analysis of the cen/tr 12101-5 calculation methodology by ... · engineering for granting me a free...

Kevin Smeyers

means of CFD modelling with FDS 6Analysis of the CEN/TR 12101-5 calculation methodology by

Academic year 2017-2018Faculty of Engineering and ArchitectureChair: Prof. dr. ir. Jan VierendeelsDepartment of Flow, Heat and Combustion Mechanics

Postgraduaat Fire Safety EngineeringMaster's dissertation submitted in order to obtain the academic degree of

Supervisors: Dr. Tarek Beji, Prof. dr. ir. Bart Merci

Analysis of the CEN/TR 12101-5 calculation methodology

by means of CFD modelling with FDS 6

Preface

Dear reader

The book you are holding in your hands right now would not have existed if not for the following people who have,

each in their own way, contributed to this work. I would sincerely like to thank each and every one of them.

First of all, my promotors at the University of Ghent, Bart Merci and Tarek Beji, for their support of my chosen topic

and their patience when answering my seemingly endless stream of questions.

Secondly, my colleagues at FPC Risk, more specifically Ralf Bruyninckx for endorsing and encouraging me to obtain

this degree and Kris De Troch for handing me the idea for the topic of this master thesis and the follow-up thereof.

I would also like to thank Lieven Schoonbaert at FireProNet for providing me with some useful information on the

subject and for his contribution to one of the main documents used in this master thesis: the BRE Design

Methodology, BR 368.

Special thanks to Reinier Maas and Mike Van der Heijden at Actiflow, for their professional advice and useful

pointers when using FDS. Without them, I would still be looking for the correct box to check/uncheck to get some

smoke into the model.

I also wish to express my gratitude towards Kyle Perkuhn, Bryan Klein and Daniel Swenson at Thunderhead

Engineering for granting me a free student license for the use of PyroSim and providing support. This has helped

me a great deal in designing my FDS model.

Since I am not a native speaker of the English language, I asked a friend of mine, whose mother tongue is English

quite literally, to get the worst blunders and mistakes out of this document, to make it somewhat of an easier read.

Thank you, Niklaas Reinhold for the proofreading.

On a more personal note, I owe my girlfriend Marijke eternal gratitude for her endless patience, support and her

help with the layout of this document. And I would like to apologise to her for all the sleepless nights.

And although they were not directly involved in the writing of this work, I would like to thank my Post-Graduate

classmates, with whom I embarked on this mission to become Fire Risk Engineers. Dorien and Bart (The Dream

Team), Charlotte, Martial, Jonas, Marco, Jan, René, Dirk, Ruben, Khan and Thierry; it has been a fun ride!

Thank you all!

Kind regards,

Kevin



Copyright

"The author gives permission to make this master dissertation available for consultation and to copy parts of this

master dissertation for personal use. In the case of any other use, the copyright terms must be respected, in

particular with regard to the obligation to state expressly the source when quoting results from this master

dissertation."

Kevin Smeyers, 15th of January 2018

"De auteur geeft de toelating deze masterproef voor consultatie beschikbaar te stellen en delen van de

masterproef te kopiëren voor persoonlijk gebruik. Elk ander gebruik valt onder de bepalingen van het auteursrecht,

in het bijzonder met betrekking tot de verplichting de bron uitdrukkelijk te vermelden bij het aanhalen van

resultaten uit deze masterproef."

Kevin Smeyers, 15 januari 2018



Abstract



Master’s dissertation submitted in order to obtain the academic degree of

Postgraduate in Fire Safety Engineering

Student: Kevin Smeyers

Promotor: Dr. Tarek Beji

Supervision: Prof. Dr. Ir. Bart Merci

Faculty: Engineering and Architecture

Department: Flow, Heat and Combustion Mechanics

Academic Year: 2017-2018

A Smoke and Heat Exhaust Ventilation Systems (or SHEVS) is a widely applied technique to extract smoke and heat

from any building in case of a fire, by means of mechanical or natural ventilation. Such a system can prevent the

spread of smoke throughout the building and avoid reaching flash-over conditions by removing heat from the

smoke and hot combustible gases. This makes it safer for occupants to evacuate the premises and for fire

departments to organise a safe intervention.

In order to design an effective system, we need to calculate the amount of smoke that can be reasonably expected

when a fire should occur. Therefore, a design fire and scenario is proposed, usually based on a risk analysis to

estimate the potential fire size and fire spread, but also the location of the fire source, the nature of combustible

materials and the geometry of the building have an effect on the smoke formation and propagation.

For designing a SHEVS, different standards or codes of good practice can be consulted, each of them based on

their proper assumptions, mathematical models and empirical formulas. When an atrium is present, the European

standard CEN/TR 12101-5 is most commonly used. This standard contains a well-documented procedure on

designing a SHEVS, when there is outflow of smoke from an adjacent fire room into an atrium. The calculations are

based on the technical report BR 368, which follows a rather complex, seven-step procedure for defining the mass

flow of a rising smoke plume in an atrium. This is considered a rather conservative approach in this document.

CFD-calculations are gaining popularity nowadays, since the software packages are constantly being improved and

computers have more computational capacity. The objective of this study is to make a comparison between the

BRE calculation method and a ‘real-life’ CFD-analysis to see if the BRE-method has a too conservative approach to

the SHEVS design and to check de applicability of CFD-modelling in SHEVS design.



Extended Abstract

Smoke and heat exhaust ventilation systems

A Smoke and Heat Exhaust Ventilation Systems (or SHEVS) is a widely applied technique to extract smoke and heat

from any building in fire conditions, whether it is by means of mechanical or natural ventilation. Such a system can

prevent the spread of smoke throughout the building, making it safer for occupants to evacuate the premises and

avoiding flash-over situations by removing heat from the smoke and hot combustible gases.

In order to design an effective system, we need to calculate the amount of smoke that can be reasonably expected

when a fire should occur. Therefore, a design fire and scenario is proposed, usually based on a risk analysis to

estimate the potential fire size and fire spread, but also the location of the fire source, the nature of combustible

materials and the geometry of the building have an effect on the smoke formation and propagation.

For designing a SHEVS, different standards or codes of good practice can be consulted, each of them based on

their proper assumptions, mathematical models and empirical formulas. In Belgian legislation, two standards are

most commonly used: the Belgian NBN S21-208-1 and the European CEN/TR 12101-5. However, when an atrium

is involved or the outflow from an adjacent fire room, the Belgian standard does not cover these calculations and

we are referred to use the CEN. This standard contains a well-documented procedure on designing a SHEVS, when

there is outflow of smoke from an adjacent fire room into an atrium. The calculation procedure is based on the

technical report BR 368, that follows a rather complex, seven-step calculation method for defining the mass flow of

an uprising smoke plume in an atrium.

Objective of the study

The use of these design specifications in professional experience, taught us that this standard tends to be on the

conservative side. In itself, it is of course not a problem to be on the safer side and to have some safety factors

included, but it is our belief that the CEN/BRE-method has a very conservative approach and presents an

exaggeration in both the safety factors as final design.

The objective of this study is to make a comparison between the CEN/BRE-calculation method and a ‘real-life’ CFD-

analysis, using the well-known and widely accepted software package FDS, to see if the manual calculation has a

too conservative approach to the SHEVS design and to check de applicability of CFD/FDS in SHEVS design.

In both cases we will be looking at the mass flow rate of the smoke at ceiling level, where the smoke leaves the

building. This is the main parameter on which the design of a SHEVS is based and that is why we will be comparing

both values.

Design scenario

As stated before, we need to create a scenario, usually based on a fire risk analysis, which contains a description of

the building geometry and the parameters that define the design fire. In order to make a relevant comparison

between the mathematical and modelling calculations, we need to define exactly the same geometry and design

fire for both procedures.

The geometry of the construction is therefore kept rather simple and consists of a three-level building, with a

central atrium and rooms on both sides of it, mutually connected by a 2m wide balcony, with a 1,5m high

balustrade. Each floor has three rooms on each side of the atrium, each of them connected to the atrium with a

door opening of 3m high and 2m wide.

Variations on this design are proposed and calculated in later stages of this project, but this design and geometry is

the starting point for the largest part of the work.



To get the worst-case scenario, the design fire was put in the middle room on the lowest floor. This will create the

biggest rise-height of the smoke plume into the atrium and will therefore generate the largest mass flow rate at the

ceiling level. In both cases, the design fire was taken from the CEN-standard and has the following characteristics:

• Fire area: Af = 5m²

• Fire perimeter: P = 9m

• Heat release rate (per unit area): qf = 625kW/m²

• The total heat release rate (HRR): Q = 3.125kW

This is an assumption used in the European standards for a fire in an office or a retail shop, equipped with quick

response sprinklers.

Figure 1: Building geometry and design fire location

CEN/BRE Calculations

The calculations as defined in the European standard and the BR 368 technical report, is a rather complex, seven-

step procedure, which is well-documented and explained step-by-step in both documents. These phases describe

the different steps in the total movement of the smoke plume, from fire source to ceiling vent. The movement is

divided in three major zones:

• The horizontal movement out of the fire room and (if present) underneath the balcony.

• The rotational movement around the spill edge, where the plume changes over a 90° direction.

• The vertical rising of the spill plume over the total height of the atrium.

The seven phases are shortly mentioned here, but fully described in this document, with explication of the

assumptions, standard values, used formulas and constants.

• Phases 1: Determination of convective HRRC and mass flux

This is the starting point where the mass flow in the fire room is determined, using the design fire

characteristics and the room dimensions.

• Phase 2: The smoke layer underneath the balcony

This is the result of the outflow out of the fire room, underneath the balcony. The most important factor here

is the presence of a downstand. A downstand will lead to more entrainment, but a lower horizontal

momentum, the absence of a downstand will do the exact opposite.

• Phase 3: Mass flux after the spill edge

This is the phase where the oncoming smoke layer changes direction from horizontal movement to vertical

rising plume, curling around the edge of the balcony.



• Phase 4: Determination equivalent Gaussian source term

In this phase, we make a correction for the virtual fire source, from where the vertical rising plume is supposed

to start. Once the plume is forming, it rises towards the ceiling, entraining air from the accessible sides of the

plume. Therefore, we distinguish two types of plumes in this phase: an adhered or single-sided plume and a

free or double-sided plume. Each of them uses a different entrainment coefficient in the calculations, leading

to a different final result. The double-sided plumes are completely surrounded by air and therefore have a

larger smoke mass flow in the end. Adhered plumes however, are only accounted for roughly half the plume

volume and a correction factor of 2 is incorporated in the calculations.

• Phase 5: Entrainment in rising plume

This is the phase where the entrainment over the complete height of the atrium is calculated. Main factor here

is the entrainment coefficient α, depending on the type of plume we’re considering, as explained in the

previous phase.

• Phase 6: Entrainment at the free plume ends

At the edges of the plume more ‘free surface’ is available for entrainment an in contact with the air. In this

phase, we make an extra calculation for the extra mass flow generated in these ends.

• Phase 7: Modification of Gaussian source term

This phase is only used when it concerns an adhered plume and forms a correction on the factor 2 we

incorporated in phase 4.

Each step builds further on the previous and amounts to a certain total mass flow at a pre-defined height.

CFD/FDS-Modelling

Computational Fluid Dynamics (CFD) is a modelling technique in which the flow of fluids is described and predicted

by numerically solving the Navier-Stokes equations, which describe the equilibrium of a fluid in motion. Since

smoke can be characterised as a thermally driven, slow-speed, fluid in motion, it can be modelled in a CFD

software environment, given the implementation of the correct physical properties and parameters for the

geometry, the materials and the fluids.

Whenever a CFD model is created, the geometrical space and its surroundings is discretised using a 3-dimensional

grid, or mesh, composed of individual cells. On the edges of each of these cells (also called control volumes) the

software solves the equations for:

• Conservation of mass

• Conservation of total momentum

• Conservation of energy.

When applied to a fire situation, this translates roughly to what a fire creates in mass (particles yield, unburnt

products and soot) and energy (heat release rate, combustion energy and temperature rise) and what the

environment supplies (fresh air, other particles, lower temperatures) is conserved within the system. In short: what

goes in, must come out. These equations are solved for every individual cell, for discrete periods of time, thusly

creating a dynamic solution at different timesteps.

The software used in this project is FDS 6.6.0, a well-known and widely distributed package developed by the

National Institute for Standards and Technology. For this project, we will be using a combination of three packages:

PyroSim, FDS and SmokeView.

• Pre-processor: Building the model using PyroSim

The scenario, geometry and design fire we’ve established for the manual calculations must be repeated as

closely as possible in the modelling software I to be able to compare the results in a relevant way. For this

purpose we use PyroSim, a graphical interface to create the needed FDS-code in an easier and more hands-



on approach. Here we will also setup all parameters needed for the materials, the geometry, the fire source,

the combustion and the actual modelling that will be done by the processor.

• Processor: Calculations using FDS 6.6.0

This is the solver of the Navier-Stokes equations, according to the parameters we’ve put in during the pre-

processing, using the principle of Large Eddy Simulation (LES), for the modelling of the small-scale turbulence

in the smoke. The key-element here is the mesh-size. This will determine the detail of the results, but also the

computational capacity needed to solve the balance equations.

• Post-processor: Results using SmokeView

SmokeView is an interface that allows visual representation of the matrices of numbers that are generated by

the solver in the form of graphs, pictures and time-step generated videos. In the pre-processor, we needed to

define the quantities, values and parameters we want visualised, the post-processor shows us the results.

Figure 2: Output of the generated smoke in one of the executed models

A range of models, each with their own specifications and variations in measuring techniques have been tested and

compared with the results from the manual calculations, leading to some surprising results.

Conclusions

In the document, we will show that the initial assumption, that the CEN/BRE-method is too conservative, is only

partially true. For some of the models, where the geometry is equipped with a balcony, we see that the FDS-model,

which we assume approximates reality, shows a smaller mass flow rate than what we calculated with the CEN/BRE-

method. A difference of 5% to 15% is observed.

When there is no balcony present however, and we are dealing with a single sided plume, we see the exact

opposite and the CEN/BRE-method leaves us with a shortcoming of 10% to a staggering 40%.

So, the most important conclusion we must draw here, is that a lot more modelling and matching those models to

live fire tests should be done before we can blindly use one method or the other in design of a SHEVS.



Table of contents

1 Introduction 1

1.1 Fire safety in buildings 1

1.2 Legislation, standards and codes of good practice 1

1.3 Smoke and heat exhaust ventilation systems 3

2 Objective of the study 5

3 Design scenario 6

3.1 Goal of the scenario 6

3.2 Geometry of the building 7

3.3 Design fire 8

4 Technical report CEN/TR 12101-5 12

4.1 Principles 12

4.2 Design fire 12

4.3 Fire room 12

4.4 Presence of a balcony or canopy 13

4.5 Rising line plume 13

4.6 Fresh air supply 14

4.7 Smoke reservoir and exhaust 14

4.8 External influences 15

4.9 Validity of CEN 15

4.10 Design methodology BR 368 15

5 CEN/BRE Calculations 17

5.1 Summary of starting points 17

5.2 Phase 1: Determination of convective HRRC and mass flux 17

5.3 Phase 2: The smoke layer underneath the balcony 20



5.4 Phase 3: Mass flux after the spill edge 20

5.5 Phase 4: Determination equivalent Gaussian source term 22

5.6 Phase 5: Entrainment in rising plume 23

5.7 Phase 6: Entrainment at the free plume ends 28

5.8 Phase 7: Modification of Gaussian source term 29

5.9 SHEVS design 29

5.10 Comparison with NBN S21-208-1 31

6 Principles of Computational Fluid Dynamics 33

6.1 Computational Fluid Dynamics 33

6.2 Fire Dynamics Simulator 33

6.3 Large Eddy Simulation 34

6.4 FDS Solver 35

7 FDS Pre-processor: Building the model 36

7.1 Software: PyroSim 36

7.2 Geometry 37

7.3 Materials 39

7.4 Design fire 40

7.5 Mesh 42

7.6 Desired results 48

8 FDS Processor: Calculations 54

8.1 Software: FDS 54

8.2 Properties and settings 54

8.3 Running the program 55

9 FDS Post-processor: Results 57

9.1 Software: Smokeview 57

9.2 Various models and techniques 57



9.3 Models 1 to 6: Visual results 59

9.4 Model 7: Single-point detection 60

9.5 Model 8: Multiple-point detection 61

9.6 Models 9 to 11: Area integral 62

9.7 Model 12: Area integral over smaller zones 65

9.8 Model 14 and 15: Sensitivity study 68

9.9 Models 16 to 18: Variations 72

9.10 Models 20 to 23: Mass Flow + 79

9.11 Temperature profiles 80

10 Conclusions & Recommendations 84

10.1 Comparison of results 84

10.2 Recommendations: Future research to be done? 85

10.3 General conclusion 86

11 Referenced works 87

11.1 Standards 87

11.2 Technical reports 87

11.3 Course notes 87

11.4 Websites 87



Symbols and abbreviations

BRE Building Research Establishment

CEN Comité Européen de Normalisation

CFD Computational Fluid Dynamics

FDS Fire Dynamics Simulator

FSE Fire Safety Engineering

HRR Heat Release Rate

HRRPUA Heat Release Rate Per Unit Area

NBN Bureau voor Normalisatie

NIST National Institute of Standards and Technology

PS PyroSim

SHEVS Smoke and Heat Exhaust Ventilation System

SV SmokeView

TR Technical Report

All symbols used in the equations are directly from either CEN/TR 12101-5 or BRE 368 and are specifically

explained in the appendices and, where needed, in the text of this document.


by means of CFD modelling with FDS 6 Page | 1

1 Introduction

1.1 Fire safety in buildings

Within the field of Fire Safety and Fire Safety Engineering, there are two main categories of fire protection systems

that can be used to prevent fires, to prevent fires from spreading too fast or becoming too large and to extinguish

fires: active and passive systems.

Passive systems are, in general, only designed to prevent fires from spreading to other buildings or compartments

or to protect the integrity of a structure. This is mostly obtained using fire doors and fire walls, dampers,

intumescent paints and coatings, fire retardant or fire proof materials and so on. When installed according to the

application prescriptions and used correctly, these systems will always function correctly, as they do not need an

extra operation to be activated.

This as opposed to active fire protection systems, for example sprinklers, SHEVS or fire detection, which need an

external activator, like fire pumps, electricity, flow or other switches to be fully functional. These systems therefore

have a higher failure rate, as there are more components involved. On the other hand, active systems usually do

more than just prevent fire spread. Some sprinkler systems are designed to actually extinguish the fire and smoke

and fire detection is designed to alert occupants and the fire department of the imminent danger. It is in this

capacity that we find the added value of active systems on top of the passive protection or even as replacement for

such systems.

All these methods are in place to limit the effects of a fire inside a building, with regards to life safety, property

protection, business continuity, damage (and cost) reduction, safe intervention and every other objective that might

be of interest to everyone involved.

1.2 Legislation, standards and codes of good practice

Each of these systems, both active and passive, need to be designed, fabricated, installed, maintained and

inspected according to methods and standards that guarantee their functionality and prove that the installations

meet the requirements, demanded by legislation, the architects, designer, fire department, insurance company or

fire risk engineer.

Some of these standards are obligatory when they are included in legislation, others are mandatory because they

are demanded in contracts, such as insurance policies and others are just a ‘code of good practice’ on which

everyone agrees and accepts the design criteria as being sufficient.

1.2.1 Legislation

The Belgian building regulations (Royal Decree of 7 July 1994 setting out the mandatory basic standards applicable

to new buildings in the field of explosion and fire prevention, including amendments) make some references to

certain NBN standards.

Whenever a fire-resistance is mentioned, they should be defined according the following methods:

• NBN EN 1363: Fire resistance tests: General requirements, Alternative Procedures and Verification.

• NBN EN 1364-x: Fire resistance tests for non-loadbearing elements: Walls, Ceilings and Curtain Walling.

• NBN EN 1365-x: Fire resistance tests for loadbearing elements: Walls, Floors and Roofs, Beams, Columns,

Balconies and Walkways and Stairs.

• NBN EN 1366-x: Fire resistance tests for service installations: Ducts, Fire Dampers, Shafts, Raised Floors, ...



• NBN EN 1634-x: Fire resistance tests for door and shutter assemblies: Fire Doors and Smoke Control Doors.

• NBN EN 13381-x: Test methods for determining the contribution to fire resistance of structural members.

• NBN EN 13501–3: Fire classification of construction products and building elements.

If a sprinkler installation is used to prevent flashover between compartments, they should be designed according to

the criteria in the following standard:

• NBN EN 12845: Fixed firefighting systems. Automatic sprinkler systems. Design, installation and maintenance.

However, when a sprinkler installation is required to protect a storage room specifically for trash and debris, the

design must be done according to a different standard:

• NBN EN 12259-1: Fixed firefighting systems. Components for sprinkler and water spray systems.

For the design of a SHEVS, according to Belgian legislation, a Fire Risk Engineer is free to choose any design

criterion he wishes, since every SHEVS is verified and must be approved by the Derogation Committee of Internal

Affairs. However, when it concerns a SHEVS specifically for an industrial building, it should be calculated according

to the Belgian standard:

• NBN S 21-208-1: Fire protection in buildings - Design and calculation of smoke and heat extraction installations

Part 1: Large single storey spaces without partitions.

These are just a few examples of mandatory standards as mentioned in Belgian (Federal) legislation. There are a lot

more, usually concerning fire safety systems or components of those systems like elevators, pipes, ducts, electrical

cables and so on.

1.2.2 Non-legislative mandatory standards

On this topic, there are no specifics to be mentioned, because these demands are usually included in contracts or

other agreements between the designers and the stakeholders. An insurance company, for example, may ask their

clients to protect their buildings and installations with a sprinkler designed according to different standards, if they

believe it will protect the investment better. A lot of USA-based companies will need to follow NFPA-regulations for

the protection of their facilities, even though they are not mandatory by legislation.

1.2.3 Codes of good practice

Most of the active systems in buildings are not mandatory. When a building is passively protected and well

compartmented, no additional systems are required by (Belgian) law, although this depends on whether one is

designing for a residential, commercial or industrial building. Some specific buildings, for example a hospital, a

hotel or a high-rise apartment building, are required to have an automatic detection system and a sprinkler

installation. Whenever a building does not meet the legislative requirements, active systems can be used to obtain

an equivalent fire safety level and to prove that equivalence in the derogation request with the Ministry of Internal

Affairs.

When these systems are put in place, they are usually designed according to a certain standard or code of good

practice. These are standards and technical reports, written by a variety of stakeholders (government, fire

department, study groups, certification companies, …) which are generally accepted as being a valid installation

guide for certain fire protection systems.

Examples of this are the guidelines written and published by WTCB, regarding the proper placement of fire door

and -dampers, the installation of evacuation stairs, the rules to follow when evacuating persons with reduced

mobility, the placement and design criteria for wall hydrants, based on the risk and size of the building, and so on.

