scholarly journals Experimental Study on Fire Sources for Full-Scale Fire Testing of Simple Sprinkler Systems Installed in Multiplexes

Fire ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 8
Author(s):  
Jeonghwa Park ◽  
Jihyun Kwark
Keyword(s):  
Large Scale ◽  
Fire Suppression ◽  
National Fire Protection Association ◽  
Control Performance ◽  
Fire Testing ◽  
Fire Control ◽  
Wood Crib ◽  
Fire Source ◽  
Sprinkler Systems ◽  
Cotton Wick

Fires are accidents that can cause numerous human casualties in multiplexes. The simple sprinkler systems applied in South Korea employ sprinklers to protect people against residential fires, as specified by the National Fire Protection Association (NFPA) standard 13D. Therefore, it is necessary to evaluate the fire control performance of multiplexes, which are at a greater risk than residential facilities. This study aims to verify the fire control performance of simple sprinklers in multiplexes and to develop a fire source that can be used as a protocol for testing fire suppression methods. The fire source was evaluated by using a 3 MW large-scale calorimeter (ISO 13784). The proposed fire source for multiplexes was applied in various forms according to the application methods, with ignition sources including cotton wick, wood crib, and heptane, and then the fire tests were conducted.

The Experimental Study on the Fire Suppression Effectiveness of Water Mist with the FeCl2 Additives

2013 ◽  
Vol 790 ◽  
pp. 53-56
Author(s):  
Chen Jian ◽  
Xu Yan Ying ◽  
Wang Na
Keyword(s):  
Experimental Study ◽  
Fire Suppression ◽  
Water Mist ◽  
Experimental Results ◽  
Additive Concentration ◽  
Experimental Conditions ◽  
Fire Source ◽  
Fire Extinguishing ◽  
Nozzle Position

This paper presents an experimental study of fire suppression effectiveness with water mist containing FeCl2 additives.The investigation focuses on suppression effectiveness under various FeCl2 additives concentrations,working pressures and nozzle different height above the fire source . The experimental results show that: there is a significant impact on fire suppression effectiveness when adding FeCl2 to water mist. There is an optimum additive concentration of extinguishing fire, corresponding to the shortest extinguishing time, the least amount of water, the highest efficiency of extinguishing fire. The nozzle working pressures and nozzle position have effect on the performance of the water mist extinguishing: the greater the pressure is, the shorter water mist fire extinguishing time is. Under the same experimental conditions, the closer the water mist nozzles are to the oil pan, the shorter extinguishing time is.

Phenomenon Identification and Ranking Exercise and a Review of Large-Scale Spray Modeling Technology

2008 ◽  
Author(s):  
Alexander L. Brown ◽  
Sam S. Yoon ◽  
Richard A. Jepsen
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Fire Suppression ◽  
Particle Surface ◽  
Liquid Fuels ◽  
Fire Propagation ◽  
Research Activities ◽  
Ranking Exercise ◽  
Productive Research ◽  
Multi Phase

We are engaged in efforts to model spray phenomena. Applications of principal interest include the high-speed impact of large vessels of fuel and the subsequent fire, fire suppression, solid propellant fires, pressurized pipe or tank rupture, and fire propagation for cascading liquid fuels. To help guide research and development efforts geared towards designing an appropriate spray modeling capability, a Phenomenon Identification and Ranking exercise was conducted. The summarized results of the exercise in tabular format, a Phenomenon Identification and Ranking Table (PIRT), are presented. The table forms the context for a textual literature review of the existing state of knowledge for modeling applications of interest. This exercise highlights some of the shortcomings in existing tools and knowledge, and suggests productive research activities that can help advance the modeling capabilities for the desired applications. Notable needs exist for research in high Weber number particle-surface impacts, particle collisions, multi-physics couplings, and low void fraction multi-phase coupling.

scholarly journals Semiquantitative Fire Risk Grade Model and Response Plans on a National Highway Bridge

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Hojune Ann ◽  
Youngjin Choi ◽  
Jin Hyuk Lee ◽  
Young Ik Jang ◽  
Jung Sik Kong
Keyword(s):  
Large Scale ◽  
Fire Suppression ◽  
Fire Risk ◽  
Surface Damage ◽  
Dynamics Simulation ◽  
Damage State ◽  
Effective Response ◽  
Surface Temperatures ◽  
Secondary Damage ◽  
Risk Grade

For the last ten years, the number of cases of large-scale fires which occur on bridges, tunnels, and underpasses has increased. Such fires cause primary and secondary damage, including loss of human life, traffic congestion, and extensive financial damage. Therefore, a risk grade model and effective response plan need to be established for such cases in order to minimize the social and economic costs of bridge fires. In this study, the hazard factors contributing to bridge fires were selected to apply a risk grade model. A total of 144 bridge fire simulations were performed to calculate a surface temperature based on time by using Fire Dynamics Simulation (FDS). A risk grade in accordance with the degree of surface damage state caused by temperature of bridges was presented, and the mobilization time criteria for fire suppression were proposed. The surface temperatures based on time can be classified according to the vertical clearance and mobilization time criteria for fire suppression. Through the classified maximum surface temperatures based on time for bridges, the risk grade can be estimated according to the degree of surface damage state caused by temperature. In order to evaluate the applicability of the established risk grade model to the actual bridge, the arrival time taken from the bridge to the fire station was calculated through a Geographic Information System (GIS) network analysis, and the grades for actual bridge cases were assessed. The purpose of this bridge fire risk grade model is to establish a disaster prevention strategy based on risk grades and to minimize the subsequent social damage by determining a priori the disaster scale.

