CFD Analysis of Smoke Management in Multi-Storey Buildings: A Project

This project presents a Computational Fluid Dynamics (CFD) analysis of smoke management system strategies in multi-storey structures, focusing on the role of HVAC operations in controlling smoke propagation during fires. The study employs Ansys workbench to model smoke behavior based on varying air supply quantities and temperature changes. The introduction emphasizes the importance of fire safety in high-rise buildings, the challenges of evacuation, and the need for strategies to control smoke and toxic fumes. The literature review covers multi-storey structures, their fire resistance, and the significance of well-defined control measures. The methodology section details the CFD simulation setup, numerical model, boundary conditions, and design of smoke management systems. Results and discussions are presented, followed by conclusions and suggestions for future work. The project aims to assess smoke propagation, develop predictive models, and evaluate the effects of complex geometries on smoke movement, ultimately contributing to improved fire safety in urban environments. The research also investigates the effects of HVAC and supply air for smoke management in multi-level buildings.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 1
CFD Analysis of Smoke Management
System Strategies in Multi-Storey
Structures
line 1: 1st Given Name Surname
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(of Affiliation)
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(of Affiliation)
line 4: City, Country
line 5: email address or ORCID

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 2
ABSTRACT
Fire prevalence in multi-story structures has become an immediate serviceability concern and
often poses a significant challenge when it comes to evacuating people during such emergencies.
Though fire resistance contributes heavily to the structural durability of a building, detection and
control systems are equally as important to address smoke which accounts appreciably for
casualty tolls. Thus, fire and smoke control strategies have become a crucial aspect integrated
into the holistic design of any building. Accordingly, there are several methods used for smoke
detection and control. This discourse investigates the use and efficacy of HVAC operations as a
technique of smoke management, air supply, and smoke dissipation system, particularly for
multi-storey buildings under fire. The adopted methodological approach relies on Computational
Fluid dynamics (CFD) with Ansys workbench, which models smoke propagation in a building
on fire based on the air supply quantities with varying temperature change. The study establishes
the importance of HVAC operations as a strategic tool in smoke detection and control, air supply
and exhaust systems in curbing smoke propagation.
NOMENCLATURES
E Illuminance [lx] z Height in a fire plume [m]

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 3
K Visibility factor [-] Fire diameter [m]
Hceff Effective heat of combustion
[MJ/kg]
Heat Release Rate [kW] Greek
Km Mass extinction coefficient [m²] density [kg/m3] ms mass flux of smoke [kg/s] λ
Wavelength [nm]
l σ Specific mass extinction coefficient
Length of light path [m] [m²/g] cp Specific heat [kJ/kg·K] subscripts
Temperature [°C or K] into the plume
I Luminous intensity [cd] 0 ambient
Ys Soot yield [g/g] fl flame
Index Terms – Computational Fluid dynamics (CFD), Heating, Ventilation and Air
Conditioning (HVAC), Finite Element Analysis (FEA), Computer-Aided Design (CAD), ANSYS
Simulation Software
Acknowledgement

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 4
Contents
ABSTRACT............................................................................................................................................2
NOMENCLATURES..................................................................................................................................2
Acknowledgement.......................................................................................................................................3
1. CHAPTER 1-GENERAL INTRODUCTION.........................................................................................5
1.1 INTRODUCTION.................................................................................................................................5
1.1 objectives...........................................................................................................................................6
2.CHAPTER 2-LITERATURE REVIEW...................................................................................................7
2.1 Multi-Storey Structures................................................................................................................7
3. CHAPTER 3-RESEARCH METHOLOGY..........................................................................................12
3.1 . Setup of the Model and Solution Development.............................................................................13
3.2 CFD Simulation Numerical Model..................................................................................................16
3.3 CFD Simulation Boundary Conditions............................................................................................20
3.4 SMOKE CONTROL SYSTEMS.....................................................................................................24
3.5 DESIGN OF SMOKE MANAGEMENT SYSTEM........................................................................32
3.5.1 Design Fundamentals................................................................................................................33
3.5.2 Basis of Design.........................................................................................................................35
3.5.3 Additional Design Considerations............................................................................................37
3.6 ENGINEERED SMOKE CONTROL CYCLE TEST.....................................................................40
CHAPTER 4-CFD SIMULATION RESULTS AND DISCUSSION........................................................43
5. CONCLUSION AND FUTURE WORK...............................................................................................53
5.1 CONCLUSION...............................................................................................................................53
5.2 Future works...................................................................................................................................54
REFERENCES......................................................................................................................................58
Table 1 TYPICAL HIGH-RISE BUILDING MODEL SPECIFICATION................................................15
Table 2 BOUNDARY CONDITIONS FOR CFD ANALYSIS IN HIGH-RISE STRUCTURES.............22
Table 3 CFD ANALYSIS TEMPERATURE COUNTER RESULTS.......................................................48

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 5
1. CHAPTER 1-GENERAL INTRODUCTION
1.1 INTRODUCTION
Urbanization plays a significant role particularly in the development leading to the
improvement in life quality which translates to population increase. Since contemporary designs,
structures ought to effectively integrate fire safety in design and construction to ensure that a
building can sufficiently resist fire outbreaks and that further measures of fire and smoke control
are incorporated to enhance the serviceability of the building. Notably, fire outbreaks pose a
major challenge in high rise buildings as the priority concern becomes safely evacuating and
rescuing affected people. In most cases, firefighters tend to have difficulties in accessing higher
floors, delaying rescue operations. As such, it is vital to come up with strategies that curb smoke
propagation which reduces the quantity of air supply, eventually causing respiratory health
complications. Further, combustion of some elements making up the structure leads to the
release of toxic fumes which are very detrimental when inhaled. This realization has prompted
researchers as well as engineers to study. Various propositions have been developed, and a
combination of several strategies has proven to be efficient in air supply, the exhaust of toxic
fumes as well as inhibition of flame penetration and heat transmission.
The construction segment is now cognizant of the need for a sustainable building after
numerous research publications covering social, environmental and structural concerns after
reported cases of fire-related incidents and their effects on the aforementioned aspects. Presently,
the industry strives to achieve competency by addressing structural needs and safety precautions
in service utilities so that a building can be rendered fully compliable to the minimally

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 6
acceptable standards. Fire resilience in multi-story structures necessitates a detailed study to
investigate the patterns of smoke movement in high rise buildings, accommodating provided
ventilation. Understanding the behavior of smoke molecules and their path in relation to
temperature change greatly influences control mechanisms under investigation since the goal of
fire safety is to minimize accumulation of toxic fumes while promoting air supply. The CFD
method provides an assessment tool in determining the path of smoke, particularly in a mixed-
development building which has become the major attraction subject of modern-day
urbanization. Therefore, smoke flow control should guarantee the occupants’ safety, firefighting
personnel during evacuation and rescue operations,
and optimally safeguard property.
1.1 Aims and objectives
1.1.1 Aims
The primary aim of this project is to assess smoke propagation in high-rise structures by
assessing patterns in order to develop a predictive model that can be used for effective smoke
and fire control
1.1.2 Objectives
The aim statement outlined aboved will be achieved through the following stated objectives:
1) To determine the neutral plane of smoke movement
2) Establish the relationship between smoke movements and heat from fire released
3) Evaluate the effects of complex geometries on smoke movements by utilizing the
simple geometries
4) To predict the paths of smoke movements in high rise buildings
5) Provide details on heat transfer and temperature of structures during high rise

