Since there are no legally defined testing requirements for mobile positive pressure fans, they may be tested based on methods that do not correspond to their actual operating conditions. Adequate assessment of the technical and operating conditions for this type of equipment is particularly important for equipment used in rescue operations. Such units should be characterized by efficient and reliable operation. This article investigates the influence of measurement methods of the volumetric airflow rate on the performance of a power unit. The article shows that the applied measurement method, whether it is PN-EN ISO 5801 (test conditions in a pipe duct—Method A) or other methods, i.e., ANSI/AMCA 240-15 and testing of the characteristics of the velocity profile (tests in open flow—Method B), can cause differences in the power demand of fans of from 3.2% to 4.5%. The differences in the requirements of propulsion power translate into fuel consumption and emissions of harmful exhaust gases generated by the combustion drive units (4 kW). It was also observed that fans with conventional impellers (W1) show a lower power demand when applying Method B (open flow) tests, while fans with turbo impellers (W2) show a lower power demand when Method A (duct) tests are applied. Comparative analysis of the parameters of the drive unit in the test group of fans without taking into account the measurement method can cause errors of up to about 7.7%, 6.4%, and 2.4% for the power, torque, and speed, respectively.
Aim: The aim of the article is to indicate the possible scope of application of mobile fans during the execution of rescue actions and identification of the parameters conditioning the effectiveness of using this type of units. Method Design: Mobile overpressure fans are a tool used during rescue operations mainly to remove hot gases and smoke, which accumulate in confined spaces covered by fire – primarily within the evacuation routes, but also in the rooms. In literature there are examples of other uses of the considered fans, e.g. to support the liquidation of fire hazards of free-standing objects (i.e. fires of cars or containers) and the rescue of trapped people in inaccessible spaces by supplying fresh air. This paper, which is based on literature review, is devoted to providing an approximation of the above applications. The effective use of mobile fans requires specialized theoretical and practical preparation. Therefore, the study also identified factors that may determine the successful implementation of the adopted tactical intent, which include in particular: the selection of appropriate openings (outlet and inlet), the selection of the gas exchange path and the proper positioning of a mobile fan. Conclusions: Literature analysis of the problem presented in this paper will be a fundamental point of reference for the research work carried out in subsequent stages related to the evaluation of the efficiency of mobile fans. As part of this work, large-scale tests will be carried out using appropriately designed and constructed test benches to evaluate the effectiveness of mobile units in real conditions. The knowledge gained in this way is intended to serve as material for further considerations on the creation of concepts of both subsequent methodologies and test stands required for their implemen- tation, enabling the verification of parameters characterizing the efficiency and reliability of mobile fans. Keywords: mobile positive pressure fans, tactical mechanical ventilation, rescue operations Type of article: review article
Machines and devices for the production, transport and segregation of products are placed in production and storage rooms. Flat conveyor and drive belts are very often used for their construction. Due to heavy loads and difficult operating conditions, these belts can catch fire and, as a result, become the main source of air contaminants harmful to human health and life. This article examines the emission level of toxic chemical compounds most often produced during the thermal decomposition and combustion of flat drive and conveyor belts. Six types of flat belts, which were made of various polymer materials, i.e., polyamide, rubber, and polyurethane, and were pyrolyzed in a tube furnace at 950 °C, were tested for emission. Using an Fourier transform infrared spectroscopy gas analyser, five gaseous products of combustion were identified, i.e., carbon mono oxide, carbon dioxide, hydrogen cyanide, hydrogen bromide and sulfur dioxide (SO2). Chemical analysis showed that SO2 compounds and hydrogen bromide were present in only two samples. The test results indicate that gas emission concentration limits for all the tested belts were significantly exceeded. A comparative analysis of the concentration limits of V-belts described in the authors' earlier works shows that flat belts demonstrate lower emission levels of harmful compounds than V-belts. In addition, research has shown that compared to traditional rubber-based belts, belts made of modern materials exhibit no emission of hydrogen chloride compounds during thermal decomposition and combustion.
Proper positioning of the positive pressure ventilator is an important aspect of conducting rescue operations. The purpose of this article was to determine the effect of the parameter of the distance of setting up a mobile fan (distance from 1 to 7 m) on the efficiency of implemented ventilation in a multistory building. The volumetric airflow rate was determined by measuring the flow velocity at 120 measurement points on the surface of the window opening (which served as the measurement plane) of a four-story building. Two positive pressure ventilators were tested (one was a conventional fan and the second a turbo type). The obtained volumetric airflow values ranged from 8591 to 15,656 m3/h, depending on the type of unit and positioning distance, respectively. The analysis performed in the article showed that the general guidelines for the distance of mobile fan positioning that are present in the literature may be inaccurate and outdated.
Aim: The aim of the article is to indicate the essential technical and operational parameters of mobile fans and to present the proposed testing method- ologies (as well as dedicated infrastructure) allowing to confirm the indicated features. Project and methods: In many places around the world, scientists conduct tests related to the use of mechanical tactical ventilation with the use of mobile positive pressure ventilation fans. These devices are used by fire protection units, among others, for the removal of thermal decomposition products resulting from fires, posing a threat to people staying in construction facilities during events and hindering rescue operations. Achieving the expected effects through the use of mechanical tactical ventilation depends on many factors, among others, on the appropriate technical parameters and the ability to use the fan. Describing the essential features that should be characterized by the devices in question, attention in particular should be paid to: mobility, durability, reliability and effectiveness. To confirm these features, mobile fans should be tested using properly validated test methodologies. This publication presents a draft of the test program that allows to confirm the effectiveness of mobile fans, i.e. aerodynamic efficiency (flow rate), stream shape (area of the effective speed distribution), operating time, noise, weight and dimensions. Conclusions: Mobile fans used by fire protection units are an important tool supporting the effectiveness of rescue operations. However, in order for them to be used in an optimal way, it is necessary to comprehensively examine the technical parameters, and then – adequately to these parameters – to develop appropriate procedures for their use. In the context of the aforementioned testing, despite the large scientific achievements in this field, there are still areas that require improvement, with particular emphasis on standardized testing methodologies and the measurement infrastructure dedicated to them. For this reason, the authors indicated important technical and functional features that determine the effectiveness of mobile fans and recom - mended selected methods on the basis of which these features can be verified. The intention of the project is to provide rescuers with greater comfort when choosing and using the devices in question. The basis for this comfort is to be aware of the availability of equipment with confirmed functional characteristics and the possibility of referring to the developed guidelines for the proper use of fans in accordance with their parameters. Key words: mobile positive pressure ventilation fans, tests of mobile fans, functional properties of fans Article type: review article
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