scholarly journals A contemporary review of large-scale non-standard structural fire testing

2013 ◽  
Vol 2 (1) ◽  
pp. 1 ◽  
Author(s):  
Luke Bisby ◽  
John Gales ◽  
Cristián Maluk
Keyword(s):  
Large Scale ◽  
Fire Testing ◽  
Structural Fire

scholarly journals The Application of a New PID Autotuning Method for the Steam/Water Loop in Large Scale Ships

Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 196 ◽  
Author(s):  
Shiquan Zhao ◽  
Sheng Liu ◽  
Robain De Keyser ◽  
Clara-Mihaela Ionescu
Keyword(s):  
Predictive Control ◽  
Large Scale ◽  
Pid Controllers ◽  
Empirical Knowledge ◽  
Control Performance ◽  
Proportional Integral Derivative ◽  
Controlled System ◽  
Performance Requirements ◽  
Gain Margin ◽  
Forbidden Region

In large scale ships, the most used controllers for the steam/water loop are still the proportional-integral-derivative (PID) controllers. However, the tuning rules for the PID parameters are based on empirical knowledge and the performance for the loops is not satisfying. In order to improve the control performance of the steam/water loop, the application of a recently developed PID autotuning method is studied. Firstly, a ‘forbidden region’ on the Nyquist plane can be obtained based on user-defined performance requirements such as robustness or gain margin and phase margin. Secondly, the dynamic of the system can be obtained with a sine test around the operation point. Finally, the PID controller’s parameters can be obtained by locating the frequency response of the controlled system at the edge of the ‘forbidden region’. To verify the effectiveness of the new PID autotuning method, comparisons are presented with other PID autotuning methods, as well as the model predictive control. The results show the superiority of the new PID autotuning method.

Wildland fire spread modelling using cellular automata: evolution in large-scale spatially heterogeneous environments under fire suppression tactics

2011 ◽  
Vol 20 (5) ◽  
pp. 633 ◽  
Author(s):  
A. Alexandridis ◽  
L. Russo ◽  
D. Vakalis ◽  
G. V. Bafas ◽  
C. I. Siettos
Keyword(s):  
Cellular Automata ◽  
Geographical Information Systems ◽  
Large Scale ◽  
Fire Suppression ◽  
Meteorological Data ◽  
Fire Spread ◽  
Geographical Information ◽  
Heterogeneous Environments ◽  
Detailed Model ◽  
Technical Specifications

We show how microscopic modelling techniques such as Cellular Automata linked with detailed geographical information systems (GIS) and meteorological data can be used to efficiently predict the evolution of fire fronts on mountainous and heterogeneous wild forest landscapes. In particular, we present a lattice-based dynamic model that includes various factors, ranging from landscape and earth statistics, attributes of vegetation and wind field data to the humidity of the fuel and the spotting transfer mechanism. We also attempt to model specific fire suppression tactics based on air tanker attacks utilising technical specifications as well as operational capabilities of the aircrafts. We use the detailed model to approximate the dynamics of a large-scale fire that broke out in a region on the west flank of the Greek National Park of Parnitha Mountain in June of 2007. The comparison between the simulation and the actual results showed that the proposed model predicts the fire-spread characteristics in an adequate manner. Finally, we discuss how such a detailed model can be exploited in order to design and develop, in a systematic way, fire risk management policies.

Calculated Interaction of Sprays With Large-Scale Buoyant Flows

1984 ◽  
Vol 106 (2) ◽  
pp. 310-317 ◽  
Author(s):  
R. L. Alpert
Keyword(s):  
Large Scale ◽  
Fire Suppression ◽  
Computer Time ◽  
Vapor Concentration ◽  
Numerical Techniques ◽  
Buoyant Jet ◽  
Numerical Predictions ◽  
Vapor Cloud ◽  
Lift Off ◽  
Time Required

Turbulent, recirculating gas flows resulting from interactions of water droplet sprays with large-scale buoyancy sources are difficult to predict without the use of numerical techniques, especially when spray-induced gas motion is considered. One such flow occurs when a negatively buoyant methane cloud, generated during LNG spills in a wind, is dispersed by a line water spray. Numerical predictions of the ratio of average methane vapor concentration downwind of the line spray to the upwind value correlate as a function of the ratio of methane momentum in the vapor cloud to water momentum in the spray. Warming of the cloud, which occurs when small drops in the spray freeze, leads to the production of positive cloud buoyancy and the possibility of cloud lift off from the ground. Numerical calculations have also been used to predict how a near-ceiling, downward-directed spray interacts with an opposed, buoyant jet issuing from floor level. Recirculating gas motion induced by droplet trajectories is again an important part of the problem. This opposed spray-plume arrangement, which is important in the process of fire suppression by automatic sprinklers, allows the effectiveness of spray cooling of the near-ceiling environment to be determined as a function of droplet injection characteristics. Because of the excessive amounts of computer time required for the solution of both turbulent, buoyant flow problems, it is concluded that much more efficient numerical techniques are needed.

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