Fire Modelling and Transfer of Heat

8/18/2019 Fire Modelling and Transfer of Heat

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9-2. Fire behaviour

František Wald

Czech Technical Universit in Pra ue


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Objectives

Repetition Nominal fire

curves

Parametric fire

• Models of fire

• Software supports

u v

Advanced fire

models

• Models of transfer of heat into structure Assessment 1

Thermal response

• o ware suppor s• Example of test on building

Unprotected steel

Protected steel

Software support

Assessment 2

Fire tests

in Cardington

Conclusions

Notes

Lecture 9-1, V001, April 092


3/66

Objectives

Repetition

Nominal fire

curves

Parametric fire

u v

Advanced fire

modelsDesign of building

Design of building

Assessment 1

Thermal responseFire safety requirements

National fire regulations

Fire safety requirements

National fire regulations

Unprotected steel

Protected steel

Software support

Advanced modelsFire test of elements Parametric curves Nominal curves

. .

Calcul . of structure temp.

Assessment 2

Fire tests

in Cardington

Fire safety

Struct. analyses

Step by step procedure Fire testsFinite element

based on elements

Conclusions

Notes

Fire safety of structure

rucura eemenoe s ruc ure ar o e s ruc ure



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Objectives

Repetition

Nominal fire

curves

Parametric fire

EurocodesFire design

u v

Advanced fire

models

Fire behaviour

EN 1991-1-2Modelling of the gas temparature

Assessment 1

Thermal response

in the fire compartmentUnprotected steel

Protected steel

Software support

EN 1991-1-x

Transfer of heatand development in structure

Assessment 2

Fire tests

in Cardington

Mechanical load

x- -

Structural response

Conclusions

Notes


Design of structure at elevated temparature


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Objectives


curves

Parametric fire

Parametric curves

u v

Advanced fire

models

Zone models

Assessment 1

Thermal response

CFDComputational Fluid Dynamics

Unprotected steel

Protected steel

Software support

Assessment 2Fire tests

in Cardington

Conclusions

Notes


ruc ura response

5


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Objectives

Repetition

Nominal firecurvesParametric fire

Temperature, °C

Pre- flashover Post- flashover

°

u v

Advanced fire

models

-

Flashover

Assessment 1

Thermal response

Unprotected steel

Protected steel

Software support

Nominal standard

fire curve

Temperature

during fire

Assessment 2

Fire tests

in Cardington

Time, min

Conclusions

Notes


Cooling ….gn on ea ng


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Objectives


curves

Parametric fire

( )18log34520 10g ++=

t θ

u v

Advanced fire

models

Nominal external curve

t t 38,032,0 −− −−=

Assessment 1

Thermal response

Nominal hydrocarbon curve

g ,,Unprotected steelProtected steel

Software support

( )t t 5,2167,0g e675,0e325,01108020 −− −−+=θ Assessment 2

Fire tests

in Cardington

Conclusions

Notes

Lecture 9-1, V001, April 09 7


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Objectives

Repetition

•

Nominal fire

curves

Parametric fire

u v

Advanced fire

models

Nominal h drocarbon curve1200

Gas temparature, °C

Assessment 1

Thermal response

1000

Unprotected steel

Protected steel

Software support

Nominal standard fire curve800

Assessment 2

Fire tests

in Cardington

400Conclusions

Notes200


0 15 30 45 60 90 120 150 180

,0


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Objectives


curves

Parametric fire

• Has limitations

– Not based on real fire data

u v

Advanced fire

models

– Test repeatability difficult

– No cooling phase

Assessment 1

Thermal response

– Uniform heating

– Uses as tem erature “not fair”

Unprotected steel

Protected steel

Software support

• But Assessment 2

Fire tests

in Cardington –

– Can be useful for crudely comparing products

Conclusions

Notes



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Objectives


curves

Parametric f ire

Parametric curves

u v

Advanced fire

models

Zone models

Assessment 1

Thermal response


Unprotected steel

Protected steel

Software support


in Cardington

Conclusions

Notes


ruc ura response

10


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Objectives


curves

Parametric f ire

• No heat built-up in pre-flashover phase of fire

• Temperature uniform in the compartment

u v

Advanced fire

models

• Uniform heat transfer coefficient in compartment

boundaries

Assessment 1

Thermal response

• com us on a es p ace n e compar menUnprotected steel

Protected steel

Software support

Assessment 2

Fire tests

in Cardington

Conclusions

Notes



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Objectives


curves

Parametric f ire

The calculation is in Annex A of EN 1991-1-2

• The size of the compartment is limited to 500 m2

u v

Advanced fire

models

• The openings are in the walls only(no openings in the roof)

