Annual Report 2002–03

社會科學院 Faculty of Social Science 風閘效應對病毒上下傳播的研究 SARS 在二零零三年三月爆發後，建築學系利用計 算流體動力學，詳細研究淘大花園的特殊環境， 結果發現 E 座與 F 座的相對位置，加上背景風向， 導致兩座建築物之間產生快速氣流，從而造成一 道「風閘」，封住了天井的出口，令天井內空氣的 橫向流動非常緩慢。因此，排放至天井中的微細 水珠如果含有病毒，將會徘徊不散，只能上下流 動，增加進入其他樓層的機會。其他建築物只要 沒有相若的「風閘」，就沒有類似的風險。 研究人員針對淘大花園的特殊情況，提出改善方 案——在天井出口附近，選擇適當位置，安裝定 風板，以改變天井出口處的壓力分布，從而破解 「風閘」，改善天井裡的通風情況。這方案簡單， 安裝工程容易。由於淘大 E 座疫情也與排污管失 修和 U 型聚水器乾涸有關，若能經常維修排污管 和改進 U 型聚水器，更可免除病毒散播的威脅。 研究報吿獲香港特區政府衛生署和中國建設部引 用，向世界衛生組織匯報。建築學系的計算機模 擬研究小組其後又研發了一個評估建築物凹口處 通風狀況的科學風模擬架構，可於樓宇建成前了 解其凹口天井的局部風環境。小組並已向政府的 屋宇署介紹研究的初步成果。 Study on the Wind Curtain Effect and the Vertical Spread of the SARS Virus in Amoy Gardens A f t er the outbreak o f SARS i n Ma r ch 2003, the Architecture Department conducted a detailed computational fluid dynamics (CFD) study of the entire A m o y Gardens complex. It was found that the placement o f Blocks E and F, relative to each other and to the prevailing w i n d direction, leads to a ' w i n d curtain' effect, sealing o f f the reentrant area (light well), in which horizontal air-flow becomes nearly stagnant. Thus, any droplets laden w i th the SARS virus that might be released into the reentrant area w o u ld have a high tendency to remain in the area, and to spread vertically and contaminate other floors. The risk was associated w i th the unfortunate convergence o f a number o f factors, including problems w i th sewage and U-tubes. Buildings that do not have this topography are unlikely to be at the same level o f risk. The researchers recommended the installation o f a simple panel (spoilers) at a suitable position in the reentrant area to disrupt the ' w i n d curtain'. This w o u ld provide a simple retro-fitting solution (in addition to rectification o f sewage problems) to many buildings. The investigation report was quoted by the Health Department o f the H K S A R and the Ministry o f Construction of China in their report to the Wo r ld Health Organization. The department's Computational/Simulation Research Unit has also carried out an in-depth research on ‘Developing Scientific Simulation Framework to Evaluate the Ventilation o f Reentrant Areas' to understand the complex micro w i n d environment in the reentrant areas. Preliminary findings have been presented to the in-house task force o f the Buildings Department, H K S A R. 研究 Research 59