Improvement of a discharge nozzle damping attachment to suppress fires of class D

Marych

et al. 2020

The scope of magnesium and aluminium and their alloys in industry, construction and life are expanding over time. As a rule, there are no clean fires of class D, which include combustion of magnesium, aluminium and their alloys. The problem is that the temperature of combustion of magnesium and its alloys can rise above 2800 Celsius degree. Magnesium burns even in the atmosphere of nitrogen and carbon dioxide and such fire is very difficult to extinguish. When water contacts the magnesium or other light metals, the area of fire expands. The main purpose of this work is to study the combined extinguishing of light metals fires, Class A fires and class B fires with a special dry chemical powder and high resistance foaming agent. The problem of extinguishing fires at objects with the using of light metals (magnesium, aluminium) and their alloys has been explored. Class D fires usually lead to class A and class B fires. They occur at high temperatures, and may cause explosions. Scenarios for the development of fires can be as follows: burning of light metals or solid combustible materials ad initium and light metal fire that requires combined extinguishing methods afterwards. Dry chemical powder formulation for extinguishing class A, B, D and and electrical installations under voltage, which includes: sodium chloride, blast furnace slag, ammophos, aerosol has been developed. Testing of this powder has been carried out in the laboratory using chips of magnesium and aluminium alloys. The combustion area in all experiments has been equal to 2.85 × 10-2 sq. m. The quality of the powder has been evaluated by the intensity of the D class fire and the extinguishing time of the B class fier. Dry chemical powder KM-2 has been tested for extinguishing fires 21B, 1A. and for magnesium alloy chips fires. Combined extinguishing tests were conducted on class D, class A and class B fires in field conditions. Method of combined extinguishing with the dry chemical powder followed by covering the entire burning area with high-expansion foam has been proposed (the fire with total area of 2.5 square meters has been extinguished for 45 s). Extinguishing methods have been tested on model fires. Safety measures for light metal extinguishing have been developed. Conclusions: formulation for universal KM 2 dry chemical powder for extinguishing class D, A, B fires, which consists of sodium chloride, ammophos, slag, aerosil, has been developed. Successful extinguishing of class D and B fires has been carried out succesfully; technology of combined fire fighting D and A has been substantiated.

Section: комбіноване гасіння пожеж класу D та а вunclassified

Combined Extinguishing of Class D, Class a and Class B Fires

Husar

Marych

et al. 2020

“…Magnesium alloys, depending on the content of magnesium in the alloy, a layer of chips, granules, and dust may have combustion temperature from 1,100 to 2,800 °C [1,2]. At this temperature, water is decomposed into hydrogen and oxygen, the combustion takes place with a blast, conventional fire-extinguishing powders burn out.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

“…Light metals burn when they are present in the form of products of processing: powders of different dispersion, chips. Class D fires happen in the world every year [1]. The features of light metals, which are combustible, explosive, and flammable, include the ability to explode in the crushed state in the interaction of burning metals with water and some gas fire-extinguishing compounds.…”

mentioning

confidence: 99%

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Thermotechnical properties of the fire-extinguishing powder for extinguishing materials based on magnesium alloy chips

Gusar

Pozdieiev

et al. 2020

EEJET

Self Cite

46 als, such as aluminum, magnesium, beryllium, titanium, and their alloys), D2 (combustion of alkaline metals), D3 (combustions of metal-containing compounds, such as hydrides). Now combustion of metals in accordance with EN-2:2014 is included in the fires of class D. The most hazardous fires are the combustion of magnesium, aluminum, and their alloys. IntroductionLight metals include magnesium, aluminum, titanium, sodium, lithium, and others. Combustion of these metals and their alloys belongs to the fires of class D. By 2014, the fires of class D were divided in fires D1 (combustion of light met-

“…Проаналізуємо масштабні пожежі, під час яких відбувалось горіння легких металів [5,6] -розміри металевого каркаса з листової сталі зі стороною (500±10) мм, висотою (150±5) мм і товщиною стінок від 2,5 мм до 3,0 мм для проведення випробувань з використанням магнієвої стружки є малими;…”

unclassified

Jusitfication of Dry Chemical Powders Testing Procedure

Marych

Gusar

et al. 2019

The analysis of the problem of extinguishing fires of magnesium and its alloys is carried out. The urgency of studying the problem is confirmed by the fact that during the extinguishing of class D fires there are factors that can complicate the quenching process. Often, these metals actively react with water, which leads to an even greater spread of the fire and even an explosion. Therefore, special fire extinguishers, which have passed the proper test, are more effective in locating the fire and prevent the burning of the powder to form the "tongues" of the flame. In Ukraine, there is no method for testing the effectiveness of fire extinguishants of special purpose for the extinguishing of class D fires. The normative documents have been analyzed, which specify the procedures for testing extinguishing fire-extinguishing special-purpose fire extinguishing class D. Specifically: the methods are described in the international standard ISO 7165: 2017 «Fire fighting – Portable fire extinguishers – Performance and construction» and GOST 53280.5-2009 Fire fighting systems automatic. Extinguishing agents. Both methods have a number of shortcomings that need to be addressed when creating a Ukrainian fire test method for extinguishing fire extinguishing class D, namely: the dimensions of the metal frame made of sheet steel with a side (500 ± 10) mm, height (150 ± 5) mm for testing with magnesium chips are small; Not specified quantity of gasoline necessary for the rise of magnesium; The gas or oxygen torch used to dissolve magnesium does not provide full-value combustion throughout the area, but only creates separate cells of ignition. A draft methodology has been developed that determines the fire-extinguishing efficiency of powdered powders used in Ukraine. The required amount of fuel for burning magnesium and its alloys is determined. It was ascertained that for the firing of magnesium chips it is necessary to use at least 127 grams of gasoline of the mark A 92. Key words: test method, fire extinguishers of special purpose, extinguishing of fires of magnesium alloys