Assessment 1

Thermal response

• The fire load density qt,d from 50 to 1000 MJ/m2

(about 3,5 kg to 70 kg of timber / m2)

Unprotected steel

Protected steel

Software support

• Cellulosic type of fire load1000

Gas temperature, °C

Assessment 2

Fire tests

in Cardington

400

600

Heating Cooling

Conclusions

Notes


0 0 15 30 45 60 90 120 Time, min

13


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Objectives

Repetition

In ut data

Nominal fire

curves

Parametric f ire

Fire load density qt,d for calculation of t tmax

u v

Advanced fire

models

Geometry of the fire compartment[ ]21 /

t

v m A

h AO =

Assessment 1

Thermal response

Thermal properties of boundary of enclosure[ ]K smJ c b / 212λ ρ =

Unprotected steel

Protected steel

Software support

Time modification factor

2

⎟⎟

⎠

⎞⎜⎜

⎝

⎛

= ref O

O Assessment 2

Fire tests

in Cardington

⎟⎟ ⎠

⎞⎜⎜⎝

⎛

ref b

bConclusions

Notes


c ve me n ours t t Γ =

14


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Objectives

Repetition

Two arts of the arametric fire curve

Nominal fire

curves

Parametric f ire

The curve in the burning phase

***

u v

Advanced fire

models

,,tg, e,e,e,

−−− −−−+= Assessment 1

Thermal response

The curve in the cooling phase (depends on t *

max , e.g.)

x t t *max*

maxtg, 250 −−= θ θ

Unprotected steel

Protected steel

Software support

600

800

1000Gas temperature, °C Assessment 2

Fire tests

in Cardington

0

200

400

0 15 30 45 60 90 120 Time, min

Heating CoolingConclusions

Notes



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Objectives

Repetition

•

Nominal firecurves

Parametric f ire

– t max = 0,2 10-3 q

t,d

/ O

u v

Advanced fire

models

– max = max

Assessment 1

Thermal response

• Fire driven by fire load – t max = t lim = 25 min (fast fire or 20 min and 15 min slow fire)

Unprotected steel

Protected steel

Software support

– t* max = t max Γ lim800

1000Gas temperature, °C Assessment 2

Fire tests

in Cardington

200

400

600

Heating Cooling

Conclusions

Notes


0

0 15 30 45 60 90 120 Time, min


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Objectives


curves

Parametric f ire

Av

u v

Advanced fire

models

[ ]21t

v / m A

O = Af

H hb

Assessment 1

Thermal response

Av area of openingh height of opening

Unprotected steel

Protected steel

Software support

At total surface area of the enclosure(walls, ceiling and floor, including the openings)

Assessment 2

Fire tests

in Cardington

Conclusions

Notes



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Objectives


curves

Parametric f ire

• Small openings - longer and colder fires

• Large openings - faster and hotter fires

u v

Advanced fire

models

1200

Temperature, °C)

Assessment 1

Thermal response

800

1000

Unprotected steel

Protected steel

Software support

400

600

0,02

1/2

0,02

factor O [m ]

Small openings

Opening Assessment 2

Fire tests

in Cardington

200

,

0,1

0,15

0,2

,

0,1

0,15

0,2 Large openings

Conclusions

Notes


0 15 30 60 Time, min45


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Objectives


curves

Parametric f ire

• Low fire load - shorter and coulder fires

• High fire load - longer and wormer fires

u v

Advanced fire

models

1000

θ

Fire load density [MJ/m ]22

Temperature, °C

Assessment 1

Thermal response

800

200

400

600

Unprotected steel

Protected steel

Software support

400

6001000

Assessment 2

Fire tests

in Cardington

200

Conclusions

Notes


0

0 60 1200 15 30 60 90 120 Time, min45


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Objectives


curves

Parametric f ire

- – .

