The dubious path of development of powder fire extinguishing: Fiction or reality?!

The dubious path of development of powder fire extinguishing: Fiction or reality?!.

The dubious path of development of powder fire extinguishing: Fiction or reality?!

Information of a dubious nature

The article by S. Yu. Serebrennikov «The Doubtful Path of Development of Powder Fire Extinguishing«, first of all, attracts attention by the emotionality of the presentation, and, by and large, is not intended for specialists. In support of what has been said, let us consider the issues of extinguishing motor vehicles in garages, raised in this article.
It is not serious to say that if a fire occurs in the engine compartment, and at the same time to try to scare the average person with TNT blocks and prove that a “fast-acting explosion-proof powder system” (meaning based on OPAN brand modules) will cope with the fire. Well, firstly, if a fire starts in the engine compartment, no existing powder fire extinguishing system will cope with the fire. To solve this problem, the system must be placed directly in the engine compartment. Some companies, for example, “PromEPOTOS”, are following this path and successfully solving the tasks set. A TNT block itself does not pose a danger and will never explode, but will simply melt and burn, and fire extinguishing powders can successfully extinguish it. Another question is if an explosive device goes off, and this is really a problem for the Ministry of Internal Affairs and the FSB, but then, after the explosion, no one will be in trouble, including any fire extinguishing system, which will be destroyed, even if it is explosion-proof. Here we will reveal one small trick of the author of the article, which he resorted to. Let us emphasize that the explosion-proof design applies to the electrical circuits of fire extinguishing systems and has nothing to do with the special design of the module body or the supply pipeline in terms of strength parameters, in addition to what is defined in GOST R 53286-2009 «Automatic powder fire extinguishing installations. Modules. General technical requirements. Test methods», — it has nothing to do with it. And what will happen after a powerful explosion with the bodies and pipelines of the OPAN modules advertised by the authors? And in terms of inertia, these products are significantly inferior to pulse modules. Therefore, the phrase of the author of the article S.Yu. Serebrennikova: “What is needed here is a fast-acting…powder system,” to put it mildly, is not a strong argument in favor of OPAN.

Controversial information

It should be emphasized that to date, despite numerous scientific publications, the mechanism of extinguishing a fire with fire extinguishing powders has not been fully studied.

At the beginning of the article «The Doubtful Path of Development of Powder Fire Extinguishing» the author writes that extinguishing with pulse systems is based only on mechanical flame breakdown. This premise is incorrect. If the whole point were only in flame breakdown, it would be possible to supply powders based on cheap inert minerals from modules, such experiments were conducted, but in this case, for effective extinguishing, it is necessary to quantitatively increase the mass of the supplied substance several times, compared to the extinguishing powder, and this path was abandoned.

As follows from the analysis of the article, the extinguishing mechanism is a complex physical and chemical effect on the source of combustion, where the mechanical effect on the flame is present, but is not decisive in pulse powder fire extinguishing. Then the question naturally arises: due to what do pulse systems extinguish fire sources with low flow rates? One of the answers is the high intensity of the supply of fire extinguishing powders, which is an order of magnitude higher compared to short-term systems and a high, more than 500 g/m3 concentration of fire extinguishing powder in the supply front. For extinguishing, a concentration of 200-300 g/m3 is required.

Another question is how long will this concentration be maintained and how to support it? Research has shown that extinguishing will occur instantly if the required concentration of extinguishing powder is created in the flame volume at one time. Then it becomes clear why OPAN-50 modules extinguish the maximum rank of the fire source 55V (1.73 m2), and pulse modules, for example MPP-6, with a much smaller amount of powder, extinguish the fire source 233V (7.32 m2). To create a concentration in the flame volume, it is necessary to overcome the convective column of the combustion source and to do this with the OPAN module with initially low rates of supply of extinguishing powder and, consequently, lower supply intensity is problematic, but for pulse modules this task is quite feasible and is achieved precisely due to the high concentration of powder in the extinguishing supply front. Accordingly, when designing powder fire extinguishing systems aimed at extinguishing spills of flammable liquids (FL), it is necessary to take into account the speed characteristics of the fire extinguishing agent supply, taking into account the speed of ascending flows from the source of combustion, which, unfortunately, is not yet practiced. Therefore, the author of the article makes a mistake in mixing up the concepts of extinguishing class 2B FL sources on an area and extinguishing sources of the maximum rank 233B. Perhaps the author of the article wanted to say that the existing regulatory framework for assessing the effectiveness of powder fire extinguishing modules during certification tests and the regulatory framework for design are not perfect enough? We can agree with this. Thus, we have come to the third category of information, which we will discuss in the next chapter.

