Fire resistance of structural components protecting escape routes

FIRE AND MATERIALSFire Mater. 2004; 28:343–354 (DOI: 10.1002/fam.853)

Fire resistance of structural components protectingescape routes

Geoff Thomas1,n,y and Delwyn Lloydd2

1School of Architecture, Victoria University of Wellington, PO Box 600, Wellington, New Zealand2Envirnomental Control Business Unit, Wellington City Council, Wellington, New Zealand

SUMMARY

Generally, fire resistant structures are expected to survive a fire in an adjoining compartment.Some structures, such as floors, may be designed to provide time for the occupants to escape fromcompartments other than the one where the fire occurs. In the fire compartment smoke developmentgoverns the time available for egress. A common misconception is that the fire resistance rating (FRR), thetime an assembly will survive in a test furnace, is the time available to escape. In small compartments suchas those in residential accommodation their FRR is significantly longer than the times the assemblieswould survive in real compartment fires. Some fire engineering designs for retrofitted accommodationbuildings use FRR times for light timber frame walls and floors as the available egress time, which isunconservative.The method of time equivalence can provide a prediction of the FRR required to survive a compartment

burnout. The ratio of the total burning time of the fire to the time equivalent for the compartment and fuelload can be used to provide an estimate of the time taken for an assembly of given fire resistance to fail bymultiplying the FRR by the ratio. Although this method is shown to be non-conservative when a computermodel of light timber frame wall assemblies is run using both realistic time-temperature curvesand the ISO-834 standard fire test time-temperature curve, it is more conservative than assuming thatan assembly will last as long in a compartment fire as predicted by the FRR. Copyright# 2004 John Wiley& Sons, Ltd.

KEY WORDS: fire severity; fire resistance; time to escape; FRR

1. INTRODUCTION

When carrying out a fire engineering design for egress, calculations of detection time anddetection time lag, estimates of occupant response and calculations for travel and queuing timeare added together to give a required safe egress time (RSET). In order to determine whether afactor of safety is achieved, then an available safe egress time (ASET) must be determined.

Received 10 May 2002Accepted 15 January 2004Copyright # 2004 John Wiley & Sons, Ltd.

yE-mail: [email protected]

nCorrespondence to: G. Thomas, School of Architecture, Victoria University of Wellington, PO Box 600, Wellington,New Zealand.

In the room where the fire originates, or adjacent rooms open to the room of fire origin,then a computer model such as CFAST [1] can be used to determine the time to untenableconditions due to smoke development. In some situations, such as a hotel, or high-rise building,fire rated barriers such as doors between hotel bedrooms and corridors or floor/ceiling systemsprotecting upper floors, the time that the barriers remain in place in a fire is the available safeegress time.

A common approach among designers is to assume that the ASET is the fire resistancerating (FRR) of the assembly. Anecdotal evidence suggests that real fires are more severethan furnace tests; however designers appear to ignore this. The FRR is the time anassembly will survive in a standard test furnace such as ISO834 [2] following a specified time-temperature curve. The temperature reaches 8348C after 30min and increases gradually withtime after that. The furnaces are also lined with firebricks and are relatively small with a volumeof about 10m3. In a real fire in a real compartment, the fire will tend to have a growth phaseuntil flashover occurs. Flashover is an almost instantaneous rise in temperature typicallystarting at about 508C and may reach as high as 13008C, although temperatures of 10008–11008C are more common [3]. In addition to the temperature being higher and highertemperatures being reached more quickly in a real fire compared with a test furnace, the size ofthe furnace and the type of lining material also result in differences between the thermalenvironment in a furnace and real fire.

In a large redevelopment it may be realistic to model the compartment fire and theresponse of a structure to it. In a smaller project such as a large house that is to beconverted to low cost accommodation this is not reasonable or practical. In this situation theremay be bedrooms upstairs with kitchens, lounges and similar spaces downstairs. The upper floorand the walls supporting it must remain in place long enough for the occupants upstairs toescape.