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 7
buildings fire.
6) To study the effect of HVAC and supply air for smoke management in multi-level
building
2.CHAPTER 2-LITERATURE REVIEW
2.1 Multi-Storey Structures:
Multi-story structures are buildings with an appreciable vertical height whereby occupants
depend on lifts/elevators to reach their preferred destination. There is no internationally agreed
definition and often it will have several synonyms. Nevertheless, most high-rise buildings are
always at a height greater than the available reach of fire-fighting equipment, hence affecting
evacuation mechanisms during a fire tragedy. [1] presents a preparatory study on fire and how it
compromises the structural integrity of high-rise buildings. Multi-level structures greatly
comprise of reinforced concrete, steel members and may incorporate timber; all whose
mechanical properties vary when exposed to heat and fire. Consequently, these buildings pose a
critical design challenge for geotechnical and structural engineers as well as firefighters during
dynamic fire emergencies.
The durability of a building will depend on whether it will perform satisfactorily for its
intended purpose during the design period, safely transferring all ultimate loads to a structural
bracing/foundation, and meeting the serviceability needs of the building. Essentially, it will
involve the design phase, construction phase, and maintenance phase in the life of the building,
accounting for adverse weather conditions. [2] elaborates the need for well-defined control

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 8
measures for multi-level structures cladded with a façade on both sides, highlighting how such
structures are affected by extreme heat seasons. As such, it is imperative that one develops clear
guidelines on inspection details, material and record up-keep, identification of elements that
increase potential failure in the structure and exploring measures that address robustness,
construction, and workmanship. Proper documentation of the above provides a history on the
structure and ensures that a structure will meet its design life. Consideration during design will
involve the Engineer selecting appropriate fire resistance hours to prevent structural members
from flame penetration, heat transmission and ultimate collapse of the structure. These
considerations will influence the design loads acting on the structure factoring inappropriate
cover to embedded steel and good quality concrete.
Similarly, it enables the Engineer to carefully assess the stress-strain behavior patterns for
normal-weight concrete and reinforcement in relation to temper increase, thus allowing for the
development of heat control techniques to regulate the temperature in the event of unforeseen
loading due to an emergency. Construction activities may incorporate the use of heat-tolerant
admixtures, or the integration of thermal insulators to prevent heat transmission. Some materials
are known to have minimal absorbable rates of the varying compounds and fumes which damage
reinforced concrete structures which are exposed to fire. The preliminary design will include
assessment of fire susceptibility and gives a breakdown of measures and combination thereof,
which serves to achieve hazard control. Essentially, such approaches will cover the scope of the
ventilation system of the building, emergency exits and lift assessment to develop economically
viable, quick and safe control mechanisms. [3] studies the behavior of fire-induced smoke
control through a system of hybrid ventilation, and highlights the enjoyed advantages within the
setup of a transit terminal subway station. Most structural designers tend to under-look the

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 9
significance of fire safety during design, construction and maintenance routine schedules thus
lacking to adequately comply with building standards and codes of practice.
In the present-day world, multi-story structures are developed to meet different functions, as
developers aim to meet the demands of the clients and the purpose of the structure. Some of the
most vibrant use in relation to urban settings delves into mixed-use developments and can be
categorized into residential space, office space, storage space, places that attract public service
use such as malls, recreational centers, art galleries amongst many potential usage forms.
Unforeseen calamities such as fire outbreaks introduce dynamic loadings as a result of
temperature change and impact on structural members, which may in turn increase vibration
beyond the building’s natural frequency. As a result, high rise buildings may fail in different
modes both factoring the ultimate and serviceability limit states, considering the structure as a
frame in response to lateral loads and other dynamic loadings.
The second consideration focusses on sub-frames which comprises of beams and a series of
columns built-in, below and above the beams being considered. Fire incidents may develop
lateral stresses that will affect internal forces and moments, specifically at the supports. [4]
advocates for adherence to provided codes of design, construction as well as a safety control.
Consequently, is thus the responsibility of all involved entities to ensure that a high-rise building
can adequately handle all developed stresses as well as use fire detection and smoke control to
ease safe evacuation of occupants as well as ensuring that the building will not collapse.
2.2 Pros and Cons of High-Rise Buildings

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 10
High rise buildings offer advantages and disadvantages to urbanization in equal measure. The
study investigates and lists them below in the following order:
I) Pros of High-Rise Buildings
1) They present a suitable housing solution, especially in highly populated regions.
2) They present an integrated land and human activity management system.
3) Maintenance services are easy to execute if well planned.
4) Most high-rise buildings are representative of national growth and development in the
ever-competitive world economies.
5) Some artistic works act as sources of tourism
6) Development generally tends to attract foreign investors who may wish to expand
regional territories.
II) Cons of High-Rise Buildings
1) They require complex design which in most cases tends to be expensive.
2) There is an increased serviceability aspect in relation to fire resistance requiring
informed designs, thorough attention during construction and maintenance of the
structure at the proposed occupancy.
3) They pose a challenge to firefighters in the event of fire breakouts as equipment may not
necessarily reach the top floors.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 11
4) Evacuation of people may also prove to be difficult as it requires a well-coordinated plan
to reduce injuries that may result due to panic.
5) Often require a holistic approach as functionality and serviceability within the context of
urban development are intertwined, thus necessitating advanced forms of analysis in the
event of a catastrophe.
The design should optimally depend on the geotechnical conditions of the region, as these
will determine crucial elements which affect how the frame of the structure will safely
transferring working loads from the highest point to the structural bracing or foundations.
Accordingly, it is important to mention that most failures affecting the foundation of a high-rise
building, exceeding beyond design limits will lead to the collapse of the structure. Natural
disasters that affect the tectonic plates which appreciably form the very foundation with safe
bearing capacity compromises the building under consideration. They include disasters such as
earthquakes and landslides. On the other hand, human-made disasters such as blast explosions
could compromise the future likelihood of developing a multi-story structure within the area, as
this could prove expensive and a worst-case scenario. High-rise buildings also tend to have high
accident-related injuries and to some extent death, especially if site and work safety is not
effectively observed. These could occur due to ineffective bracing of props supporting
earthworks, consequently leading to the collapse of weak soil strata to the labor force. Failure to
adhere to safety standards concerning personal protective equipment (PPEs) could translate to
many avoidable accidents that put the lives of workers at risk.
2.3 High-Rise Buildings Evacuation Patterns

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 12
Evacuation patterns are good indicators in the design of safety controls and influence the
placement of fire-fighting equipment in the layout of a building. An efficient operation high-rise
structure requires a team of highly skilled personnel who understand the complexities associated
with fire safety. Similarly, they help formulate policies not just even during the construction
phase as site emergencies do occur. These include strategic positioning of First aid equipment,
lifting and evacuation equipment, protection equipment and hazard control equipment.
As such, the paper relies on principles of structural engineering, to discuss smoke control
strategies implemented to ensure occupants of these buildings are safe. [5] discusses smoke
control characteristics of a longitudinally ventilated tunnel, and the study draws a comparison of
similar dynamic characteristics in ensuring sustainable development. Dynamic loading due to
fire-related stresses and smoke propagation prerequisites the need to have a clear guideline on
crucial aspects which contribute to safe evacuation. They include the use of personal protective
equipment such as helmets, fire-resistant safety clothes, smoke control equipment and a secure
communication system to guide occupants from the evacuation point to a safe destination. The
span of the structure will define the required evacuation time since, with every vertical height
increase, the design should adopt a more detailed analysis to increase safety efficiency.
3. CHAPTER 3-RESEARCH METHOLOGY
The study adopts quantitative analysis methods which rely on secondary sources and
empirical CFD techniques in analyzing HVAC operations. The former will serve to define
concepts and definitions in dynamic smoke patterns during a fire outbreak, which will form the
theoretical framework of validating results from the CFD analysis. These theoretical