Information of a reasonable nature

The most pressing question that arises after reading the article by S. Yu. Serebrennikov «The Doubtful Path of Development of Powder Fire Extinguishing» is the question of assessing the efficiency of powder fire extinguishing modules. Why, when conducting tests according to GOST R 53286-2009 «Automatic powder fire extinguishing installations. Modules. General technical requirements. Test methods» is there a large spread in the fire extinguishing efficiency of identical modules, which is often not confirmed during tests under other conditions? The second major problem that follows from the article is the problem of a competent design solution using powder fire extinguishing modules. This is mainly what is associated with cases of unauthorized activation, issues of correct creation and maintenance of fire extinguishing concentration, etc., which S. Yu. Serebrennikov dwelt on in detail in his publication. The questions posed are of concern to all manufacturers of powder fire extinguishing modules. The presence of these problems, if not addressed in a meaningful way, may lead to some discrediting of powder fire extinguishing as an independent direction of automatic fire extinguishing.

These issues have been raised before. Thus, special attention was paid to changes in the testing methods for modules back in 2007 in the article by M.N. Vaisman, A.V. Dolgovidov and E.M. Dorofeev «Assessment of Powder Fire Extinguishing Modules». The problems of correct application and competent design taking into account the shortcomings of a particular type of module are described in detail in the book by A.V. Dolgovidov and V.V. Terebnev «Automatic Powder Fire Extinguishing Systems». However, proper, consolidated support from module manufacturers on the issues raised in these works was not received, and they were not taken into account when developing the new GOST R 53286-2009 and the set of design rules SP 5.13130.2009 «Fire protection systems. Automatic fire alarm and fire extinguishing systems. Design standards and rules». The main conflict that is currently arising in the market of automatic powder fire extinguishing means is that, according to existing regulatory documents, the designer independently selects the type of module and issues of economic feasibility become the first, even often to the detriment of reliability and common sense. That is, it is necessary to change the rules or, in other words, to amend the existing regulatory framework for the design, testing and certification of automatic powder fire extinguishing means. This approach can only be implemented through the combined efforts of manufacturers of these fire extinguishing means with the involvement of specialists from design organizations, the Federal State Institution VNIIPO EMERCOM of Russia, the Academy of the GPS EMERCOM of Russia. After all, it is known that any path can become a dead end, which is what the manufacturers of OPAN modules faced if the regulatory rules are imperfect, especially given Russian realities.
In conclusion, it should be noted that there is increased interest in pulse powder fire extinguishing technologies abroad. Large quantities of pulse modules are purchased by countries such as India, the USA, Finland, Romania, etc. A number of countries — South Korea, China — have purchased Russian production technologies and designs of powder fire extinguishing modules, established their mass production, actively creating their own regulatory framework in this area, for example, the «General Industry Standard of the People's Republic of China for Public Safety GA 602-2006 «Powder Fire Extinguishing Systems», which our specialists should definitely try to familiarize themselves with in detail. As examples (shown in the illustrations to the article), we provide ways in which foreign partners are actively mastering pulse powder fire extinguishing technologies. To refuse or question the use of pulse powder fire extinguishing systems for the sake of primarily opportunistic considerations means losing superiority in one of the few areas of science and technology that Russia still has.

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A.V. Dolgovidov,
Ph.D., senior researcher,
lecturer of the fire-fighting equipment department
of the Academy of the State Fire Service of the Ministry of Emergency Situations of Russia