Smoke Control Strategy in a High-Rise Building - Example

Running Head: Study on smoke control strategy in a high-rise building A STUDY ON SMOKE CONTROL STRATEGY IN A HIGH-RISE BUILDING By (Name) Course Tutor Institution (City and State) Date Introduction Evacuation of occupants from high-rise buildings remains a key priority in the unfortunate event of a fire incidence. Smoke causes the highest proportion of fatalities during fire outbreaks due to its capacity to travel very long distances hence the need for air curtains to prevent transportation of carbon monoxide. Use of heating, ventilating, and air conditioning (HVAC) operations are useful in slowing the propagation of smoke on the floor and may be optimized to improve safety during fires by controlling heat change, smoke conditions as well as fluid flow. Conventional chimney systems allow for stabilized temperature and smoke stratification within buildings while creating a hot layer of smoke above a floor as opposed to louver systems. Enhancement of safety on modern buildings relies on fully automated HVAC systems to create a safe environment by ensuring the directional flow of air. The system saves energy and influences smoke propagation, the fire alarm, smoke exhaust as well as the evacuation systems (Yu et al., 2014). Strengths and weaknesses HVAC systems improve the conditioned room’s capacity for latent air-cooling through the supply of cold air. Some of the merits of the system include its central location for ease of maintenance, minimal noise disturbances due to adequate control measures, the amenability of the system in smoke control setups, and its ability to permit simultaneous cooling as well as heating. The demerits of the system include the high requirement for energy amounts for efficient operations, difficulties in air balancing, difficulties in providing comfort in places experiencing low outdoor temperatures, and prompt maintenance of the system requires a multidisciplinary approach (Wang and Ma, 2008). Details of the research This study focuses on the impact of HVAC operations, smoke exhaust systems, and air supply systems. It involves the development of a model for smoke propagation by use of the Large Eddy Simulation in order to evaluate the propagation of smoke in varied HVAC operations. The results of the simulations will entail temperature details at the exit of the fire room for varied quantities of air supply. In addition, the building’s smoke exhaust and air supply system influence the method of smoke propagation (Yu et al., 2014). Evaluation of the modeling/statistics In the study, a numerical model was developed to aid feasibility studies for using HVAC operations in enhancing a building's safety. An office setup was simulated with typical features such as the staircase, elevators and equipment rooms with exits to the corridor. The simulated office covered 2000m2 whereas the central core covered 700m2 (Yu et al., 2014) Figure 1: Smoke simulation model The fire zone’s building height and the clear height were approximately 4m and 2.7m respectively with clear wall locations, smoke extraction ventilators, VAV HVAC ventilators, and a fire set-up in the right upper corner. The simulation model relied on the equations for smoke movement namely mass equation, momentum equation, component equation, energy equation, and gaseous state equation. The study then evaluated various fire simulations to study HVAC operations with a propane gas combustor as the supposed fire source spread over 4m2 (Yu et al., 2014) The significance of the results The study results entailed three parameters namely a discussion on orthogonal experiments, a discussion of moderate quantity air supply, and discussion on the strategy of fire control. In orthogonal experiments, strategies for smoke control were studied using FDS adopted from NIST. The figures below show the different setups of orthogonal experiments: The results of the experiments confirmed that the quantity of air supply, the height of the ventilator supply, and the distance from the fire to the supply vent have varied effects on the fire room’s exit temperature. The results further confirmed the quantity of air supply as the most important factor followed by the height of the supply vent. However, the later needs further investigations to ascertain its exact contribution in smoke propagation. Consequently, adjustments in air supply for HVAC systems may be targeted to improve safety in buildings particularly during fire outbreaks to ease the evacuation of people (Yu et al., 2014). In regards to supply of moderate quantities of air, the simulation results confirmed that it is possible to reduce the fire room's exit temperatures by moderately supplying air but the use of larger quantities of air alters the smoke propagation towards the exit hampering the smooth evacuation of people. Similarly, ensuring tight controls on air supply within the buildings is useful in minimizing the devastating effects of a fire thus making the buildings more safer for the occupants (Yu et al., 2014). During a fire outbreak, the fire alarm systems usually detect the location of the fire source thus turning on the smoke exhaust systems on the floor on which there is a fire as well as the neighboring floor. The simulation results confirmed that HVAC operations minimize the propagation of smoke into rooms with occupants and instead redirect fresh air to the said rooms. Similarly, HVAC systems can prevent propagation of smoke to rooms not yet torched by fire. Automating the systems may come in handy especially during fire outbreaks to allow for faster evacuation of the occupants within a building and ensuring the fire is contained with minimal effects (Yu et al., 2014). The figures below show how slowing down the propagation of smoke is possible using HVAC systems Conclusion Air supply remains the main factor in smoke propagation during a fire outbreak and temperatures at the fire room’s exit can be adjusted through manipulation of airflow thus useful in aiding evacuation. Lastly, smoke control simulation results confirm the simultaneous turning on of HVAC and the smoke exhaust systems do not delay propagation of smoke to a room that has no fire whereas turning on the air supply as well as the smoke exhaust systems delays propagation of smoke in the posterior room. Air supply, smoke exhaust systems, and door controllers are useful in isolating a fire following the evacuation, containing the smoke and the fire, improving the safety of the para-safety area, developing controls using door sensors, air supply, and the smoke exhaust system. There is the need for more studies on smoke propagation within a building's network, which is affected by natural air supply and the smoke exhaust systems. References Wang, S., Ma, Z., 2008. Supervisory and optimal control of building HVAC systems: a review. HVACR Res. 14, 3–32. Yu, Y., Chu, Y., Liang, D., 2014. Study on smoke control strategy in a high-rise building fire. Procedia Eng. 71, 145–152.  Read More