In this work, we will take a closer look at one specific European standard, which is in fact a technical report, used in

the design of smoke and heat control systems, more specifically for atria:



• Technical Report CEN/TR 12101 - Smoke and heat control systems - Part 5: Guidelines on functional

recommendations and calculation methods for smoke and heat exhaust ventilation systems.

1.3 Smoke and heat exhaust ventilation systems

1.3.1 Smoke effects

Contrary to popular belief, it is usually not the flames but rather the smoke and hot combustion gases that form the

most dangerous part of a fire. Smoke can be lethal because of the combination of three main aspects:

• Poisoning due to inhalation of carbon monoxide and hydrogen cyanide. This can very quickly lead to

incapacitation and loss of consciousness and is therefore the primary cause of death when it comes to victims of

indoor fires.

• Irritation, specifically of the respiratory system, caused when combustion products like sulphur oxides, hydrogen

chloride and hydrogen fluoride react with water vapour to form sulfuric, hydrochloric and hydrofluoric acid,

which are corrosive to skin, eyes, lungs and even materials.

• Thermal damage due to radiation and convection of the hot smoke and gases. This thermal damage is not

limited to personal injuries. When the temperature of the smoke layer, containing hot gases and unburnt

reaction products and combustibles, reaches critical values, the fire room can go to ‘flash-over conditions’,

meaning that all combustible materials in the vicinity of the fire automatically ignite due to the radiation from

the soot and other particles in the smoke layer.

We specify ‘indoor’ fires in closed compartments, because when smoke gets out in the open air it rises up and is

quickly diluted and carried away, greatly reducing the negative effects. It is therefore of great importance to design

systems that can easily and quickly evacuate large amounts of smoke and hot gases out of a burning building,

before it can cause severe injuries to the occupants or grave damage to the stability or integrity of the building.

1.3.2 SHEVS design

Smoke and Heat Exhaust Ventilation Systems, or SHEVS, are active fire protection systems, which are installed to

evacuate hot smoke and combustion gases from enclosures and compartments. This can be done naturally, using

the thermal buoyant force of the smoke plume to push the smoke out through the ceiling vents, or mechanically,

using fans to create under pressure near the vents so that the smoke and hot air is drawn towards it by a pressure

gradient.

These systems are generally activated in combination with automatic fire detection, in order to get a quick response

as opposed to manual activation by human intervention. The smoke hatches in the ceiling are usually electrically or

pneumatically activated in case of natural ventilation. The fans used for mechanical extraction are of course

electrically driven.

Figure 1: Mechanical versus natural smoke extraction

How does one design such a system and what are the specifications with which it must comply? These questions

are answered in the various design standards that are available. As stated before, we will take a closer look to one



of these standards, namely: Technical Report CEN/TR 12101 - Smoke and heat control systems - Part 5: Guidelines

on functional recommendations and calculation methods for smoke and heat exhaust ventilation systems.

This European standard explains in a very thorough and well-documented way, how to design a SHEVS, starting

from the choice of the design fire, specifications of the geometry and validity of the calculations. It then guides you

step by step through the calculations and formulas used to obtain an estimate of the expected amount of smoke

that needs to be extracted by the SHEVS you are designing. For a part of the calculation, the CEN refers to another

technical report called BR 368, written by the Building Research Establishment (BRE) that describes in a very

detailed manner the calculation of a smoke plume. Once this amount is known, the dimensions of the installation

can be determined.

Apart from the calculation methodology, the standard also includes rules for maintenance, installation guidelines,

points of attention, common mistakes and a look at different styles of hatches that are allowed and those which are

not.



2 Objective of the study

When using the CEN 12101 standard in manual calculations for SHEVS-design, there are always some assumptions

to be made regarding the design fire, the flow of the smoke, the interaction with the surrounding building

(obstacles, walls, openings, …), the mathematical model that is used to approximate the turbulence and the air

entrainment in the smoke and other factors.

Each of these factors used in the calculations or assumed as a starting point, introduces an uncertainty in the

results. Therefore, a few safety factors were introduced in the procedure, or rather, exaggerations regarding some

of the parameters, so that each calculation would be a somewhat conservative approach towards the design,

making sure that every design meets the criteria.

The question I will try to answer in this project is: just how conservative is the CEN/BRE method, compared to a

‘real’ situation modelling?

To answer this question, I created a scenario, with a standard and rather simple atrium-based geometry and a

design fire as described in the CEN standard. The so-called ‘real situation’ will be the result of a CFD-analysis of the

same building and scenario with parameters chosen in a manner so that the model will reflect the same starting

points as the manual calculation, according to CEN/BRE.

What we are exactly looking for is the difference in total mass flow rate of the smoke/hot air/combustion gases at a

certain height (we will be taking the ceiling vent as a reference height) between the mathematical method, based

on empirical formulas and assumptions on one side and the FDS modelling, based on the solutions of the physical

laws of conservation of mass, energy and momentum on the other side.



3 Design scenario

3.1 Goal of the scenario

The procedure described in CEN 12101-5 is used as a design method for a SHEVS. If we can calculate the amount

of smoke that is formed at a certain height, considering a smoke layer depth, serving as a smoke buffer or

reservoir, we can derive the minimal dimensions necessary to evacuate that amount of smoke. When the mass flow

entering the smoke layer is equal to the amount of smoke extracted from the building, either with natural or

mechanical ventilation, we get an equilibrium at which the smoke reservoir stays stabilized at a certain predefined

height that is considered safe for evacuation of occupants or intervention of the fire department.

In this project, however, we are not designing a SHEVS, but rather analysing the calculation method itself. Once the

mass flow rate is determined, mathematically or by means of the CFD model, the results are compared to see if the

CEN/BRE method can be reproduced by the model, or to see if the BRE is a too conservative approach to the

design of a SHEVS, leading to oversized and expensive systems.

For this scenario, we will not choose a smoke-free height based on the safe evacuation of the occupants and we

will not design the ventilation openings to be as small, and therefore as economical, as possible. We will simply

make an opening large enough for the entire mass flow to pass unobstructed, without creating a smoke reservoir

under the ceiling. This will lead to a rather large amount of fresh air entering the building through the same

opening, which might disrupt the plume flow and alter the results. We will need to verify these steps every time to

check the validity of the results.

To make a valid comparison between a mathematical method based on assumptions and empirical formulas and a

model using physical equations, we will need to define a scenario with a fixed set of references. This scenario

describes the geometry of the building, the size and location of the design fire and the parameters attributed to the

building materials and the surroundings.

There is of course a limit to the number of parameters one should consider when using the mathematical method.

Calculations are based on the parameters that mainly influence the entrainment of air and create an additional

volume of smoke. These parameters are:

• The size (surface and perimeter) of the design fire;

• The heat release rate (HRR) of the design fire;

• The height of the fire room;

• The dimensions of the outflow opening towards the atrium;

• The presence or absence of a downstand;

• The presence or absence of a balcony or canopy;

• The height of the atrium and of the rising smoke plume.

When the values for these parameters have been determined, they can be used to fill in the basic set of equations

as described in the CEN standard and, making some assumptions for a couple of constants and other values,

calculate the mass flow rate of smoke at a certain height in the atrium.

Some important physical parameters influencing the mass flow rate which are not considered in the mathematical

method are:

• The used building materials:

This will have an influence on the heat loss to the surroundings and will more or less lead to heat being

radiated towards the fire room.



• Fire spread and fire growth:

The BRE method calculates an equilibrium state, where the fire has already reached its maximum potential. In

reality, the fire will start small, with a little smoke developing and steadily growing following, for example, an

αt²-curve until it reaches its peak in HRR.

• Soot yield and smoke formation:

The creation of soot is not considered when calculating according to the BRE method. The mass flow that is

obtained from this method is, in fact, the mass flow of hot air. In reality, a certain amount of soot is generated

which will change the density of the air and which will have an influence on the temperature of the air/soot

mixture due to radiation of the particles.

• Assumptions based on empirical research:

Most of the parameters and formulas in the BRE method are based on empirical research, which means they

approximate a real-life situation, but they are in fact a mathematical average of a (sometimes limited) series of

experiments, whereas the CFD-model uses equations based on the laws of physics, the conservation of mass,

energy and momentum.

• Various external influences:

The mathematical method calculates in ‘perfect conditions’, this means, among other things, that there is no

influence of wind, there are no pressure effects, there is only one ambient temperature throughout the entire

calculation which is valid for the air, the building and the outside environment, stratification is not considered,

the interaction with sprinklers is ‘included’ in the size of the design fire, but the actual effect of a sprinkler

installation on the rising smoke plume is not.

There are several other factors that alter the flow of the smoke by introducing extra turbulence or that modify the

temperature and therefore change the thermal buoyant force of the uprising smoke. All these factors can be of

greater or minor influence on the rising plume and on the efficiency of the SHEVS we are designing.

3.2 Geometry of the building

The geometry is kept rather simple and consists of a three-story building, with a central atrium, following the

principle layout of a small, standard shopping centre or office building. Around the atrium, shops or offices are

located, each with a door leading towards the balcony in the atrium.

Figure 2: Building geometry – Front view

The footprint of the building is 30m by 41m, with 10m for each ‘store compartment’ and 20m for the atrium. The

walls in between each compartment have a thickness of 0,25m. A large vent or open roof structure is created in the

4m

4m

4,25m

13m 12,75m



ceiling which measures 20m by 20m. This is large enough to make sure that all smoke will leave the building and

there is no build-up of a smoke reservoir under the ceiling.

The ground floor and first floor have a height of 4m, the top floor has 4,25m, the floors and the ceiling have a

thickness of 0,25m, leading to a total building height of 13m, and a ceiling/atrium height of 12,75m. This is the

height at which we will measure and calculate the mass flow rate of the air/smoke mixture as it passes through the

opening in the ceiling.

Figure 3: Building geometry - Fire room close-up

The fire room is a 10m by 10m by 4m room, located at ground level, in the middle of the left side of the building.

Basically, every floor is divided in three such rooms, but this is of no influence on the model or the calculations, so

these rooms are not individually defined. Only the fire room has clear boundaries.

The fire source is located in the middle of the room, the specifications regarding the design fire are in the next

paragraph. The opening towards the atrium is represented by a 3m by 2m door. This leaves a 1m free space above

the opening, which will serve as a ‘downstand’ in the primary design. The balconies or walkways are all similar, 2m

wide and have a balustrade of 1,5m high.

3.3 Design fire

Since we are analysing and comparing the results of the European Norm, CEN 12101-5, it is only logical to follow

the design specifications as stated in this standard, even though any design fire can be chosen, given that it has a

logical heat release versus fire size ratio. CEN 12101-5 gives a range of ‘default values of design fires’ based on the

average fire load in some typical rooms, considering whether the room is sprinklered and with which kind of

sprinkler system. This is where the aforementioned influence of a sprinkler system comes into play. When a room is

sprinklered, it is considered to limit the fire growth, so instead of taking into account the entire surface of the fire

room, we will only use a partial fire area, but with the same heat release rate per unit area. The sprinkler will

however not lower the temperature of the uprising smoke or interact with the soot particles.

The design fire is chosen as a ‘default’ fire within a retail compartment that is equipped with quick response

sprinklers. This gives a design fire with the following characteristics:

4m

10m

10m

3m

1m

1,5m

2m 2m



• Fire area:

Af = 5m²

• Fire perimeter:

P = 9m

• Heat release rate (per unit area):

qf = 625kW/m²

• The total heat release rate (HRR):

Q = 3.125kW

The CEN standard only allows for steady

state situations, so the calculation yields, the

mass flow of smoke into the smoke layer at a

certain height, when the fire burns at full

capacity at an HRR of 3.125kW.

In reality, the fire needs a certain time to

obtain that maximum potential and this time

depends on the fire growth coefficient α,

provided we assume a quadratic fire growth

which follows that the fire growth follows an

αt²-curve.

A couple of default fire growth coefficients, their corresponding curves and some typical combustible materials that

show such a fire growth and some typical functions where these growth rates are applicable, are shown in the table

below.

Table 2: Default fire growth rate coefficients

Table 1: Default design fires - from CEN/TR 12101-5



Graph 1: Fire growth rate curves

According to these graphs, an ordinary fire in a retail compartment would be defined as a 3,125 MW fire with a

‘medium’ growth. To have a more conservative approach we might define the fire as being ‘fast’, to take into

account larger amounts of clothing and fabrics, decorations and other, more combustible, materials. Such a fire

would reach its peak-HRR after about 260 seconds.

However, since the mathematical method takes no fire growth into account, but only works at steady state

conditions, it is not necessary to take this 260 seconds delay into account. In the composition of the FDS model, we

will see that we can use a custom value for α so that we can achieve an extremely fast growth, so that the peak

value will be reached in 1 symbolic second.



Manual calculation method



4 Technical report CEN/TR 12101-5

4.1 Principles

For the manual calculation method, we will be following the guidelines and formulas as prescribed in the Technical

report CEN/TR 12101 - Smoke and heat control systems - Part 5: Guidelines on functional recommendations and

calculation methods for smoke and heat exhaust ventilation systems.

In Belgian regulations, CEN 12101-5 is a non-mandatory standard used for the design of SHEVS. This procedure is

followed especially when atria are considered, because the Belgian standard for the design of SHEVS (NBN S 21-

208-1) does not cover outflow of smoke into an atrium, but only a vertical rising smoke plume in a single, large-

space volume. So, the additional entrainment along the spill edge and a possible downstand, balcony and outflow

opening, are not considered.

According to CEN-regulations, there are seven main components to consider in a SHEVS design, as indicated in the

figure below.

Figure 4: Principles of a spill plume in an atrium – CEN 12101-5

4.2 Design fire

The design fire is chosen according to the default table of design fire characteristics as mentioned in the previous

chapter. For this project, the design fire does not need to be based on a risk analysis, because we are not actually

designing a smoke ventilation system. It is sufficient to define a ‘realistic’ fire and use this in both the mathematical

calculations and the CFD-model.

4.3 Fire room

The outflow of smoke from the fire room follows from the design fire, the dimensions of both the room (ceiling

height), the opening towards the atrium and the presence or absence of a (deep) downstand. An empirical

constant is attributed to the depth of a downstand, when it is present, usually between 0,6 and 1,0.



4.4 Presence of a balcony or canopy

If a balcony is present, a ‘new’ smoke layer is formed, once the smoke flows out of the fire room. In the absence of

a downstand, this will have more or less the same layer thickness as inside the room. When a downstand is present,

the extra turbulence created when the smoke curls around it will cause extra entrainment of fresh air surrounding

the smoke plume. This, in turn, will lead to a thicker smoke layer underneath the balcony.

Once the smoke arrives at the spill edge, being the edge of the balcony, it will make a rotational movement, from a

horizontal flux to the vertical flux of the rising plume. This creates additional turbulence and entrainment and will

lead to a bigger smoke plume.

One of the major factors defining the amount of turbulence, is the horizontal velocity of the smoke: a fast-flowing

smoke layer will ‘shoot past’ the spill edge, creating more turbulence, whereas a slower moving smoke layer will

have a smaller momentum and curl around the spill edge, with less additional turbulence. The presence of a

downstand at the opening out of the fire room will in fact decrease the momentum of the oncoming smoke layer,

but will generate turbulence at the point of outflow. If there would be a significant downstand at the spill edge, this

would need to be considered as well. The depth of the balcony also has an effect on the entrainment, as the smoke

gets caught under the above balconies more easily when they are ‘shallow’, creating more turbulence, more

entrainment and thus more smoke volume. The under pressure as a result of the entrainment, leads to so-called

‘smoke logging’. CEN takes a balcony depth of 2m as a limit, but this has been established empirically and is

strongly dependent on various factors.

Figure 5: Shallow vs Deep balcony

4.5 Rising line plume

The rising spill plume in the atrium, after the rotation point, follows a ‘standard pattern’ of entrainment, meaning

that it is mainly dependent on the smoke layer height. CEN does make a difference between an adhered plume or

a free plume regarding the entrainment coefficient α. The idea is that a so-called ‘adhered plume’, rising along a

facade, ‘sticks’ to the facade and therefore has less contact with the surrounding air, compared to a free plume,

which is completely surrounded with fresh air. This will lead to less entrainment in the adhered plume.



Figure 6: Free vs Adhered plume

4.6 Fresh air supply

Fresh air supply is important for the efficient outflow of the smoke and hot gases. It replaces the outflowing hot

smoky gases and is needed to avoid an under pressure in the atrium. The openings through which the fresh air is

supplied should be well-dimensioned and the total air supply area should be large enough, so that the velocity of

the entering air does not exceed 5 m/s. Otherwise it will generate disturbances in the line plume and the smoke

reservoir.

4.7 Smoke reservoir and exhaust

As stated before, the mathematical calculations are for the design of a steady-state situation, where the inflow into

the smoke layer equals the outflow out of the exhausts. These can be natural (vents) or mechanical (fans).

The reason we create a certain smoke layer beneath the ceiling, called the smoke reservoir, is that the build-up of a

stabilized smoke layer reduces the total area of exhausts needed, because of its buffer capacity. Furthermore, the

smoke buffer improves the efficiency of the outlets, as they remove only smoke and no fresh air, so-called

‘plugholing’.

Figure 7: Principle of 'Plugholing'



For this project, we are interested in the mass flow at a certain height. We will take this height to be the bottom of

the smoke layer. So, we are looking at the mass flow ‘IN’ in both mathematical and CFD-procedures. The actual

layer thickness is of no consequence for this study, because it only influences the number of exhausts needed to

maintain a stabilized smoke layer and the maximum surface area of each vent to avoid ‘plugholing’.

4.8 External influences

When designing an actual SHEVS, there are a lot of external influences that need to be considered.

Wind influence is by far the most important, as it can disrupt the functionality of a vent completely, if it is not

handled correctly. High wind speeds can create an overpressure on top of the vents, making it harder for the

smoke to exit or even push the smoke back into the building, depending on the thermal buoyant force pushing the

smoke out. This occurs easily in higher buildings, as the smoke cools off a great deal before reaching the ceiling

and therefore has less buoyant force. In that case it is needed to install wind breakers or other obstructions that

prevent the wind from creating overpressure over the smoke hatches. Alternatively, the hatches can be placed in

such a manner that the wind creates negative wind pressure. This can even improve the functionality of the smoke

vents. But this implies that the direction of the wind must be a known and considered constant throughout the

entire period.

Snow and other loads can cause the smoke hatches to become unable to open on detection. This is not something

that can be resolved in the calculation of the hatches, but needs to be included in the design and layout of the

hatches.

There are several other factors influencing the correct operation of smoke vents, but since we are not designing the

vents in this project, these external influences are not taken into account. Roughly, we can state that our field of

interest lies within the building and our calculation stops before the smoke reaches the vents.

4.9 Validity of CEN

The CEN standard can be used for the SHEVS design applicable for a whole range of buildings, going from single-

storey buildings, mezzanines, warehouses with or without palletized stacking, to open structures, multi-storey

shopping malls, buildings equipped with an atrium and even car parks.

It is stated, however, that the standard is not valid when it concerns a fire room which is beyond flash-over

conditions, meaning that it is fully involved in the fire. CEN sets the limit at a temperature rise of more than 550°C,

which is considered the critical flash-over temperature.

4.10 Design methodology BR 368

Every step of the basic calculations right up to the spill edge of the balcony is explained and well-documented in

the CEN standard, but when it comes to the detailed calculations concerning the entrainment of air in the spill

plume, the CEN refers to the BRE-method as explained in BR 368 - Design Methodologies for Smoke and Heat

Exhaust Ventilation, written and published by BRE.

The BRE-method consists of a rather complex seven-step calculation procedure. While both CEN and BRE are

similar at first, BRE has more detailed calculations for the entrainment in the uprising smoke plume in the atrium.

BRE uses correction factors for the effective rise height and velocity, takes into account the Equivalent Gaussian

Source and does not only include entrainment in the rising plume, but also in the plume ends, leading to a more

correct solution. The details of this calculation are explained in the following paragraphs.

BRE defines three distinct phases in the development of an uprising smoke plume, when it flows out of an adjacent

fire room into an atrium:



• The oncoming flow of smoke, from

within the fire room, through the

opening towards the atrium, taking into

account the presence of a downstand if

necessary, and underneath the canopy

or balcony if these are present. The

main components are the smoke layer

thickness and the dimensions of the

opening.

• The rotational movement of the smoke

as it curls around the spill edge.

Horizontal movement is transferred to

vertical movement as the smoke plume

starts to rise in the atrium. The main

component here is the smoke layer

thickness under the balcony and the

horizontal momentum, arriving at the

spill edge.

• The vertical rising spill plume in the

atrium with correction factors taken into

account for the mass flow, the heat flux,

the corrected rise height and the

Equivalent Gaussian Source.

Entrainment is not only considered in

the rising plume, but also at the free plume ends.

Each of these phases is calculated sequentially in different steps. Together these steps form the aforementioned

seven-step-method. In the next paragraphs, we will explain and execute the manual calculations, according to the

CEN / BRE combined method. In reference to the book “Design Methodologies for SHEVS”, we will be following the

procedure as explained in chapter 5, Smoke control on the storey of fire origin, for the first part, right up to the

mass flow at the spill edge. From there on, the calculations are explained in Annex E, User’s guide to BRE spill-

plume calculations, of the same book, describing the entrainment in the line plume once it enters the atrium.

Figure 8: Principles of a spill plume in an atrium - BR 368



5 CEN/BRE Calculations

5.1 Summary of starting points

The summary of the dimensions, design choices and assumptions in our building, are the starting points for the

calculation.

• The size of the design fire:

Af = 5m² (surface)

Pf = 9m (perimeter)

• The heat release rate (HRR) of the design fire:

qf = 625 kW/m²

Total Q = 3.125 kW

• The height of the fire room:

H = 4m.

• The dimensions of the outflow opening towards the atrium:

W = 2m (width)

h = 3m (height)

• The presence or absence of a downstand:

Deep downstand, with Dd = 1m

• The presence or absence of a balcony or canopy:

Balcony depth of 2m and a balustrade of 1,5m. This is however not included in the calculations.

Balcony height = 4m. This is of importance for the effective rise height.

• The height of the atrium and of the rising smoke plume:

Ceiling height, Hc = 13m

Smoke free height, Y = 12,75m (this corresponds with the bottom of the smoke reservoir).

These last dimensions mean that the smoke reservoir itself is only 0,25m thick, which is not a realistic buffer for an

actual SHEVS design. But since we’re only interested in the mass flow at the bottom of the smoke layer, we do not

need a realistic situation above the smoke layer.

All calculations are actually done in an excel sheet, but will be further explained where necessary.

5.2 Phase 1: Determination of convective HRRC and mass flux

To determine the mass flow out of the fire room, we need the size of the fire (P) and the dimensions of the room

opening (W and h). Two extra parameters are defined, namely Ce and Cd, which are respectively the entrainment

coefficient and the effective discharge coefficient. With these parameters, we calculate the mass flow, the

outflowing smoke layer depth and the average temperature of the smoke.