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 13
backgrounds are heavily borrowed from building codes of practice as well as safety standards.
Once data are collected, CFD techniques will be deployed to evaluate the effectiveness of the
identified systems technologies and the results will be analyzed and discussed thereafter. During
pre-processing, the physical bounds, as well as the geometry of the problem, will utilize
computer-aided design (CAD) whereby data can be cleaned up and the fluid domain extracted.
The study defines the physical model by accounting for the equations used in species
conservation, fluid motion, radiation likely to develop and enthalpy. The volume occupied by the
fluid will be divided into discrete cells contained in the mesh, assumed to be tetrahedral for this
study. The scientific process will use the iterative approach to fully scrutinize research findings.
Finally, based on the obtained results, a post-processer is used for analysis and visualization of
the resulting solution.
3.1 . Setup of the Model and Solution Development
Every model should be developed under considerations of sustainable development and
appropriate transfer of toxic compounds to safe ground. Fire incidents are common in multi-level
buildings as compared to low-level structures. The model will comprise of a smoke and fire
detection devices simulated to replicate a real-time building, and the efficiency of the test model
in activating control and mitigation measures. Further, the model will show the importance of
supplying area to affected zones, rendering it to a scenario where the lives of occupants are at
risk.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 14
(a) (b)
Fig. 5 (a) Plan layout of smoke simulation model. (b) 3D layout of of smoke simulation
model
Fig 5. (a) presents a plan layout of a smoke simulation model, whereas (b) present the three-
dimensional layout.
A typical high-rise building will consist of:
1) Office zone and a core which forms the anchor supporting the framework of
the structure.
2) Elevators to allow for movement of people and goods during construction
and at proposed occupancy.
3) Utility services to meet the serviceability and function of the structure.
4) Equipment to aid in fire-fighting, smoke control as well as evacuation means
in complex scenarios.
5) Evacuation staircase spiraling down the core to safe exit, used by occupants
in the event of emergencies.
The detail model specification for the CFD analysis are provided in the table below:

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 15
Table 1 TYPICAL HIGH-RISE BUILDING MODEL SPECIFICATION
Model detail specifications
Model specification Quantity /size
Building area 2700 m2
Building height 4 m
Clear height 2.7 m
Area of the office zone 2000 m2
Area of the central core 700 m2
The volume of fire model 8 m3
VAV Ventilators of
HVAC (air makeup)
24
Smoke extraction vents 12
Doors 4
Fire material Propane
Building material Concrete
3.2 CFD Simulation Numerical Model
Smoke propagation is created by the turbulent flow of air that is caused by a difference in
pressure and heat levels in the geometry of the structure. The fluctuation of smoke density could
be used to predict the classification of fire. Notably, CFD is an accurate analytical tool, and is

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 16
used in combination with ANSYS workbench. The control equations governing smoke focus on
turbulent flow model and the heat transfer concepts of the fire in high rise buildings. This
discourse focusses on CFD analysis illustrated on ANSYS CFX with K-epsilon (2eqn)-stationary
standard well function turbulent flow model.
The governing equation forms (Algorithms) of the solution is as shown below:
The mass of smoke introduced into the model can be presented as:
Q
ms YsHc,eff
ρ ( u2 . ∇ ) u2=∇ . (− p2 I + K ) + F
∇ . ( p2 I )=0
K= ( μ+μT ) ( ∇ u2 + ( ∇ u2 )T
)− 2
3 ( μ+ μT ) ((∇ u2) I − 2
3 ρk 2 I )
ρ ( u2 . ∇ ) k 2=∇ . [ ( μ+ μT
σ k ) ∇ k2 ] + ρk −ρε
ρ ( u2 . ∇ ) ε=∇ . [ (μ+ μT
σk )∇ ε ]+ cε 1 ϵ
k 2 ρk− cε 2 ρ ε2
k 2 ϵ=ep 2

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 17
μT = ρCμ
k2
2
ϵ
K=μT ¿
Tn = Cn(Tmax – Tb) + Tb
be used, where
Tn = interface height temperature
Tmax = maximum temperature (at the ceiling)
Tb = temperature near bottom of atrium
Cn = interpolation constant (typically assumed to
be 0.15 or 0.2)
Conservation of Mass:
+ ∇⋅ρu = 0
∂t
Conservation of Momentum:
(1)
⎛ ∂uv v v⎞ v v
ρ⎜ + (u ⋅∇)u⎟ + ∇p = ρg + f + ∇⋅τ (2)
∂ρ v
⎝ ∂t ⎠
Conservation of Energy:
∂ v Dp v

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 18
∂t (ρh)+∇⋅ρhu = Dt −∇⋅qr +∇⋅k∇T +∑l ∇⋅hlρDl∇Yl (3)
Conservation of Species:
∂ v
∂t (ρYl )+∇⋅ρYlu =∇⋅ρDl∇Yl + m& l′′′ (4)
where ρ is density, uv is velocity vector; p is pressure; gv is gravity vector; τ is viscous stress
tensor; fv is external force vector (excluding gravity); h is enthalpy; qvr is radiative heat flux
vector; T is temperature; k is thermal conductivity; D is diffusion coefficient; Yl is mass fraction
of lth species. m& l′′′ is mass production rate of lth species per unit volume.
The viscous stress tensor,τ, in the momentum equation is defined as
τ= μ⎜2def u − (∇⋅u)I ⎟
⎝ 3 ⎠ v where I is the identity matrix and the deformation tensor is given by
(5)
⎛ v 2 v v⎞
def uv (6)
The dynamic viscosity,μ, can be defined as
μijk = ρijk (CsΔ)2 S (7)
and
S = 2⎛⎜ ∂ux ⎞⎟2 + 2⎛⎜⎜ ∂∂yv ⎟⎟⎞2 + 2⎛⎝⎜ ∂∂wz ⎞⎠⎟2 + ⎛⎜ ∂∂uy + ∂vx⎠⎟⎞2 +
⎝⎛⎜ ∂u + ∂w⎞⎟2 + ⎜⎛ ∂v + ∂w⎟⎞2 − 2 (∇⋅uv)2 (8)
⎜

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 19
⎝ ∂ ⎠ ⎝ ⎠ ⎝ ∂ ⎟ ∂z ∂x ⎠ ⎝⎜ ∂z ∂y ⎠⎟ 3
where Cs is an empirical constant; Δ = (δxδyδz)1/ 3 , is length on the order of a grid cell; S is
magnitude of the stress tensor.
In an LES calculation, the thermal conductivity and material diffusivity are related to the
turbulent viscosity by
cp,0μijk μijk
kijk = Pr ; (ρD)ijk = Sc (9)
where cp,0 is the specific heat of the dominant species of the mixture; Pr is the Prandtl
number and Sc is the Schmidt number. Based on simulation of smoke plumes, Pr and Sc are 0.5.
3.3 CFD Simulation Boundary Conditions

