Experimental Studies on Mechanical Smoke Exhaust System in an Atrium

Abstract

Mechanical smoke exhaust systems are usually required in big atria of the Far East. However, the design criteria are not clearly demonstrated to be worked out through systematic full-scale tests. There are many arguments on sizing the exhaust fans, and whether a high exhaust rate is required in an atrium is a puzzle. Atrium hot smoke tests might be required to be carried out occasionally to evaluate their performance, especially when the design does not comply with the prescriptive code in having a high-enough exhaust rate.

Experimental studies on mechanical smoke exhaust systems are necessary and have been carried out. The results are reported in this paper. The measured results are also compared with the empirical equations used in designs, following NFPA-92B derived by a two-layer picture. A simple zone model reported earlier is applied to justify the results. This model is also developed based on a two-layer picture.

There are significant deviations of the measured results from those predicted by the equations with a two-layer pattern. Mass exchange through the two layers in an atrium fire is suggested to be the key point. By taking the estimated mass flow rate across the two layers by experiments to be 30% of the exhaust rate under high ventilation conditions, the two-layer zone model is modified. Slightly better argument with the experiments was found for the self-developed two-layer zone model, but still there are large deviations for the NFPA-92B equations.

Keywords

atrium hot smoke tests mechanical exhaust clear height mass flow rate across interface heat lost to solid walls

References

Chow, W.K. (2004). On Carrying Out Atrium Hot Smoke Tests, Architectural Science Review (accepted to publish).

NFPA-92B . (2000). Guide for Smoke Management Systems in Malls, Atria, and Large Areas, National Fire Protection Association, Quincy, Mass., USA .

Klote, J.H. and Milke, J.A. (2002). Principles of Smoke Management, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Atlanta, GA .

Codes of Practice for Minimum Fire Service Installations and Equipment and Inspection, Testing and Maintenance of Installations and Equipment (1998). Fire Services Department, Hong Kong , p. 120.

Hot Smoke Test on Smoke Extraction System. F.S.D. Circular Letters 2/2002, FS 107A (Rev.10/95). Fire Services Department, Hong Kong, 18 November, 2002.

AS 4391-1999 Smoke Management Systems - Hot Smoke Test. 1999. Australian StandardTM, Standards Australia (Standards Association of Australia), NSW , p. 25.

Atkinson, B. (1999). HST Verification of Smoke Management Systems using the Australian Method , In: Institute of Fire Engineers (Belgium Branch) (ed.), Underground, on the Ground and into the Air, Brussels: IFE (Belgium Branch) . Paper presented at the EUROFIRE ’99 Conference, 24-27 November, Affligen (Essene), Belgium, 1999, pp. 1-18 .

Proceedings of One-day Seminar on Hot Smoke Test, 12 March, 1999, Regal Kowloon Hotel, Hong Kong. Organized by Hong Kong Institution of Engineering-Building Services Division, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Hong Kong, 1999.

Tanaka, T. and Yamana, T. (1985). Smoke Control in Large Scale Spaces - Part 1 , Fire Science and Technology, 5(1): 31-40 .

10.

Walton, W.D. and Notarianni, K.A. (1993). Comparison of Ceiling Jet Temperatures Measured in an Aircraft Hanger Test Fire with Temperatures Predicted by the DETACT-QS and LAVENT Computer Models. NISTIR 4947, National Institute of Standards and Technology, USA .

11.

Chow, W.K. , Li, Y.Z. , Cui, E. and Huo, R. (2001). Natural Smoke Filling in Atrium with Liquid Pool Fires up to 1.6 MW , Building and Environment, 36: 121-127 .

12.

Cooper, L.Y. , Harkleroad, M. , Quintiere, J. and Reinkinen, W. (1982). An Experimental Study of Upper Hot Layer Stratification in Full-scale Multi-room Fire Scenarios , Journal of Heat Transfer, 104: 741-749 .

13.

Li, Y.Z. (2001). Smoke Flow and Control in Large Space Atrium Buildings, PhD Thesis. University of Science and Technology of China, Hefei, Anhui, China.

14.

Chow, W.K. , Yi, L. , Shi, C.L. , Li, Y.Z. and Huo, R. (2004). Mass Flow Rates Across Layer Interface in a Two-layer Zone Model in an Atrium with Mechanical Exhaust System, Building & Environment (submitted for consideration to publish).

15.

Yi, L. , Chow, W.K. , Li, Y.Z. and Huo, R. (2005). A Simple Two-layer Zone Model on Mechanical Exhaust in an Atrium , Building & Environment, 40(7): 869-880 .