Table 3: Calculation of Phase 1 of the BRE-method

Ce depends on the amount of fresh air that can reach the fire and the smoke plume inside the fire room and is

therefore a direct consequence of the room geometry. Smaller rooms will lead to more turbulence and

entrainment. However, the values for Ce are empirically determined and the limit to what is considered a ‘large

room’ (dimensions are more than 5 times the fire diameter) are arbitrarily chosen. Since we are using a 5m² fire, it

has a 2,5m diameter. The room dimension (width) is 10m, which is smaller than 5 x 2,5m. Our fire room is

considered a ‘small room’, so we need to use a value of 0.377 kg/m(5/2).s for Ce.

Figure 9: Small fire room with restricted air flow

Cd, the effective discharge coefficient, indicates the amount of additional entrainment that occurs because of the

presence of a downstand at the outflow opening. If no downstand is present, Cd has a value of 1,0 and does not



contribute to more mass flow out of the opening. For what is considered a ‘deep downstand’, Cd is taken as 0,65 in

the following formula for the mass flow Mw.

𝑀𝑤 =𝐶𝑒𝑃𝑊ℎ3/2

[𝑊2/3 +1

𝐶𝑑(

𝐶𝑒𝑃2

)2/3

]

3/2

For the determination of the smoke layer thickness underneath the downstand (Dw), we need to execute a small

iteration. Dw is dependent on the Cd factor, but empirical research has shown that the jump between the values 1,0

and 0,65 is too large and that there should be a third value, set at 0,8. For this calculation, the coefficient is called

Cd0 to avoid confusion. First, we need to calculate Dw, using the following formula, with Cd0, initially set at 0,65.

𝐷𝑤 = 1

𝐶𝑑0

[𝑀𝑤

2𝑊]

2/3

This yields a value for Dw = 1,739 m. We need to check the validity of this value with the following conditions for

the actual depth of the downstand Dd (1m in our design):

• Dd = 0 (i.e. no downstand) or Dd < 0,25 x Dw We can safely ignore the downstand and take Cd0 = 1,0

• Dd > 2 x Dw This counts as a ‘deep downstand’ and Cd0 = 0,65

• Any intermediate case, where 0,25 x Dw < Dd < 2 x Dw Use the intermediate value for Cd0 = 0,8

For our design, we are in the intermediate case and we need to recalculate Dw, using the aforementioned formula,

but with Cd0 = 0,8 instead of 0,65.

In the final part of this phase, we need to calculate the temperature rise within the smoke layer, using the mass flow

and the convective heat release (Qw) from the design fire. For these calculations, we assume the convective HRR as

80% of the total HRR, as is mostly done for engineering purposes (α = 0,8).

𝑄𝑤 = 𝛼𝐴𝑞𝑓

The temperature rise in the smoke layer (θ) follows from the equation:

𝜃 = 𝑄𝑤

𝑀𝑤𝑐

Where c is the specific heat capacity of the smoke, taken constant at 1,010 kJ/kg.K. We get a temperature rise of

515°C, which is very close to what CEN sets as a limit for validity of the calculations. BRE mentions 600°C as a limit,

so we can continue the calculations, bearing in mind that we need to verify the temperature.

The mass flow leaving the room is determined as:

Mw = 4,806 kg/s



5.3 Phase 2: The smoke layer underneath the balcony

In a first assumption, we take the calculated mass flow from the previous phase and multiply it by 2, to incorporate

the extra entrainment from the downstand into the smoke layer. We call the new mass flow MB, to indicate the

location beneath the balcony. The factor 2 is again an empirical constant and seem rather exaggerated. Other

studies have shown that this value should be closer to 1,6.

The positive effect of this extra entrainment into the smoke is that the average temperature of the smoke layer

instantly drops. Mathematically it is divided by a factor 2, since the mass flow is multiplied by 2 and the HRR

remains the same. In reality, the temperature drop will be smaller.


The other variables calculated in this phase 2, are needed in case the smoke should be contained underneath the

balcony or canopy and cannot flow into the atrium. The smoke layer depth under the balcony, denoted Db, is the

minimal depth a smoke screen should have in order to capture the smoke underneath the balcony. Therefore, it

has no use for us in this project, as we want the smoke to flow and rise into the atrium.

The formula for Db uses the same discharge coefficient as before (Cd) if a downstand is present, perpendicular to

the flow of the smoke layer. Furthermore, it is dependent on the calculated mass flow Mw or MB, the ratio of the hot

gas temperature and the ambient temperature and the width between the channelling screens underneath the

balcony, used to guide the smoke to the extraction points. In absence of these channelling screens, we take the

width of the outflow opening for this value. If the balcony is not too deep, this is initially a reasonable assumption.

After some time, the smoke spreads longitudinally along the balcony and becomes a lot wider that the width of the

outflow opening.

From this phase, we remember that the mass flow has been doubled because of the presence of a downstand.

MB = 9,612 kg/s

5.4 Phase 3: Mass flux after the spill edge

In the next phase, we will enter the rotational part of the calculation as we are determining the mass flux over the

spill edge, denoted My.

It is in this phase that CEN refers to BRE and that in BRE we switch from chapter 5 to the Annex E, for further

explanation. In the appendices of this book, you can find the complete calculation sheet, with references to either

the BRE or the CEN or both.




Again, we start with the mass flow as determined in the previous step, being Mw or MB. Since we have a deep

downstand, we will continue with MB = 9,612 kg/s. Values for Qw and θw are calculated in the same manner as

before.

In this phase, a correction factor for the heat flux (KQ) and for the mass flux (Km) is introduced. These are

temperature-dependent values, but are usually taken as constants in most calculations.

KQ = 0,95 and Km = 1,3

With the correction factors and the average smoke layer temperature (θw) we can calculate the temperature

difference at the top of the smoke layer (θcw) and from there the actual temperature (Tcw), using the formula:

𝜃𝑐𝑤 = 𝜃𝑤

𝐾𝑚

𝐾𝑄

Tcw then becomes θcw + 298 K, as we assume the ambient temperature (T0) to be 25°C.

Then we need to calculate the smoke layer depth at the spill edge (dw). For this the following formula is used:

𝑑𝑤 = [3𝑀𝑤𝑇𝑐𝑤

2𝐶𝑑3/2

𝐾𝑚𝑊𝜌0√2𝑔𝜃𝑐𝑤𝑇0

]

2/3

Since we have an undisturbed outflow from underneath the balcony towards the atrium, we will take the

mentioned Cd as 1,0 (i.e. no downstand). The ambient air density is denoted by ρ0 and equals 1,225 kg/m³ and the

gravitational constant is of course 9,81 m/s².

Apart from the layer thickness, we also need to calculate the oncoming smoke layer velocity (v) and the horizontal

flux of potential energy (B) according to the following formulas:



𝑣 = 0,96𝐶𝑑𝐾𝑚

𝐾𝑄1/3

[𝑔𝑄𝑤𝑇𝑐𝑤

𝑐𝜌0𝑊𝑇02]

1/3

This formula can be simplified by filling in the constant values for K and be choosing Cd, depending on the

presence of a downstand. But since we are working in an excel environment, it is easier to use the general formula.

𝐵 = 𝜌0

2

𝜃𝑐𝑤

𝑇𝑐𝑤

𝑔𝑣𝑑𝑤2

B is expressed in W/m, where W is the potential energy content of the smoke layer relative to the void edge,

meaning that this energy is expressed per meter of spill edge width (not the depth of the balcony).

As a final step in this phase, the mass flow around the spill edge My is calculated:

𝑀𝑦 = 2

3𝜌0𝑊𝛼′ (2𝑔

𝜃𝑐𝑤

𝑇0

)1/2

𝑑𝑤3/2

+ 𝑀𝑤

With al parameters known, except for α’ which is an entrainment constant, empirically determined as 1,1 and W

which should be the width between channelling screens, but is now taken as the width of the outflow opening.

My = 27,363 kg/s

5.5 Phase 4: Determination equivalent Gaussian source term

It is important to point out here is that, B, Qw and My are immediately multiplied by 2 in the case of a single-sided

or adhered plume. This will form a correction on the Gaussian Source, by creating a ‘real’ and an ‘imaginary’ plume

half, where the ‘imaginary’ part lies within the facade of the atrium and the centre line coincides with it. At the end

of the calculations, the final result Mr will be divided by 2 again. Take note that, if this would be the case, the

entrainment factor α would be taken as 0,077 instead of 0,16 (see phase 5). In this specific case, we will be looking

at a free-flowing plume because of the presence of a large enough balcony, which is accessible on both sides for

the surrounding fresh air. This plume has a larger surface at which entrainment can occur and therefore creates

more volume (α = 0,16). The correction factor (x 2) for the Gaussian Source does not need to be taken into

consideration and we can continue with the values for B, Qw and My as calculated in the previous phases.

In a first step, Qw and My are converted to the corresponding parameters per unit of length. This characteristic

length is based on the channelling screen width, or in absence of such screen, the width of the opening towards

the atrium (W), which is 2m in this case. Qw (kW) becomes Q0 (kW/m) and My (kg/s) becomes A (kg/s.m).




We determine the parameters for the Equivalent Gaussian Source as [θ/T]G, UG and bG according to the following

formulas, with the empirical thermal constant λ= 0,9.

[𝜃

𝑇]

𝐺=

𝑄0√1 + 𝜆2

𝑇0𝑐𝜆 [𝐴 +𝑄0

𝑇0𝑐]

𝜉 = [𝐴 +𝑄0

𝑇0𝑐]

1

𝜌0√𝜋 and 𝜁 =

2𝐵

𝜌0[1

√3−[

𝜃

𝑇]𝐺

𝜆

√1+3𝜆2]√𝜋

𝑈𝐺 = √𝜁

𝜉

𝑏𝐺 = 𝜉

𝑈𝐺

5.6 Phase 5: Entrainment in rising plume

In this phase, the entrainment in the rising plume is calculated, once past the spill edge (or void edge). Remember

that we are still calculating with parameters per unit length from the previous phase, so the resulting mass flow is

still expressed in kg/s.m.

In order to determine the entrainment, we have to adjust for the actual rise height, using the Gaussian Source and

the Source Froude number for the line plume, following the formula:

𝐹 = [2

𝜋]

1/4

[𝛼

𝜆 [𝜃𝑇

]𝐺

]

1/2

𝑈𝐺

(𝑔𝑏𝐺)1/2

An important distinction is made between a single-sided or double-sided plume, by means of the entrainment

coefficient α.




Then we calculate the transformed parameter for the Equivalent Gaussian Source term, υG.

𝜐𝐺 =1

(1 − 𝐹2)1/3

We will use this term to define the modified distance above the virtual source (Il(υG)) and together with the

transformed height parameter (x’), the modified rise height of the spill plume is calculated [ Il(υ) = Il(υG) + ΔIl(υ) ].

The determination of Il(υG) can be done graphically following the graph shown below, where the value for υG is

represented on the vertical axis and the value for Il(υG) can be read across the solid curve in the middle. This yields

a value of roughly 0,2.



Graph 2: Graphical determination of Il(υ)

Because of the coarseness of this scale, it is advised to follow the analytical method, done by verifying the

conditional formulas, depending on υG. (these formulas are explained in paragraph E.6 of annex E in BRE).

• υG ≥ 1,549 Il(υG) = (υG – 0,75) / 0,9607

• 1,242 < υG ≤ 1,549 Il(υG) = (υG – 0,843) / 0,8594

• 1,059 < υG ≤ 1,242 Il(υG) = (υG – 0,9429) / 0,6243

• υG ≤ 1,059 Il(υG) = (υG – 1) / 0,3714

Since we found that υG = 1,086 we need to use the third formula to determine Il(υG) = 0,229, which is more correct

than the approximated 0,2 from the graphical method.

We continue by determining the transformed height parameter (x’):

𝑥′ =2

√𝜋𝛼

𝑥

𝑏𝐺

Here x represents the actual rise height, between the balcony spill edge and the bottom of the smoke reservoir, or

the smoke free height. In this specific case this value is 12,75m (Y) – 4,0m = 8,75m.



Next, the correction factor for the rise height of the spill plume, ΔIl(υ) is calculated, which is defined as:

∆𝐼𝑙(𝜐) =𝑥′

√𝐹2(1 − 𝐹2)3

And this finally gives us the modified rise height of the spill plume:

𝐼𝑙(𝜐) = 𝐼𝑙(𝜐𝐺) + Δ𝐼𝑙(𝜐)

This new-found value for Il(υ) = 1,446m, is then used to find three parameters (u”, p” and b”). Again, these can be

graphically derived from the beforementioned graph, by putting the value for I l(υ) on the X-axis, and reading the

values for u”, p” and b” on the intersection with the corresponding curves, giving us values of respectively 0,8; 2,1

and 2,3.

Graph 3: Graphical determination of values for u", p" and b" in function of Il(υ)

Alternatively, and more correctly, there is an analytical way to determine the values for u”, p” and b”, again by using

conditional formulas, depending on the calculated value of Il(υ). These formulas are explained in paragraph E.7 of

annex E in BRE. Note that the conditions are different for each of the three parameters.



Determination of u”

• Il(υ) > 1,896 u” = 1,0

• 0,786 < Il(υ) ≤ 1,896 u” = 0,0908.Il(υ) + 0,821

• Il(υ) ≤ 0,786 u” = Il(υ)0,35

Determination of p”

• Il(υ) > 0,832 p” = 0,9607.Il(υ) + 0,75

• 0,464 < Il(υ) ≤ 0,832 p” = 0,8594.Il(υ) + 0,8429

• 0,186 < Il(υ) ≤ 0,464 p” = 0,6243.Il(υ) + 0,9429

• Il(υ) ≤ 0,186 p” = 0,3714.Il(υ) + 1,0

Determination of b”

• Il(υ) > 2,161 b” = 0,8381.Il(υ) + 0,82

• 1,296 < Il(υ) ≤ 2,161 b” = 0,89.Il(υ) + 0,95

• 0,896 < Il(υ) ≤ 1,296 b” = 0,81.Il(υ) + 1,071

• 0,65 < Il(υ) ≤ 0,896 b” = 0,619.Il(υ) + 1,214

• 0,543 < Il(υ) ≤ 0,65 b” = 0,331.Il(υ) + 1,414

• 0,421 < Il(υ) ≤ 0,543 b” = 0,0627.Il(υ) + 1,55

• 0,348 < Il(υ) ≤ 0,421 b” = 1,821 - 0,6.Il(υ)

• Il(υ) ≤ 0,348 b” = Il(υ)-0,4

With the value of Il(υ) being equal to 1,446, we need to use the second, the first and the second formula, for u”, p”

and b” respectively. With these values, we need to calculate u’, p’ and b’ and therefrom we get the parameters b

and u, with b being the characteristic half-width of the line plume at height x and u being the axial vertical velocity

of the gases at height x.

𝑢′ = 𝑢" √𝐹3

𝑝′ = 1

(1−𝐹²)1/3𝑝" 𝑏′ = 𝑏" √𝐹²(1 − 𝐹²)

3

𝑏 = 𝑏′𝑏𝐺 𝑢 = 𝑢′𝑢𝐺

𝐹

With these parameters, we can calculate the actual mass flow per unit length mr for the rising plume, not

considering the entrainment in the free ends yet.

𝑚𝑟 = √𝜋2

𝜌0𝑢𝑏 [1 − 𝑝′ [𝜃

𝑇]

𝐺

𝜆

√1 + 𝜆²2

]

This gives us a mass flow rate per meter spill plume width plume of:

mr = 30,849 kg/s.m



Please note that, except for the mass flow rate (mr), the effective rise height (x), the half-width (b) and axial velocity

(u), all values and parameters in this phase are dimensionless numbers.

5.7 Phase 6: Entrainment at the free plume ends

In order to know the entrainment at the plume ends at a certain plume height x, we need the dimensions of the

plume at that height. Both width (b) and axial velocity (u) can be taken nearly constant over the rise height,

therefore we take the average value between the values for b and u at the Gaussian Source and those at rise height

x. This is of course an approximation, that is only valid if the rise height isn’t too large.

�̅� =(𝑏𝐺 + 𝑏)

2

�̅� =(𝑢𝐺 + 𝑢)

2

The entrainment into the free plume ends is then defined as δMr and has the following formula:

𝛿𝑀𝑟 = 4�̅��̅�𝛼𝑥𝜌0

In which α is the same entrainment constant as in the previous phase, namely 0,16 for free plumes.


The combined result of these two equations give the total mass flow rate at height x (Mr).

𝑀𝑟 = 𝑚𝑟𝑊 + 𝛿𝑀𝑟

In which W is the channelling screen width, which is here still taken as the width of the outflow opening (2m). This

leads to a total mass flow rate of:

Mr = 143,162 kg/s



5.8 Phase 7: Modification of Gaussian source term


In the final phase of the calculations, we divide the total mass flow rate by 2, in order to correct for the

multiplication of B, My and Q by 2 in the earlier phase 4. Please note that this is only applicable in the case of a

single-sided plume and therefore not in this specific calculation.

The BRE methods then proceeds to convert the mass flow rate into a volumetric flow rate, using the temperature

difference at height x (θr) and the specific heat capacity (c), which is still considered a constant value.

𝑉𝑟 =𝑀𝑟(𝑇0 + 𝜃𝑟)

300𝑥1,1774

In which:

𝜃𝑟 =𝑄𝑤

𝑐𝑀𝑟

This results in a volumetric flow rate of

Vr = 127,788 m²/s.

5.9 SHEVS design

In an actual SHEVS design, the result for Mr or Vr is the basis to determine the size and capacity of the mechanical

or natural ventilation systems. They should be designed in such a manner that the mass flow rate entering the

smoke reservoir at the bottom (here at height x = 12,75m, being the smoke free height Y) is the same as the flow

rate that is being extracted through the vents at the top of the smoke reservoir (here this is represented by the

ceiling height of 13m).

We choose the difference between ceiling height and smoke free height very small, because we are not actually

looking to design a SHEVS, rather than calculating the mass flow that flows through the ceiling opening. It is

calculated this way because a large opening with smoke flowing unhindered through it, is easier to describe in a

model, that creating a stable smoke free height and a smoke reservoir. There are always fluctuations at the bottom

of the reservoir, meaning that is practically impossible to get a relevant measurements of outgoing mass flow at

that height. If we want to eliminate these fluctuations, we can’t use a smoke reservoir. The downside of this

approach is that we get a very unrealistic SHEVS design, because of the very thin smoke layer.

When designing a SHEVS with natural ventilation, once the mass flow has been established, we have a minimal

aerodynamic surface (AvCv) we need to create; i.e. a minimal surface area that needs to be open (in fire conditions)

in order to evacuate the mass flow that has been determined. We need to consider a certain discharge coefficient,

specific to the dimension, design, geometry and materials used in the construction of the smoke hatch. These

coefficients are determined by test-protocols and are provided by the certificates by the suppliers of these hatches.



These coefficients, called the Cv-factor, are usually somewhere between 0,5 and 0,7. As a consequence of this flow

loss, we get an effective surface area which is 40% to 100% larger than the aerodynamic surface.

Furthermore, it is not enough to install that surface in any way we see fit. To avoid plugholing, as mentioned

before, there is a maximum mass flow we can attribute to each extraction point. The smaller the smoke layer is, the

easier plugholing can occur and the smaller the maximum mass flow per unit can be. In this case this would lead to

an unrealistically large amount of extraction points: 4785 vents, each with a maximum of 0,03 kg/s mass flow

exhaust, because the smoke layer thickness is only 0,25m.

Table 10: Needed aerodynamic surface and number of extraction points

If we were to double the smoke layer up to 0,5m, the number of vents would be 846 vents of 0,169 kg/s each. This

is clearly not a linear ratio. Mcritical is determined according to the following formula:

𝑀𝑐𝑟𝑖𝑡 = 1,3√(𝑔𝐷5𝑇0𝜃𝑙

𝑇𝑙2 )

2

Wherein D is the smoke layer thickness, which has a x5/2 proportion with Mcrit. The number of extraction points (N) is

than simply defined as the ratio of Mr and Mcrit, rounded up.

Graph 4: N and Mcritical in function of the smoke layer thickness



5.10 Comparison with NBN S21-208-1

Since we are not designing an actual SHEVS, there is no need to go further into details about the specifications of

vents, fans, cupolas, ducts compressors and other components related to the proper functioning of a SHEVS.

Concerning this project, the manual calculation procedure stops at the determination of the mass flow rate at

height x. We got that Mr = 143,162 kg/s at height 12,75m in the atrium.

When we compare this result to the results when calculated according to the Belgian standard NBNS21-208-1, we

get an idea of the impact of the extra entrainment caused by the downstand and the balcony. We take the same

design fire, placed at the ground level of the atrium, using the same rise height only without outflow from an

adjacent fire room.

Table 11: SHEVS Design according to NBN S21-208-1

The rising plume in the atrium (considered a large, single, and undivided room) has a mass flow of 77,03 kg/s at

height 12,75m. Compared to 143,162 kg/s, this is an increase of 85% over the same rise height. This clearly shows

the necessity to take outflow from an adjacent room and the extra entrainment it causes into consideration when

designing a SHEVS.

Noteworthy is also the difference in resulting smoke layer temperature: where CEN ends with a temperature of

42°C (315 K), the NBN has a final temperature of 57°C (330 K). This difference can be explained by the extra

entrainment of cold air into the smoke plume.

The next step is to create a 3D model of this very same scenario and run it in a CFD-software package. For this we

will use FSD 6.6.0. The model will be created in a way that the mass flow at a certain height can be determined or

otherwise derived from the output files and compared with the manual results.



CFD modelling using FDS



6 Principles of Computational Fluid Dynamics

6.1 Computational Fluid Dynamics

Computational Fluid Dynamics (CFD) is a modelling technique in which the flow of fluids is described and predicted

by numerically solving the Navier-Stokes equations, which describe the equilibrium of a fluid in motion. Since

smoke can be characterised as a thermally driven, slow-speed, fluid in motion, it can be modelled in a CFD

software environment, given the implementation of the correct physical properties and parameters for the

geometry, the materials and the fluids.

Other uses for CFD include the hydrodynamics of fluids in tubes and pipes, but it is even more used in

aerodynamics, where windspeeds and flows are modelled when designing for example airplanes and race-cars, but

also when determining the wind loads on high rise buildings, we can use CFD calculation and modelling

techniques.

Whenever a CFD model is created, the geometrical space (building, wind tunnel, car, airplane…) and its

surroundings is discretised using a 3-dimensional grid, or mesh, composed of individual cells, usually of

approximately the same size. On the edges of each of these cells (also called control volumes) the software solves

the equations for:

• Conservation of mass

• Conservation of total momentum

• Conservation of energy.