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 20
Boundary conditions refer to the initial input values used in ANSYS workbench as check
parameters. This software allows for the determination and integration of boundary conditions
using the CFX tool solver. Critical boundary conditions are smoke exhaust mass flow rate, air
HVAC inlet mass flow rate supply, material data, and building area, turbulence model properties,
and operating pressure and heat generation. Solution domains used for the study include concrete
for the building, propane for the flame and air for the internal fluid model. The maximum heat
loss puts iterations of ten megawatts at varying time intervals. Similarly, CFX requires the input
of several parameters and they include the use of a tetrahedral mesh with skewness of 0.9 in a
steady-state solver type. The information is presented in Table 2.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 21

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 22
Table 2 BOUNDARY CONDITIONS FOR CFD ANALYSIS IN HIGH-RISE STRUCTURES
Boundary conditions and input parameters of the CFD Analysis of Smoke Control System
Strategies in high rise building in ANSYS CFX
No
Maximum Heat Lose input iterations at 10 MW Maximum power with different
time interval
Time in (se) Max. Heat loss
(w/s) at 10 MW
Rate of Heat generation (w/m3)
1 100 se 100000 w/s 12500
2 200 se 50000 w/s 6250
3 800 se 12,500 w/s 1562.3
4 1200 se 8334 w/s 1041.75
CFX input parameters
5 Analysis system ANSYS CFX
6 Physics preference CFD
7 Solver preference CFX
8 Mesh type Tetrahedral mesh
9 Mesh number of elements 102446

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 23
10 Mesh number of nodes 23934
11 Mesh skewness 0.9
12 Solver type Steady-state
Solution Domains
Domain Material
14 Internal fluid model Air
15 Fire model Propane (c3h8)
16 Building Concrete
Boundary conditions
Parameters Input values
18 Smoke exhaust mass flow rate 1.8 kg/m3
Air HVAC inlet mass flow rate 1.8 kg/m3
Heat generation Given from 1-4 with different time
interval
Table.2 Boundary conditions and input parameters of the CFD Analysis of Smoke Control
System.
3.4 SMOKE CONTROL SYSTEMS
Smoke management systems are scientific techniques of identifying smoke fumes and
responding with the appropriate measure of mitigating the fire and the cause. These systems
may be passive or active, and their main objective is promoting safety in such environments.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 24
Early identification of fire and smoke related incidents could help protect the structure from
damage. CFD is used as a key analysis tool to establish the performance characteristics of
smoke control and management system. [6] explains CFD as an important analytical tool that
can be used to predict the free-flow of fluids at varying temperature. The common control
systems covered in most codes are:
a) Atrium Smoke Exhaust Systems
Atrium smoke control systems depends on whether hot smoke will be thrusted upwards
in the event of a fire. Hot fumes rise, translating to the reduction of temperature in the plume
causing an increment in its mass flow as the fire levels intensifies. Smoke rises and after a
while, it begins to form layers under the ceiling. Atrium smoke exhaust strives to dispose of
this layer to ensure it does not come into contact with people.
b) Stair Pressurization Mechanisms
Shafts in staircase layout prove to be very beneficial especially in the event of a fire
disaster, and hence require to be easily accessible and tenable as occupants are evacuated to
safety. [7] describes smoke movement in elevator shafts for high-rise structures and the
challenges they may pose to opening and closure of safe exits. Stair pressurization systems
prevent the entry of smoke into the stair-shaft by pressurizing it with air from outside using a
supply fan. Notably, stair-shafts often face the challenge of over-pressurization experienced
when there is an intermittent loss which could lead to smoke entry or difficulty in opening
the door. Hence, stair-shaft pressurization integrates relief features such as varying the supply
of air through mechanical components such as the variation in the speed of the fan, bypass,

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 25
and variable-pitch blade fan. Additionally, they may have relief openings such as barometric
damper and an exit door relief. with relief openings such as a barometric damper and exit
door relief, or the opening of doors during evacuation results to intermittent energy losses.
However, specialized zones that are either pressurized or exhausted can adopt zoned
management specific to each floor.
The International Building Code (IBC) has been widely adopted as a base code standard,
and outlines mandatory provisions for smoke management. IBC has prepared mandatory
provisions for such fire safety systems. These are categorized into two non-mandatory
documents; recommendations for smoke control in areas attracting a lot of people such as
Atria and malls (NFPA 92B), and safety guidelines according to NFPA 92A. The manual
controls are a fundamental aspect of fire service, and they can be used to override automatic
control. Further, they can be used as a reference in assessing whether automatic controls are
functioning as required when fire department personnel arrive. The manual calls for
configuration of individual controls of each damper, fan and linked devices, though allows
for combination.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 26
c) Heat and Smoke Rooftop Vents
Fig. 1. Plastic roof vents
The two aforementioned control measures work from the operational principle of providing
an outlet to fire and trapped smoke fumes. They are structured such that their perforations
located in the roof will release heat and smoke often propagated by the buoyancy effect in high
temperature, which explains why they’re also referred to as “gravity vents”. In-depth, they are
preferably installed in large open spaces with voluminous storage occupancies. High-piled

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 27
storage commodities tend to release great heat amounts and hence, some fire protection
professionals advocate for desirable heat release towards the external environment to ensure high
levels do not compromise the structural integrity of the roof layout and members. It also
increases visibility in the interior allowing for safe evacuation of people during fire tragedies.
The two most common types of automatic smoke vents are drop-out vent and mechanically
opened vent. Mechanically opened vents may be powered by electric motors, springs or
pneumatic actuators, whereas dropout vents are made out of plastic that shrinks in heat presence,
thus dropping out. Available guidance in the design of heat and smoke building vents tends to be
restricted to single-story buildings that are non-sprinkled, subsequent to warehouse industry
practices. Automatic smoke and heat control vents should be jointly used with fire sprinklers as a
control mode but should be limited to suppression modes.
d) Smoke Dampers

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 28
Fig. 2 Smoke Dampers
They are considered as passive fire safety means adopted for ventilation and air supply
particularly to the ducts that may be built into smoke barriers such as walls. Their purpose is to
regulate the propagation of fumes from one area to another within the building origin of the fire
to other spaces within the structure. A technical combination of dampers and fans will ensure
that an area is free of smoke by pressurizing the smoke-free zones thus inhibiting smoke
infiltration to other areas. They may be installed to ensure the clean agent is in high quantities
and that it is maintained at this level. They are activated by detectors or appropriate control
systems, and can manually be reset to the pneumatic or electric actuator. The combination is
possible especially if utilizing barriers located at specified locations.
Similarly, the design and operation of smoke dampers is subject to various codes of practice
that integrate pressure differences, air leakage and associated ratings categorizing them into three
distinct classes. Degradation is highly associated to temperature change in the damper. They
should be tested under ideal and real time situations to ensure they are effective.
Fire Dampers
Similarly, this category of dampers is regarded as passive, and utilizes HVAC operations
to function adequately in the duct. In most instances necessitates the use of fire protection
techniques that are used in HVAC ducts regulate the spread of fire inside the layout by
incorporating fire resistant structural members. An optimum fire resistance time of ninety
minutes is advised for most designs, to accurately predict thermal change. Increase in

