Experimental study for the hold time of clean extinguishing agent interpreted as function of time. (March 2022) - Kim, Goonho
Abstract: This paper proposes a new model to predict the hold time in enclosures protected with clean extinguishing agent (CEA). The limitations of three existing theoretical models are analyzed, and the proposed model is validated. Existing theoretical models employ the enclosure height as a variable in predicting the hold time of CEA; hence, the prediction of diffusion according to time change has limitation. In this study, a theoretical model is proposed in which species diffusion is defined as a function of time rather than elevation, based on the theory of diffusion in fluids. The proposed model was experimentally verified using five CEAs. The predicted hold time in each theoretical model was compared to the height-specific hold time measured in the test enclosure. Existing theoretical models, which are expressed as a function of elevation, will have varying errors between the predicted and measured hold times depending on the input parameters. Also, the maximum error range is approximately 46%. However, in the proposed model expressed as a function of time, the error of the hold time does not change. In addition, the maximum error range is approximately 16%, which increases the accuracy approximately 3 times compared to the existing theoretical model. Highlights: CEA hold time should be expressed as a function of time, not elevation. A new theoretical model for hold time is proposed based on the theory of diffusion in fluids. Proposed models are compared and validated through experimental evaluation.