Automatic Suppression Systems Research Articles

Исследование тока утечки по струе тонкораспылённой воды из автоматической установки пожаротушения на электрооборудование под напряжением

Purpose. The article is devoted to the safety issue of applying an automatic fine water spray suppression system for extinguishing fires of live electrical equipment. The study examined the worst-case scenario, in which fire suppression system is manually activated by an operator. The results of a series of experiments to determine the leakage current when discharging extinguishing agent from automatic fire suppression systems onto live electrical equipment are presented. Methods. To achieve the goal of the research the authors used analysis and experiment methods. Findings. An experimental study on automatic water spray fire suppression system was carried out, and as a result of the experiment the values of leakage current on the pumping unit body and nozzle-head were determined. Power and linear regression equations were obtained by the least squares method. Based on regression equations, diagrams of dependence of the leakage current value on the intensity (k-factor) supply of fine water spray to the nozzle-head and the pumping unit body were created. Research application field. The obtained experimental data confirm the possibility of safely using automatic suppression systems with fine water spray for live electrical equipment extinguishment while meeting certain values of the intensity of extinguishing agent supply. Conclusions. Based on the analysis of experimental data and the obtained regression equations, it can be concluded that the intensity of the extinguishing agent supply (k-factor) has a significant impact on the leakage current on the body of an automatic fire suppression system and nozzle-head.

Effect of sprinklers on the patient's survival probability in hospital room fires

The effectiveness of sprinklers in protecting a patient in a hospital room fire was investigated by performing 26 sprinklered and four free-burn experiments in real hospital rooms equipped with water-based automatic suppression system. Three different fire loads were used: UL 1626 corner test fire and two different textile fires. The measurements included temperatures, pipe pressure, and concentrations of about 20 different gas compounds. Based on the measurement results, we calculated the Fractional Effective Dose (FED) and Fractional Irritant Concentration (FIC) –values, and estimated the likelihood of incapacitation as a function of time. The results showed that sprinklers maintained temperatures at low level and reduced toxicity, mainly through fire development control. In UL1626 and large textile fires, sprinklers decreased the patient's incapacitation probability from 0.9 or above to the level of 0.4. In small textile fires, the difference between the incapacitation probabilities of sprinklered fires and free-burns was less than the measurement uncertainty. FED results were sensitive to the calculation method due to the different treatment of NOx –gases.

Special Issue on Automatic Suppression Systems

Special Issue on Automatic Suppression Systems

Retrofitting Sprinkler Systems for Suppressing Dust Generated by Moving Vehicles Inside Farms

Abstract Fugitive dust is one of the well known problems in agriculture and it affects both humans and machine producing quality. Dust problems can seriously cause harmful diseases to workers and ruin expensive equipments. In this study, a dust formation generated in open environment by vehicles was analyzed on unpaved roads. Formed dust was measured by calculating total forces on the PM 10 (airborne particles smaller than 10 mm) of dust particles, such as air velocity, gravity forces and air turbulence generated by the moving vehicle. The water fogger nozzle discharge was measured to determine the approximate droplets quantity in the air. The foggers were used to suppress the generated dust in an open environment via installing a proposed automatic suppression system which opens automatically when vehicles pass under the system. The relationship between water droplet speed and ability of collecting fugitive dust showed that high air temperature above 40°C and wind speed above 10 m s −1 have negative effects on the system's ability of collecting dust due to evaporation of small radius droplets and/or drifting water droplets away from the effective area. The overall system efficiency was found to be 85% and the proposed dust suppression system was found to be a satisfying solution for reducing fugitive dust hazards.

Morphological capacitive sensors for air bag applications

The Federal Motor Vehicle Safety Standards No. 208 includes directives rendering the morphological estimation of passengers mandatory for advanced air bag systems. The dynamic automatic suppression system uses both the morphological and positional information about the passenger to allow or prevent air bag deployment. Various solutions have been proposed to obtain these information by using capacitive sensors. This paper presents a method, that makes possible use of such sensors in the car industry by correcting their responses from these perturbing parameters.

