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NUS prof explains merlion lightning strike

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  • skythewood's Avatar
    7,346 posts since Jul '07
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      Lightning strikes all too often <!--<span class="timestamp">10 min</span>-->

      <!-- headline one : end --> Lightning has been detected 186 days per year here, one of the world's highest rates <!-- Author -->   <!-- show image if available -->

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      THE Merlion statue, which was slightly damaged in a lightning strike last Saturday afternoon, is only one of many structures hit by the frequent lightning storms that zap across Singapore each year.

      The country has one of the highest rates of lightning activity in the world as its hot tropical weather is ideal for the formation of storm clouds.

      Most lightning dissolves harmlessly into the ground. But if a building is struck, residents can find their power and telecommunications disrupted by the massive surge in electrical current.

      An average lightning strike carries a current of up to 200,000 amps. In comparison, a 100-watt bulb carries a current of about 0.4 amp.

      Lightning expert Liew Ah Choy of the National University of Singapore's Electrical and Computer Engineering department said that during a lightning strike, 'a current burrows its way into a non-conductive material like concrete or fibreglass, burning and cracking it in the process'.

      Lightning can be lethal. In 2004, Jiang Tao, a footballer with Chinese club Sinchi, was killed when he was struck while training at the Jurong Stadium.

      Between 1982 and last year, the National Environment Agency's Meteorological Services Division detected lightning on an average of 186 days per year.

      And lightning hits each square kilometre of land 12 to 20 times each year. Because of this, lightning rods on buildings have been mandatory since 1979, as they help intercept lightning bolts.

      Under the current Building Regulations, only buildings, observation towers and other structures housing occupants need shielding from lightning. The Merlion, which has no occupants, does not need a lightning rod.

      But Professor Liew said the Merlion statue could be too far away from the One Fullerton building to be adequately protected by its lightning rod. 'Anything about 50m away (from protection) is too far,' he said. This is regardless of the height of the protected building.

      Edited by skythewood 03 Mar `09, 12:51PM
    • Code to be updated
      THE building code, which governs lightning protection here, will get its first update in 13 years, detailing more information on how to safeguard electronic systems and taller buildings.

      The Singapore Lightning Protection Code CP33 was first compiled in 1985 and revised in 1996.

      It is used by engineers, electrical contractors and those in the building industry.

      Lightning expert Liew Ah Choy, of the National University of Singapore's electrical and computer engineering department, is chairman of the revision committee.

      He said an update would be released in about six months. Updates would include more guidelines on how to protect electrical and electronic equipment, which is more widespread and essential than ever, he added.

      'There are so many important systems today which depend on electronics,' Prof Liew said.

      The updated code will also include new knowledge on risk analysis, and guidelines relevant to the towering buildings of Singapore's ever-rising skyline.

      GRACE CHUA

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