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 29
temperature level activates the thermal element which in turn force closes its blades through
the springs.
The best place to place a fire damper would be in an air-distribution system where they can close
automatically control during heat recognition which may hinder airflow, thus restricting the
passage of flame and smoke. Mechanical dampers act by disconnecting the duct’s cross-sectional
area in the event of a fire by use of steel shutters or pivoting a fire-resistance board. The turning
mechanism may allow the dampers to be grouted in place, thus creating heat sink from fires
acting on ducts and damper, preventing propagation to other areas. Maintenance efforts include
removal of foreign objects in the dampers to allow opening. The design codes and standards
recommend that such dampers should be tested within the boundary conditions of ninety or one-
eighty minutes before failure, as they inhibit smoke movement in the event of a fire.
Fig. 3 Fire damper
Dynamic system dampers are
categorized based on three fundamental
aspects. These include the direction of
the airflow to the system, a detailed
analysis of the acceptable rated airflow
that automatically closes the damper
and pressure differences particularly when closed. Installation and maintenance of these
dampers rely entirely on the manufacturer’s installation. The positioning is dependent on the
choice of the installer as they may be arranged in a vertical or horizontal direction.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 30
Nonetheless, design codes recommend the vertical direction. Additionally, one can choose to
combine both axes.
Every fire safety duct should have an access point. This facilitates routine maintenance
activities, inspection and identification of potential failure. This access point will vary in size
across different models, and the characteristics of your building. However, specialists suggest
the optimum location for the access door should be as close as possible to the damper as it
eases the process of manually overriding automatic commands. Professional designs
advocate for the duct opening based on international standards. As per accepted international
duct sizing standards, the sizing must be a base minimum of 0.5 inches. The least acceptable
dimensions of the access door should measure eighteen inches in length and sixteen inches in
wings. Where these dimensions are too small to allow for access, the code recommends
increase in length to twenty four inches whereas the width should remain the same.
Human Behavior and Fire
Understanding human behavior in times of an incident like a fire is an important safety
aspect as it helps model evacuation patterns and human instinct within the context of a high-
rise building as well as defining activities of fire-fighting departments. Population
consideration during such times should be wholly inclusive, accommodating even disabled
people or those with limited movement, who in most times may be ignored. The following
breakdown lists steps and activities that may be conducted in the event of a fire-related
tragedy for a multi-storey building:

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 31
1) Develop fire set up and afford an estimate of the effective time of operation for the first
responding firefighters.
2) Sort the negative and positive aspects of human behavior that people exhibit in fire
situations as they affect the emergency evacuation.
3) Outline fire setups and describe the possible physiological impact different human
behavior may have on high rise building occupants and the responding firefighters.
4) Find four psychological characters of building occupants which may affect their
identification of and response to a fire.
5) Find at least three occupancies where human behavior and response
characteristics are unique to occupancies and where there is a high potential for life loss.
6) Summarize the human behavior factoring in chances of high life loss in a major fire and
smoke propagation. an incident in high rise building
7) Identify how human behavior factors and high-rise building design in any occupancy may
be a major factor in the emergency evacuation during fire and smoke incidents. For one of
these occupancies, list fire department procedures and control system strategies which
should be implemented to deal with a major incident.
3.5 DESIGN OF SMOKE MANAGEMENT SYSTEM
Several considerations to make while designing a safe and efficient smoke management system.
The design process is very engaging and requires the keen design to detail of the control system,
building requirements, and purpose of proposed occupancy.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 32
Fig. 3 Simulation of smoke
control design and analysis
The main objective of designing
for the smoke control system is:
1) It helps appreciate design
recommendations and
international standards
which explore all aspects and principles of management.
2) It gives an in-depth understanding of dynamic fire distribution, smoke control systems
and combination thereof.
3) Gives a chance for one to assess critical and analytical engineering skills that can be
deployed for the improvement of in the design, construction and maintenance phases of
the entire project.
4) To adhere to safe working conditions to achieve ultimate and serviceability limits to
render a structure structurally sound.
5) To engage all skilled expertise in the design phase as the approach is entirely holistic.
6) To give a better understanding of dynamic loads that may develop due to accidents such
as fire outbreaks, and how the structure can safely transfer them to foundations without
risking human life.
7) Mitigate on accidents such as fires which pose a challenge in evacuation activities, and
increase sudden structural loads that may cause the collapse of the structure. This helps

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 33
save lives.
8) Smoke management is not an isolated discipline but rather a broad branch of technical
knowledge. Accordingly, it requires continuous engagement with all the involved
specialists in order to solve the problem at hand holistically. Such conventions would
easily help address smove growth patterns in buildings under fire.
9) Incorporate emergent fire safety developments that control smoke and reduce the
probability of propagation to other areas. These may range from changing degrees of
partition ranging from corridor walls to installation of thermal insulators according to
required standards, smoke and fire barriers.
3.5.1 Design Fundamentals
The fundamentals of Smoke control design heavily borrow across different fields of expertise
and serves to contain smoke in the region of outbreak and contain the smoke within the given
space, mostluy a surface volume. Control systems need to have specific and tailored control,
operation and design aspects. The flowing principles influence the framework of the system:
Ensuring that the smoke within the area of outburst, and exhuming it in open space where the
fumes can be neutralized.
[1] Creating acceptable environments within fire and smoke exits to ensure evacuation of
occupants to safe grounds.
[2] Preserving the structural integrity of the building at serviceability levels to ensure it
conforms to design limits.
[3] Prevention of explosions that may be as a direct or indirect result of fire and smoke relate
accidents

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 34
The International Building Code (IBC) presents various recommendations for smoke control
system design criteria. Additionally, these requirements facilitate smooth procedures for
conducting evacuation activities. However, the intention of design criteria mostly ignores
common limitations such as inadequacy to effectively protect contents in the building. Moreover,
some concepts may miss out on timely restoration of control operations, which may help in
covering fire explosions. All these limitations contributre to inefficiencies of most smoke
management systems. Hence, a competent engineer ensures that they use balancing factors to
keep these limitations in check. Additionally, the designer’s expertise and innovation may be
called upon in dire times to help restore situations
The design ought to be workable in the sense that if one was to imagine themselves on
the highest level of a multi-story structure on fire in lower floors, they should have some level of
confidence that they can safely be evacuated, or that smoke would not create health concerns.
Such assurance provides building developers with the confidence of the reduction in amounts of
possible property damage, and low risk of occupancy casualties.
3.5.2 Basis of Design
The basis of the smoke control system design (BOSCSD) analysis breaks down into a brief
explanation of the system’s objectives, strengths and weaknesses.The designers should work in
constant engagement with all involved architectural and structural experts involved in the project
in order to achieve the intended objectives. These normally vary depending on the smoke control
system being considered for the structure, and whether the design advocates for the combination
of containment using methods like stair pressurization and management such as exhaust

