scholarly journals Efficiency of fire suppression systems using dry powder sprays to extinguish fires amid non-steady heat exchange processes and heterogeneous inhibition of active flame centres by powder particles

2020 ◽  
Vol 29 (5) ◽  
pp. 89-99
Author(s):  
A. I. Kitsak
Keyword(s):  
Heat Exchange ◽  
Fire Suppression ◽  
Efficiency Analysis ◽  
General Purpose ◽  
Dry Powder ◽  
Fire Extinguishing ◽  
Exchange Processes ◽  
Powder Particles ◽  
Steady Heat ◽  
Suppression Systems

Introduction. Presently, there are several problems in the field of dry powder fire suppression that require the indepth study of the physics and technology of fire suppression processes using these substances. One of the ways to find the solution to these problems is the efficiency analysis (theoretical and experimental) of frequently implemented fire extinguishing patterns involving fire suppression systems spraying dry powder, when the term of interaction between the dry fire extinguishing powder and the burning material is close to the duration of principal fire extinguishing patterns, or thermal and heterogeneous inhibition of active flame centres.Purpose and objectives. The purpose of the work was to assess the efficiency of principal fire extinguishing patterns (thermal and heterogeneous inhibition of active flame centres) amid non-stable heat exchange processes and heterogeneous inhibition of active combustion product particles by powder particles.Methods. The pre-set objective was achieved through theoretical modeling of patterns of thermal fire extinguishing and heterogeneous inhibition of active flame centres by dry chemical powder particles.Results. It was established that fire suppression with the help of general purpose dry chemical powder under non-steady conditions is the more effective, the smaller the effective size of powder particles, the longer the time of their stay in the combustion area and the shorter the characteristic period of heat transfer to powder particles and heterogeneous inhibition of active flame centres.Conclusions. The results optimize conditions and patterns of dry fire extinguishing powder application to a combustion area to achieve the highest extinguishing effect and to conduct a targeted search for new dry chemical powders having pre-set thermal and physical specifications.

scholarly journals Model of Thermal Mechanism of Subclass A1 Fire Extinguishing with General Purpose Fire Extinguishing Powder in Non-Stationary Heat Exchange Conditions

2019 ◽  
Vol 10 (4) ◽  
pp. 391-401
Author(s):  
A. I. Kitsak
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
General Purpose ◽  
Short Term ◽  
Stationary Heat ◽  
Fire Extinguishing ◽  
Thermal Mechanism ◽  
Powder Particles ◽  
The Mathematical Model ◽  
Intensity Of Feeding

The aim of the paper was to develop a model of thermal extinguishing mechanism using dry chemical powder taking into account the inertia of heat transfer to powder particles during unsteady heat exchange to identify the optimal conditions for extinguishing of A1 class fires with powders.The method of experimental and mathematical modelling of fire extinguishing process using dry chemical powder with short-term effect on the fire was used to achieve the goal. The experimental dependences of the extinguishing time and unit consumption of the extinguishing powder on the intensity of the powder supply to the combustion zone in extinguishing of subclass A1 fire in same area and in a limited volume were obtained. The mathematical model of a thermal extinguishing mechanism using dry chemical powder has been developed, taking into account the inertia of heat transfer to powder particles during unsteady heat exchange.Analysis of the regularities of extinguishing the subclass A1 fire using powder with a short feeding it into the fire indicates the presence of optimum values of unity consumption of powder on the fire from the intensity of feeding it into the fire. The presence of this optimum is due to the inertia of extinguishing the subclass A1 fire using powder due to the finiteness of the heat transfer time to the particles of the extinguishing powder and the limited time of interaction of particles with the combustible material.The theoretical analysis of the fire extinguishing process over the area taking into account the inertia of heat transfer to the powder particles at non-stationary heat exchange are carried out. The results of the analysis are in qualitative agreement with the results of the experimental study of the regularities of extinguishing of model fire foci of subclass A1 with General-purpose fire extinguishing powder.

scholarly journals Efficiency of fire extinguishing with general purpose fire extinguishing powder in case of non-stationary interaction of its particles with burning material

2020 ◽  
Vol 65 (4) ◽  
pp. 476-486
Author(s):  
A. I. Kitsak
Keyword(s):  
Heat Transfer ◽  
Combustion Zone ◽  
General Purpose ◽  
Active Centers ◽  
Theoretical Dependence ◽  
Fire Extinguishing ◽  
Exchange Processes ◽  
Powder Particles ◽  
Stationary Conditions ◽  
Inhibition Reaction

Evaluation of the effectiveness of fire extinguishing by jet systems of powder fire extinguishing in conditions of non-stationary heat exchange processes and heterogeneous inhibition of active flame centers by powder particles was the aim of the work. The theoretical dependence of the amount of heat, absorbed by the particles of fire extinguishing powder, and the reaction rate of heterogeneous active centers of flame, inhibiting them, in non-stationary conditions of heat transfer, as well as inhibition reaction for fire extinguishing ink jet systems were obtained. The extinguishing of a flame with a fire extinguishing powder under non-stationary conditions is more effective, the smaller is the effective size of the powder particles, the longer is their stay in the combustion zone, and the shorter are the characteristic times of heat transfer and inhibition reaction. Comparison of the estimates of the characteristic duration of heat transfer and inhibition reaction for widely used fire extinguishing powders has shown a large inertia of the thermal mechanism of fire extinguishing, which greatly reduces its effectiveness at high speeds of powder particles in the combustion zone.

