Prediction of smoke movement paths in high-rise buildings using mine ventilation simulation techniques

Stack, buoyancy and thermal expansion (temperature difference induced) effects in building ventilation are known to exist in buildings under fire produced emergency conditions. In mine ventilation these effects are given a collective name of natural ventilation. Natural ventilation caused by fires in buildings disturbs all their ventilation systems and makes it difficult to predict smoke free paths needed for their evacuation.;The MFIRE has been verified to be capable of handling thousands of flow paths taking into consideration all heat transfer processes; heating, cooling and ventilating units and wind pressure effects. The program considers the frictional headlosses throughout the building and shock headlosses in addition to frictional headlosses in sheet metal ventilation ducts. It can accommodate both constant and variable pressure ventilating fans (fans with characteristic, i.e. airflow vs. pressure produced curves). In case some spaces require constant airflow rates supplied to or exhausted from them, it can predict the adjusted airflow resistances or the size of the fans which are required.;Based on user specified critical criteria of smoke concentration, temperature or pressure difference across flow paths, the program sorts out such critical flow paths and spaces along with their critical conditions.;The MFIRE program has handled about two thousand airflow paths and over one thousand nodes, e.g. rooms predicting all the above mentioned parameters accommodating all kinds of normal and emergency conditions.;Current simulation techniques available in mine ventilation allow a pretty accurate prediction of smoke movement paths during mine fires. This dissertation shows how to use a mine ventilation simulation computer program, the MFIRE, along with necessary modifications in order to accurately predict the location of smoke fronts, the smoke concentration, the smoke and/or air temperature, the fire room temperature, the air and/or smoke flow rates in and the pressure difference across the flow paths throughout a building. The MFIRE also predicts the flow paths where the flow directions are reversed by fire and detects intentional or unintentional recirculation loops. It has proved itself not only the best tool for designing the best HVAC system but also the best smoke control system for a building by way of predicting the effectiveness of these systems. It can incorporate most changes of conditions taking place as a result of the activation of the smoke control system of a building, e.g. the switching on or off of a fan, the opening or closing of a flow path in a fire damper operation, a door being opened or closed or another fire being started or extinguished at the same or different times.;In the future, when simplified interactive PC versions with graphic capabilities will be developed, it will be widely used by fire researchers and building ventilation engineers.