When applied to a fire situation, this translates roughly to what a fire creates in mass (particles yield, unburnt

products and soot) and energy (heat release rate, combustion energy and temperature rise) and what the

environment supplies (fresh air, other particles, lower temperatures) is conserved within the system. In short: what

goes in, must come out. These equations are solved for every individual cell, for discrete periods of time, thusly

creating a dynamic solution at different timesteps.

6.2 Fire Dynamics Simulator

FDS, short for Fire Dynamics Simulator, is a well-known, widely used and thoroughly validated CFD software

package, specially created for CFD-analyses with an emphasis on smoke and heat transport from fires.

It follows the same principles as CFD of course, and gives numerical solutions for the conservation of mass, energy

and momentum equations and it is herein that the biggest difference between a simplified 2-zone model and a

FDS calculation lies: in a 2-zone model, the equations for momentum are not taken into account, but rather

simplified using empirical correlations. This saves a lot of computational capacity and time, but leaves a lot of

margin for error of course. A 2-zone model can give a good ‘first impression’ of a situation and can give a very fast

answer to the basic questions concerning smoke layer height and temperature, even time-dependant, but it is not

detailed enough to answer the questions for more difficult scenarios or anything but a rectangular shaped

geometry.

Even though the momentum equation is included, this is a physical phenomenon that plays in the ‘larger scale’ of

things. However, there are a lot of physical parameters that happen in a much smaller scale, such as turbulence,

combustion, radiation etc. To calculate all this information on such a small scale we should use a technique called

DNS, Direct Numerical Simulation, but this is a time and money-consuming process.

Therefore, it is practically impossible to solve all those equations in a mesh that is small enough to include these

phenomena within its boundaries. Some of these parameters will be modelled and some assumptions will have to

be made. Again, this leaves any FDS calculation prone to errors. We will therefore use as little modelling as possible



and will limit this to the LES turbulence models (Large Eddy Simulations), excluding any combustion, radiation or

advanced product yield models.

6.3 Large Eddy Simulation

The principal idea behind LES, introduced by Smagorinsky and Deardorff is to reduce the computational time (and

cost) by ignoring the smallest length scales, which are the most computationally expensive to resolve, because of

the extremely small mesh-size. This principle is called low-pass filtering of the Navier–Stokes equations and it

comes down to a time- and spatial averaging of the turbulent eddies. This effectively removes all small-scale

information from the numerical solution, but to compensate for that loss of information, the results and their effect

on the flow is modelled, rather than calculated.

Other simplifications of the Navier-Stokes equations can be done, like for example the Reynolds Averaged Navier-

Stokes (RANS) modelling, which will make use of time-averaged values.

Figure 10: Schematic representation of DNS, LES and RANS

An example of the difference in results might be like the one shown below, where a certain velocity field is shown

according to the three principles, mentioned above. It is of course up to the designer to decide if the LES or RANS

results offers enough information for the intended application and if the extra time and costs of the DNS-method is

justifiable.



Figure 11: Possible difference in result DNS, LES and RANS

In our FDS model we will be using the LES modelling.

6.4 FDS Solver

Every FDS modelling consists of three basic steps:

• Pre-processor

The pre-processor is the part where the model is actually built and defined. It is here that the geometry of the

building is ‘constructed’, the used materials and their physical properties are chosen and defined, boundary

conditions are setup, physical and chemical model are introduced and the computational mesh is defined as

well as the time steps and the numerical accuracy.

• Processor or Solver

This is the actual calculation and numerical solving of the algebraic equations and it uses the input from the

pre-processor to decide which equations to solve and in what order this should be executed.

• Post-processor

This is the visualisation of the input and output. This is a graphical representation of the geometry and of the

requested output. This can vary from the soot yield and the rising smoke plume or the temperature profile of

the fire source, to the vectoral representation of the air velocity at a certain height or at a specific location, as

long as it is within the boundaries of the computational mesh. The desired results should be already specified

in the pre-processor.

In the following chapters, we will go further into detail of each of these three steps.



7 FDS Pre-processor: Building the model

7.1 Software: PyroSim

The FDS solver uses a text-based file, called an ‘FDS-file’ to interpret. This can be as easy as a “txt-file”, renamed

with the extension .fds that contains the correct codes and properties. This requires a good 3D insight, as you have

no visual aid until you run the post-processor to verify the model. The process resembles a computer programming

language and is very sensitive to errors. A compiler will however, indicate errors before running the simulation,

giving the user a heads up about the code being faulty.

Most frequent users of FDS can generate the code directly, without the use of a pre-processor, but since a visual

aid comes in very handy, the people at Thunderhead Engineering created PyroSim, a “what you see is what you

get” principle building program, that allows you to create your geometry (building, atrium, tunnel or other, more

complex designs), apply all necessary parameters and properties to the materials, include a fire source, import CAD

and other drawings if needed, helps you create a computational mesh and which exports the needed FDS-file

before running the actual solver.

Figure 12: General layout of PyroSim

A “what you see is what you get” environment means that, while designing graphically, the program immediately

writes the corresponding code for every element. So instead of defining all coordinates, headings and parameters,

we simply ‘draw’ the building, fill in the parameters in pop-up windows and the code gets generated automatically.

The figure below shows the FDS-code generated from the above-mentioned design.

Created Meshes

Defined Surfaces

Defined

Measuring

Devices

Desired Results

Geometry

Elements

Design Fire

Measuring Device

“Temp Ceiling”

3D Defined

Geometry



Figure 13: Automatically generated code

7.2 Geometry

The geometry of the building is kept rather simple and is already partly explained in Chapter 3, “Design Scenario”.

We use of course, the exact same geometry as was used for the manual calculations, otherwise the comparison

would not be valid.

Figure 14: Building geometry – Top view

41m

10m 20m 10m

20m

20m 30m



The building has a footprint of 30m by 41m, with 10m width for each ‘store compartment’ and 20m for the atrium.

The walls, floors, balconies, balustrades and ceiling all have a thickness of 0,25m.

In the roof of the atrium a vent is defined measuring 20m by 20m, to have an opening large enough for all the

smoke to rise up and leave the atrium. For the sake of this project, we do not need to define a smoke reservoir and

all smoke must be evacuated. We are only interested in the mass flow of smoke at a height of 12,75m as the smoke

flows through.

Figure 15: Building geometry – Front view

The ground floor and first floor have a height of 4m, the top floor has 4,25m, the floors and the ceiling have a

thickness of 0,25m, leading to a total building height of 13m, and a ceiling/atrium height of 12,75m. These

dimensions were also used in the CEN/BRE-procedure.

The fire room is a 10m by 10m by 4m room, located at ground level, in the middle of the left side of the building.

In principle, every floor is divided on each side in three of such rooms, but this is of no influence on the model or

the calculations, so these rooms are not individually defined. Only the fire room has clear boundaries.

The fire source is located in the middle of the room, the specifications regarding the design fire are in the next

paragraph. The opening towards the atrium is represented by a 3m by 2m door.

Figure 16: Building geometry - Fire room close-up

When making the calculations following the CEN/BRE-method, a few parameters stand out as being of the biggest

influence on the entrainment of fresh air into the smoke and are therefore key in the total mass flow in the atrium.

4m

4m

4,25m

13m 12,75m

4m

10m

10m

3m

1m

1,5m

2m 2m



And these parameters are the presence or absence of a (deep) downstand and the presence or absence of a

balcony. These two items define a lot of the entrainment constants in the calculations, and are of great significance

in the difference between a single-sided or double-sided smoke plume.

In this primary model, we introduce both a downstand of 1m, represented by the free space above the opening, as

well as a balcony of 2m wide, making it a ‘deep’ balcony. This situation should represent the worst-case scenario, as

we have extra turbulence around the downstand and a free plume, with maximum entrainment.

In later stages of this project, we will take a look at the secondary models, where we will make a comparison

between whether or not to have a downstand and/or a balcony.

7.3 Materials

If we want to have a valid comparison between an FDS-model and the manual calculation method, we have to

create a model that describes these ‘perfect conditions’ as defined in the CEN/BRE-method as close as possible.

This means we need to generate a realistic model with perfect and therefore unrealistic parameters.

As far as the construction materials are concerned, we will all assume they are all adiabatic and have no heat

exchange with the environment, the fire or the hot smoky gases. There will be no heat loss to the walls, ceilings or

other items that are designed in the model. This is a conservative approach, since in reality of course, a substantial

part of the heat release rate is lost to the surroundings through convection and conduction. These parameters can

be easily added in the model, as we define new surfaces ourselves, attributing physical properties like emissivity and

specific heat transfer coefficients to it.

Figure 17: Surface parameters



In the mathematical procedure however, these losses are not included individually for each independent surface,

but rather as fixed percentage of heat loss. This is introduced in the form of α, being the convective part of the

HRR, by default taken as 80%, leaving 20% of radiative losses to the surroundings. This is defined in the model

when formatting the design fire.

We will use the ‘adiabatic’ property for all so-called obstructions, and we use the ‘open’ property to indicate a vent

at the edges of the computational domain, otherwise FDS will interpret the edge of the mesh as a solid obstruction.

The other types of default surfaces are not used, in this model. We did define one new surface and that is the one

called ‘burner’, which defines the burning surface of our fire source.

At the bottom of the screen, the FDS-code as it will appear in the FDS-file is shown in preview.

7.4 Design fire

When designing the fire source, we must take care to use the exact same parameters as the design fire of the

manual method. There the fire source had the following key characteristics:

• Af = 5m² (surface)

• Pf = 9m (perimeter)

• qf = 625 kW/m²

• Q = 3.125 kW

These characteristics must be attributed to the design fire in the model as well, but this is not defined as a single

‘item’, but rather as an obstruction, with a ‘burner’ surface and a defined ‘reaction’ at that surface. So, there are in

fact, three parameters that need to be defined to create a design fire according to certain specifications.

7.4.1 The obstruction

We create a square object in the middle of the fire room, and for each side we choose the length in such a manner

that the surface of the fire equals 5m² and the perimeter equals 9m. This means, each side has a length of 2,25m.

The height of the obstruction is kept small, because we simulate a fire at ground level and putting the fire source

too high would change the rising smoke plume within the fire room.

Figure 18: Design fire: Object properties

The six surface areas of the object are defined as ‘adiabatic’, except for the top, called ‘Max Z’, this is the burning

surface and gets attributed the newly defined ‘burner’ property.

7.4.2 The burner surface

On this so-called ‘burner’ surface, we have defined a few characteristic values that indicate the properties of the

fire, like the heat release rate per unit area (625 kW/m²) and the fire growth.



Figure 19: Design fire: Burner surface properties

The fire growth is expressed as a timestep in which the αt²-curve reaches its maximum potential. Theoretically this

takes 260 seconds, as stated in Chapter 3. Since the mathematical method does not consider the fire growth, but

only takes into account the steady state phase, when the equilibrium is reached, it is not useful to model the

complete 300 seconds. Therefore, we put this timestep at 1 second. This means that the fire will almost immediately

reach its maximum heat release rate and the entire system will reach steady-state phase a lot faster.

Figure 20: Heat release rate: reality vs steady-state simulation

However, it does not mean that the equilibrium will also be established immediately, because the smoke still needs

the time to rise up to the ceiling and ‘settle’. But this will take roughly 30 to 60 seconds instead of the theoretical

300, which means that the calculation time can be severely reduced.

7.4.3 The reaction

The reaction describes what kind of combustion reaction takes place at the burning surface, i.e. what materials are

burning, what products are released due to the process and at what rate. Traditionally a propane burner is used for

modelling purposes, but this gives a rather ‘clean’ fire, with almost complete combustion and very little soot

formation. Also, it is not a realistic fire source for a shopping mall or an office building. We chose for the

combustion of pine wood to simulate a furniture fire and other cellulose based materials, like clothing, textiles and

upholstery.

3125 kW

3125 kW



Figure 21: Design fire: Reaction properties

The left screen shows the composition of the combustible material and therefore the products that will be released

when combustion occurs (C, H, O and N). We used the default combustion model for Pine Wood as described in

the SFPE Handbook. These ratios of components approximate the chemical structure of cellulose.

In the right screen, we can define some other properties of the combustion reaction, like the heat release rate per

unit oxygen and the radiative fraction of the HRR. This latter has a standard value of 0,35, but to approach the

manual method as close as possible, we take it as 0,2 (to match the convective part of 80%). We kept the CO yield

and hydrogen fraction at its default values, but we did change the soot yield to 0,12 g/g. NFPA states in an article

on soot yields that upholstered furniture has a soot yield of about 0,05 g/g, while plastics generate a soot yield of

about 0,1 g/g. We chose 0,12 to include in some way the fact that the fire is situated in a rather small enclosure,

which leads to a less effective combustion, which in turn leads to a higher soot yield. The experience from earlier

cooperation with Actiflow taught us that 0,12 g/g is an acceptable soot yield to use in indoor fires. On top of that, it

is a more conservative approach which guarantees more safety from the fire safety engineers point of view.

This is only one of the default models in the FDS library, which includes also combustion models for methane,

ethanol vapour, propylene, poly methyl methacrylate, polyurethane and oak wood, all based on the SFPE

Handbook. New and customised models can be integrated, given that all necessary parameters are known.

7.5 Mesh

Once we’ve setup the geometry and the design fire, we need to define the 3-dimensional areas in which we are

actually interested. Since we want to see the smoke flowing from the fire room, into the atrium and through the

opening in the roof, it is of no use to us what happens in the adjacent rooms for example. So, we are not creating a

mesh there, because the larger we make the computational mesh, the more cells there will be and the longer the

calculations will take, only to model regions we’re not interested in.

It is not necessary that all the cells of each computational zone are equal, but it is however necessary that the

boundaries of the cells of the different meshes are in line with each other. The easiest way to do that is to make

sure that the outer boundaries of the mesh zones are the same, and that the cell size of the biggest mesh is a

multiple of the size of the smaller cells.



Figure 22: Mesh: Outer boundaries

We defined three different meshes in this model:

• Fire room

• Atrium

• Open air

7.5.1 Fire room mesh

The mesh of the fire room is of course very important, since it is the starting point of the smoke flow and the

location of the fire source and the corresponding HRR. So, it is important to make the cells small enough to

generate enough information, but not so small that computational time would unrealistically long.

The default value for cells, suggested by PyroSim is a square with an edge length of 0,25m, creating control

volumes of 0,015m³. In the first models, we will use these values to see if the result they generate are acceptable

and plausible.

The room has dimension of 10,25m by 10m by 4m, which gives 41 x 40 x 16 cells in the volume, with a total of

26.240 cells within the fire room. Please note that the atrium wall, which spans 10,25m to 10,5m in X-direction is

included within this mesh.



Figure 23: Mesh: Definition of the fire room mesh

7.5.2 Atrium mesh

The mesh in the atrium is of course very crucial as well, as this will describe the uprising smoke plume through the

atrium. And it is within this mesh that we will need to define our measuring points for the smoke mass flow at

height 12,75m. Therefore, we will use the same mesh as in the fire room, 0,25m x 0,25m x 0,25m squares.

Defining the mesh will be the same as in the fire room and will result in an 80 x 80 x 56 cell sized computational

region, with 358.400 cells.



We deliberately made the mesh reach higher than the ceiling and describe a part of ‘open air’, because measuring

at the edge of a computational zone, may cause unexpected results. The edge of the mesh is considered a

boundary and when a flow is ‘cut off’ at a boundary, it will not represent the correct situation. Therefore, we extend

the mesh up to 1m above the roof, creating a mesh of 14m high instead of the expected 13m. When the model is

executed, the fact that the mesh borders at the physical edge of the geometry of the opening in the ceiling will

generate a warning. PyroSim will suggest expanding the mesh just a little bit, so that the borders no longer

coincide.

Figure 24: Mesh: Definition of the atrium mesh

Important here, is that the atrium mesh must be aligned with the fire room mesh in the YZ-plane, where X =

10,5m, so that the calculations, which are executed at the boundaries of the cells, encounter no discrepancies. The

program indicates if the mesh alignment is valid or not. It will display “Passed” if the alignment is in order. In case of

a misalignment of the mesh, it will indicate “Failure to align” and it will indicate at which bordering mesh the

problem occurs.

Figure 25: Mesh: Failure to align mesh



Figure 26: Mesh: Alignment between fire room and atrium

The figure above shows the fire room mesh (blue) and the atrium mesh (yellow) as seen along the X-axis. So, the

blue and yellow rectangle are located in the same YZ-plane. The mesh alignment in the overlapping plane should

be verified.

7.5.3 Open air mesh

Initially this mesh wasn’t created, since the atrium mesh already exceeded the buildings boundaries, but a few test

runs showed that the supplementary 1m wasn’t enough to effectively extract all the smoke and a part of the smoke

descended back into the building. This disrupts the calculation of the mass flow through the ceiling vent and

therefore an extra mesh was created on top of the atrium mesh.

Since we are not interested in what happens to the smoke outside the building, we can give this mesh a coarser cell

size, but always bearing in mind that the alignment must be respected.

Figure 27: Mesh: Alignment between two meshes with different cell sizes



We choose a mesh size of 1m³ per control volume. This leads to 20 x 20 x 6 or 2.400 cells.

Figure 28: Mesh: Definition of the open-air mesh

The height of the open-air mesh is taken from 14m up to 20m, creating enough buffer capacity to make sure no

smoke re-enters the building. Because we use such a coarse mesh, the computational time needed for the extra

height is very limited and only has a small impact on the total modelling time, whereas the atrium mesh will use the

larger part of the computational time.

7.5.4 Open air vents

After a few runs, we’ve learned that the mesh is considered a solid boundary by the FDS calculation program and

that meshes bordering open air should be equipped with an ‘open’ surface vent to simulate an open-air situation.

Figure 29: Mesh: Open air vents



It suffices to define an area and to attribute the surface property ‘open’ to it, as described in the paragraph on

surface properties. The surface vents can be mesh transcending, meaning that a single vent can describe an open

air ‘facade’ over multiple meshes. The surface must however, coincide with the mesh boundary for it to have effect.

In this model, we took the top of the open-air mesh and the four sides of the open-air mesh and the top 1m of the

atrium mesh as being in open air.

This was added later in the modelling process. In principle, the open-air mesh would then become obsolete, but

I’ve decided to leave it in as an example for the alignment and to point out the difference in results, when it comes

to cell size.

7.5.5 Total mesh

The total number of cells amounts to 387.040 which is altogether an acceptable number. The first couple of test

runs of this model, in order to optimize it, took about 4 to 6 hours to complete, depending on the computer use at

that time of course. Adding a mesh, or increasing the number of cells, drastically increases the computational time.

This mesh configuration has been unchanged for the greater part of the following models. Except when specifically

mentioned, we used this mesh and mesh size.

7.6 Desired results

7.6.1 What to detect?

When the geometry is built and all parameters and properties are attributed, the model is ready to run. This would

generate a matrix full of numbers without specifications. It is therefore very important to clearly define what you

want to get out of the model as a result.

One might be interested in the air velocity passing over an airplane, or specific pressure planes working on a

building because of wind effects. In our case we specifically need the mass flow of smoke out of the ceiling vent at

12,75m height. Additionally, we can look at a temperature-curve and verify if we are still within the limits of validity

of the manual calculations and we can look at the visibility limits to get an idea of the presence and the density of

the smoke/soot.

Smoke itself is not a parameter FDS can define, since ‘smoke’ has no fixed composition. This depends on the

combustion reaction, the soot yield, the density and temperature of the air and the smoke and so on. So, it is

impossible to measure the smoke mass flow as a value, but it is possible to measure the components that form the

smoke individually.

When it comes to default components, PyroSim offers to measure the following species:

• Air

• Carbon dioxide (CO2)

• Carbon monoxide (CO)

• Nitrogen (N2)

• Oxygen (O2)

• Soot (C)

• Combustion products

• Reaction products

• Water vapour (H2O)

Of course, we need to make some assumptions with these measurements.

‘Air’ as defined by FDS, consists of 79% N2 and 21% O2. That would mean that if we measure ‘Air’ and ‘N2’ and ‘O2’,

we would be counting the mass flow of air twice. So, we need to choose whether we install a measuring device for

air of for its components, but not both. Of course, both devices can be installed, but in the interpretation of the

results, we need to be careful not to make the wrong summation.

Secondly, we assume practically complete combustion, because of the simplified reaction model that we use. So,

we can assume that the amount of combustion products in the rising smoke plume will zero. In the end, we will

only setup measuring devices for Air, CO, CO2, Soot, Reaction products and water vapour.



7.6.2 2D and 3D slices

For the visualisation of results, we need to introduce 2D and/or 3D-slices in the model. These represent a location

in which we are interested. We can define a slice with certain dimensions, in a plane within a mesh and we indicate

the property we want to visualise.

Figure 30: Defining 2D slices

The above-mentioned slice is defined in the XY-plane, at Z = 13m, within the atrium mesh, making it a 20m by 20m

area slice. We request to measure the temperature gradient and the visibility. Whenever the ‘planar slice’ window is

activated, the defined slices are shown in yellow in the model.

The visual representation of these results can be with a colour gradient or with a vector field. In the following figure,

it is indicated that we can combine those two visualisations, when defining the planar slices.




We still have the temperature gradient, measured at Z = 13m, but now we added a temperature profile, a heat

release rate profile and a velocity profile, in the XZ-plane, at Y = 15m, which coincides with the centreline of the

fire, the fire room and the atrium. The slice is automatically enclosed by the boundaries of the meshes through

which it cuts.

A typical result from these 2D-slices is shown here, where we have a temperature gradient and a velocity vectoral

visualisation.

Figure 32: Visualisation of 2D-slices

The same principle is valid for the 3D slices, with that exception that a 3D slice can be located anywhere within the

mesh volume, and is not limited to a certain plane. It is a three-dimensional slice, through which several quantities

can be measured. This can vary from the mass flux of particles and species (air, N2, O2, H2O, CO, CO2 or other

combustion products) in the X, Y or Z direction to vertical, horizontal or averaged velocities, heat release rates,

pressure changes, etc.


These 2D and 3D-slices are designed to result in a graphical output. They are interpreted by the post-processor to

show the changes over time of a certain parameter as the fire burns, the HRR rises and the smoke flows through

the building. And although it gives a good impression of the properties of the smoke (temperature, density,

visibility and so on) it is very hard to extract analytical results from it. So, we will be using these slices as a visual aid

mainly, but we will need other ways of getting the exact numbers.

7.6.3 Devices

Another way of measuring a certain quantity is using a so-called ‘device’. This is a singular measuring point, defined

by three coordinates (XYZ), and possible a rotation angle and a direction in which it should measure.

A device can measure all the same quantities a 3D slice can, but in one single point. A mass flow for example,

would be expressed as kg/s.m² and is therefore dependent on the area through which it flows.



Just as with the slices, a device is highlighted in yellow, once the devices window is activated, and again similar to

the slices, it is possible to define multiple devices on the same spot while measuring different quantities.

Figure 34: Defining a detection device

A single measuring point over a larger surface area does not reflect the correct result, especially when the

measured quantity is fluctuating over that area and does not have a constant flow, like smoke does.

