An Investigation of the Factors Affecting the Mechanical Smoke Extraction System for A Building with an Atrium

Abstract
The purpose of this paper is to better understand the behavior of smoke movement 
in an atrium. Thus, gives first responders and civilians in and out of the building a 
better understanding of the best ways to save lives and minimize losses Due to fire or 
smoke damage.
This study aims to investigate the operation efficiency analysis of the atrium 
proposed ventilation system using axial exhaust fans mounted at the atrium void high 
level in achieving smoke clearance and suitable conditions for safe egress of 
occupants during a fire scenario that lasts for 10 minutes.
This study consists of a fire and smoke propagation analysis which consists of the 
descriptive part, a general principle of operation of the axial smoke fans ventilation 
fans to achieve smoke clearance during an axisymmetric atrium fire scenario, for that 
purpose a simplified fire scenario of fire and ventilation parameters are considered 
and discussed and the following chapters describe the software used to perform 
numerical calculations, results and conclusions and recommendations from the 
analysis. 
With the advancements of modern technology, computers, and software make 
simulation models possible such as fire models to simulate fire and smoke 
movements, in this paper computational fluid dynamic (CFD) software Fire Dynamic 
Simulator (FDS) PyroSim is used to conduct a series of atrium tests to investigate the 
effectiveness of smoke exhaust systems.
FDS solves the Navier-Stokes equations appropriate for low-speed flows (Ma < 
0:3) with an emphasis on smoke, heat transport, and CO2 concentrations from fires, 
the default turbulence model used in FDS simulation is the Large Eddy Simulation 
(LES), which is the solution of Navier-Stokes equations at the low speed [1].
In this study, the compartment tested was 38 m×5.7 m×13 m in height, and the 
measured exhaust rates used ranged from 2.0 to 5.0 kg/s with thermocouples placed 
at various heights to see the upper smoke layer and the lower air layer along with the
convective boundary layer or interface layer the building smoke rises from the originof fire due to its buoyancy [2]. 
CO2 concentrations, heat release rates, and temperatures are looked at to better 
understand the behavior of smoke, it is only a short-term test of 600 seconds of 
simulation time.