• Isolated walls – lower cooling - higher temp.

u v

Advanced fire

models

Temperature, °C

b = 702

[ ]K sJ/m λc ρb / 212=

Assessment 1

Thermal response

800

1000

b = 2000

Unprotected steel

Protected steel

Software support

600 Gypsum board

Light weight concreteb = 1120

Assessment 2

Fire tests

in Cardington

200

Normal concrete

Nominal standard fire curve

For fire load qf d = 700 MJ/m2

Conclusions

Notes


00 30 60 90 120 Time, min

,


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Objectives


curves

Parametric fire

• More sophisticated energy balance models

• Assume uniform temperatures in each zone

u v

Advanced fire

models

• Normally computer based

Assessment 1

Thermal response

• evera commerc a co es ava a e eg.

Ozone, CFast

Unprotected steel

Protected steel

Software support

• Similar drawbacks and benefits to parametric

curves

Assessment 2

Fire tests

in Cardington

Conclusions

Notes



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Objectives


curves

Parametric fire

Parametric curves

u v

Advanced fire

models

Zone models

Assessment 1

Thermal response


Unprotected steel

Protected steel

Software support


in Cardington

Conclusions

Notes


ruc ura response

22


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Objectives


curves

Parametric fire

• Based on partial differential equations:

–Mass balance

u v

Advanced fire

models

• the air (oxygen) entering the fire compartment is used for burning of the

fuel, the amount of the incoming air and the gases created as result of

the burning is equal to the amount of gas escaping through the openings

Assessment 1

Thermal response

–Energy balance• the energy released from the burning is used to heat the gas in the fire

Unprotected steel

Protected steel

Software support

compartment, the walls, floor and ceiling, some energy is „lost“ as the

gas exits the compartment through the openings

Assessment 2

Fire tests

in Cardington

Two zone model

Conclusions

Notes


One zone model

23


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Objectives


curves

Parametric fire

Parametric curves

u v

Advanced fire

models

Zone models

Assessment 1

Thermal response


Unprotected steel

Protected steel

Software support


in Cardington

Conclusions

Notes


ruc ura response

24


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Objectives


curves

Parametric fire

• Computational Fluid Dynamics

• Can predict huge range of phenomena

u v

Advanced fire

models

• Difficult to use

due to man uncertainties in in ut variables

Assessment 1

Thermal response

• Still more a research method

Unprotected steel

Protected steel

Software support

xamp e o s mu a onthe influence of the ceiling surface on the temperature development during the

seventh Cardington large fire test

Assessment 2

Fire tests

in Cardington

Conclusions

Notes



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Objectives


curves

Parametric fire

• The simple tools are developped for

– Parametric fire curves

u v

Advanced fire

models

• eg. DIFISEK-EN 1991-1-2 Annex A

–

Assessment 1

Thermal response

• eg. Ozone programme

Unprotected steel

Protected steel

Software support

•

summarised in Assessment 2

Fire tests

in Cardington

• a a aseConclusions

Notes



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Objectives


curves

Parametric fire

• Are there some advantages of nominal fire curves?

• What are the advantages of parametric fire curves?

u v

Advanced fire

models

• What determine the maximal temperature of the parametric

fire curve?

Assessment 1

Thermal response

• ow s s mu a e coo ng y parame r c re curve

• Describe the principles of zone models?

Unprotected steel

Protected steel

Software support

Assessment 2

Fire tests

in Cardington

Conclusions

Notes



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Objectives


curves

Parametric fire

u v

Advanced fire

models

Fire behaviour (based on Standard fire curve) Assessment 1

Thermal response

Simple heattransfer models

Unprotected steel

Protected steel

Software support

(step by step procedure) Assessment 2

Fire tests

in Cardington

Structural response

transfer models

(Finite Elemet Methods)

Conclusions

Notes



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Principles of step by step procedureObjectives

Repetition

• One-dimensional heat transfer

for the fire unprotected steel elementNominal firecurvesParametric fire

• Equilibrium of increase of temperature of structural element

and heat received on surface of the element in time period Δt

u v

Advanced fire

models

t h Ac V Δθ Δ ρ dnet,mta,aa =The heat

received

on surface

Increase

of en element

temperature

Assessment 1

Thermal response

where

V volume of the element m3 er unit len th

Unprotected steel

Protected steel

Software support

Am surface area of the element [m2] per unit length

c a specific heat of steel [simplified c a = 650 J/kgK]