A solution to this could be using multiple devices for each quantity placed at well-chosen locations and averaging

the results from every one of them. This would even out the fluctuations, but is of course a lot more difficult to do,

as there are a lot more numbers to process.

7.6.4 Area integral

If we were to add infinitesimal small devices in every point of the considered area, we get an integral function over

that area. PyroSim has this included in his software in the ‘statistic’ function. The result is a total flow over the

selected area, so in the specific case of a mass flow, this would be an amount expressed in kg/s.

Again, this is recorded in a certain plane and again we choose for Z = 12,75m, but the dimensions of the area do

not need to coincide with the boundaries of the surrounding mesh. We can define any surface area in any plane

through which we want to measure a flux.

The interpretation of the results does deserve some caution, because the integral function calculates the total flux

through a certain area, meaning that both outflowing smoke as incoming air are being included. Since we cannot

define smoke as a quantity, we need to use the combination of air, soot and the other combustion products. But

this implies that the quantity ‘air’ will be measured in both directions and the calculated flux will be a resultant flow,

instead of the total outflow. So, it is important to verify the correct areas and choose the right function to obtain

only the outgoing flows.



Figure 35: Defining area statistics

7.6.5 Flow Measuring Device: Mass Flow +

During the process of modelling, we were informed of a function that defines the entire flux (positive or negative)

through an opening or a certain area. This would be a possible answer to this problem. However, at that time we

failed to run a model with the correct FDS-code. Since we did not arrive at the correct analytical solution, an

approximation to the problem was made, with rather satisfying results. These are explained in the ‘Results Chapter’.

Later, we ran the code successfully and we able to compare the semi-analytical approach to the effective mass flow

out of the system. These comparison is also explained in the results chapter.

This function is called a ‘flow measuring device’ and it gives the total mass flux through a predefined area, positive,

negative or both. Downside of this principle is that there can be no subdivision into different species. We measure

the complete flow in or out.



Figure 36: Defining mass flow measuring device



8 FDS Processor: Calculations

8.1 Software: FDS

As explained earlier, the pre-processor generates an FDS-file, containing all the necessary codes for the model to

run and for the processor to solve the mass-, energy- and momentum-equations.

We used FDS, version 6.6.0, released in November 2016, by NIST, the American National Institute of Standards and

Technology, a well-known and validated CFD package.

PyroSim was designed to work with FDS 6.6 and has a function included to verify and alter the settings for the

calculations. It is also possible to activate the FDS-module from within PyroSim, opening a new window that shows

the propagation of the calculations in timesteps. Alternatively, it is possible to start FDS from a DSO-environment

and load the FDS-file into it, to start the calculations.

8.2 Properties and settings

In the PyroSim menu bar we find the Simulation Parameters and these define a couple of key properties for the

calculations. It is perfectly acceptable to use the default settings, which we will do for the greater part, but some

settings are necessary to indicate manually.

Figure 37: FDS: Timestep and Output properties



Figure 38: FDS: Environment and Simulator properties

Initially we took the total modelling time as 300”, considering the fire growth of 260” before reaching maximum

HRR. After a few runs, we changed the setting to 120”, when the ramp-up time was reduced to 1”, so we could

reduce calculation times by 60%.

The default ambient temperature is set to 20°C. Since we used an ambient temperature of 25°C in the manual

calculation procedure (298 K), we changed it in these settings as well, to approximate the calculations as close as

possible. Although the impact of a 5-degree difference is most likely neglectable. or all other parameters, regarding

the environment (ambient pressure, oxygen mass fraction in the air, relative humidity, etc) and regarding the

turbulence models (Smagorinsky constant, Von Neumann region, Schmidt and Prandtl numbers, etc) we took the

default values.

8.3 Running the program

While the program runs, the progress can be monitored. This is somewhat more user friendly in the PyroSim

environment as opposed to the default DOS environment for FDS.

Figure 39: Largest model running with DOS, after 24 hours of runtime only 22 second have been modelled



Figure 40: Smaller model running with PyroSim, with a predicted runtime of about 6 and a half hours



9 FDS Post-processor: Results

9.1 Software: Smokeview

The post-processor affiliated with FDS is aptly named Smokeview. It is a graphical interface that renders images

from the data-matrix that is the result of the numerical solving of the Navier-Stokes equations over the cell

boundaries of the defined meshes.

Depending on which quantities have been requested in the pre-processor, the results in Smokeview are variable. By

default, the soot yield and HRR are shown, but the user interface allows to not show certain properties and to

activate other, on the condition that they were defined in the FDS-file.

9.2 Various models and techniques

As already mentioned in the chapter on the pre-processor, there are different methods of measuring the mass flow

through the ceiling vent. In a series of models, I’ve experimented with some of them, trying the different techniques

at different locations and analysing the outcome.

At this time, I have a running total of 23 different models, which will not be explained in full in this project, as some

of the earlier models were experiments to render a working model. These were models 1 to 6. They did not

generate any usable results and were mere try-outs to check the functionalities of PyroSim/FDS/Smokeview and to

see if the model was fit for the intended scenario.

Later models were try-outs with different measuring techniques. In the following paragraphs, I will explain in further

detail those models which generated relevant information and valid results, or those who render invalid results, but

for a specific reason, worth mentioning.

Table 12: Model variations



Table 13: Model variations (cont.)

The first actual results were generated in model 6, where we tried the volume mean and mass mean functions over

an area of 400m² for air and soot. Although this did not render a valid result, it did show two important issues:

• The mean function over an area (mass or volume) cannot be used to obtain the mass flowrate out of an

opening, as it calculates the average between incoming and outgoing air. Overall, we get a negative result,

meaning that there is more inflow of air through the opening that outflow.

• The amount of soot is a lot smaller than the amount of air. Later models will show that this is about a factor

1.000 – 10.000 smaller.

For the following model (model 7) we used the single-point detection. This was repeated in model 8, where we

used multiple-point detection. These results did not turn out to be valid, but they are worth mentioning because of

the used technique and the difference between both results. In these models, we also incorporated the first area

integral function over an area of 200m² (half of the ceiling vent).



Models 9, 10 and 11 were created to research the correct way to measure the flow over an area and are to be

considered as preliminary models to model 12, which has, to my opinion, the best possible, realistic approach using

the area integral function. This is also the model used as a basis for the sensitivity study (model 15) and for the

variations on the geometry (models 16, 17 and 18).

Model 14 was the first attempt at a sensitivity study, but had an extremely long runtime, due to the enormous

number of computational cells (6.000.000 cells with an estimated runtime of 550+ hours). This model was therefore

not continued, but simplified to model 15, which has about half of the number of cells.

In extremis, models 20, 21, 22 and 23 were executed, using the same geometries as 12, 16, 17 and 18 respectively,

but with the mass flow + function instead of the area integral function.

9.3 Models 1 to 6: Visual results

Although the first couple of runs did not generate any useful analytical results, they did yield some interesting

visuals regarding the size and location of the smoke plume in the atrium and the location where it leaves the

building through the ceiling vent. It shows for example, that not the entire vent is used, but roughly only the left

half of it.

Figure 41: Model 6: Results after 4 seconds + Results after 7 seconds

These figures show that the smoke leaves the fire room after only 4 seconds. This is of course because we put the

time-ramp for the αt²-curve at 1 second.

At 7 seconds, we notice that the horizontal flux is very big and that the initial entry into the atrium is almost

completely horizontal. This is a very short phase and quickly hereafter the smoke plume start to rise. In later phases,

we see that this horizontal flux becomes smaller and has less of an impact. The smoke doesn’t ‘shoot’ past the spill

edge anymore, but will curl around it.


After about 12 seconds, the plume reaches the ceiling vent and starts to flow outside. At this point the equilibrium

starts to form. We also see that the entire fire room has already filled up completely with smoke. In reality, this

would generate a higher soot yield and lower heat release rate from the fire source. In the model this is

incorporated, in the manual calculations it is not. And since this happens well before the equilibrium sets in, this will

have an impact on the outcome of the calculations.



At 30 seconds into the model, we can say the equilibrium has formed. Notable here is that the smoke plume starts

to curl underneath the balcony on the second floor, as it is explained in the CEN principles. This is not considered in

the calculations, but has clearly an effect on the rising plume.


The timesteps at 60 and 120 seconds show practically the same picture, indicating that equilibrium indeed has been

reached. An important remark to make here is whether this smoke plume can still be considered a ‘free plume’,

since it is enclosed at the left atrium wall. Still, in the manual calculation method, it is assumed that, in equilibrium,

the spill plume is a double-sided plume.

To have a clear view on where the smoke leaves the atrium at equilibrium, we take a top view of the smoke plume,

combined with the visibility graph at 13m height. We do this, because otherwise it is hard to get a decent depth

perception of the plume into the atrium.

Figure 44: Model 6: Results for visibility and temperature after 120 seconds

Where the red zone on the left graph indicates maximum visibility, and therefore absence of smoke, the

discoloured zones indicate a reduced visibility, right down to 1m, due to the presence of soot and smoke. So, this

graph is not only a representation of the visibility, but also of the density of the smoke.

The graph on the right shows the smoke temperature at 13m height. We see a peak of 85°C, which seems

contradictory to the CEN/BRE calculated method, but those are average smoke layer temperatures and if we take a

look at the areas around the 85°-peak, we see smoke temperatures varying from 25° (ambient fresh air) up to 50°

– 60°C. It is not hard to imagine that this leads to an average temperature of 40° to 50°C.

9.4 Model 7: Single-point detection

In model 7 we placed a single point detection device to measure the smoke mass flow. As stated before, to

approximate smoke, we need to measure air (or N2 and O2), soot and combustion products, so we place a

measuring device for each product at the same spot, more or less in the middle of the uprising smoke plume

(X=15m, Y=15m, Z=12,75m), where the density is highest, according to the visuals.



Table 14: Model 7: Partial results from single-point devices

The single-point devices measure the mass flow per area and are expressed as kg/s.m². Now we must ask ourselves

the question: “what will be the area we are considering?”. The opening in the ceiling has a surface of 400m², so

theoretically, the smoke can use the entire surface to flow out and we would have to use 400m² as multiplicator for

the calculation of the total mass flow rate. But since we saw that the smoke only uses roughly half of the opening, a

first approximation would be to use half of the surface. So, in this model we took 200m² as multiplicator for the

mass flow rate.

The results table above represents only partial results of course, as it contains about 1.000 lines of numbers.

The column named ‘Mass Flow’ expresses the sum of all measuring devices, multiplied by the surface. The column

‘Mass Flow -Air’ expresses the sum of all devices except for the air flux. We see that the ‘mass flow without air’ is

about half of the ‘total mass flow’. Since the amount of air is the bulk of the smoke flow, this proves that if we take

‘air’ and ‘N2 + O2’ together, we are actually counting the volume of air twice, which of course is a very large

deviation. In future calculation, we shall only consider the product-flows and leave the ‘air-flow out of the equation.

Underneath the column, we calculate the average value of the mass flow (with and without air). We do not consider

the first 30 seconds of the model, since we know from the visuals that equilibrium only starts to form after 20 to 25

seconds. The flows between the start and 30 seconds into the model are zero at first and rise very slowly until

equilibrium, so they would decrease the average mass flow rate. Remember that we are looking for the mass flow

rate at equilibrium to compare with the theoretical values, calculated in the CEN/BRE procedure.

We get a mass flow rate of 874 kg/s, which is of course a severe overestimation as it is 6 times the calculated

amount. The reason for this is related to the location where we put the device. It was positioned in the densest part

of the smoke plume and therefor has a higher flow rate. Within the 200m² area we could place a device that would

measure a lot less than the flow rate we would expect to see, and there will be a device somewhere that gives the

exact amount, but there is no way for us to know that location.

If we were to place more detection devices, spread out over that 200m² area and average them out, we will get a

more correct approximation of the effective mass flow.

9.5 Model 8: Multiple-point detection

In model 8, we placed 9 single-point devices within the limit of the smoke plume as it leaves the atrium. They are all

placed within the left half of the opening, so we can still limit the area to 200m² instead of using the complete

400m².



Figure 45: Model 8: Location of the single-point devices

Table 15: Model 8: Results from multiple single-point devices

This, also partial, results table contains the measurements of all 9 devices, for all defined products. Just as before

the column ‘mass flow’ represents the sum of all devices and the ‘mass flow -air’ represents all devices except the

air flows. The difference is that here, the devices have been averaged out. The column ‘total average detection’

represents the sum of all devices divided by 9. This gives a mean value over a larger area (within the 200m²) and

should approximate the real value closer.

This method gets us a mass flow rate for ‘smoke’ of 149 kg/s, which is rather close to the calculated value. But we

still should consider the differences in smoke density over the total 200m² area and the fact that the smoke doesn’t

form a rectangular shape as it exits the building. So again, we may conclude that this is an overestimation of the

actual mass flow rate.

As stated before, working with an integral over the area gets an analytical value for the mass flow, so in the

following models we’re going to look at that technique.

9.6 Models 9 to 11: Area integral

As explained earlier, this technique consists of defining a certain area and then the mass flux (or any other quantity)

is measured over the entire area. But we need to beware that a flux is measured in both direction. So, incoming

airflow will decrease the amount of outgoing air. In fact, using this method it is possible that the total flux becomes

zero or negative, if, at a certain timestep, more air enters the building than leaves it.

In model 9, we have used the complete 400m² of ceiling opening. It is logical that the inflow of air is very large

here, as the ‘non-used’ half of the ceiling vent will serve as an air-inlet, due to pressure differences created by the



fire and the hot smoky gases. We will see in the results table, shown below, that the mass flow of air balances

around a zero-value and even becomes negative quite often. The total mass flux over the total area of 400m² using

this integral method comes to 2,378 kg/s, which is of course an extremely unrealistic result, considering the size of

the fire and the rise height of the atrium.

We will not see this phenomenon for the soot yield, combustion products, CO or CO2 concentrations as it assumed

that these products are not present in the surrounding environment. So, we can safely assume that the flux of these

products is completely positive and going out. In the end, this is of little importance, as the airflow is by far the

largest component in the total mass flow through the ceiling vent.

Another remarkable result is that in the ‘reaction products’ column. These are zero during the whole process,

meaning that no unburnt material is being transported with the smoke plume, only combustion products and air. In

future models, this quantity shall not be measured.

Table 16: Model 9: Results from area integral flow over 400m²

Models 10 and 11 are similar to model 9, except here we used only half the surface and measured all quantities

over 200m² instead of 400m². Obviously, we took the same half as used in models 7 and 8. The difference between

model 10 and 11, is that we also measured the flow through the door towards the atrium, but no useful or relevant

information came out of those results.



Table 17: Model 10: Results from area integral flow over 200m²

We now get an average mass flow rate of 95,8 kg/s. This is most likely too low, because of the same reasons as

with model 9, but the impact of the inflow of air is seriously reduced, by eliminating that part of the surface where

no smoke exits the atrium.

In model 11, we tried to use the Volume Statistics ‘Minimum’ and ‘Maximum’ for the air flux, assuming that this

would generate the positive and negative flow. Unfortunately, that is not the case, as it merely indicated the

maximum and minimum value within the area at each timestep. This function could not be used to eliminate the

inflow of air out of the results. Neither the averaged value, not the differential value is usable as the basis for a mass

flow rate calculation.

We did however, add a 3D-slice in the ceiling vent, to visualise the mass flux in Z-direction (kg/s.m²) and this shows

clearly where the biggest concentration of outgoing air is present, and where the inflow of air occurs.

Figure 46: Model 11: Mass flux of AIR in Z-direction through the ceiling vent, after 30 and 60 seconds



Figure 47: Model 11: Mass flux of AIR in Z-direction through the ceiling vent, after 90 and 120 seconds

At the 30 second mark, when we assume equilibrium starts to take form, we see a low-density cloud on the rights

side of the vent (±1 kg/s.m²). This is a remainder of the initial cloud of smoke that was blown horizontally into the

atrium (remember the graph at 12 seconds, where the horizontal flux is highest). During the rest of the process,

hardly any air exits the building on the right side of the vent.

After 60 seconds, we see that the smoke plume expands towards the front and back of the building, along the

balconies and the left atrium facade. Before that time, these voids are used for incoming air.

This trend continues and after 90 seconds, we see that a small amount of air escapes the building around the

edges of the vent, but again in rather low densities. The bulk of the air is in the centre left art and along the left

atrium wall.

The only way to approximate the real mass flow any further is to reduce the flux area even more, but without losing

valuable information regarding the outgoing smoke. Therefore, we will follow the smoke flow and expansion, as

shown on the above-mentioned figures.

9.7 Model 12: Area integral over smaller zones

To reduce the integral area, we need to verify where the smoke will be at what exact time. We do this based on the

mass flux of air as shown in the previous paragraph. We take the same 4 figures, but in a top view, with the mesh

of the open air visible, so we have a frame of reference. The cells are 1m by 1m, so it is easy to visually define the

areas.



Figure 48: Model 12: Areas with bulk density of air flux, after 30, 60, 90 and 120 seconds

The yellow squares indicate the bulk of air flow through the ceiling. If we apply the integral function on those areas,

we reduce the surface to the locations where the inflow is air is very small and the outflow is maximized. I believe

this is the closest approximation of the real situation possible, when using this function.

Since we cannot alter the measuring areas during the process, we must define the areas in advance, using the

Statistics function. What we can do however, is to choose to account for a certain area in the results afterwards. The

areas are referenced as 1, 2 and 3. The first 30 seconds will not be included in the calculations same as before,

because the equilibrium hasn’t set yet. Between 30 and 60 seconds we will only consider area 2, as the sides (1 and

3) are at that time only taking air in. As from 60 to 120 seconds, we will take the situation as depicted in the last two

figures.

Table 18: Areas considered in the final mass flow calculation

1

2

3

1

2

3



Table 19: Model 12: Results from area integral flow over Zone 1 - 24m²





Even though the entire building is symmetrical and we defined the areas symmetrical with respect to the centre

line, we see that zone 1 and zone 3, who both have an area of 24m², do not generate the same result. Although

the difference is not that large (24 kg/s versus 27 kg/s) it is not to be neglected.

If we combine these average values, we get a total mass flow rate of 122,8329 kg/s, which lies within the

expectations and the order of magnitude.

As an approximation, this is, according to me, as close as we can get, without using the exact analytical method, for

which I could not get the model working. So, this principle will be maintained and used in any further modelling we

will be executing.

9.8 Model 14 and 15: Sensitivity study

An important part of this project is the sensitivity study, in which we verify if the models we used before, and then

more specifically the fineness of the meshes, are valid and represent a valid result. The way to do this is to refine

the mesh in the relevant areas, without changing any of the other parameters.

The reason this is necessary, is because of the errors and deviations that are created when we use a mesh that is

too coarse. The changes within the larger cell are bigger than what will be described by the modelled turbulence

and this will lead to rather large deviations in the outcome of the model. Smaller cells will describe the small-scale

changes better, less modelling will be required and more equations will be solved numerically.

A simple example shows what we mean by that. Where we defined the open-air mesh with 1m³ cells and outlined it

with the atrium mesh, using 0,25m cubed cells, we can see the difference in the visual output of the smoke plume.

Although it is not very clear in the picture, there is a difference in output between the rising plume in the atrium

and the outflow in the open-air mesh. The open-air part is more ‘pixelated’ and is coarser around the edges of the

smoke plume, where the atrium mesh gives a smoother edge. It is not hard to imagine that the mathematical

results of which this is a representation, are more detailed and accurate when the mesh is smaller.



Figure 49: Difference in mesh size

To verify the used models, we based versions 14 and 15 on model version 12, as described in the previous

paragraph. So, we will be using the same measuring methods (area integral over 3 defines, smaller zones) and the

same model parameters. Only the cell size of the mesh will be a lot smaller, meaning that there will be a lot more

cells to cover the entire geometry.

We first setup model 14, where we changed the cell dimensions from 0,25m cubed to 0,1m cubed, giving us

control volumes of 0.001m³ instead of 0.015m³. This is a factor of 15 difference, meaning that we will get over 6

million cells instead of 387.000. When I tried to run model 14 it indicated a run time of well over 550 computational

hours, for which unfortunately I did not have the time at hand. Therefore, model 14 was cancelled and I searched a

way to run the model without spending an eternity on running time.

In model 15 is decided to define only the left half of the atrium mesh with smaller cell sizes. So, I introduced a new

mesh, called ‘Atrium 2’, which spans from the left atrium wall to the centre, since the smoke plume is almost entirely

situated within that half. The picture below shows the newly defined mesh. A few things should be considered of

course, before we can use this mesh and run the model.

• The larger part of the smoke plume should be described by the mesh. The only part of the smoke plume that

crosses into the other half is the initial flow from underneath the balcony. If we take the same averaged values

as we did in model 12, that ‘first puff’ will not be included in the calculations and can therefore be dismissed.

• The measured areas in the ceiling vent must fall within the range of the mesh. These areas span from the left

atrium wall to 6 or 8m into the atrium, while the mesh spans 10m. The entire area is located within the

computational mesh.

• The sides of the mesh mustn’t alter the flow of the smoke plume. If a part of the plume should cross the

mesh’s boundaries, it must be able to do so freely, so that the flow does not get altered. To obtain that effect,

we made the sides of the mesh open, towards the atrium, so that smoke can move freely through the atrium.

It is to be believed, if we take these rules into consideration, this model will represent the same situation as model

12 and will generate the same results, but calculated in more detail.



Figure 50: Model 15: Newly created mesh with cell size 0,1m and open facades

We added some temperature devices, to verify the smoke layer temperature at various locations in order to

compare it with the intermediate temperature from the manual calculations. After 10 days of runtime, we got the

following results for this model.




This gets us a total mass flow of 136.918 kg/s, which is about 10% more than what we calculated with the larger

mesh size. We assume that the difference is situated mainly in the edge of the plume, where a smaller cell-size

defines the incoming and outgoing flow better and therefor gives a more detailed result. We do believe that this

approach is acceptable and we will continue using this model and measuring technique in the rest of the

calculations, considering a 10% deviation in the results.

9.9 Models 16 to 18: Variations

To have an idea of the impact of a downstand, the presence of a balcony and the difference between an adhered

of a free plume, we created variations on model 12, in which we changed certain parts of the geometry to see what

the effect would be. These changes were applied to both the mathematical procedure as to the modelling

software. Of course, we will not go into the same amount of detail as for the basic model, which was assumed to

be the worst-case scenario, but we do want to point out some differences in geometry and in resulting mass flow.

9.9.1 Model 16: No downstand present

In this model, we only changed the height of the opening between the fire room and the atrium. So, it now has

dimensions:

• Height h = 4m

• Width W = 2m

Since there is no downstand anymore, some settings change:

• Discharge coefficient Cd = 1,0

• Discharge coefficient Cd0 = 1,0

• Depth of downstand Dd = 0m

This also means that we do not need to multiply Mw by a factor 2, when the smoke enters underneath the balcony.

