本研究以流體力學的觀點，探討廂型式氣罩(偏重於化學氣櫃類型)的參數變化對流場狀態的影響，並發展一套全新的氣簾式設計，大幅改善傳統上吸式氣櫃的缺點。採用流場可視化實驗技術進行研究，並以追蹤氣體濃度偵測方式來評估氣櫃的洩漏。為了瞭解傳統氣櫃在運作時櫃內及櫃門附近的流場型態，使用雷射光頁配合煙霧釋放技術來診測流場，分析流場型態並推測造成櫃內污染物洩漏及不良流場的原因。由實驗得知傳統氣櫃抽氣無效性的原因，所以針對此問題設計了下吸式氣櫃，主要目的是為了就污染源附近排除污染物，來達到抽氣的功效，並在氣櫃門加上一吹氣噴嘴，配合下吸式氣罩，使氣櫃門開口處形成一道空氣簾幕，以此來加強防護櫃內污染物的洩漏，稱此一安排為氣簾式氣櫃。氣簾式氣櫃透過吹氣速度、吸氣速度及氣門開口高度三個參數變化來改變流場。由流場可視化實驗中，可以識別出內凹、筆直、弱吸、過吹四種特徵模態區域；針對這四種模態的流場型態加以判斷，發現內凹模態與弱吸模態可能會是較佳的操作區域。經由SF6濃度測量實驗，以美國及歐洲所制定的實驗室氣櫃測試方法為基準，包括穩態及動態追蹤氣體濃度測試，測量數據顯示在穩態無側流因素的影響下，操作在內凹、筆直、弱吸三種模態時具有優越的捕集污染物能力。動態追蹤氣體濃度測試數據顯示，操作在內凹模態下具有較佳的抗擾動能力。以流場觀察配合濃度測量，結果說明內凹模態為氣簾式氣櫃最佳的操作區域。以ANSI/ASHRAE 110-1995追蹤氣體(SF6)測試方法進行有假人的穩態測試結果，氣簾式氣櫃的洩漏濃度為0.000115 ppm(一般較好的傳統型氣櫃的洩漏濃度為0.01 ppm；美國柏克萊大學勞倫斯國家實驗室新發展成功的氣櫃之洩漏濃度為0.002 ppm)。以prEN14175-3穩態測試之結果顯示氣簾式氣櫃在開口的各個位置的洩漏濃度也幾乎趨近於零，然而傳統式氣櫃無可避免的在門檻及兩邊門柱附近均有嚴重洩漏，雖然ANSI/ASHRAE 110-1995的方法測試是合格的。prEN14175-3動態強健度測試的結果亦顯示，濃度洩漏為0.0001 ppm(德國的BG Chemie所規定的濃度束限值為0.65 ppm)，而較好的傳統氣櫃則高達1.30 ppm，柏克萊大學勞倫斯國家實驗室的氣櫃則未經此項測試。

An innovative chemical fume hood which operates based on the aerodynamic principle of air-curtain isolation is developed. The flow visualization and tracer-gas test methods are performed to diagnose the flow characteristics and containment performance of the air-curtain hood. A real-size, transparent air-curtain hood and a commercial grade conventional chemical fume hood are constructed for experimental study. The experimental results of the conventional hood are used for comparison. Through the application of the laser-assisted smoke flow visualization method, the characteristic flow patterns are clearly observed and recorded. The results presented that the conventional fume hood has several regions that the pollutants issued from the smoke ejector placed in the fume hood would leak or disperse out of the sash opening due to some inherent flow physics. Firstly, the geometric arrangement of the conventional fume hood would inevitably induce several large recirculation regions inside and behind the sash. The large recirculating bubble may induce turbulent dispersion and leakage of the pollutants when the sash is open or in opening process. Secondly, around the doorsill and the side poles of the fume hood, there are high risks of pollutant leakage. These local leakages are induced by existence of local recirculation bubble, which are formed when the inlet flows pass over the non-aerodynamically-streamlined (bluff) bodies of the hood structure. The bluff bodies would induce significant flow separation and subsequently lead to flow recirculation. From the flow visualization results, these local flow recirculations obviously bring large amount of in-hood pollutants out to the atmosphere through the sash opening. These global and local flow deficits are not easy to overcome. Contradictorily, the flow fields of the air-curtain hood shows no global recirculations. The local recirculation bubbles may exist, although much weaker. No apparent traces of the in-cabinet released smoke particles are entrained out of the hood and go into these local recirculation bubbles. It seems that the leakage of the air-curtain hood would be less than that of the traditional fume hood if the aerodynamic consideration can be extended to an extent of the mass transport. The tracer-gas concentration measurements present extra-ordinarily satisfactory results. By employing both the ANSI/ASHRAE 110-1995 and prEN14175-3 standard methods to test the performance of the air-curtain fume hood under both the static and dynamic situations, the leakages of the tracer gas approach almost null. The observed flow patterns and the measured tracer-gas concentrations are closely related.