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 35
techniques. Notably, under desirable design considerations, gravity control venting can be used
as a smoke exhaust technique.
Primarily, smoke control system design (BOSCSD) needs to carefully review design
assumptions which include outflow rates, compatibility and reliability of other fire protection
systems and nflow times. As such, BOSCSD carefully assesses ambient weather conditions such
as effect of wind, humidity, pressure and climate. In depth, it offers guidelines for the
requirements of an automatic sprayer in relation to heat release rates. If design shifts and centers
on the effect of temperature, pressure and wind, (IBC) recommends that these special conditions
be attended to individually, and combination of the same to assess the worst case scenario. The
code highlights minimum and maximum values to be used in relation to stair pressurization at
the time of a calamity.
Moreover, the building codes prerequisites that all analytical calculations factor the number
of possible openings that the system can create at any instance, and how elements may force the
exit doors to close during an emergency. The different assumptions regarding the door positions
will define anticipated pressure levels, evident in the IBC manual and NFPA 92. Design
Engineers may conduct laboratory prototypes and model tests within the setup of an ideal
environment, under steady fires with constant heat release rates. [8] focusses on a laboratory
setup whereby a prototype is exposed to two air intake strategy to assess the impact of air and
smoke quantity. Unsteady fires with varied heat release rates are also considered, and so in
combination thereof. The design fires and smoke control systems should conduct iterative
experiments to investigate the fuel type, amount of fuel, fuel configuration and spacing.
Additionally, simulation of the prototype under the action of fire can help determine likely

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 36
positions of fire and smoke locations in a theoretical building. [8] presents the recommendations
for visualization of simulation data to be able to model the behavior of the structure at working
and dynamic loads. This realization helps identify expected smoke production based on the
plume nature which may be situated at the fire outbreak point.
[9] also suggests how large eddy simulations can be analyzed to explain smoke movement to
establish its properties. Similarly, [10] further investigates the motion characteristics of fire and
smoke propagation in a place with relatively low air flow such as an underground mall, depicting
smoke propagation and possible evacuation patterns. The required duration of smoke control
system performance is examined, by widening the use of the applicable code and standard. For
example, according to U.S code, time interval allocated for each activity should be standard, and
the guidelines suggest twenty minutes as the base of the minimum operational time. This value
may be modified and therefore increased by 1.5 times, when the computed outlet time is more
than 20 minutes. These values correspond to what the earlier editions of the (IBC) suggest, and
supplement previously misinformed aspects. Nonetheless, the IBC maintains the minimum
minutes of operation that should be achieved is 20 minutes, increasable to1.5 times the calculated
outlet time that may override the acceptable time frame (20 minutes).

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 37
3.5.3 Additional Design Considerations
Fig 4. Additional design requirements
Though applicable codes and standards present recommendations for design, there are
several misunderstandings that may develop as this specialized area of knowledge is shared
across disciplines. They include:
a) System startup time: Time is an important aspect and should be properly defined in
order to effect response. In any smoke management system, the pre-determined start-
up time should include detection time, time elapsed after emergency alert, smoke
propagation rate, explosions, the time taken to process and relay communication
signals and the time taken to activate it. It’s a common misunderstanding arising from

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 38
incorrect estimation of the startup time, delay in sending, processimg and relaying
signals or the activities involved in activating the entire system.
b) Large fires and smoke proclamation to the system: Fires may spread beyond
anticipated levels leading to higher propagation rates as well as creation of an
immediate pressure deficiency. The reverse is also true in that small fires may take
longer to detect since the spray system is compromised, and pose a potential risk of a
fire outbreak.
c) Makeup air: Ineffective smoke control system are considered to be faulty designs
which do not accurately reflect the required air supply amounts and vent systems,
despite that this plays an important role in the aerodynamic space. [11] gives an
insight into the impact of air supply in transporting fsmoke induced by fire and
generated compounds upon combustion such as carbon monoxide. These compounds
reduce visibility and cause breathing constraints in a multi-storey building under fire.
Air curtain channels ensure they confine such smoke forms while absorbing the
generated compounds. Change in air velocity could impact the opening and closing
of safety exits, thus design should rely on model tests and prototypes developed under
adverse conditions to present an all-round approach.
d) Inter-Communication: This aspect refers to the coordination of a control system with
others in the vicinity, provided they work sufficiently in the high-rise building.
Accordingly, the International Building Code posits that multiple smoke control
systems could prove to be more successful as compared to individual systems.
e) Smoke Control System reliability: Data from the management systems is crucial in
understanding the interaction between the signals sent to the main control centre and

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 39
the response provided. The reliability of this data presents a performance-based
approach, and could prove fruitful in investigating the potential failure of a system
f) Harmonization of design specifications: In most cases, advanced design of a
functioning smoke management system requires a joint effort from different sets of
engineers as the area of specialized knowledge cuts across so many disciplines. This
often presents a challenge in harmonizing design documents as it requires constant
consultations and extreme professionalism as well as proper documentation of the
same to minimize confusion and help execute tests with promising results.
g) Indicate acceptance test procedures: Acceptance test procedures are vital and will
address errors that may arise in a real situation. For instance, smoke control bomb
tests provide the parameter boundary conditions such as temparature, buoyancy, and
penetration of flames. Nonetheless, ijust because a system has been designed
accurately it doesn’t guarantee that it will pass the standard bomb test. On the other
hand, one can engineer a system which passes the smoke bomb check, but still fail to
perform satisfactorily during a fire. Design engineers should identify and rely on
appropriate procedures in the standard.
An efficient smoke management system particularly for multi-storey structures combines
both passive and active control systems, as one may have advantages and disadvantages over
the other in equal measure. The designer is advised to follow the indicated guidelines, but
should be flexible enough to tailor situations based on the nature of the predicament on the
ground. Just because the codes instruct you to do something, it does not mean that you should
not critically analyze the situation and choose the remedy you think will solve the issue at

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 40
hand. This decision should be passed to all other specialsists involved in the building, and
could be subject to disapproval if flawed.
3.6 ENGINEERED SMOKE CONTROL CYCLE TEST
These are engineered performance tests which assess the impact of inhibiting smoke
movement, and relies on the pressure deficit between the region with fire and other regions.
There are several satisfactions that the engineer ought to meet at this stage, and they include:
control cycle is designed to inhibit the movement of smoke by preserving air pressure
differentials between the event zone and the rest of the building. Pre-functional checklist
substances include, but are not limited to the following:
1) HVAC operations as well as any other smoke management system is executed on time
and as per the manufacturer’s instructions on installation and use.
2) An assessment of the physical setup before and after the tests toensure all elements are
correctly held together.
3) An available source of power required to run the smoke management system at
appropriate current and voltage requirements.
4) Every control system should be balanced per the agreement documents to ensure they
are functioning optimally.
5) Every central HVAC and air supply system should meet the threshold of requirements
which guarantees proper use of these systems in delivering on intended task.
6) All protective cover and element making up components of the
management system such as relief doors should be installed as per the

