos protection to steel built homes. Additionally steel framing results in less air loss around windows and doors as well as foundation and roofing connections.

Economic benefits

  • Steel Framed construction is comparable in price to timber framed construction.
  • Manufacture is typically computer controlled for speed and precision. Flat pre-coated steel strip passes through a series of roll formers and punches which provide strength, holes and dimples automatically.
  • Efficient installation methods can make homes that are easier and faster to build than with other methods. After wet weather steel framing requires no lengthy drying-out time so lining can always proceed quickly. Steel frames weigh about 30% less than timber frames. Trained builders and installers are available.
  • Steel Framing is a stable and consistent product that means walls, roofs and ceilings are straight and true for the life of the home. Steel Frames will not warp, or creak with weather changes.
  • Some lining manufacturers recommend fixing linings to steel battens and frames to minimise cracking and promote a better overall finish.
  • The high strength to weight ratio of steel framing allows features like high-stud walls in high wind zones and large spans to extend open interior spaces.
  • Frames have holes pre-punched ready for the plumber and electrician. The liner, cladder and roofer apply fastening methods which are rapid and straightforward to use.

Health and safety benefits

  • Steel frames are designed to meet the loading requirements of all relevant Standards. Steel frames made from steel from New Zealand Steel carries a 50-year durability statement.
  • Steel frames cause no interference to radios, phones or TV. It provides occupants extra protection from lightning.
  • Steel frames are effectively protected by its barrier coating from the atmosphere and by galvanic action (sacrificial protection). Steel framed construction can perform well in coastal and industrial environments.
  • Steel frames will not rot, grow toxic mould or absorb moisture.
  • Because of its properties including high strength and lightness, steel framing is an excellent material to resist earthquakes.
  • Steel framing resists fire. Under high heat it will deform but not burn.
  • Steel framing cannot be attacked by vermin or insects such as borer moth and termites.
  • Precise manufacturing to exact dimensions and consistent quality mean steel frames are efficient to manufacture and greatly reduce wastage for landfill.
  • Being extremely lightweight, steel frame construction requires lighter foundations and reduced footprint. On steeply sloping terrain, this can reduce site disturbance.
  • Steel frames can be used in all climate conditions.

Steel: Building Better