[1] ACGIH, Industrial Ventilation, A manual of recommended practice, 24th ed. American Conference of Governmental Industrial Hygienists, 2001, pp. 108-109.
[2] Mosovsky, J. A., “Sulfur Hexafluoride Tracer Gas Evaluation on Hood Exhaust Reductions,” AIHA J., Vol. 56, Jan 1995, pp. 44-49.
[3] 勞委會勞工安全衛生研究所，生物安全櫃操作安全技術手冊，勞委會勞工安全衛生研究所著，ISBN 957-01-6772-6, 2004。
[4] McDermott, H. J., “Handbook of Ventilation for Contaminant Control,” 2nd Ed., Butterworth-Heinemann, Boston, 1985.
[5] 行政院勞工委員會，有機溶劑中毒預防規則，台北，1991。
[6] 行政院勞工委員會，特定化學物質危害預防標準，台北，1991。
[7] 內政部，鉛中毒預防規則，台北，1974。
[8] 內政部，粉塵危害預防標準，台北，1981。
[9] 行政院勞工委員會，勞工安全衛生組織管理及自動檢查辦法，台北，1993。
[10] Numano, Y. (沼野雄志)，局排設計教室，第三版，中央勞動災害防止協會，東京，1996。
[11] Caplan, Knowlton J. and Knutson, Gerhard W. “A Performance Fume Hoods: Influence of Room Air Supply,” AIHA Journal, Vol 84, 1978, pp511-512.
[12] Woodrow, L.M.: “An Evaluation of Four Quantitative Laboratory Fume Hood Performance Test Method,” (LA-11143-T, thesis). Los Alamos, Los Alamos National Laboratory, 1987.
[13] Maupins, Karen and Hitchings, Dale T., “Reducing employee exposure potential using the ANSI/ASHRAE 110 Method of Testing Performance of Laboratory Fume Hoods as a Diagnostic tool.” AIHA Journal, Vol. 59, No. 2, February 1998, pp. 133-138.
[14] ANSI/AIHA, “American National Standard-Laboratory Ventilation,” ANSI/AIHA Z9.5-2003, American Industrial Hygiene Association, 2003, pp. 58.
[15] DIN 12924-1994, “Laboratory Furniture; Fume Cupboards; General Purpose Fume Cupboards; Types, Main Dimensions, Requirements and Testing,” Beuth Verlag GmbH, 1994.
[16] BS, “Laboratory Fume Cupboards. Part 4. Method for determination of the containment value of a laboratory fume cupboard,” British Standards Institution, London, 1994.

[17] ANSI/ASHRAE 110-1995, “Method of Testing Performance of Laboratory Fume Hoods,” American Society of Heating, Refrigeration and Air Conditioning Engineers, Atlanta, GA, USA , February 1995.
[18] NFPA 45-2000, “Standard on Fire Protection for Laboratories Using Chemicals,” National Fire Protection Association, 2000 Edition.
[19] EN “Fume Cupboards-Parts 3: Type test method(prEN 14175-3),” European Committee for Standardization, 2003.
[20] Invent-UK, “Specifications handbook for fume cupboard performance tests: procedures, requirements and gradings,” Revision 5, February 2004, Invent UK Ltd.
[21] First, M. W., “Laboratory Chemical Hoods: A Historical Perspective,” AIHA Journal, Vol. 64, March/April 2003, pp. 251-259.
[22] DiBerardinis, L. J., First, M. W., Party, E., Smith, T. C., Warfield, C. A., Carpenter, J. P., Cook, J. L., Walters, D. B., Flynn, M. R., Galson, E. L., Greenley, P. L., Hitchings, D. T., Knutson, G. W., Price, J. M., Baum, J. S., Burton, J. D., Finucane, M. D., Ghidoni, D. A., Koenigsberg, J., Lyons, M., Memarzadeh, F., Norton, D. C., Schuyler, G., Zboralski, J., and Barkley, W. E., “Report of the Howard Hughes Medical Institute's Workshop on the Performance of Laboratory Chemical Hoods,” AIHA Journal, Vol. 64, March/April 2003, pp. 228-237.
[23] 勞委會勞工安全衛生研究所，作業場所空氣有害物預估與控制研究-側風對外裝型氣罩捕集效果之探討，勞委會勞工安全衛生研究所研究報告，IOSH88-H103, 1999。
[24] 勞委會勞工安全衛生研究所，外裝型氣罩控制風速與捕集能力探討，勞委會勞工安全衛生研究所研究報告，IOSH89-H104, 2000。
[25] 勞委會勞工安全衛生研究所，氣罩凸緣對捕集效果相關性探討，勞委會勞工安全衛生研究所研究報告，IOSH90-H102, 2001。
[26] 勞委會勞工安全衛生研究所，發散式危害源氣罩設計模式研究，勞委會勞工安全衛生研究所研究報告，IOSH91-H121, 2002。
[27] 勞委會勞工安全衛生研究所，吹吸式氣罩設計與操作指引研究，勞委會勞工安全衛生研究所研究報告，IOSH92-H102, 2003。
[28] Huang, R. F., Chen, J. L., Chen, Y. K., Chen, C. C., Yeh, W. Y., and Chen, C. W., “The capture envelope of a flanged circular hood in cross drafts,” AIHA Journal, Vol. 62, March/April 2001, pp. 199-207.