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 41
requirements of the manufacturer.
It is essential to verify the sequence of control operations as the order in which they
are to be executed will depend on the different smoke control systems and whether there is
a possible combination of the same for the building being considered. Personnel involved at
control rooms should be highly skilled and conversant with manual controls that can be
used in the event automatic controls fail. In addition, they should be capable of reading
control manuals to effect required changes. Nonetheless, varying operational conditions pose
unforeseen issues especially if not addressed on time in relation to the following parameters:
1) A detailed study of the desired smoke management system to plan the sequential
arrangement of operating conditions as well as response efficiency to address
operational challenges that may arise. [12] sensitizes on the need to have a hierarchical
approach in operating activities in order to achieve sustainable building development.
2) Utilizing the dynamic brake feature controlling air supply to to the fan, which
slows down the fan and ensures it comes to a halt upon detection, thus shutting down all utilities
that increase risk. Notably, dampers that are unable to operate against a constant supply of
airflow tend to malfunction.
Proper verification of smoke control signals ensures the following is achieved:
1) Each HVAC and air supply to the fans in smoke dampers should be closed to prevent the
likelihood of fire spread.
2) Every individual smoke management component such as fans respond correctly to the the
design position as per the requirements.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 42
3) Pressure deficit between the fire zone and sorrounding zones should be bridged and should
accommodate the environmental pressure. As such, it should be routinely checked and some
operating conditions would require authorization.
4) Adhering to the provisions made by safety standards and building charcateristics to conduct
proper technical checks for dynamic loads such as wind loads which may distort the balanced
pressure levels.
A. The desired prototype used for simulation should be tested for different climatic
conditions such as cooling, freezing, thawing and buoyancy to effectively monitor
possible environments.
B. Present Investigation
Current research in Smoke Control System Strategies, particularly for high rise building,
relies on commercial software such as ANSYS, CFD, FEA, FDS v.5 and COMSOL
Multiphysics. These software have widely been used over time, and each performs a specific
function. This discourse presents a detailed study of smoke control in multi-storey buildings
based on propagation and HVAC operations. The air supply is also addressed for different time
intervals.
CHAPTER 4-CFD SIMULATION RESULTS AND DISCUSSION
This segment particularly focusses on the results of the CFD simulation and the point at
which iterations converge. As per findings of this study, the solution system converges at forty-
five iterations. CAD applications are adopted to accurately carry out the complex calculations
simulating the streamflow of the smoke particles in the event of a turbulent flow. Thus, it
involves assessing the temperature contours at different time intervals. The study conducted four

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 43
simulations at 100 se, 200 se, 800 se, and 1200 se. the maximum temperature contour results
corresponding from the trans-processor are 969.7k, 621.4k, 360.2k and 331.1k respectively. The
ratio of mass flow rate for smoke exhumation and air supply is set to 0.967 kg/se. In the ANSYS
workbench, physics preference relies on CFD whereas solver preferences will rely on CFX. The
adopted stem analysis approach is ANSYS CFX, whereas the mesh nodes and mesh elements are
23934 and 102446 respectively.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 44
Fig.6 CFX solution at 45 iterations
Different heat levels will translate to different smoke control temperature results and have
varying meanings altogether. ANSYS workbench proves to be an efficient analysis tool that
presents meaningful future propositions in HVAC operations. The results indicate that the
structural design phase of any project, construction thereof as well as routine maintenance
schedules should greatly incorporate smoke identification and control measures. Further,
building design should emphasize the vitality of ventilation which is often not fully addressed
during construction activities. There should be appropriate means of containing smoke through
the use of pressurized systems that ensure the difference in pressure levels between the affected
zone and nearby zone are not exceeded since this translates to an inflow of air which could
potentially cause the doors to fail to open.
The study presents an informative guide on CFD applications to fluid dynamics in
understanding the propagation of smoke, and assumes that all doors, air supply fans and smoke
exhaust exits are completely open during burning.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 45
(a) Temperature contour at 100 se (b) Temperature
contour at 200 se
(c) Temperature contour at 100 se (d) Temperature contour at

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 46
200 se
Fig.3 (a) counter temperatures on the fire at 100 se. (b) counter temperatures on the fire
at 200 se
Fig. 3 (continued). © counter temperatures on the fire at 800 se (d) counter temperatures on the
fire at 1200 se

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 47
Findings from the CFD Analysis indicating the maximum temperature contour results at
different time interval is summarized as shown in the table below;

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 48
Table 3 CFD ANALYSIS TEMPERATURE COUNTER RESULTS
CFD Analysis Temperature counter results
Simulation Time Max temperature contour result
Simulation (a) 100 se 969.7 k
Simulation
(b)
200 se 621.4 k
Simulation (c) 800 se 360.2 k
Simulation
(d)
1200 se 331.2 k
• The mass density of smoke and visibility in smoke (K=3), in point in a middle
of the room (x = 12.5 m, y = 10 m, z = 2.00 m) Fig. 14;
• The mass density of smoke and visibility in smoke (K=3) in a plot (axis y =
9.00 m) through the fire, in the 420th second of the analysis,
Fig. 14.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 49
Plot of the mass density of smoke (left) and visibility in smoke (right) in a point in
the middle of the compartmentMass density of smoke
[g/m3] Visibility
in smoke (K = 3) [m]
Ys = 0.02 g/g
Ys = 0.04 g/g
Ys = 0.06 g/g
Ys = 0.08 g/g
Ys = 0.10 g/g
Ys = 0.12 g/g
Ys = 0.14 g/g
Ys = 0.16 g/g
Fig. 4 Mass density of smoke and visibility in smoke in a plot through the compartment, t = 420
s

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 50
Obscuration density vs. Soot Yield
Visibility range vs. Soot Yield for K=3 and K=8
Simulation relies on principles of Finite volume methods (FVM) since it is advantageous in
matters memory and solution speed, especially where problems are big. Consequently, it utilizes
the Reynold number and uses partial differential equations (turbulence equations, Navier-Stokes

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 51
equations and mass, and energy conservative equations). They are optimized in a conservative
form and solved through integration and differentiation procedures, guaranteeing flux
conservation through specific control volumes. From the provided results, increase in time
intervals translates to a lower value of maximum contour temperature in HVAC operations. For
instance, if the air supply is maintained for100 se with the same air supply rate and smoke outlet
channelled towards the exhaust vent, the maximum temperature contour is 969.7 k. On the other
hand, maintaining the same boundary conditions but increasing the time interval to 1200 se
decreases the contour temperature to 331.2k. Nonetheless, the continued increase in time
intervals gradually leads to the achievement of optimum value.
The hypothetical framework adopted by this study sensitizes on studying the behavior of all
models (affiliative, design) as well as behavior of people (cost affordance ansd social effect).
Research establishes that in most cases of fire incidents, people are often afraid and unwilling to
go through with an evacuation plan, due to the fear of the unknown. The concern can be
expounded further by the factors below:
.
1) That person should have a tendency to maintain their roles during the evacuation at fir
incidents.
2) The absence of fast, clear and clear information regarding the fire and smoke hazards
3) The uncertainty of the indictors from the source of fire and smoke incidents
4) The presence of social influence

