Sustainable Construction A Life Cycle Approach in Engineering

ing to be burnt or sent to a disposal site. The plot of land can be returned to nature without any
fear of contamination or residual waste.( Sobek.2005)
2.3 Material selection principles
Around 50% of all global resources go into the construction industry, with a specific example
being that 70% of all timber is used for building.( Hyett 2001) It is therefore very important
that a sustainable approach to choosing and using materials is adopted, in order that the industry
can meet the target of, '...providing for people of today and not endangering the generations
of tomorrow...'.
The environmental and economic benefits of sustainability are inherently linked when considering
building materials, due to the long-term financial advantages of recycling, using recycled
products and sourcing heavy materials locally.
The 20th century has seen remarkable developments in material technology and the two dozen
materials which were used by Victorian forebears has been replaced by anything between
40000 and 80000 different materials.(Asby,2003)
Whereas two dozen materials of 19th century would be used to meet all known applications
builders and engineers have to be wildering array to choose from. In general construction does
not use high –technology materials, but a larger range of materials are now available than ever
before. (Gmoriconi,2004). For example UK construction consumes something over 400 million
tonnes of material per annum, and the total value of UK construction materials is 20 billion
pounds. This includes new built and repairs and refurbishment. (Gmoriconi,2004)
Concrete is one of the most widely used construction materials in the world. However, the production
of porland cement, an essencitial constituent of concrete, leads to the release of significant
amount of CO2, a green house gas ; one ton of porland cement clinker production is said to
creates approximately one ton of CO2 and other green house gases. (GHGs) (
Sturges,2006)
A variety of decision-aiding tools exist, which can help to evaluate the environmental cost of a
manufactured product in the context of social and economic benefit. These include Life-Cycle
Assessment, Eco-Labelling and Embodied Energy Audits, all of which could help when choosing
materials and suppliers to assess the balance between short-term costs and long-term environmental,
social and financial benefits.
Materials Efficiency
Select sustainable construction materials and products by evaluating several characteristics
such as reused and recycled content, zero or low off-gassing of harmful air
emissions, zero or low toxicity, sustainably harvested materials, high recyclability, durability,
longevity, and local production.
Use dimensional planning and other material efficiency strategies. These strategies
reduce the amount of building materials needed and cut construction costs
Reuse and recycle construction and demolition materials.
Require plans for managing materials through deconstruction, demolition, and construction.
Design with adequate space to facilitate recycling collection and to incorporate a solid
waste management program that prevents waste generation.( Davoudi 2001)
2.4. Water efficiency principles
Design for dual plumbing to use recycled water for toilet flushing or a gray water
system that recovers rainwater or other nonpotable water for site irrigation.
Minimize wastewater by using ultra low-flush toilets, low-flow shower heads, and
other water-conserving fixtures.
Use recirculating systems for centralized hot water distribution.
Install point-of-use water heating systems for more distant locations.
36