We do need to verify if the correct formulas for Il(υG), u”, p” and b” are still applied and if not, they need to be

changed according to the conditional formulas as mentioned in chapter 5.

We would expect less entrainment, because there is no extra turbulence from the downstand, but we also have a

higher horizontal velocity when the smoke leaves the balcony. This in its turn creates more turbulence.

When we alter all these parameters, we obtain a final mass flow rate of 146,483 kg/s. This is somewhat higher than

I expected, since it would mean that this is the most critical model, and not the one with both downstand and

balcony. Although the difference is not that much between 143 and 146 of course.

When we run the model, we notice a few small differences, but nothing so big, that we would need to change the

model to generate valid results.

Figure 51: Model 16: Comparison between model 12 and 16, horizontal flow at 7 seconds

The first figure shows the difference between model 12 and model 16 at 7 seconds in the process, when the

horizontal flux is the highest. We see that, even though the latter does not ‘shoot’ into the atrium as far as the first,



it does have a more compact and dense smoke plume. It also seems that in the situation without the downstand

the smoke plume tends to curl upwards faster than the one with a downstand. I believe this is to be explained by

the momentum of the oncoming flow, that is broken by the downstand and the temperature drop due to the extra

entrainment at the opening.

Figure 52: Model 16: Comparison between model 12 and 16, horizontal flow at 12 and at 60 seconds

We also notice that, when the plume reaches the ceiling around the twelfth second, it is somewhat more located

near the centre of the opening at first. This is of course due to the higher momentum of the initial plume. The

shape of the plume however, does not differ so much. After that, the plume seems to retract towards the left

atrium wall, like before, and the differences become minimal. If we use the same calculation method on the results

table, we can make a valid comparison.






This amounts to a total mass flow of 121,217 kg/s. Which is very close to the previous model when the downstand

was present. Both manual calculations as modelling methods indicate that the influence of a downstand is minimal

when there is also a balcony present.

In the following models, we will verify this for the situation without balconies in the atrium.



9.9.2 Model 17: No balcony present

In this model, I only changed the presence of the balconies. So, the rising plume starts begins to form the moment

it leaves the fire room underneath the downstand. This means that the total rise height is now 9,75m instead of

8,75m.

The dimensions of the opening are again as in the first calculations and so are the parameters for the downstand.

And we need to multiply Mw by a factor 2 again, when it curls underneath it.

The biggest difference here is that we also need to multiply B, My and Qw by 2 to correct for the Gaussian Source,

as we are now dealing with an adhered plume. And therefore, we mustn’t forget to change the entrainment

coefficient α from 0,16 to 0,077.

We verify each time if the correct formulas for Il(υG), u”, p” and b” are still applied and if not, they need to be

changed according to the conditional formulas as mentioned in chapter 5.

At the end, the final mass flow rate must be divided by 2 again, to correct for the Gaussian Source.

We would expect a lot less entrainment, because of the adhered plume and the entrainment constant which is less

than half in case of a free plume. There is of course some extra turbulence from the downstand, but practically no

horizontal velocity when the smoke leaves the fire room, since there is no layer build-up under balcony.

When we alter all these parameters, we obtain a final mass flow rate of 100,816 kg/s. This lies in the line of the

expectations and shows that the presence of a balcony and a spill edge at a certain distance from the room

opening has a large impact on the development of smoke.

When we run the model, we notice again a few small differences, but nothing so big, that we would need to

change the model to generate valid results.


The figure above shows the difference between model 12 and model 17 at 7 seconds in the process, when the

horizontal flux is the highest. We see a very similar flow, leaving the fire room and entering the atrium equally far

and more or less equally ‘diluted’. That would indicate that the presence of the balcony does not impact the

horizontal flux all that much, but rather that the downstand is responsible for the value of ‘B’. Logically, we also see

that there is an uprising part of the plume adhered to the atrium wall from the beginning.




Both the plume from under the balcony as the plume straight out of the fire room have the exact same flow and

initially leave the atrium in the centre of the ceiling vent, before retracting towards the left atrium wall.

We do indeed notice the adhered part from the beginning, but we can ask ourselves the question if the plume in

this stage can be considered ‘adhered’ or single-sided, while we can clearly see a free-flowing double-sided plume

in the centre of the atrium. At least in the first 30 seconds of the process.


After that, the plume seems to retract towards the left atrium wall, like before, and the differences become minimal,

although the adhered plume seems to have a wider outflow area. When we take a look at the top view however,

we see a totally different story. Since there are no balconies present, there is no sideways dissipation of the smoke

plume and almost the entire volume goes straight upwards.

Figure 56: Model 17: Top view of the smoke outflow at 60 and 120 seconds

This clearly shows that the entire smoke plume is pinpointed in the middle part of the left atrium side and that the

measurements made in zones 1 and 3 are not necessary for this model. Only the results from zone 2 (64m²)

between 30 and 120 seconds will be considered in the final result.

The table below gives a total mass flow through zone 2 of 111,458 kg/s which is roughly 10% more than what the

CEN/BRE calculated. This means that for this particular case the manual method is not conservative at all and even

designs too small for the expected mass flow rate. A SHEVS design, created following this calculation would be

insufficient to extract all smoke entering the smoke layer. And the smoke free height would not be maintained

when the equilibrium set in.

This is altogether a surprising and unexpected result which we will look into further, outside the scope of this report.




9.9.3 Model 18: No downstand nor balcony present

This model would represent the exact opposite of the standard model we’ve been using. Both the downstand and

the balconies are gone, so this is the model with the biggest impact. Or at least this is what we would expect.

The rising plume starts to form again the moment it leaves the fire room, but since there is no downstand, the total

rise height remains at 8,75m. The opening between the fire room and the atrium again has dimensions:

• Height h = 4m

• Width W = 2m

Since there is no downstand, we change the discharge coefficients again:

• Discharge coefficient Cd = 1,0

• Discharge coefficient Cd0 = 1,0

• Depth of downstand Dd = 0m

We do not need to multiply Mw by a factor 2, when the smoke enters the atrium, but, just as in the previous model,

we have no balcony and the plume is considered to be adhered, so we need to multiply B, My and Qw by 2 to

correct for the Gaussian Source again and use the smaller entrainment coefficient α.

We verify the formulas for Il(υG), u”, p” and b” and apply the correct versions, and at the end, the final mass flow

rate must be divided by 2 again, to correct for the Gaussian Source.

We would expect even less entrainment than in model 17, because now there is no more downstand. We do

expect a higher horizontal flux, resembling the situation of model 16.

When we alter all these parameters, we obtain a final mass flow rate of 70,307 kg/s.

The following figures will show if the model follows these principles.




Remarkable here is that, even though there is a higher horizontal flux, then when there is a downstand present, the

plume almost immediately starts to curl around the spill edge and starts to move upwards. The thermal buoyancy

has a bigger effect that the horizontal velocity. I believe that this is a consequence of the smoke layer having a

higher temperature, as it is leaving the fire room, unhindered by an obstruction.

Figure 58:Model 17: Comparison between model 12 and 18, horizontal flow at 12 seconds

Whereas the plume in model 17 was initially arguably an adhered plume, we see here that the smoke has indeed

the tendency to start forming an adhered plume from the very beginning, since it curls up straight away after

leaving the fire room.


After 30 to 40 seconds, there is little difference between the equilibrium states of the different models.

Figure 60: Model 18: Top view of the smoke outflow at 60 and 120 seconds



We do need to take care about the regions we are considering for the interpretation of the results. Like the plume

in model 17, we see that there is almost no horizontal spread of the smoke along the atrium walls and the smoke

plume stays well-centred in the left half of the ceiling vent, because of the lack of balconies. So again, in the results

we will only be looking at zone 2.


Again, this is an unexpected result. Not only is the modelling result 37% larger than the CEN/BRE-calculations, but

we also notice that the difference between this model and the previous one is practically nil, making the influence

of the presence of a downstand almost negligible.

9.10 Models 20 to 23: Mass Flow +

Since the geometries and design fires used in models 20 to 23 are exactly the same as those used in models 12, 16,

17 and 18, they show the exact same flow and smoke development. So, there is no need to show them here.

The only difference here is the manner of measuring. The mass flow + principle measures the total mass flow in a

single direction (out) over the total area of the ceiling vent (400m²). And since there is only one ‘quantity’ that can

be specified, namely ‘mass flow’, there is actually only one single column of results to be shown. For practical

reasons, we’re showing them here together, each one with their corresponding average values between the 30 th

and 120th second of the model.



Table 30: Models 20 to 23: Results from mass flow over total area

When we compare the results from the approximative method (models 12, 16, 17 and 18) with the results from the

analytical method (models 20, 21, 22 and 23) we get an average deviation of about 10%.

Table 31: Comparison between approximative and analytical method

This difference is due to the rectangular shape of the area we chose as the measuring area. When trying to

‘capture’ the smoke plume, we also select small parts where fresh air is entering the building, diminishing the

integral value over the area. A finer division into more Zones, would be an even closer approximation.

9.11 Temperature profiles

The smoke layer temperatures have been measured in most models at different strategic places: above the fire

source, at the atrium opening, at the spill edge and at the ceiling vent. In this paragraph, we take a closer look to

some of these profiles, how they correspond with the theory and how they influence the validity of the calculations.

The first graphs shown, represent the temperature of the smoke layer right at the ceiling of the fire room (4m)

located right above the fire source in the middle of the room. Logically this is the highest temperature measured in

the model because of the location. We see a large difference in effective temperature between the rooms with and

without a downstand. This is logical as the room without a downstand has a larger opening towards the atrium,

allowing more smoke and heat to escape and simultaneously allowing more fresh (and cold) air to enter. The

average difference is between 1.200 and 950 degrees.



Graph 5: Temperature profiles of models 12, 16, 17 and 18, measured above the fire source

Graph 6: Temperature profiles of models 12, 16, 17 and 18, measured at the outflow opening



The difference at the outflow opening becomes smaller between the two different situations, with 950°C for the

downstand scenario and about 800°C with the other scenario. This is due to the fact that the smoke layer clashes

here with the cold air upon exiting the fire room.

When there is a downstand, the temperature difference between inside the room and at the opening is about

250°C, while the difference in the other scenario is only 150°C. This can be explained by the smoke leaving the fire

room. In the case of a downstand there has already been some extra entrainment from when the smoke hits the

obstruction and causes turbulence. At that moment, the temperature dropped already a certain amount and

furthermore, the smoke will be more diffused when it enters the atrium, making it easier to give off heat.

Either way, this temperature is in principle too high to fall within the limits of the CEN/BRE methodology. That

would mean, even though theoretically the limits are not reached, in reality they would go well beyond said limits

and that would render the use of the CEN/BRE procedure invalid for this scenario. This raises questions about the

general applicability of the European standard. However, almost no other standards or calculation methods are

available that consider the flash-over situation in the design of a SHEVS.

Graph 7: Temperature profiles of models 12 and 16, measured at the spill edge

This graph only compares models 12 and 16, because 17 and 18, do not have a spill edge at the edge of the

balcony. In principle, the spill edge for 17 and 18 would be the top of the outflow opening. For models 12 and 16,

the spill edge temperature is around 650°C. The larger fluctuations we see on the left graph are again due to the

presence of the downstand and the more turbulent mixing of hot gases and air while the smoke flows out of the

fire room, whereas model 16 has a more steady outflow.

The final graph shows the temperature profiles of the devices placed at the ceiling vent, where the smoke leaves

the building. This device is placed at 2m from the left atrium wall and will, generally, measure the centre line of the

rising smoke plume. We notice a few differences in the graphs as the results vary quite a lot:

• Model 12: 86°C

• Model 16: 123°C

• Model 17: 67°C

• Model 18: 64°C

I believe the reason for these outliers is the arbitrary position of the measuring device. If the centre line of the

smoke plume is more near the device, it will result in a higher temperature at that exact location. And we should

not forget that the theoretical method describes the average smoke layer temperature and not the maximum. If we



want to make a more accurate profile for the smoke temperature, we should use the multiple device method and

average the values out.

Graph 8: Temperature profiles of models 12, 16, 17 and 18, measured at the ceiling vent

Overall, we can say that the modelled temperatures are quite a lot higher than the theoretically determined

temperatures, on every location or measuring point.



10 Conclusions & Recommendations

10.1 Comparison of results

The following table shows the summary of the manually calculated and modelled results and the difference

between them.

Table 32: Summarizing table of results for smoke mass flow

The percentage expresses the difference as being a surplus on top of the FDS results, to indicate how much the

manual calculations are actually an overestimation of the modelled reality.

Initially we noticed, as expected that the FDS-results for the first models, although based on the exact same

scenario, design fire and geometry, are a considerable amount smaller than the manually calculated results. This

lead us to believe that the CEN/BRE-method is indeed too conservative in its approach to the design of SHEVS

systems. At least, this is true for models 12, 15 and 16, where a balcony is present and the plume is considered a

double-sided or free plume.

Unexpected however are the results of the models with adhered plumes (models 17 and 18). They both turned out

to yield a larger smoke mass flow than calculated in the CEN/BRE-method. The reasons for this, assuming the used

models are valid, must be sought in either the entrainment coefficient, which might be too small for adhered

plumes, when using 0,077 for α or in the correction for the Gaussian Source. The latter considers the smoke plume

as adhered from the start and uses only half of the plume for the calculations of the entrainment, the other half of

the plume is assumed ‘virtually’ on the outside of the atrium walls. In the models, we saw that it takes quite some

time before the plume actually becomes single-sided and before that, extra entrainment from all around the plume

must be considered, which the mathematical procedure doesn’t do. But is this rather short time window enough to

generate 37% more smoke mass, compared to the theory? More modelling should be done to support this claim.

Another rather unexpected result is that the presence of a downstand does not seem to have a large influence on

the final results. Where model 17 and 18 differ quite a lot for the manual calculations (100 versus 70 kg/s), this is

not reflected in the modelling, where we see equal values for both models 12 and 16 and models 17 and 18. It

seems that the presence of a balcony has a larger impact than the presence of a downstand, meaning that the

factor 2, used for multiplying Mw, might be a serious exaggeration. This was already the subject of a study by B.

Merci and N. Tilley and the PhD of R. Harrison, who shared the same concerns.



Since our approximative method differs about 10% in average from the analytical method, which me may assume

as correct, the difference in conservative approach of the CEN/BRE-method becomes a lot smaller and where

CEN/BRE is insufficient in its design, the difference only becomes bigger.

Although we focussed mainly on the mass flow through the opening in this study, it needs to be mentioned that in

most of the models we had temperature devices installed, measuring the temperature at strategic places. These

often show that the temperature in the fire room above the fire source and in the outflow opening surpass well

above 550°C, which is considered the upper limit of validity for the CEN to apply, because we should assume the

entire room is involved in the fire at that time.

Table 33: Summarizing table of results for smoke layer temperature

We should therefore also question the validity of the manual calculations for this project, but also for the use of the

CEN/BRE-method for similar buildings. Is CEN/BRE usable for a shopping mall atrium, if the adjacent shops are only

100m² or if the ceiling height is only 4m? In general, this method is only used for these types of areas where ceiling

height is limited to even less than 4m (offices, shops, classrooms…). If this research would be continued, a few other

recommendations might be considered.

10.2 Recommendations: Future research to be done?

All these numbers and conclusions are of course the result of one single scenario, with only small modifications. In

order to make clear statements over the validity of the mathematical procedures, a lot more models should be

performed, considering a wider range of parameters, all within the limits of the CEN/BRE-procedure.

The following are a small list of possible, but still rather simple, changes that can be easily verified using the FDS

modelling technique.

10.2.1 Larger mesh

Using a larger mesh, with smaller cells on all models would get more detailed calculations and give more correct

results. Given enough time, it would be advised to re-run the models with smaller cells and a larger mesh. Because

this only gives a difference of about 10%, we need to assess whether this is needed and justifiable regarding time

and costs.

10.2.2 Higher atrium

We now used the same geometry for all calculations, because we needed a fixed reference, but this way we could

not verify the impact of the rise height, as it was always exactly the same (give or take 1m for model 17). But what

would the mass flow be at 20m height? Will the thermal buoyancy still be large enough to use natural ventilation?

10.2.3 Larger fire room

The impact of the fire room seems to be of great importance. A larger room, would lead to a smaller entrainment

factor to begin with and a higher ceiling would give a lower average temperature of the outflowing smoke layer.

This would improve the applicability of the CEN/BRE-method and might lead to a closer correlation.



10.2.4 Different design fire

Of course, changing the basic premise of the whole procedure changes everything. But we could verify the validity

of both the model and the calculation method, using a smaller design fire. We could also use a larger fire, model

the output and see how much it differs from what the standard would suggest.

10.2.5 Changing the geometry

We’ve been using a very basic model, with either a downstand or no downstand, a deep balcony or no balcony at

all. What would be the impact of an extremely deep balcony, for example a passage way of 5m? What would the

impact of a downstand of 0,5m be? Would this still be considered a ‘deep downstand or rather an ‘in between’

solution? What I the opening towards the atrium would be a large sliding door of 5m wide?

What would the effect of channelling screens be? How big was the deviation by assuming the width of the smoke

as wide as the opening? We used the width of the door, but over the length of 2m (depth of the balcony) the

smoke plume would become somewhat wider than 2m. It is practically impossible to calculate just how much that

would be, but if we would assume the smoke would spread out at an angle of only 15°, after 2m of depth we

would have 1m extra smoke plume width (2 x tan15°), which is a considerable difference.

10.2.6 Parameters of the modelling

In these models, we’ve been using the standard setting for the largest part. This included assumptions for the

combustible materials, the building materials and its thermal properties, a limitation of the fire spread and so on.

This was all done to approximate the ‘perfect’ conditions of the CEN/BRE-method of course, but other models

could be made to obtain more realistic results with a more realistic approach to the scenario.

10.3 General conclusion

The first conclusion here, is clearly that there is quite a difference, both positive and negative, between the manual

calculation method and the modelling. So, it is advised to combine, or to at least verify, both methods.

CEN/BRE seems to be, as we suggested, on the conservative side, even exaggerated at times. This turns out to be

correct for the first models we ran, when both a balcony and a downstand are present. No less than 16 to 20%

overestimation comparing the manual methods to the CFD-analysis. This is most likely the effect of the use of some

assumed constants, like the factor 2 we need to multiply the mass flow underneath the ceiling with, when the

smoke meets a deep downstand.

Even though we expected the CEN/BRE-method to be conservative in general, this doesn’t always seem to be the

case. On the contrary, when dealing with an adhered plume, it seems that there’s more entrainment than

theoretically determined by the 7-step-procedure. The reason for this might be sought in the entrainment

coefficient α or the Gaussian Source.

On top of this, we’ve noticed that the analytical method gives about 10% more mass flow rate that the

approximation, due to the shape of the chosen areas. This gives smaller exaggerations for the free-plume models

and larger shortcomings for the bounded plume models.

But this means that there is no general conclusion on whether the CEN/BRE is always usable as a design criterion,

even within his validity-limits.

And a third important conclusion is regarding that validity. Even when theoretically, we operate within the

temperature limits of the procedure, temperature profiles of the CFD-model indicate otherwise.

It is therefore strongly advised to do more research on this matter, with a wider variety of scenarios, parameters

and design fires. And maybe after that, we might develop a more detailed calculation method, suitable for a wider

range of situations and scenarios.



11 Referenced works

11.1 Standards

NPR-CEN/TR 12101-5

Smoke and heat control systems - Part 5: Guidelines on functional recommendations and calculation methods for

smoke and heat exhaust ventilation systems

NEN, 2005

NBN S21-208-1

Fire protection in buildings - Design and calculation of smoke and heat extraction installations -

Part 1: Large single storey spaces without partitions

BIN, 1995

11.2 Technical reports

Design methodologies for smoke and heat exhaust ventilation (BR 368)

H. Morgan, B. Ghosh, G. Garrad, R. Pamlitschka, JC. De Smedt, L. Schoonbaert

BRE, 1999

ISBN 10: 1 86081 289 9

Design Approaches for Smoke Control in Atrium Buildings (BR 258)

G. Hansell, H. Morgan

Garston, CRC, 1994

ISBN 10: 0 85125 615 5

Design Principles of Smoke Ventilation in Enclosed Shopping Centres (BR 186)

H. Morgan, J. Gardner

Garston CRC, 1990

ISBN 10: 0 85125 462 4

11.3 Course notes

Active Fire Protection II: Smoke and Heat Control

B. Merci

Universiteit Gent, Vakgroep Mechanica van Stroming, Warmte en Verbranding, 2014

11.4 Websites

Thunderhead Engineering Consultants, Inc. (2015)

Fire Dynamics and Smoke Control, quickly build Fire Dynamics Simulator (FDS) models with PyroSim

Consulted between December 23, 2017 and January 7, 2018

https://www.thunderheadeng.com/pyrosim/

National Institute of Standards and Technology (2017)

Fire Dynamics Simulator (FDS) and Smokeview (SMV)


https://pages.nist.gov/fds-smv/

https://www.nist.gov/engineering-laboratory/fire-modeling-programs

https://www.nist.gov/services-resources/software/fds-and-smokeview

https://www.nist.gov/engineering-laboratory/fire-modeling-programs

https://www.nist.gov/services-resources/software/fds-and-smokeview

https://pages.nist.gov/fds-smv/

https://www.thunderheadeng.com/pyrosim/



GitHub, Inc (2017-2018)

Fire Dynamics Simulator and Smokeview, Continuous Integration. Continuous Improvement.


https://github.com/firemodels/fds

https://github.com/firemodels/fds/wiki

Michael Ferreira (January 1, 2008)

Fire Dynamics Simulator, Ensure your software provides the safest atrium design for real world enforcement.


http://www.nfpa.org/News-and-Research/Publications/NFPA-Journal/2008/January-February-2008/Features/Fire-

Dynamics-Simulator

Kristopher Overholt (2018)

T-squared Fire Ramp Calculator (online tool)


https://www.koverholt.com/t-squared-fire-ramp-calculator

http://www.nfpa.org/News-and-Research/Publications/NFPA-Journal/2008/January-February-2008/Features/Fire-Dynamics-Simulator

https://github.com/firemodels/fds/wiki

https://www.koverholt.com/t-squared-fire-ramp-calculator

https://github.com/firemodels/fds

http://www.nfpa.org/News-and-Research/Publications/NFPA-Journal/2008/January-February-2008/Features/Fire-Dynamics-Simulator



Appendices



A. CEN calculation sheets A1. CEN 12101-5 - Model 12

A2. CEN 12101-5 - Model 16

A3. CEN 12101-5 - Model 17

A4. CEN 12101-5 - Model 18

B. NBN calculation sheet

B1. NBN 21-208-1

C. Model Versions

D. Models FDS files

D1. Design Model V1

D2. Design Model V2

D3. Design Model V3

D4. Design Model V4

D5. Design Model V5

D6. Design Model V6

D7. Design Model V7

D8. Design Model V8

D9. Design Model V9

D10. Design Model V10














E. Model Results

E1. Model V6 – Flow Area

E2. Model V7 – Devices

E3. Model V8 – Devices




E7. Model V12 – Zones





E12. Model V20/23 – Mass flow

SHEVS Design according to CEN/TR 12101-5 Symbol Value Unit Explanation Source CEN Source BRE