[29] Huang, R. F., Sir, S. Y., Chen, Y. K., Yeh, W. Y., Chen, C. W., and Chen, C. C., “Capture envelopes of rectangular hoods in cross drafts,” AIHA Journal, Vol. 62, Sep./Oct. 2001, pp. 563-571.
[30] Huang, R. F., Liu, G. S., Chen, Y. K., Yeh, W. Y., Chen, C. W. and Chen, C. C., “Effects of flange size on dividing streamline of exterior hoods in cross drafts,” Journal of Occupational and Environmental Hygiene, Vol. 1, No. 5, May 2004, pp. 283-288.
[31] Huang, R. F., Liu, G. S., Lin, S. Y., Chen, Y. K., Wang, S. C., Peng, C. Y., Yeh, W. Y., Chen, C. W., and Chang, C. P., “Development and Characterization of a Wake-Controlled Exterior Hood,” Journal of Occupational and Environmental Hygiene, Vol. 1, No. 12, December 2004, pp. 283-288.
[32] Huang, R. F., Lin, S. Y., Jan, S. Y., Hsieh, R. H., Chen, Y. K., Chen, C. W., Yeh, W. Y., Chang, C. P., Shih, T. S., and Chen, C. C., “Aerodynamic Characteristics and Design Guidelines of Push-Pull Ventilation Systems ,” Annals of Occupational Hygiene, Vol. 49, No. 1, January 2005, pp. 1-15.
[33] 行政院勞工委員會，有機溶劑中毒預防規則，台北，2003。
[34] 行政院勞工委員會，特定化學物質危害預防標準，行政院勞工委員會，台北，2001。
[35] 行政院勞工委員會，鉛中毒預防規則，行政院勞工委員會，台北，2002。
[36] 行政院勞工委員會，粉塵危害預防標準，行政院勞工委員會，台北，2003。
[37] 勞委會勞工安全衛生研究所，崗亭式氣罩最佳化設計研究，勞委會勞工安全衛生研究所研究報告，IOSH94-H101, 2004。
[38] Bell, G. C., Sator, D., and Mills, E. “The Berkeley Hood: Development and Commercialization of an Innovative High-Performance Laboratory Fume Hood,” Progress Report and Research Status: 1995-2003, LBNL-48983, HT, Lawrence Berkeley National Laboratory, Berkeley, California, U.S.A., October 2003, pp. 3-50.
[39] Flagan, R. C. and Seinfeld, J. H., Fundamentals of Air Pollution Engineering, Prentice Hall, Englewood Cliffs, New Jersey, 1988, pp. 290-357.
[40] Saunders, T., “Laboratory fume hoods, a user’s manual,” John Wiley & Sons, Inc, Professional, Reference and Trade Group. New York, 1993, pp.56.

[41] Durst, F. and Pereira, J. C., “Experimental and numerical investigations of the performance of fume cupboards”, Building and Environment, Vol, 59, No. 2, February 1991, pp. 153-164.
[42] Tschudi, W., Bell, G. C., and Sartor, D. “Side-by-Side Fume Hood Testing: ASHRAE 110 Containment Report,” (LBID-2560). Lawrence Berkeley National Laboratory, Berkeley, California, U.S.A., October 2004, pp. 3-4.