Assessment 2

Fire tests

in Cardington

ρ a density of steel [ ρ a = 7850 kg/m3 ]

hnet,d net heat flux received by the surface of the element [W/m2 ]

Conclusions

Notes


me per o max = s

29


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Step by step procedureObjectives

Repetition

for the fire unprotected steel element in EN 1993-1-2Nominal firecurves

Parametric fire

- ,

the temperature increase in time period Δt is

u v

Advanced fire

models

t hc

m Δ ρ

θ Δ dnet,aa

ta, = Assessment 1Thermal response

where Am /V is the section factor [m-1]

• cannot be used for Am /V smaller than 10 m-1

Unprotected steel

Protected steel

Software support

• w en m s arger an a ou m- ,

the computation gives θ a,t ≅ θ g,t

• the time period Δt should not be longer than 5 s

Assessment 2

Fire tests

in Cardington

The temperature increase depends on the section factor Am /V

Conclusions

Notes



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Thermal propertiesObjectives

Repetition

of carbon steel at elevated temperaturesNominal firecurves

Parametric fire

Specific heat Thermal conductivity

u v

Advanced fire

models

1600

ca [J/kgK]

60

λa [W/mK]

Assessment 1

Thermal response

1200

40

50Unprotected steel

Protected steel

Software support

800

20oC 735

oC

30

20oC

Assessment 2

Fire tests

in Cardington

0 200 400 600 800 1000 1200

θa [oC]

0 200 400 600 800 1000 1200

θa [oC]

Conclusions

Notes



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Section factor Am/VObjectives

Repetition

or e re unpro ec e s ee e emen

b

Nominal firecurves

Parametric fire

u v

Advanced fire

models

h

Assessment 1

Thermal response

Perimeter Ex osed erimeter 2 b+h

Unprotected steel

Protected steel

Software support

Area Area Area Assessment 2

Fire tests

in Cardington

Conclusions

NotesThe surface area of the element per unit length of the member

Lecture 9-1, V001, April 0932The figure – I. Burgess, STESSA project

by the volume of the member per unit length .


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Shadow effectObjectives

Repetition

Nominal firecurves

Parametric fire

t hV A

k Δθ Δ dnetmshta/

=

u v

Advanced fire

models

is applied for the total heat flux

c ρ aa

Assessment 1

Thermal response

• k sh

= 1 for hollow sections of convex shape

• k sh = 0,9 ( Am /V )b/ ( Am /V ) for I sections

Unprotected steel

Protected steel

Software support

• k sh = ( Am /V )b/ ( Am /V ) for other sections Assessment 2

Fire tests

in Cardington

For I sections may be simplified

( ) V AV AV A mbmm ///

Conclusions

Notes


c V Ac t a

ρ ρ dnet,

aam

dnet,

aa

sh,/

,

33


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Section factor ( Am/V)bObjectives

Repetition

for shadow effect, unprotected steel element

b

Nominal firecurves

Parametric fire

u v

Advanced fire

models

h

Assessment 1

Thermal response

Perimeter Exposed perimeter 2(b+h)

Unprotected steel

Protected steel

Software support

Assessment 2

Fire tests

in Cardington

Conclusions

Notes The box value of the the surface area of the element per unit

length of the member


devided by the volume of the member per unit length.


35/66

Heat fluxObjectives

Repetition

Nominal firecurves

Parametric fire

net

convection and

u v

Advanced fire

models

radiation

Assessment 1

Thermal response

The design value is given by

=

Unprotected steel

Protected steel

Software support

where

r ne ,cne ,ne , Assessment 2

Fire tests

in Cardington

hnet,c is effect off convection, heat flux from convection [W/m2]

hnet,r is effect off radiation, heat flux from radiation [W/m2]

Conclusions

Notes



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Convective heat fluxObjectives

Repetition

2

Nominal firecurves

Parametric fire

mgccnet, θ θ α −=

h

u v

Advanced fire

models

where

Assessment 1

Thermal response

α c s eat trans er coe c ent

• α c = 25 W/m2K for standard curve

Unprotected steel

Protected steel

Software support

• α c = 35 W/m2K for parametric curve

• α c

= 50 W/m2K for hydrocarbon curve

Assessment 2

Fire tests

in Cardington

• α c = 35 W/m2K for zone models and localized fires

θ g is gas temperature in proximity of the element [°C]

