Nanotechnology is used, to an increasing extent, in practically every aspect of the economy and society. One area where nanotechnology is constantly advancing is fire protection. Nanostructures are found in elements used in direct protection, such as in protective clothing, filters, and helmets. Solutions in the field of nanotechnology are also used in elements reducing the fire risk and increasing the fire safety, such as building materials and structures, paints, coatings, or fire safety equipment (e.g., fire detectors). However, new solutions may also pose a threat to the safety of people and the environment. As a result of operation or combustion and degradation processes, the emission of nano-substances with toxic properties may occur. Therefore, knowledge in this field is necessary, as it allows for the appropriate targeting and use of nanotechnology.

Determining the appropriate position of a positive pressure ventilator, where it exhibits the highest efficiency (measured by the achieved volumetric flow rate), can influence the success of rescue operations conducted by fire protection units. The aim of this article is to evaluate the possibility of using LES (Large Eddy Simulation) analyses to verify the positioning parameters of positive pressure ventilators in numerical simulation conditions, without the need for time-consuming experiments. The article presents a comparative analysis of full-scale experimental studies (conducted on a test setup to assess the velocity profile of the air jet in open flow) and CFD numerical analyses. The analysis confirmed the convergence of the flow rate parameter entering the surface of the door opening model installed on the test setup. Depending on the distance of the ventilator position (1–7 m), a convergence degree ranging from 1.6% to 3.8% was achieved for the volumetric flow rate. This publication demonstrates that the LES model is a suitable tool for effectively determining the working positions of positive pressure ventilators, as defined in real working conditions (open flow). The analysis may serve as a helpful tool for manufacturers of mobile ventilators, who can use the method for the technological testing of their units without conducting time-consuming experiments.

Using a wheelchair over uneven terrain generates vibrations of the human body. These vibrations result from mechanical energy impulses transferred from the ground through the wheelchair components to the user’s body, which may negatively affect the quality of the wheelchair use and the user’s health. This energy can be dissipated through the structure of the wheelchair frame, such as polymer and carbon fiber composites. This article aims to compare a wheelchair with an aluminum alloy frame and a carbon fiber frame in terms of reducing kinematic excitation acting on the user’s body. Three wheelchairs were used in the study, one with an aluminum alloy frame (reference) and two innovative ones with composite frames. The user was sitting in the tested wheelchairs and had an accelerometer attached to their forehead. The vibrations were generated by applying impulses to the rear wheels of the wheelchair. The obtained results were analyzed and compared, especially regarding differences in the damping decrement. The research shows that using modern materials in the wheelchair frame has a beneficial effect on vibration damping. Although the frame structure and material did not significantly impact the reduction in the acceleration vector, the material and geometry had a beneficial effect on the short dissipation time of the mechanical energy generated by the kinematic excitation. Research has shown that modern construction materials, especially carbon fiber-reinforced composites, may be an alternative to traditional wheelchair suspension modules, effectively damping vibrations.

Purpose: The aim of this publication is to present the results of theoretical research-evaluation of normative and legal documents used for the design and installation of voice alarm systems (VAS) in selected European countries. The aim of the research was to analyze and compare the functioning of voice alarm systems in Poland against the background of selected European countries. Introduction: Voice alarm systems are systems installed in buildings that enable the broadcast of warning signals and voice messages for the safety of people in the building. Mandatory use of voice alarm systems in selected buildings became applicable in Poland on January 16, 2006. In Europe, these systems have been present before. Over the years, there has been development of both the devices included in the systems, as well as the normative documents and legal acts that describe these systems. Methods: Within the research process, theoretical research was used, such as: analysis of literature and legal documents, synthesis, generalization, inference, comparison and analogy. As part of the research, documents from such countries as Poland, Great Britain (mainly England), Sweden, Norway, Germany and the Netherlands were analyzed. The selection of individual countries was guided by the level of development of these systems in a given country and the availability of source documents. Conclusions: The presented analysis of the requirements for the use of voice alarm systems shows how different the approach to the use of this type of systems is. Depending on individual experiences and the administrative structure of a given country, a variety of regulations, whether legal or normative (not always normative documents issued by state standardization institutions), can be seen in the field of voice alarm systems application. Unfortunately, one can get the impression that voice alarm systems are still not as popular as fire detection systems. The definition of the requirements for buildings in which the use of voice alarm systems should be obligatory and the requirements for the determination of the required level of speech intelligibility constitute the basis for the consistent development of this type of fire protection equipment. Such requirements should be specified either in legal regulations or in normative acts dedicated to voice alarm systems.

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informujące swoich czytelników o najnowszych osiągnięciach naukowych i nowoczesnych rozwiązaniach technicznych w Polsce i na świecie, popularyzuje problemy techniczne oraz poszerza wiedzę i kulturę techniczną.