Increase of Heat Exchange Processes Efficiency at Production Site

2017 ◽  
pp. 18-21
Author(s):  
A.F. Khasanova ◽  
◽  
M.A. Gallyamov ◽  
Z.A. Zakirova ◽  
◽  
...  
Keyword(s):  
Heat Exchange ◽  
Production Site ◽  
Exchange Processes

A REVIEW OF WATER MIST FIRE SUPPRESSION SYSTEMS

2001 ◽  
Vol 10 (3) ◽  
pp. 277-294 ◽  
Author(s):  
B. YAO ◽  
W. K. CHOW
Keyword(s):  
Fire Suppression ◽  
Water Mist ◽  
Suppression Systems

scholarly journals Qualitative Fire Vulnerability Assessments for Museums and Their Collections: A Case Study from Kosovo

Fire ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 11
Author(s):  
Charlotte Fafet ◽  
Erinë Mulolli Zajmi
Keyword(s):  
Cultural Heritage ◽  
Fire Suppression ◽  
Mitigation Measures ◽  
Risk Awareness ◽  
Staff Members ◽  
Heritage Sites ◽  
Vulnerability Assessments ◽  
Suppression Systems ◽  
Simulation Exercises

Fires are among the most frequently recurring hazards affecting museums and cultural heritage sites. The fires of the National Museum of Brazil in 2018 and of Notre Dame de Paris in 2019 showed that the consequences of such events can be heavy and lead to irreversible heritage losses. In Kosovo, few studies were made about the risks that can affect cultural heritage sites. A project led by the NGO Kosovo Foundation for Cultural Heritage without Borders (CHwB Kosova) in 2018 explored the most prevalent risks for the cultural heritage sites of the country and highlighted fire as a predominant risk in Kosovo. In order to better understand it, vulnerability assessments were conducted in several museums in Kosovo. Data were collected through field visits in the different museums, in which interviews with staff members as well as observations were conducted. The aim of this paper is to present the main results of the fire vulnerability assessments conducted in Kosovo’s museums in 2018. An important aspect of this project is the approach to collect information in data-scarce environments. It is believed that the questionnaires used to lead interviews with museums’ staff members could help other practitioners to collect data in such contexts and evaluate more easily the risk of fire for the museums and their collections. In the context of Kosovo, one of the main findings is the identification and prioritisation of measures to ensure better protection of Kosovar museums. Structural mitigation measures such as alarm and fire suppression systems are not the only elements necessary to improve the resilience of Kosovar museums to fire. Indeed, the promotion of risk awareness, the training of staff members and the realisation of crisis simulation exercises are just as important in order to prevent and detect a fire, and above all, to respond quickly and accurately if a fire occurs.

Numerical Simulation and Experimental Study on Water Mist Fire Suppression for Cooking Fog Discharge Pipe

2014 ◽  
Vol 915-916 ◽  
pp. 356-361
Author(s):  
Zheng Wen Xie
Keyword(s):  
Design Method ◽  
Fire Suppression ◽  
Orthogonal Design ◽  
Water Mist ◽  
Simulation Software ◽  
Droplet Radius ◽  
Test Analysis ◽  
Injection Angle ◽  
Fire Extinguishing ◽  
Flow Quantity

FDS simulation software was used to establish the full size lampblack physics model of single wind pipe, using the orthogonal design method design of analog calculation conditions, research in the nozzle pressure, the droplet radius, nozzle, flow quantity and injection angle parameters under different conditions of water mist fire extinguishing effect. Based on a full-scale combustion and water mist fire extinguishing experiment, the water mist fire suppression was observed and test analysis etc, to better understand the flue water mist fire extinguishing feasibility, provides the theory basis for the design of efficient, reliable flue fire extinguishing system.

scholarly journals ON THE SOLUTION OF ENERGY BALANCE EQUATION SYSTEM TO PREDICT TEMPERATURE DISTRIBUTION IN THE BUILDING ELEMENTS WITH VENTILATED AIR GAP

2014 ◽  
Vol 21 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Edmundas Monstvilas ◽  
Karolis Banionis ◽  
Jurga Poderytė ◽  
Raimondas Bliūdžius ◽  
Arūnas Burlingis
Keyword(s):  
Heat Exchange ◽  
Balance Equation ◽  
Heat Balance ◽  
Internal Surface ◽  
Equation System ◽  
Energy Balance Equation ◽  
Air Gap ◽  
Exchange Processes ◽  
Calculation Results ◽  
Thermal Indicators

The article presents the solution of heat balance equation system, describing heat exchange processes in ventilated envelopes, which was applied to derive formulas for the calculation of temperatures in the ventilated layers of the envelopes. The accurateness of the formulas was assessed by experimental research and analysis of the calculation results. During the process of heat exchange balance equation solution, the equations were simplified by introducing the following restriction into the derived formulas: they may only be applied for the ventilated envelopes with steel or similar coatings as their external layers, i.e. coatings having small heat capacity and minor difference between the external and internal surface temperatures. The derived formulas enable the calculation of the temperatures of the ventilated envelopes in the distance which does not exceed a half of the ventilated air gap length measuring from the air entrance into the gap. However, this restriction does not impede the estimation of the average thermal indicators of the ventilated envelopes.

Sign in / Sign up

Export Citation Format

Share Document