Conclusions

Notes


θ m

is surface temperature of the element [°C]

36


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Radiative heat fluxObjectives

Repetition

Nominal firecurves

Parametric fire

( ) ( )4

m

48resr net, 2732731067,5 +−+⋅=

−

θ θ ε φ r h

u v

Advanced fire

models

where

Assessment 1

Thermal response

φ is configuration factor, usually φ = 1,0

ε res is resulting emissivity, see next page

Unprotected steel

Protected steel

Software support

θ r is radiating temperature [°C ]

can be taken equal to the gas

Assessment 2

Fire tests

in Cardington

g

θ m is surface temperature of steel element [°C ]

-

Conclusions

Notes


, · -

37


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Resultin emissivitObjectives

Repetition

Nominal firecurves

Parametric fire

by amount of carbon particles and dust in the smoke,

and the colour and temperature of the surface.

u v

Advanced fire

models

mf res ε ε ε =

Assessment 1

Thermal response

w ere

ε f is emissivity of f ire, usually ε f = 1,0

Unprotected steel

Protected steel

Software support

ε m is emisivity of material surface for

• carbon steel element ε m = 0,7

Assessment 2

Fire tests

in Cardington

• stainless steel element ε m = 0,4

• aluminum alloys not painted ε m = 0,3

Conclusions

Notes


• aluminum alloys painted ε m

= 0,7

38

Obj ti


39/66

Techni ue of ste b ste recedureObjectives

Repetition

V A /

Nominal firecurves

Parametric fire

Spreadsheet technique (excel, etc.)Temperature increment

c ρ dnet,

aa

shta, =u v

Advanced fire

models

Gas temperature (according to temperature-time curve)

Com onents of the heat flux S ecific heat

Temperature

of the

element

Assessment 1

Thermal response

t Θ g h net,r h net,c h net,d c a ΔΘ a,t Θ a,t t

of steel at time t TimeUnprotected steel

Protected steel

Software support

min sec min 20,0 J/kg K 20,0

0 0 0 20,0 0 0 0 440 0,00 20,0

0 5 0,083 96,5 448 2679 3126 440 1,18 21,2

0 10 0,167 147,0 937 4402 5339 441 2,00 23,2

0 15 0,250 184,6 1435 5650 7085 442 2,65 25,8

Assessment 2

Fire tests

in Cardington

, , , ,

0 25 0,417 239,7 2412 7374 9787 446 3,63 32,6

0 30 0,500 261,1 2885 7998 10882 449

Conclusions

Notes


Objectives


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Result of ste b ste recedureObjectives

Repetition

Nominal firecurves

Parametric fire

empera ure o upro ec e s ee e emen

heated by nominal standard curve

u v

Advanced fire

models

°

Assessment 1

Thermal response

,

800

Gas temperature,

1000

nominal standard

Unprotected steel

Protected steel

Software support600

Influence of the specific heat leap of steel

Assessment 2

Fire tests

in Cardington

400

npro ec e e emen , sec on

Unprotected element, section IPN 400

Conclusions

Notes

0

200


0 10 20 30 40 50 60 70 Time, min

Objectives


41/66

Result of ste b ste recedureObjectives

Repetition

Nominal firecurves

Parametric fireSteel temperature, °C

of the fire

unprotected

u v

Advanced fire

models900

100150200

40

250

60

stee

θ a,t

Assessment 1

Thermal response700

2025

m m-110 A / V =

15

as function

of time t

Unprotected steel

Protected steel

Software support500

600 ec on ac or

and

section factor

Assessment 2

Fire tests

in Cardington300

400

mConclusions

Notes100

200


Time, min

15 30 45 60 75 900

0

Objectives


42/66

Principle of step by step procedureObjectives

Repetition

for the fire protected steel element

The surface tem erature of fire rotection

Nominal firecurves

Parametric fire

- the same as the gas temperature θ g - θ m


43/66

Step by step procedureObjectives

Repetition

or e re pro ec e s ee e emen n - -Nominal firecurves

Parametric fire

( )13/1

/tg,

10/ta,tg,ppta, −−

+

−= θ ΔΔ

φ

θ θ

ρ

λ θ Δ φ et

c d

V A

aa p

u v

Advanced fire

models

where

0ta, ≥θ Δ

V

Ad

c

c pp

aa

pp

ρ

ρ φ =

Assessment 1

Thermal response

λ p is thermal conductivity of the fire protection [W/mK]

