Channelnewsasia, 24 April 2007
SINGAPORE : The Building and Construction Authority (BCA) has mapped out a plan to drastically cut Singapore's dependence on sand and granite.
About 95 percent of building projects in Singapore are concrete-based and highly dependent on sand.
With its Sustainable Construction Masterplan, the BCA wants to bring this down to below 50 percent over the next five years.
Dry partition walls will be a cornerstone of environmentally-friendly and sustainable construction, which calls for materials to be available on a regular basis and come from multiple sources.
They are made of metal frames and plasterboards and do not require sand and water, typically used for concrete mixes.
Such drywalls are currently installed in many private residential projects, to replace conventional brick walls that separate rooms in apartments.
Some common misconceptions about drywalls are that they are hollow and have poor sound insulation.
However, contractors have said that is not the case.
For instance, a 90mm drywall has thermal and sound insulation quality comparable to a 115mm thick brick wall, and it is just as strong.
Developers said the light weight drywalls could be put up four times faster than brick walls.
So it helps to generate some savings in the process and cut down on waste and pollution.
Allen Ang, Senior Manager, Projects Division, City Developments Limited, said, "(A) drywall uses less workers, less natural materials such as sand and water; it's faster (to put up) than traditional brick wall. If I factor all these in, the cost savings is on average 24 percent.
"From our experience (of) developing City Square Mall - a large scale shopping mall - the savings as a result of using drywalls in lieu of traditional brick walls amounted to about 50 truckloads of sand; when translated to dollars, it's about S$36,000."
To further reduce the demand on sand and granite, building designers are encouraged to explore alternative materials like steel and glass, used in projects like the National Library and the Fusionopolis.
These can cut concrete use by some 70 percent.
Though some argue that construction costs could climb by up to 10 percent, industry players said the rise in prices of sand and granite would give developers more incentive to turn to steel.
Currently, structural steel design codes here are based on British Standards, and BCA hopes to release new guidelines in steel manufactured to other standards in three months.
Recycled construction waste like concrete and incinerator ash can also get a second lease of life as a road kerb or for layering of roads.
Authorities are also working with the National University of Singapore to process "spent copper slag", a by-product of sand blasting, to partially replace natural sand.
Hardware aside, the BCA has trained 150 practitioners on advance steel design and construction since February this year, and more courses will be introduced.
It will work with the Singapore Structural Steel Society on more training programmes, as well as local universities to beef up the curriculum on structural steel design.
Also in the pipeline are discussions on whether it is time to review the legislation to ensure that all projects adopt a minimum level of sustainable construction. - CNA/ms
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