Fire Room

Height Hc 4.000 m Design

Vertical Opening

Width W 2.000 m Design

Height h 3.000 m Design

Design Fire - Smoke Outflow

Area A 5.000 m² Retail fire with QR sprinklers § 6.1.2 - Table 1 § 3.3 - Table 3.3

Perimeter P 9.000 m Retail fire with QR sprinklers § 6.1.2 - Table 1 § 3.3 - Table 3.3

Specific HRR qf 625.000 kW/m² Retail fire with QR sprinklers § 6.1.2 - Table 1 § 3.3 - Table 3.3

Convective Heat Flux Qw 2500.000 kW With α = 0.8 § 6.3.2.2 - Table 3 § 3.3 - Table 3.3

Entrainment Coefficient Ce 0.377 kg.m(-5/2)

/s

0.188 for large spaces

0.21 for large area rooms

0.337 for small spaces

§ B.1 § 5.1.1

Effective Discharge Coefficient Cd 0.650 1 with No Downstand // 0.65 with Deep Downstand § C.1 § 5.2

Massflow Mw 4.806 kg/s Formula C.1 Formula 5.7

Downstand Dd 1.000 m Design

Discharge Coefficient at Opening Cd0 0.800

When Dd < 0.25 Dw => Ignore downstand

When Dd > 2 Dw => Cd0 = 0.65

When 0.25 Dw < Dd < 2 Dw => Cd0 = 0.8

Outflowing Smoke Layer Depth Dw 1.413 m Iterative: start with Cd0 = 0.65 => Then adjust Formula C.2 Formula 5.8

Specific Heatcapacity Cp 1.010 kJ/kg.K Assumed Constant

Temperature Difference θw 515.030 If > 550 => Flash over conditions => Room fully involved in fire Formula C.3 Formula 5.10

Smoke under Balcony / Suffit

Massflow under Balcony Mb 9.612 kg/s Mb = 2x Mw, with deep downstand Formula D.1 or D.2 Formula 5.9

Heat Flux under Balcony Qb 2500.000 kW


Temperature Difference θb 257.515 K § D.2 Formula 5.10

Ambient Temperature Tamb 298.000 K 25° C = 298 K

Smoke Layer Temperature Tb or Tl 555.515 K Ambient Temperature + Temperature Rise § D.2

Effective Discharge Coefficient Cd 0.650 1 with No Downstand // 0.65 with Deep Downstand § D.2

Distance between Channeling Screens L or WB 2.000 mAssumption:

Equals Door width, with no channelling screens present

Smoke Layer Depth Db 2.527 m Formula D.3 Formula 5.11

Smoke Volume Vb 15.117 m³/s

Additional Smoke Screen Depth Δdb -0.262 m Formula D.4 Formula 5.12

Critical Mass Flow Mcrit 20.617 kg/s

Number of Extraction Points N 0.466 Formula 5.14

Spill plume into Atrium

Mass Flow Mw or MB 9.612 kg/s

Heat Flux Qw 2500.000 kW


Temperature Difference θw 257.515 K Formula 5.10

Correction on Mass Flow κm 1.300 Assumed Constant Formula E.2

Correction on Heat Flux κQ 0.950 Assumed Constant

Gravitational constant g 9.810 m/s²

Temperature Difference at top θcw 352.389 K Formula E.4

Temperature at top Tcw 650.389 K

Effective Discharge Coefficient - Towards Atrium Cd 1.000 1 with No Downstand // 0.65 with Deep Downstand

Smoke Layer Width W 2.000 m

Opening towards Atrium

Assumption:


Density of Air ρ0 1.225 kg/m³

Smoke Layer Depth at Opening dw 1.614 m Formula E.3

Characteristic Velocity v 5.296 m/s Formula E.6 / E.7

Horizontal Flux B 44.932 W/m x2 for Adhered Plumes (Correction of Gaussian term) Formula E.8

Entrainment Constant α' 1.100 § E4.3

Mass Flow over Spill Edge My 27.363 kg/s x2 for Adhered Plumes (Correction of Gaussian term) Formula E.9

Equivalent Gaussian Source § E.4.4

Heat Flux Qw 2500.000 kW x2 for Adhered Plumes (Correction of Gaussian term)

Heat Flux per length Q0 1250.000 kW/m

Mass Flow per length at edge A 13.682 kg/s.m

Specific Heatcapacity Ambient Cp 1.010 kJ/kg.K Assumed Constant

ξ 8.214 Formula E.10

Empirical Thermal Constant λ 0.900 Constant

(θ/T)G 0.348 Formula E.11

ζ 101.394 Formula E.12

uG 3.513 Formula E.13

bG 2.338 Formula E.14

Entrainment in Smoke Plume

Entrainment Constant α 0.1600.16 for Free Plume (double sided)

0.077 for Adhered Plume (single sided)

Froudenumber Source F 0.468 Formula E.15

Transformed Parameter νG 1.086 Formula E.16

Distance to Virtual Source I1 (νG) 0.229 Formula depends on value for νG ! BRE page 115-116 § E.6

ΔI1 (ν) 1.217 Formula E.18

I1 (ν) 1.446 Formula E.19

Ceiling Height Hc 13.000 m Lowest point smoke vents

Smoke Free Height Y 12.750 m Bottom of Smoke Buffer

Smokelayer Thickness dl 0.250 m

Effective Rise Height Xp 8.750 m Heigth of rising plume from the Balcony / Canopy

x' 0.676 Formula E.17

u'' 0.952 Formula depending on value for I1(ν) ! BRE page 116 § E.7

p'' 2.139 Formula depending on value for I1(ν) ! BRE page 116 § E.7

b'' 2.237 Formula depending on value for I1(ν) ! BRE page 116 § E.7

u' 0.740 Formula E.20

p' 0.508 Formula E.21

b' 1.242 Formula E.22

Characteristic Half Width at height x b 2.904 Formula E.23

Axial vertical Velocity at height x u 5.548 Formula E.24

Mass Flow per length at height x mr 30.849 kg/s.m Formula E.25

Entrainment in Plume Edges

bgem 2.621

ugem 4.531

δMr 81.464 kg/s

Total Mass Flow Mr 143.1617 kg/s x 1/2 for correction of Gaussian term for Adhered Plume

Specific Heatcapacity Cp 1.010 kJ/kg.K

Temperature Difference θr 17.290 °C

Total Volumetric Flow Vr 127.788 m³/s

Mechanical Ventilation

Diameter ventilator D v 1.000 m

Critical Mass Flow M crit 0.112 kg/s

Number of ventilators N 1279.170

Volumetric Flow 116.728 m³/s

Aerodynamic Surface (V/5) A v C v 25.558 m²

Discharge Coefficient C v 0.700

Actual surface A v 36.511 m²

Smoke Reservoir

Mass Flow M 1 143.162 kg/s

Downstand Factor ϒ 78.000

Temperature Rise of Smoke Layer θ 1 17.290 C

Temperature of Smoke Layer above ambient T 1 305.290 K

Smoke Layer Width W 1 2.000 m

Minimum Smoke Layer Thickness d 1 16.558 m

Natural Ventilation


Temperature Rise of Smoke Layer θ 1 17.290 K

Ambient Temperature T 0 298.000 K

Temperature of Smoke Layer T 1 315.290 K

Ambient Density ρ 0 1.225 kg/m³

Gravitional Constant g 9.810 m/s²

Smoke layer thinkness d 1 0.250 m

Air inflow versus smoke extraction factor AvCv/AiCi 1.000 Standard AvCv = AiCi. Other ratios are possible.

Aerodynamic Surface A v C v 323.262 Formula F.6 Formula 5.15

AvCv maximum M crit 0.029 kg/s Formula F.9 Formula 5.14

Number of extraction points N 4942.023

Discharge Coefficient C v 0.600 From supplier, usually between 0.5 and 0.7

Actual Surface A v 538.770 m²


Fire Room


Vertical Opening









/s




§ B.1 § 5.1.1






When Dd > 2 Dw => Cd0 = 0.65

When 0.25 Dw < Dd < 2 Dw => Cd0 = 0.8
















Additional Smoke Screen Depth Δdb 0.394 m Formula D.4 Formula 5.12
















Assumption:










































bgem 2.702

ugem 4.513

δMr 83.649 kg/s













Smoke Reservoir







Natural Ventilation















Fire Room


Vertical Opening









/s




§ B.1 § 5.1.1






When Dd > 2 Dw => Cd0 = 0.65

When 0.25 Dw < Dd < 2 Dw => Cd0 = 0.8
















Additional Smoke Screen Depth Δdb -0.262 m Formula D.4 Formula 5.12
















Assumption:










































bgem 5.493

ugem 5.048

δMr 101.996 kg/s













Smoke Reservoir







Natural Ventilation















Fire Room


Vertical Opening









/s




§ B.1 § 5.1.1






When Dd > 2 Dw => Cd0 = 0.65

When 0.25 Dw < Dd < 2 Dw => Cd0 = 0.8
















Additional Smoke Screen Depth Δdb 0.394 m Formula D.4 Formula 5.12
















Assumption:










































bgem 3.855

ugem 5.355

δMr 68.157 kg/s













Smoke Reservoir







Natural Ventilation














SHEVS Design according to NBN S21-208-1 Symbol Value Unit Explanation

Sprinklered High Storage? (Y/N) N Design

Sprinklered Area? (Y/N) J Design

Activation Temperature Sprinklers 68 °C Design

Height of Ceiling H 13 m Design

Smokefree Height Y 12.75 m Design

Ratio out/in AvCv/AiCi 1 Design

Ambient Temperature t0 25 °C Defined

Density of Air ρ0 1.225 kg/m³ constant

Fire Load qf 625 kW/m² NBN

Perimeter of Fire P 9 m NBN

Surface of Fire Af 5 m² NBN

Convection Factor α 0.8 NBN

Ambient Temperature T0 298 K Calc

Massflow of Smoke Mf 77.03 kg/s Calc

Total Convective Heat Flux Qf 2500 kW Calc

Smoke Layer Height db 0.25 m Calc

Smoke Layer Temperature tc 57.45 °C Calc

Smoke Layer Temperature Tc 330.45 K Calc

Aerodynamic Area A v C v 131.57 m² Calc

Maximal AvCv per smokevent A v C v 0.09 m² Calc

Cv Factor C v 0.60 From supplier, usually between 0.5 and 0.7

Actual Surface Area A v 219.28 m² Calc

Design Fire Max HRR Fire Room Roof Vent Fire Room Atrium Atrium 2 Open air # Cells Runtime 2D Slices 3D Slices Statistics Devices

1 3,125 MW 1" 10 x 9.75 10 x 10 0.25 x 0.25 0.25 x 0.25 n/a n/a 121600 300"Z: Temp°

Z: Visibilityn/a n/a n/a First try out

2 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a n/a 395920 300"Z: Temp°

Z: Visibility

Mass Air

Mass Sootn/a n/a

Increase atrium size, vent size and mesh

size

3 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 300"Z: Temp°

Z: Visibility

Mass Air

Mass Sootn/a n/a Add extra mesh

4 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 300"Z: Temp°

Z: Visibility

Mass Air

Mass Sootn/a n/a Some small edits in geometry

5 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 300"Z: Temp°

Z: Visibility

Mass Air

Mass Sootn/a n/a

Add side vents in mesh

Better outflow of smoke

6 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 300"Z: Temp°

Z: Visibilityn/a

Mass Air

Mass Sootn/a

Statistics for soot and air

Area integral over 400m²

7 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 120"

Z: Temp°

Y: Temp°

Y: Velocity

Y: HRR

n/a

Mass flow

soot, air, CO2,

CO, N2 O2,

H2O

1 - Mass flow

soot, air, CO2,

CO, N2 O2,

H2O

1 Device added for soot, air, CO2, CO,

N2 O2, H2O


8 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 120"

Z: Temp°

Y: Temp°

Y: Velocity

Y: HRR

n/a

Mass flow

soot, air, CO2,

CO, N2 O2,

H2O

9 - Mass flow

soot, air, CO2,

CO, N2 O2,

H2O

9 Devices added for soot, air, CO2, CO,

N2 O2, H2O


9 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 120"

Z: Temp°

Y: Temp°

Y: Velocity

Y: HRR

n/a

Mass flow

soot, air, CO2,

CO, H2O

n/a

Statistics for soot, air, CO2, CO, H2O,

Reac Prod.


10 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 120"

Z: Temp°

Y: Temp°

Y: Velocity

Y: HRR

n/a

Mass flow

soot, air, CO2,

CO, H2O

n/a

Edit for 2D slices Temp ° results


Reac Prod.


DimensionsDesign Fire Mesh Requiered Results

FDS Model versions

RemarksModel V

11 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 120"

Z: Temp°

Y: Temp°

Y: Velocity

Y: HRR

n/a

Mass flow

Roof

Mass flow

Door

n/a

2 x Statistics for soot, air, CO2, CO, H2O,

Products (roof and door)


12 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 120"

Z: Temp°

Y: Temp°

Y: Velocity

n/a

Mass flow

soot, air,

CO2, CO,

H2O

Temp

Door

Balcony

Ceiling


Products.

Area integral over 3 zones

Devices Temp°

13 3,125 MW 260" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040300"

HRR graph

Z: Temp°

Y: Temp°

Y: Velocity

n/a

Mass flow

soot, air, CO2,

CO, H2O

Temp

Door

Balcony

Ceiling


Products.


Devices Temp°

14 3,125 MW 1" 10 x 10 20 x 20 0.1 x 0.1 0.1 x 0.1 n/a 1.00 x 1.006014400

500+ uren120"

Z: Temp°

Y: Temp°

Y: Velocity

n/a

Mass flow

soot, air, CO2,

CO, H2O

Temp Door

Temp Balcony


Products.


Devices Temp°

15 3,125 MW 1" 10 x 10 20 x 20 0.1 x 0.1 n/a 0.1 x 0.1 1.00 x 1.00

3213200

150 uren

UGENT

120"

Z: Temp°

Y: Temp°

Y: Velocity

n/a

Mass flow

soot, air,

CO2, CO,

H2O

Temp Door

Balcony

Ceiling


Products.


Devices Temp°

16 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 120"

Z: Temp°

Y: Temp°

Y: Velocity

n/a

Mass flow

soot, air,

CO2, CO,

H2O

Temp Door

Balcony

Ceiling


Products.


Devices Temp°

17 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 120"

Z: Temp°

Y: Temp°

Y: Velocity

n/a

Mass flow

soot, air,

CO2, CO,

H2O

Temp Door

Balcony

Ceiling


Products.

Area integral over 1 zone

Devices Temp°

18 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 120"

Z: Temp°

Y: Temp°

Y: Velocity

n/a

Mass flow

soot, air,

CO2, CO,

H2O

Temp Door

Balcony

Ceiling


Products.

Area integral over 1 zone

Devices Temp°

19 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 120"

Z: Temp°

Y: Temp°

Y: Velocity

n/a

Mass flow

soot, air, CO2,

CO, H2O

Temp

Ceiling

Comparison of NBN S21-208-1

As test

20 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 120"

Z: Temp°

Y: Temp°

Y: Velocity

n/a n/a Mass Flow +Devices Mass Flow +

Devices Temp°

21 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 120"

Z: Temp°

Y: Temp°

Y: Velocity


Devices Temp°

22 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 120"

Z: Temp°

Y: Temp°

Y: Velocity


Devices Temp°

23 3,125 MW 1" 10 x 10 20 x 20 0.25 x 0.25 0.25 x 0.25 n/a 1.00 x 1.00 387040 120"

Z: Temp°

Y: Temp°

Y: Velocity


Devices Temp°

Design_Adiabatic_-_V1.fds

Generated by PyroSim - Version 2017.2.1115

7-jan-2018 22:35:44

&HEAD CHID='Design_Adiabatic_-_V1', TITLE='Atrium Test'/

&TIME T_END=300.0, DT=1.0/

&DUMP RENDER_FILE='Design_Adiabatic_-_V1.ge1', COLUMN_DUMP_LIMIT=.TRUE.,

DT_RESTART=300.0, DT_SL3D=0.25/

&MESH ID='Mesh Fire Room', FYI='Mesh Fire Room', IJK=40,40,16,

XB=0.0,10.0,10.0,20.0,0.0,4.0/

&MESH ID='Mesh Atrium', FYI='Mesh Atrium', IJK=40,40,60,

XB=10.0,20.0,10.0,20.0,0.0,15.0/

&REAC ID='WOOD_PINE',

FYI='Pine Wood, SFPE Handbook',

FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,

RADIATIVE_FRACTION=0.2/

&SURF ID='ADIABATIC',

COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',

FYI='Burner',

COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,

NET_HEAT_FLUX=625.0,

EMISSIVITY=1.0/

&OBST ID='Fire Source', XB=3.875,6.125,13.875,16.125,0.0,0.1,

SURF_IDS='BURNER','ADIABATIC','ADIABATIC'/

&OBST ID='Wall - Fire Room', XB=0.0,10.0,9.75,10.0,0.0,4.0,

COLOR='INVISIBLE', SURF_ID='ADIABATIC'/


SURF_ID='ADIABATIC'/

&OBST ID='Balcony L1', XB=11.8,12.0,0.0,30.0,4.25,5.75,




&OBST ID='Balcony R1', XB=18.0,18.2,0.0,30.0,4.25,5.75,




&OBST ID='Floor L1', XB=0.0,12.0,0.0,30.0,4.0,4.25, SURF_ID='ADIABATIC'/


&OBST ID='Floor R1', XB=18.0,30.0,0.0,30.0,4.0,4.25, SURF_ID='ADIABATIC'/

&OBST ID='Floor R2', XB=18.0,30.0,0.0,30.0,8.25,8.5, SURF_ID='ADIABATIC'/

&OBST ID='Left Facade Wall', XB=-0.25,0.0,0.0,30.0,0.0,13.0,


&OBST ID='Left Atrium Wall', XB=9.75,10.0,0.0,30.0,0.0,12.75,


&OBST ID='Right Atrium Wall', XB=20.0,20.25,0.0,30.0,0.0,12.75,


&OBST ID='Right Facade Wall', XB=30.0,30.25,0.0,30.0,0.0,13.0,


&OBST ID='Roof', XB=0.0,30.0,0.0,30.0,12.75,13.0, SURF_ID='ADIABATIC'/

&HOLE ID='Door - Fire Room', XB=9.75,10.025,14.0,16.0,-0.025,3.0/

&HOLE ID='Door', XB=20.0,20.25,14.0,16.0,-0.025,3.0/

&HOLE ID='Door', XB=9.75,10.0,14.0,16.0,4.225,7.25/

&HOLE ID='Door', XB=20.0,20.25,14.0,16.0,4.225,7.25/

&HOLE ID='Hole', XB=9.975,20.025,9.975,20.025,12.75,13.0/

&VENT ID='Vent Roof', SURF_ID='OPEN', XB=10.0,20.0,10.0,20.0,15.0,15.0,

OUTLINE=.TRUE./ Vent Roof

&SLCF QUANTITY='TEMPERATURE', PBZ=13.0/

&SLCF QUANTITY='VISIBILITY', PBZ=13.0/

&TAIL /



7-jan-2018 22:36:03


&TIME T_END=300.0, DT=1.0/




XB=0.25,10.25,9.75,20.25,0.0,4.25/


XB=10.25,30.75,5.0,25.0,0.0,14.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,



COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',

FYI='Burner Surface',

COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,


&OBST ID='Left Facade Wall', XB=0.0,0.25,0.0,30.0,0.0,12.75,










&HOLE ID='Door', XB=30.5,30.775,14.0,16.0,-0.025,3.0/

&HOLE ID='Door', XB=10.225,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.775,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.225,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.775,14.0,16.0,8.5,11.5/