A p / V is section factor of fire protected element [m-1]

²

Unprotected steel

Protected steel

Software support

p

d p is thickness of the fire protection [m]

ρ p is density of the fire protection [kg/m3]

Assessment 2

Fire tests

in Cardington

ρ a is density of steel [ ρ a = 7850 kg/m ]

c p is thermal capacity of the fire protection [J kg K]

c a is thermal capacity of steel

Conclusions

Notes


Δθ g,t is temperature increment in time step Δt

Δt is the time step in seconds, should not be bigger than 30 sec

43

Section factor A /VObjectives


44/66

Section factor Ap/VObject es

Repetition

or e re pro ec e s ee e emen

b

Nominal firecurves

Parametric fire

u v

Advanced fire

models

h

Assessment 1

Thermal response

Perimeter

Area2(b+h) Area

Exposedperimeter

Unprotected steel

Protected steel

Software support

Assessment 2

Fire tests

in Cardington

Conclusions

Notes The appropriate area of fire protection material per unit length

of the member


devided by the volume of the member per unit length .

Objectives


45/66

Result of ste b ste rocedurej

Repetition

Nominal firecurves

Parametric fire

empera ure o e re pro ec e s ee e emen

heated by nominal standard curve

u v

Advanced fire

models

°

Assessment 1

Thermal response

,

800

Gas temperature

1000

Thickness of fire protectionnominal standard

Unprotected steel

Protected steel

Software support600

10 mm

=p

Assessment 2

Fire tests

in Cardington

400

Conclusions

Notes

0

200

Steel temperature of fire protected element IPN240


0 10 20 30 40 50 60 70 Time, min

Objectives


46/66

Result of ste b ste rocedureRepetitionNominal firecurves

Parametric fire

empera ure o e re pro ec e s ee e emen s a,tas function of time t and section factor Ap /V

u v

Advanced fire

models

Temperature, °C

Assessment 1

Thermal response 700

800

35002500

45004000

3000

Unprotected steel

Protected steel

Software support

500

600

800600

1500

1000

Assessment 2

Fire tests

in Cardington300 200

300

Conclusions

Notes 100-3

[W K m ]d V

A

p

p p l -1Section factor


0 30 60 90 120 150 Time, min

Objectives


47/66

Repetition Nominal firecurves

Parametric fire

– Step by step procedure

•

u v

Advanced fire

models

– e.g. Heat transfer in steel structures or DIFISEK

– FE modelling

Assessment 1

Thermal response

– The description of tools advantages is summarised in DIFISEK+

database

•

Unprotected steel

Protected steel

Software support

– FE modelling

• Commercial acka es

Assessment 2

Fire tests

in Cardington

– The description of tools advantages is summarised in DIFISEK+

database

Conclusions

Notes


•

– e.g. for concrete and composite elementsConTemp

47

Objectives


48/66


Parametric fire

• What is the principle of step by step procedure of heat

transfer for the fire unprotected steel element?

u v

Advanced fire

models

• What is influencing the emissivity during the fire?

Assessment 1

Thermal response

• a are e pr nc p es o s ep y s ep proce ure o ea

transfer for the fire protected steel element?

•

Unprotected steel

Protected steel

Software support

and unprotected steel elements? Assessment 2

Fire tests

in Cardington

Conclusions

Notes


Objectives


49/66


Parametric fire

• The basical findings of European fire research 1980 - 2005

• Fire safety of composite steel to concrete strutures

u v

Advanced fire

models

Outside Inside

Assessment 1

Thermal response

54m

Unprotected steel

Protected steel

Software support

The 1920s

Assessment 2

Fire tests

in Cardington

Conclusions

Notes


Th lti t b idiObjectives


50/66

Three multistore buidin sRepetitionNominal firecurves

Parametric fire

u v

Advanced fire

models

Assessment 1

Thermal response

concrete

composite

building

Unprotected steel

Protected steel

Software support

finished 1994;

