Abstract
Aim: The aim of the paper is to present the results of research carried out by the authors in the field of using air barriers to separate smoke-free areas during a fire in linear spaces. The results presented in the paper are a culmination of research conducted at the Fire Research Department of the Building Research Institute
Introduction: Air barriers are used as virtual partitions for reducing heat and mass transfer between two zones adjacent to each other of different environmental parameters. It produces sufficiently high dynamic pressure at the exit, thereby preventing lateral movement through the aperture in which it is located. Air curtains can be used to limit the spread of smoke in case of a fire by separating smoke-free zones. Proper use of air barrier as part of a fire ventilation system allows to divide linear spaces such as corridors into sections, where the smoke will be maintained in the area from the curtain to the air extraction shaft. One of key aspects is to ensure the highest tightness of the curtain.
Methodology: The study presents the results of laboratory tests in real scale, which is the basis for verification of the adopted numerical model. The research referred to the measurement of velocity distribution in the axis of a flat jet limited for different widths of the inlet slot. After verification, a series of numerical analyzes was carried out to estimate the functioning of the air barrier for different variables, which included: the height of the corridor, the width of the slot diffuser, the speed in the cross-section of the corridor taking into account the interaction of gases produced by the fire.
Conclusions: In the linear spaces which are corridors and tunnels, smoke and heat caused by the fire spread much faster than in areas of large volume and extensive geometry. Due to the evacuation of people and rescue and firefighting operations, it is essential to limit the area where the smoke and heat can spread. Air barriers with properly selected parameters can effectively stop the spread of smoke and heat by creating a “partition”, which also allows free movement of people and equipment. Depending on the requirements set by the designer, an air barrier can be used as a partition for smoke and heat, or only for smoke which is associated with lower velocities at the outlet of the inlet slot. This solution can be used in tunnels, connections between stations, corridors and all areas where the use of a fixed partition in the form of solid doors is impossible.
Keywords: fire ventilation, air barrier, corridor ventilation
Type of article: original scientific article