&HOLE ID='Vent', XB=10.5,30.5,4.975,25.025,12.75,13.0/

&VENT ID='Vent Open Air', SURF_ID='OPEN',

XB=10.25,30.75,5.0,25.0,14.0,14.0/ Vent Open Air



&SLCF QUANTITY='MASS FLUX Z', SPEC_ID='SOOT', VECTOR=.TRUE.,

CELL_CENTERED=.TRUE., XB=11.0,30.0,5.5,24.5,13.0,13.1, FYI='Mass Flow

Soot'/

&SLCF QUANTITY='MASS FLUX Z', SPEC_ID='AIR', VECTOR=.TRUE.,


Air'/

&TAIL /



7-jan-2018 22:36:22


&TIME T_END=300.0, DT=1.0/




XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/

&MESH ID='Mesh Open Air', FYI='Mesh Open Air', IJK=20,20,6,

XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,



COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/

&HOLE ID='Vent in roof', XB=10.475,30.525,4.975,25.025,12.75,13.0/

Physical vent in rooftop


XB=10.5,30.5,5.0,25.0,20.0,20.0/ Vent at end of mesh





Soot'/



Air'/

&TAIL /



7-jan-2018 22:36:38


&TIME T_END=300.0, DT=1.0/




XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,



COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/









Soot'/



Air'/

&TAIL /



7-jan-2018 22:36:51


&TIME T_END=300.0, DT=1.0/




XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,



COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/





&VENT ID='Vent Left', SURF_ID='OPEN', XB=10.5,10.5,5.0,25.0,14.0,20.0/

&VENT ID='Vent Right', SURF_ID='OPEN', XB=30.5,30.5,5.0,25.0,14.0,20.0/

&VENT ID='Vent Front', SURF_ID='OPEN', XB=10.5,30.5,5.0,5.0,14.0,20.0/

&VENT ID='Vent Back', SURF_ID='OPEN', XB=10.5,30.5,25.0,25.0,14.0,20.0/





Soot'/



Air'/

&TAIL /



7-jan-2018 22:37:04


&TIME T_END=300.0, DT=1.0/




XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,



COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/











&DEVC ID='AIR flow_MASS MEAN', QUANTITY='MASS FLUX Z', SPEC_ID='AIR',

STATISTICS='MASS MEAN', XB=10.5,30.5,5.0,25.0,12.75,13.0/

&DEVC ID='AIR flow_VOLUME MEAN', QUANTITY='MASS FLUX Z', SPEC_ID='AIR',

STATISTICS='VOLUME MEAN', XB=10.5,30.5,5.0,25.0,12.75,13.0/

&DEVC ID='AIR flow_MIN', QUANTITY='MASS FLUX Z', SPEC_ID='AIR',

STATISTICS='MIN', XB=10.5,30.5,5.0,25.0,12.75,13.0/

&DEVC ID='AIR flow_MAX', QUANTITY='MASS FLUX Z', SPEC_ID='AIR',

STATISTICS='MAX', XB=10.5,30.5,5.0,25.0,12.75,13.0/

&DEVC ID='AIR flow_MEAN', QUANTITY='MASS FLUX Z', SPEC_ID='AIR',

STATISTICS='MEAN', XB=10.5,30.5,5.0,25.0,12.75,13.0/

&DEVC ID='SOOT flow_VOLUME MEAN', QUANTITY='MASS FLUX Z', SPEC_ID='SOOT',

STATISTICS='VOLUME MEAN', XB=10.5,30.5,5.0,25.0,12.75,13.0/

&DEVC ID='SOOT flow_MASS MEAN', QUANTITY='MASS FLUX Z', SPEC_ID='SOOT',

STATISTICS='MASS MEAN', XB=10.5,30.5,5.0,25.0,12.75,13.0/

&DEVC ID='SOOT flow_MIN', QUANTITY='MASS FLUX Z', SPEC_ID='SOOT',

STATISTICS='MIN', XB=10.5,30.5,5.0,25.0,12.75,13.0/

&DEVC ID='SOOT flow_MAX', QUANTITY='MASS FLUX Z', SPEC_ID='SOOT',

STATISTICS='MAX', XB=10.5,30.5,5.0,25.0,12.75,13.0/

&DEVC ID='SOOT flow_MEAN', QUANTITY='MASS FLUX Z', SPEC_ID='SOOT',

STATISTICS='MEAN', XB=10.5,30.5,5.0,25.0,12.75,13.0/

&TAIL /



7-jan-2018 22:37:19


&TIME T_END=120.0, DT=1.0/


DT_SL3D=0.25/

&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,


&DEVC ID='Air Detection', QUANTITY='MASS FLUX Z', SPEC_ID='AIR',

XYZ=15.0,15.0,12.75/

&DEVC ID='Soot Detection', QUANTITY='MASS FLUX Z', SPEC_ID='SOOT',

XYZ=15.0,15.0,12.75/

&DEVC ID='CO2 Detection', QUANTITY='MASS FLUX Z', SPEC_ID='CARBON

DIOXIDE', XYZ=15.0,15.0,12.75/

&DEVC ID='CO Detection', QUANTITY='MASS FLUX Z', SPEC_ID='CARBON

MONOXIDE', XYZ=15.0,15.0,12.75/

&DEVC ID='N2 Detection', QUANTITY='MASS FLUX Z', SPEC_ID='NITROGEN',

XYZ=15.0,15.0,12.75/

&DEVC ID='O2 Detection', QUANTITY='MASS FLUX Z', SPEC_ID='OXYGEN',

XYZ=15.0,15.0,12.75/

&DEVC ID='H2O Detection', QUANTITY='MASS FLUX Z', SPEC_ID='WATER VAPOR',

XYZ=15.0,15.0,12.75/


COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/









&SLCF QUANTITY='TEMPERATURE', CELL_CENTERED=.TRUE., PBZ=13.0/

&SLCF QUANTITY='VELOCITY', VECTOR=.TRUE., CELL_CENTERED=.TRUE., PBY=15.0/

&SLCF QUANTITY='HRRPUV', CELL_CENTERED=.TRUE., PBY=15.0/

&SLCF QUANTITY='TEMPERATURE', CELL_CENTERED=.TRUE., PBY=15.0/

&DEVC ID='AIR flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z', SPEC_ID='AIR',

STATISTICS='AREA INTEGRAL', XB=10.5,20.5,5.0,25.0,12.75,12.75/

&DEVC ID='SOOT flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',

SPEC_ID='SOOT', STATISTICS='AREA INTEGRAL',

XB=10.5,20.5,5.0,25.0,12.75,12.75/

&DEVC ID='CO2 flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',

SPEC_ID='CARBON DIOXIDE', STATISTICS='AREA INTEGRAL',

XB=10.5,20.5,5.0,25.0,12.75,12.75/

&DEVC ID='CO flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z', SPEC_ID='CARBON

MONOXIDE', STATISTICS='AREA INTEGRAL', XB=10.5,20.5,5.0,25.0,12.75,12.75/

&DEVC ID='N2 flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',

SPEC_ID='NITROGEN', STATISTICS='AREA INTEGRAL',

XB=10.5,20.5,5.0,25.0,12.75,12.75/

&DEVC ID='O2 flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',

SPEC_ID='OXYGEN', STATISTICS='AREA INTEGRAL',

XB=10.5,20.5,5.0,25.0,12.75,12.75/

&DEVC ID='H2O flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z', SPEC_ID='WATER

VAPOR', STATISTICS='AREA INTEGRAL', XB=10.5,20.5,5.0,25.0,12.75,12.75/

&TAIL /



7-jan-2018 22:37:35


&TIME T_END=120.0, DT=1.0/


DT_SL3D=0.25/

&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,


&DEVC ID='Air Detection', QUANTITY='MASS FLUX Z', SPEC_ID='AIR',

XYZ=15.0,15.0,12.75/

&DEVC ID='Soot Detection', QUANTITY='MASS FLUX Z', SPEC_ID='SOOT',

XYZ=15.0,15.0,12.75/

&DEVC ID='CO2 Detection', QUANTITY='MASS FLUX Z', SPEC_ID='CARBON

DIOXIDE', XYZ=15.0,15.0,12.75/

&DEVC ID='CO Detection', QUANTITY='MASS FLUX Z', SPEC_ID='CARBON

MONOXIDE', XYZ=15.0,15.0,12.75/

&DEVC ID='N2 Detection', QUANTITY='MASS FLUX Z', SPEC_ID='NITROGEN',

XYZ=15.0,15.0,12.75/

&DEVC ID='O2 Detection', QUANTITY='MASS FLUX Z', SPEC_ID='OXYGEN',

XYZ=15.0,15.0,12.75/

&DEVC ID='H2O Detection', QUANTITY='MASS FLUX Z', SPEC_ID='WATER VAPOR',

XYZ=15.0,15.0,12.75/

&DEVC ID='Air Detection01', QUANTITY='MASS FLUX Z', SPEC_ID='AIR',

XYZ=15.0,10.0,12.75/

&DEVC ID='Soot Detection01', QUANTITY='MASS FLUX Z', SPEC_ID='SOOT',

XYZ=15.0,10.0,12.75/

&DEVC ID='CO2 Detection01', QUANTITY='MASS FLUX Z', SPEC_ID='CARBON

DIOXIDE', XYZ=15.0,10.0,12.75/

&DEVC ID='CO Detection01', QUANTITY='MASS FLUX Z', SPEC_ID='CARBON

MONOXIDE', XYZ=15.0,10.0,12.75/

&DEVC ID='N2 Detection01', QUANTITY='MASS FLUX Z', SPEC_ID='NITROGEN',

XYZ=15.0,10.0,12.75/

&DEVC ID='O2 Detection01', QUANTITY='MASS FLUX Z', SPEC_ID='OXYGEN',

XYZ=15.0,10.0,12.75/

&DEVC ID='H2O Detection01', QUANTITY='MASS FLUX Z', SPEC_ID='WATER

VAPOR', XYZ=15.0,10.0,12.75/


XYZ=15.0,20.0,12.75/


XYZ=15.0,20.0,12.75/


DIOXIDE', XYZ=15.0,20.0,12.75/


MONOXIDE', XYZ=15.0,20.0,12.75/


XYZ=15.0,20.0,12.75/


XYZ=15.0,20.0,12.75/


VAPOR', XYZ=15.0,20.0,12.75/


XYZ=18.0,15.0,12.75/


XYZ=18.0,15.0,12.75/


DIOXIDE', XYZ=18.0,15.0,12.75/


MONOXIDE', XYZ=18.0,15.0,12.75/


XYZ=18.0,15.0,12.75/


XYZ=18.0,15.0,12.75/


VAPOR', XYZ=18.0,15.0,12.75/


XYZ=18.0,10.0,12.75/


XYZ=18.0,10.0,12.75/


DIOXIDE', XYZ=18.0,10.0,12.75/


MONOXIDE', XYZ=18.0,10.0,12.75/


XYZ=18.0,10.0,12.75/


XYZ=18.0,10.0,12.75/


VAPOR', XYZ=18.0,10.0,12.75/


XYZ=18.0,20.0,12.75/


XYZ=18.0,20.0,12.75/


DIOXIDE', XYZ=18.0,20.0,12.75/


MONOXIDE', XYZ=18.0,20.0,12.75/


XYZ=18.0,20.0,12.75/


XYZ=18.0,20.0,12.75/


VAPOR', XYZ=18.0,20.0,12.75/


XYZ=12.0,15.0,12.75/


XYZ=12.0,15.0,12.75/


DIOXIDE', XYZ=12.0,15.0,12.75/


MONOXIDE', XYZ=12.0,15.0,12.75/


XYZ=12.0,15.0,12.75/


XYZ=12.0,15.0,12.75/


VAPOR', XYZ=12.0,15.0,12.75/


XYZ=12.0,10.0,12.75/


XYZ=12.0,10.0,12.75/


DIOXIDE', XYZ=12.0,10.0,12.75/


MONOXIDE', XYZ=12.0,10.0,12.75/


XYZ=12.0,10.0,12.75/


XYZ=12.0,10.0,12.75/


VAPOR', XYZ=12.0,10.0,12.75/


XYZ=12.0,20.0,12.75/


XYZ=12.0,20.0,12.75/


DIOXIDE', XYZ=12.0,20.0,12.75/


MONOXIDE', XYZ=12.0,20.0,12.75/


XYZ=12.0,20.0,12.75/


XYZ=12.0,20.0,12.75/


VAPOR', XYZ=12.0,20.0,12.75/


COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/









&SLCF QUANTITY='TEMPERATURE', CELL_CENTERED=.TRUE., PBZ=13.0/

&SLCF QUANTITY='VELOCITY', VECTOR=.TRUE., CELL_CENTERED=.TRUE., PBY=15.0/

&SLCF QUANTITY='HRRPUV', CELL_CENTERED=.TRUE., PBY=15.0/

&SLCF QUANTITY='TEMPERATURE', CELL_CENTERED=.TRUE., PBY=15.0/





XB=10.5,20.5,5.0,25.0,12.75,12.75/



XB=10.5,20.5,5.0,25.0,12.75,12.75/



&DEVC ID='N2 flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',

SPEC_ID='NITROGEN', STATISTICS='AREA INTEGRAL',

XB=10.5,20.5,5.0,25.0,12.75,12.75/

&DEVC ID='O2 flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',

SPEC_ID='OXYGEN', STATISTICS='AREA INTEGRAL',

XB=10.5,20.5,5.0,25.0,12.75,12.75/



&TAIL /



7-jan-2018 22:37:48


&TIME T_END=120.0, DT=1.0/



&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,



COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/










&SLCF QUANTITY='VELOCITY', VECTOR=.TRUE., PBY=15.0/

&SLCF QUANTITY='HRRPUV', PBY=15.0/

&SLCF QUANTITY='TEMPERATURE', PBY=15.0/





XB=10.5,30.5,5.0,25.0,12.75,12.75/



XB=10.5,30.5,5.0,25.0,12.75,12.75/





&DEVC ID='Products_AREA INTEGRAL', QUANTITY='MASS FLUX Z',

SPEC_ID='PRODUCTS', STATISTICS='AREA INTEGRAL',

XB=10.5,30.5,5.0,25.0,12.75,12.75/

&DEVC ID='Reaction Products_AREA INTEGRAL', QUANTITY='MASS FLUX Z',

SPEC_ID='REAC_FUEL', STATISTICS='AREA INTEGRAL',

XB=10.5,30.5,5.0,25.0,12.75,12.75/

&TAIL /



7-jan-2018 22:38:06


&TIME T_END=120.0, DT=1.0/



&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,



COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/
















XB=10.5,20.5,5.0,25.0,12.75,12.75/



XB=10.5,20.5,5.0,25.0,12.75,12.75/





&DEVC ID='Products_AREA INTEGRAL', QUANTITY='MASS FLUX Z',


XB=10.5,20.5,5.0,25.0,12.75,12.75/

&TAIL /



7-jan-2018 22:38:23


&TIME T_END=120.0, DT=1.0/



&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,



COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/













&SLCF QUANTITY='VELOCITY', VECTOR=.TRUE.,

XB=10.5,30.5,5.0,25.0,12.75,13.0, FYI='AIR speed'/


XB=10.5,30.5,5.0,25.0,12.75,13.0, FYI='AIR flow'/

&DEVC ID='Z - Air flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',

SPEC_ID='AIR', STATISTICS='AREA INTEGRAL',

XB=10.5,20.5,5.0,25.0,12.75,12.75/

&DEVC ID='Z - Air flow min-max_MIN', QUANTITY='MASS FLUX Z',

SPEC_ID='AIR', STATISTICS='MIN', XB=10.5,20.5,5.0,25.0,12.75,13.0/

&DEVC ID='Z - Air flow min-max_MAX', QUANTITY='MASS FLUX Z',

SPEC_ID='AIR', STATISTICS='MAX', XB=10.5,20.5,5.0,25.0,12.75,13.0/

&DEVC ID='Z - CO flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',

SPEC_ID='CARBON MONOXIDE', STATISTICS='AREA INTEGRAL',

XB=10.5,20.5,5.0,25.0,12.75,12.75/

&DEVC ID='Z - CO2 flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',


XB=10.5,20.5,5.0,25.0,12.75,12.75/

&DEVC ID='Z - H2O flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',

SPEC_ID='WATER VAPOR', STATISTICS='AREA INTEGRAL',

XB=10.5,20.5,5.0,25.0,12.75,12.75/

&DEVC ID='Z - Products flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',


XB=10.5,20.5,5.0,25.0,12.75,12.75/

&DEVC ID='Z - Soot flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',


XB=10.5,20.5,5.0,25.0,12.75,12.75/

&DEVC ID='X - Air flow_AREA INTEGRAL', QUANTITY='MASS FLUX X',


XB=10.3,10.3,14.0,16.0,0.0,3.0/

&DEVC ID='X - CO flow_AREA INTEGRAL', QUANTITY='MASS FLUX X',


XB=10.3,10.3,14.0,16.0,0.0,3.0/

&DEVC ID='X - CO2 flow_AREA INTEGRAL', QUANTITY='MASS FLUX X',


XB=10.3,10.3,14.0,16.0,0.0,3.0/

&DEVC ID='X - H2O flow_AREA INTEGRAL', QUANTITY='MASS FLUX X',


XB=10.3,10.3,14.0,16.0,0.0,3.0/

&DEVC ID='X - Products flow_AREA INTEGRAL', QUANTITY='MASS FLUX X',


XB=10.3,10.3,14.0,16.0,0.0,3.0/

&DEVC ID='X - Soot flow_AREA INTEGRAL', QUANTITY='MASS FLUX X',


XB=10.3,10.3,14.0,16.0,0.0,3.0/

&TAIL /



7-jan-2018 22:38:36


&TIME T_END=120.0, DT=1.0/



&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,


&DEVC ID='Temp Above Fire', QUANTITY='TEMPERATURE', XYZ=5.0,15.0,3.9/

&DEVC ID='Temp Door', QUANTITY='TEMPERATURE', XYZ=10.5,15.0,2.9/

&DEVC ID='Temp Spill Edge', QUANTITY='TEMPERATURE', XYZ=12.5,15.0,3.9/

&DEVC ID='Temp Ceiling', QUANTITY='TEMPERATURE', XYZ=12.5,15.0,12.75/


COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/












&DEVC ID='3 - Air flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',


XB=10.5,14.5,5.0,11.0,12.75,12.75/

&DEVC ID='3 - Air flow min-max_MIN', QUANTITY='MASS FLUX Z',


&DEVC ID='3 - Air flow min-max_MAX', QUANTITY='MASS FLUX Z',


&DEVC ID='3 - CO flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',


XB=10.5,14.5,5.0,11.0,12.75,12.75/

&DEVC ID='3 - CO2 flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',


XB=10.5,14.5,5.0,11.0,12.75,12.75/

&DEVC ID='3 - H2O flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',


XB=10.5,14.5,5.0,11.0,12.75,12.75/

&DEVC ID='3 - Products flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',


XB=10.5,14.5,5.0,11.0,12.75,12.75/

&DEVC ID='3 - Soot flow_AREA INTEGRAL', QUANTITY='MASS FLUX Z',


XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/







XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/







XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/

&TAIL /



7-jan-2018 22:38:49


&TIME T_END=300.0, DT=1.0/



&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,


&DEVC ID='Temp Outflow Door', QUANTITY='TEMPERATURE', XYZ=10.5,15.0,2.9/

&DEVC ID='Temp Outflow Balcony', QUANTITY='TEMPERATURE',

XYZ=11.5,15.0,3.9/


COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-259.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/














XB=10.5,14.5,5.0,11.0,12.75,12.75/







XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/







XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/







XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/

&TAIL /



7-jan-2018 22:39:02


&TIME T_END=120.0, DT=1.0/



&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,


&DEVC ID='Temp Above Fire Source', QUANTITY='TEMPERATURE',

XYZ=5.0,15.0,3.9/


&DEVC ID='Temp Outflow Balcony', QUANTITY='TEMPERATURE',

XYZ=12.5,15.0,3.9/

&DEVC ID='Temp Outflow Ceiling', QUANTITY='TEMPERATURE',

XYZ=12.5,15.0,12.75/


COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/

&HOLE ID='Vent in roof', XB=10.49,30.51,4.99,25.01,12.7,13.0/ Physical

vent in rooftop












XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/

&TAIL /



7-jan-2018 22:39:14


&TIME T_END=120.0, DT=1.0/



&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,20.5,5.0,25.0,0.0,14.0/


XB=10.5,20.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,



XYZ=5.0,15.0,3.9/



&DEVC ID='Temp Ceiling', QUANTITY='TEMPERATURE', XYZ=12.5,15.0,12.75/


COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/

&HOLE ID='Vent in roof', XB=10.49,20.51,4.99,25.01,12.7,13.0/ Physical

vent in rooftop












XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/

&TAIL /



7-jan-2018 22:39:27


&TIME T_END=120.0, DT=1.0/



&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,



XYZ=5.0,15.0,3.9/




XYZ=12.5,15.0,12.75/


COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/














XB=10.5,14.5,5.0,11.0,12.75,12.75/







XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/







XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/







XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/

&TAIL /



7-jan-2018 22:39:42


&TIME T_END=120.0, DT=1.0/



&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,



XYZ=5.0,15.0,3.9/



XYZ=12.5,15.0,12.75/


COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/









&OBST ID='Floor R1', XB=30.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=30.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/














XB=10.5,14.5,5.0,11.0,12.75,12.75/







XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/







XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/







XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/

&TAIL /



7-jan-2018 22:39:57


&TIME T_END=120.0, DT=1.0/



&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,



XYZ=5.0,15.0,3.9/



XYZ=12.5,15.0,12.75/


COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/









&OBST ID='Floor R1', XB=30.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=30.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/














XB=10.5,14.5,5.0,11.0,12.75,12.75/







XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,5.0,11.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/







XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,14.5,19.0,25.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/







XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/



XB=10.5,18.5,11.0,19.0,12.75,12.75/

&TAIL /



12-jan-2018 20:41:00


&TIME T_END=120.0, DT=1.0/



&MISC TMPA=25.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12,



XYZ=20.5,15.0,12.75/


COLOR='GRAY 80',

DEFAULT=.TRUE.,

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/









&OBST ID='Floor R1', XB=30.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=30.5,40.75,0.0,30.0,8.25,8.5,











&HOLE ID='Door - Fire Room', XB=10.25,10.5,14.0,16.0,0.0,4.0/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/















XB=16.5,24.5,11.0,19.0,12.75,12.75/







XB=16.5,24.5,11.0,19.0,12.75,12.75/



XB=16.5,24.5,11.0,19.0,12.75,12.75/



XB=16.5,24.5,11.0,19.0,12.75,12.75/



XB=16.5,24.5,11.0,19.0,12.75,12.75/



XB=16.5,24.5,11.0,19.0,12.75,12.75/

&TAIL /

Design_Extra_-_V20.fds


12-jan-2018 20:50:37

&HEAD CHID='Design_Extra_-_V20', TITLE='Atrium Test'/

&TIME T_END=120.0, DT=1.0/

&DUMP RENDER_FILE='Design_Extra_-_V20.ge1', COLUMN_DUMP_LIMIT=.TRUE.,


&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12/




&DEVC ID='Temp Ceiling Vent', QUANTITY='TEMPERATURE',

XYZ=12.5,15.0,12.75/

&DEVC ID='Mass Flow', QUANTITY='MASS FLOW +',

XB=10.5,30.5,5.0,25.0,12.75,12.75/


COLOR='GRAY 80',

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/



XB=10.5,30.5,5.0,25.0,20.0,20.0/








&TAIL /



12-jan-2018 20:54:43


&TIME T_END=120.0, DT=1.0/



&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12/





XYZ=12.5,15.0,12.75/


XB=10.5,30.5,5.0,25.0,12.75,12.75/


COLOR='GRAY 80',

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/

















&OBST ID='Floor R1', XB=28.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=28.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/



XB=10.5,30.5,5.0,25.0,20.0,20.0/








&TAIL /



12-jan-2018 20:55:06


&TIME T_END=120.0, DT=1.0/



&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12/




XYZ=12.5,15.0,12.75/


XB=10.5,30.5,5.0,25.0,12.75,12.75/


COLOR='GRAY 80',

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/









&OBST ID='Floor R1', XB=30.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=30.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/



XB=10.5,30.5,5.0,25.0,20.0,20.0/








&TAIL /



12-jan-2018 20:55:47


&TIME T_END=120.0, DT=1.0/



&MISC TMPA=25.0/


XB=0.25,10.5,10.0,20.0,0.0,4.0/


XB=10.5,30.5,5.0,25.0,0.0,14.0/


XB=10.5,30.5,5.0,25.0,14.0,20.0/



FUEL='REAC_FUEL',

C=1.0,

H=1.7,

O=0.83,

CO_YIELD=5.0E-3,

SOOT_YIELD=0.12/




XYZ=12.5,15.0,12.75/


XB=10.5,30.5,5.0,25.0,12.75,12.75/


COLOR='GRAY 80',

ADIABATIC=.TRUE./

&SURF ID='BURNER',


COLOR='RED',

HRRPUA=625.0,

TAU_Q=-1.0,


EMISSIVITY=1.0/









&OBST ID='Floor R1', XB=30.5,40.75,0.0,30.0,4.0,4.25,


&OBST ID='Floor R2', XB=30.5,40.75,0.0,30.0,8.25,8.5,












&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,0.0,3.0/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,4.25,7.25/

&HOLE ID='Door', XB=10.25,10.5,14.0,16.0,8.5,11.5/

&HOLE ID='Door', XB=30.5,30.75,14.0,16.0,8.5,11.5/



XB=10.5,30.5,5.0,25.0,20.0,20.0/








&TAIL /

analysis of the cen/tr 12101-5 calculation methodology by ... · engineering for granting me a free...

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