plan area 945 m2 Assessment 2

Fire tests

in Cardington

Conclusions

Notes


Concrete structure

Ei ht fl it b ildiObjectives


51/66

Ei ht floors com osite buildinRepetitionNominal firecurves

Parametric fire

21 mu v

Advanced fire

models

Assessment 1

Thermal response

33 m

Unprotected steel

Protected steel

Software support

Assessment 2

Fire tests

in Cardington

Sand bags

Conclusions

Notes


Floor plan of composite buildingObjectives


52/66

Floor plan of composite buildingRepetitionNominal firecurves

Parametric fire

BRE corner testBS demonstration office test

FE90009000

DC

9000B

9000 A

9000

u v

Advanced fire

models

4

6000305x165x40UB (43)356x171x51UB (50)

356x171x51UB (50)

305x165x40UB (43)305x305x137 UC (50)

Assessment 1

Thermal response

3

9000

Unprotected steel

Protected steel

Software support

2

6000

610x228x101UB (43)

3000

Assessment 2

Fire tests

in Cardington

BS corner testBS restrained beam testBRE large compartment test

BS 2-D cross-frame test

1

Conclusions

Notes


CTU edge bay test 2003

52

Objectives


53/66

Repetition

Nominal fire

curves

Parametric fire

arge sca e re exper men on compos e rameu v

Advanced fire

models

Assessment 1

Thermal response

Unprotected steel

Protected steel

Software support

Assessment 2

Fire tests

in Cardington

Conclusions

Notes


Restrained beam testObjectives


54/66

Restrained beam testRepetitionNominal fire

curves

Parametric fire

1200

Temperature, °C

u v

Advanced fire

models

1000

= Assessment 1

Thermal response

600

800

528

xx

Nominal

standard fire curve

Unprotected steel

Protected steel

Software support

400525

526

x

x

Assessment 2

Fire tests

in Cardington

0

524398x x

Gas temperature

Conclusions

Notes


me, m n

54

Membrane action of com osite slabObjectives


55/66

Membrane action of com osite slabRepetitionNominal fire

curves

Parametric fire One of the develo ments of the Cardin ton laborator wasu v

Advanced fire

models

the development of the models of fire safety of partially

unprotected columns under the composite slab in steel

Compressed area

Assessment 1

Thermal response

.

Unprotected steel

Protected steel

Software support

Assessment 2

Fire tests

in Cardington

Conclusions

Notes


Membrane

55

Objectives


56/66

Repetition

4th large scale fire experiment on composite frame

Nominal fire

curves

Parametric fire

u v

Advanced fire

models

Assessment 1

Thermal response

Unprotected steel

Protected steel

Software support

Assessment 2

Fire tests

in Cardington

Conclusions

Notes


CTU ed e ba testObjectives

R titi


57/66

CTU ed e ba testRepetition

7th large scale fire experiment on composite frame

Nominal fire

curves

Parametric fire

• Connection temperatures (a widen MS PowerPoint presentation)

• Connection forces and behavior (a widen MS PowerPoint presentation)

u v

Advanced fire

models

• Composite slab

Assessment 1

Thermal response

Unprotected steel

Protected steel

Software support

Assessment 2

Fire tests

in Cardington

Conclusions

Notes


Objectives

R titi


58/66

Repetition

Nominal fire

curves

Parametric fire

• Describe the basic models of fire.

• What are the major limits of parametric fire curve?

u v

Advanced fire

models

• What is the principle of zone models of fire?

• Describe the models of transfer of heat.

Assessment 1

Thermal response

• What is difference of transfer of heat to the fire protected

and fire unprotected steel element?

Unprotected steel

Protected steel

Software support

• Which material thermal properties of fire protection are

taken into account in evaluation of transfer of heat to the

fire rotected elements?