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 52
In addition, evacuation activities can prove to be hectic and challenging when it comes to
implementing the various steps. Multi-storey structures face even more complications as
explained by some of the factors below:
1) Door-related issues whereby they fail to open and is caused by the pressure difference in
temperature between the area under fire action and the other environments.
2) The vertical height between the target location and the ground floor as this influences the
choise of evacuation equipment one may use.
3) Human psychology of choosing what they are familiar with for instance selecting familiar
safety exits though there may be other convenient ones.
4) High electrical hazards at the evacuation vents which may increase chance of an
explosion.
All the above factors are vital and individually contribute to the outcome of an accident in
multi-level building in fire incidents. As a result, the design of fire safety in high rise buildings
should be thoroughly done and if possible, consultation with other parties just in case one may
have ignored something important. The study implements a holistic methodology in finding
solutions to every nature of problem. Thus, it reaches the realization that educating people about
fire safety, how to act, what to do and what not to do helps curb panic that could save lives. Most
times accidents happen because people panic and try to find appealing escape routes though
some of them may be unsafe and inappropriate. Sensitizing occupants could increase their
chances of surviving as it provides a platform of conducting a coordinated evacuation. Similarly,
it is equally important to adequately train staff as this leads to joint effort and increases the
overall efficiency of resuce operations.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 53
In addition, lighting influences the speed and efficiency at which evacuations can be
conducted successfully as it determines choice of escape route selected by occupants and those
used by aid agents. HVAC operations have a high success rate, and research proves that they are
suitable in fire and smoke management. In addition, there is numerous research on how one can
run a multi-management system by using several techniques. The CFD simulation results show
the temperature contour at a different time interval, as the time of supply air evacuation during
HVAC operation increase the temperature decrease, as the time interval decrease the temperature
couture increase, this indicates the inverse relationship of temperature and air supply time during
the HVAC operation. The CFD analysis cannot be used on its own and will require the use of
ANSYS work bench.
5. CONCLUSION AND FUTURE WORK
5.1 CONCLUSION
From the assessments of past fire and smoke accidents, theories and models of FEA and CFD
analysis and the conducted experimental research, the study establishes that human behavior in
emergencies and fire-related accidents are complex in nature. Thus, the design of appropriate
smoke control systems requires analysis of various components such as building type and
characteristics, characteristics of different control systems, building codes of practice and fire
safety regulations. Similarly, evacuation patterns are necessary for modeling the possible
behavior of people during panic and designing applicable safety exits as well as the
determination of the type of equipment to use. High rise buildings are susceptible to damages
and loss of life especially when faced with accidents like fires, therefore affecting serviceability
and ultimate limits considered in the design. The CFD analysis is used as a tool for investigating

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 54
smoke propagation and relies on ANSYS workbench. The empirical approach utilizes boundary
conditions that define time intervals and temperature. Sustainable design and development are
necessary to ensure that emergent incidents such as fires do not lead to the loss of property or
lives.
5.2 Future works
This report investigates the design of buildings in relation to smoke control systems, ways of
mitigating fire-related incidents as well as future CFD applications in the formulation of control
strategies. High rise buildings have become a subject of concern as statistical reports indicate
they are prone to more forms of failure. In context, multi-story structures require a sophisticated
and joint effort from people of specialized skill set as the area of discipline is wide. The report
scrutinizes fundamentals of building design particularly in relation to fire safety and control. The
study highlights the importance of ensuring that stresses that develop in the structure due to
dynamic and accidental loadings due not surpass the ultimate design limits and risk collapse.
Similarly, it gives special attention to the cause of fire incidents in multi-level buildings, as well
as smoke control and management systems. It explains further some of the challenges that face
such structures, and they include evacuation problems, emergent issues such as explosions,
property destruction in the event of an emergency and structural failure of crucial elements in the
design.
Member failure may have an even bigger impact on the overall structural integrity of the
building, and this may cause problems to surrounding buildings. Further, the study presents a
breakdown of different smoke control techniques, their characteristics as well as efficiencies in
smoke management. Most are atrium based, and some examples include fire dampers and smoke
dampers. Moreover, the report sensitizes on the need of having efficient communication systems

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 55
that notify occupants of an emergent disaster as well as passing information between firefighters
and occupants during the evacuation process. Considerations have also been made for nearby
buildings that could be used to effect rescue operations through temporary means.
The research demonstrates that people’s behavior in moments of panic will most likely
influence evacuation activities. Accordingly, designers have an existent research gap to address
as to how they can accurately model people’s behavior as well as the response of the system
being designed. Such findings influence the design of exit created to safety, as well as how to
control aspects that may be ignored. These include traffic systems which help evacuate those that
are in nearby structures as well as people and vehicles below the high-rise building under fire.
Similarly, these extend to the response of firefighting services which varies from region to
region. Future works should strive to ensure that disabled people or those with limited
movements can access exits during fire predicaments. These may involve the use of dedicated
platforms that can safely evict such individuals. Ladders, as well as suspended cables, can be
utilized in the event stair-shafts offer limited solutions. Competent design is one that serves to
meet all the desired objectives and functionalities without biasing against some users.
Future works could also focus on how they can modify emergency exits by making the signs
visible, clearly marked out and occasionally performing drills to sensitize on occupants
familiarizing themselves with desired escape routes. Reliability of emergency phone calls should
also be considered to ensure that there is sufficient time to salvage an epidemic. Designers
should carefully consider optimal design in modern buildings especially if within the context of
urban development. Today’s global policy is focused on safety and the involved stakeholders
have put up numerous efforts in establishing guidelines, codes of practice and safety policies to

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 56
enhance the serviceability of multi-level buildings. Similarly, advancement of software analysis
methods could provide feasible control mechanisms that can be easily be used jointly.
The study compares findings from different sources and appreciates the input of all
researchers, scholars and the limitations of their study in relation to conducting this project.
Most problems tend to arise due to constrained movement inside the high-rise buildings. It
establishes that neglecting disabled people or those with limited movements may offer an even
bigger challenge in evacuating the rest of the occupants as the small escape routes could easily
be blocked. The study identifies and reviews such limitations to establish an informed
perspective when it comes to the floor surface, in relation to saving lives. Thus, it translates to a
deeper understanding of movement patterns, surface cover and safety in general.
As indicated, emergency education is important in any work environment as it instills
familiarism to such adverse situations, and improves the critical thinking of occupants. It can be
carried out in several ways for instance training activities, scheduled panic drills and
maintenance of available protective equipment at convenience. Nevertheless, such a study will
require the building safety operator to be actively involved and have the consistency of
conducting such procedures over a specified short-term and long-term duration, since people
may tend to forget. The developer should also commit resources to ensure that evacuation drills
and coordinate with the building safety officer to make the activities successful.
Promising future works in CFD Analysis of management system in multi-storey building
include the following:
1) Introducing high technology safety and evacuating systems and considering peoples with
a disability or limited movement.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 57
2) CFD simulation in prototype test models could help alleviate evacuation and increase
general safety as it is possible to identify limitations of HVAC and suggest
complementarily.
3) Compare the experimental data with CFD Analysis
4) Identify the effect of HVAC operation in smoke propagation in high rise building by
change the air supply quantity and time intervals.
5) Investigate the smoke control strategies, the advantages of combining the different
techniques and limitations that may arise for coordinated use.
6) Public sensitization on evacuation drills for high rise structures to simulate a near-to-
actual scenario, providing avenues of addressing some challenges that may have been
ignored in prior design. This equips occupants on critical skills which they can use in the
event of an incident, significantly reducing the casualty toll as compared to an ideal
situation.
7) Sensitizing occupants on how to control fire, flammability and smoke propagation in
high rise buildings
8) Develop better journal and strategies which helps researches and the community on how
to smoke control systems work to prevent related accidents.
9) Prepare efficient fire safety strategies to evacuate peoples, and proprieties during fire
accidentals and smoke propagation in high rise building.

CFD Analysis of Smoke Management System Strategies in Multi-Storey Structures 58
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