Estimating Water Requirements for Firefighting Operations Using FIERAsystem

A new computer model for estimating water requirements for firefighting purposes has been developed by the Fire Risk Management Program of the National Research Council of Canada. This work was done in partnership with the Canadian Department of National Defence, as part of the development of a computer model to evaluate fire protection systems in light industrial buildings (FIERAsystem). The new model considers the geometry of the building, possible fire scenarios that may occur in the building, fire detector locations and characteristics, the effect of automatic suppression systems on the fire, the locations of adjacent buildings and the response and effectiveness of the fire department. The program calculates the required flow rates of water at the time of fire department intervention for suppression of the fire and for exposure protection for each side of the building. These flow rates can then be compared to the total capacity of the fire engines available to determine if existing resources are sufficient. The program has been designed to be interactive, so that the user can immediately see the effects of various parameters on the required water flow rate. Descriptions of case studies are also included to demonstrate the use of this model.

Evaluation Of The Risk Problem And The Selection Of The Optimum Risk Management Solution

The determination of optimum fire protection engineering solutions at present is a predominantly subjective based process. An analytical technique is offered to evaluate risk and the manager's aversion toward risk to better employ the risk management options of loss transfer, loss absorption, and loss reduction. An engineering method presently exists for numerically evaluating a relative level of risk in any building. The flame movement part of the method involves the determination of the probability of success in terminating a fire within each space of a building. The effectiveness of each barrier surrounding the space, also can be evaluated whether it be a floor, ceiling, wall, or an empty void. An illustrative case study has been offered to demonstrate the incorporation of the engineering method into a decision analysis of possible alternatives based on the risk attitude of the decision maker. This case study illustrates how the three risk management options can be considered rationally and quantitatively. THE ENGINEERING METHOD AND RISK MANAGEMENT There exists today a detailed engineering method (1) which, regardless of size or occupancy, can evaluate in a consistent manner any building. Through the application of this engineering method, a COPE (*) evaluation is performed which yields relative assessments of risk. Once the fire risk of a particular building is quantified, the appropriate parties can analyze possible risk management solutions. The evaluation of these components yields a probability value in the form of an L-curve. The L-curve is a graphical representaion of the cumulative probability (from 0.0 to 1.0) that a fire will be limited to the space being considered. limited, in this sense, means that the fire will not propagate beyond the area which has been evaluated. Figure 1 shows typical L-curves. This paper will concentrate its use of the engineering method on the Flame Movement Analysis. We wish to evaluate the likelihood that a fire will be limited to an area of a building. This likelihood is based on four engineering method parameters which evaluate COPE: an evaluation of the hazard present --the I curve; the automatic suppression system--the A-curve; manual fire fighting--the M~curve, and barrier effectiveness; either physical or spatial. (*) COPE is acronym for the class of construction, occupancy, installed fire protection systems, and external exposures of a building. FIRE SAFETY SCIENCE-PROCEEDINGS OF THE FIRST INTERNATIONAL SYMPOSIUM 627 Copyright © International Association for Fire Safety Science An evaluation of a barrier is dependent on the sPecific type of fire that will attack the barrier, and of course barrier construction. A barrier can either be physical, or a space separation. A fire must penetrate the barrier to cause ignition in the next space. RISK MANAGEMENT APPLICATIONS By simply inserting a zero value for any L-curve component (1-, A-, M-,& B) into a network calculation, the effect that that component has in the L-curve can be negated. The ease of this what situation capability is ideal for an effective comparison of various loss prevention alternatives and the resources required to implement them. The extent of loss under different risk management situations is of primary importance if risk decisions are to be made. Loss estimates of the various risk management parameters can be easily assessed with the aid of the final product of the engineering method: the L-curve. This paper will address NLE and MFL risk management parameters using the L-curve.. NLE and MFL CURVES The risk management parameters commonly used are Normal Loss expectancy (NLE) and Maximum Foreseeable Loss (MFL). Though these terms are used widely by those professionals dealing with risk management, definitions of each parameter are not Widely consistent. Therefore, definitions of the risk management parameters as used in this paper will be given.