Assessment 2

Fire tests

in Cardington

Conclusions

Notes


Objectives

Repetition


59/66

Repetition

Nominal fire

curves

Parametric fire

• Simpliest model of fire is a nominal firve curve

• Zone model of fire su orted b software

curves

Advanced fire

models

brings an effective tool for practical design

•

Assessment 1

Thermal response

DIFISEK+

•

Unprotected steel

Protected steel

Software support

temperature is show on a fire test Assessment 2

Fire tests

in Cardington

Conclusions

Notes


ConclusionsObjectives

Repetition


60/66

ConclusionsRepetition

Nomo ram re ared based on ste b ste rocedure

Nominal fire

curves

Parametric fire

describes the heating of the fire protected and fire unprotected

steel members exposed to nominal standard fire curve.

u v

Advanced fire

models

700800

2000 1500 1000300

200

150 50

[ ]1m mV

A −[ ]Ca °θ⎥⎦

⎤⎢⎣

⎡λ

K m

W

d V

A3

p

p p

Assessment 1

Thermal response

500

600

500400

350

100

75

25

Unprotected steel

Protected steel

Software support

300

400 300

250

200

150

Assessment 2

Fire tests

in Cardington

100

200 100

unprotected

protected

Conclusions

Notes


0

0 15 30 45 60 75 90 105 120

Fire duration [min]

60

Objectives

Repetition


61/66

Repetition

Nominal fire

curves

Parametric fire

• The lecture introduced the bases of modelling

of the compartment fire and transfer of heat into structure

accordin to the Eurocodes.

u v

Advanced fire

models

Assessment 1

Thermal responseFire load

EurocodesFire design

Unprotected steel

Protected steel

Software support

EN 1991-1-2Modelling of the gas temparaturein the fire compartment

Assessment 2

Fire tests

in Cardington

Thermal response

Transfer of heat

Conclusions

Notes

Mechanical load

EN 199x-1-2

- -


Design of structure at elevated temparature

Structural response


62/66

an you


Objectives

Repetition


63/66

p Nominal fire

curves

Parametric fire

• s sess on s a as c n orma on a ou e mo e ng o reand transfer of heat to the structure and requires about 60 minlecturing.

u v

Advanced fire

models

www.access-steel.com and www.difisek.eu.

• The use of relevant standards of national standard institutions

Assessment 1

Thermal response

are strongly recommended.

• Formative questions should be well answered before thesummative questions completed within the tutorial session.

Unprotected steel

Protected steel

Software support

• Keywords for the lecture:

fire design, fire modelling, fire curve, transfer of heat, fire

Assessment 2

Fire tests

in Cardington

, .Conclusions

Notes


Objectives

Repetition


64/66

Nominal fire

curves

Parametric fire

Worked examples for heat transfer

• The application of the table is in AccessSteel example

u v

Advanced fire

models

• Fire

resistance of a

partially encased composite column

• The application of the graph is in AccessSteel example

Assessment 1

Thermal response

• Fire design of an unprotected beam using graphs

• The description of step by step procedure for heat transfer

Unprotected steel

Protected steel

Software support

• Fire design of an unprotected IPE section beam exposed to the

standard time temperature curve

Assessment 2

Fire tests

in Cardington

• Fire design of a protected HEB section column exposed to the

standard temperature time curve

Conclusions

Notes


Objectives

Repetition


65/66

Nominal fire

curves

Parametric fire

Worked examples for fire modelling

• The application of the nominal fire curve is in AccessSteel

u v

Advanced fire

models

examp e

• Fire design of an unprotected IPE section beam exposed to thestandard time temperature curve

Assessment 1

Thermal response

• The description of parametric fire curve is in AccessSteelexample

Unprotected steel

Protected steel

Software support

• Parametric fire curve for a fire compartment

• The application of the zone model is in the DIFISEK+

Assessment 2

Fire tests

in Cardington

• WP4 – Software for fire design, slide 10

Conclusions

Notes


Objectives

Repetition


66/66

•

Nominal fire

curves

Parametric fire.

• Lecture duration: 60 min

• Keywords: fire design, fire modelling, fire curve, transfer of heat,

u v

Advanced fire

models

fire protection, Eurocodes.

• Aspects to be discussed: high advantage of utilisation ofadvanced fire models, the simplicity of heat transfer by step by

Assessment 1

Thermal response

step procedure and its limits.

• Within the lecturing, the procedure of Eurocode fire design isex lained.

Unprotected steel

Protected steel

Software support

• Further reading: relevant documents from website ofwww.access-steel.com and www.difisek.eu.

Assessment 2

Fire tests

in Cardington

• The reached accuracy in prediction o elemenst temperature isshown on the prediction of the seveth large scale Cardington fire

test.

Conclusions

Notes


Documents

Fire Modelling and Transfer of Heat