In order to alter the simplistic approach by designers of merely assuming the FRR is theavailable safe egress time, a simple method of estimating the actual time that an assembly willsurvive in a real fire is proposed. The method is not likely to be highly accurate and may beunconservative in some instances. However, it is considerably safer than the current designapproach.

2. DESIGN APPROACH

The fire severity in different compartments depends on three factors, ventilation, fuel load andthermal properties of the compartment boundaries. There are a number of formulae, collectivelyknown as time equivalent formulae that relate these three parameters to fire severity. The timeequivalent formula in the Eurocode as modified for use in New Zealand [4] gives a value for fireseverity in terms of the time an assembly is expected to survive in a standard ISO-834 [2] testfurnace (te). Assemblies to be used in a building are tested to this standard to give a fireresistance rating (FRR). If it is assumed that the fire in a compartment is ventilation controlled,and the burning rate is constant, then the total fuel load can be divided by the burning ratebased on ventilation [3] to give a burn time (tb). The available safe egress time (ASET), which isthe time the assembly is expected to survive in a real fire would be proportional to the burn timeand the FRR, but would be inversely proportional to the fire severity giving the following

Copyright # 2004 John Wiley & Sons, Ltd. Fire Mater. 2004; 28:343–354

G. THOMAS AND D. LLOYDD344

relationships

ASET / tb;ASET / FRR;ASET /1

teCombining these gives the formula

ASET ¼ ktbFRRte

where k is a constant. In the analysis that follows k is assumed to be 1.0.In order to calculate the ASET based on the FRR rating the following procedure is

followed.

1. Determine the total fuel load. Multiply the floor area by the fuel load energydensity (FLED). The FLED is the density of fuel load expressed in MJ/m2 offloor area.

E ¼ AFef

where E is the total fuel load AF is the floor area (m2) ef is the fuel load energy density(MJ/m2)

2. Determine the window area and height (or total window area and a weighted average ofthe window heights if there is more than one opening). As fire resistance is a post-flashoverphenomenon, assume that all windows are broken.

3. Calculate the burning rate based on the ventilation using the severity correlation [5]

Qv ¼ 1:5 AV

ffiffiffiffiH

pwhere Qv is the ventilation controlled burning rate (MW). Av is the area of openings (m2)and H is the height of the windows (m).

4. Calculate the burn time by dividing the total fuel load by the burning rate

tb ¼ E=Qv

where tb is the total burn time (s)5. Calculate the time equivalent, te. The Eurocode 1996 formula is recommended with values

for the conversion factor as used in the New Zealand Acceptable Solutions for Fire, 2000[4] and also in the Fire Engineering Design Guide [5].

te ¼ efkbwf

where kb is a conversion factor given below

Construction materials kbVery light insulating materials 0.10Plasterboard ceiling and walls, timber floor 0.09Lightweight concrete ceiling and floor, plasterboard walls 0.08Normal concrete ceiling and floor, plasterboard walls 0.065Thin sheet steel roof 0.045wf is the ventilation factor given by

wf ¼6:0

H

� �0:3

0:62þ90ð0:4� avÞ

4

1þ bvah

� �> 0:5


FIRE ENGINEERING DESIGN FOR EGRESS 345

where

av ¼ Av=Af 0:0254av50:25

ah ¼ Ah=Af ah50:20

bv ¼ 12:5ð1þ 10av � a2vÞ

Ah is the area of horizontal openings in the roof

6. Ascertain the FRR of the assembly being considered. If the FRR is significantly greaterthan the time equivalent for the compartment, then the assembly will not fail and istherefore adequate.

7. Multiply the FRR by the ratio of the burn time over the time equivalent to give a morerealistic indication of the ASET.

ASET ¼ FRR ðtb=teÞ

2.1. Example

An upper floor containing bedrooms and a corridor used for egress is separated from thekitchen below with a ceiling that has a nominal FRR of 15min and the floor/ceiling is supportedon walls with a nominal FRR of 25min. The kitchen is 6.0m long, 2.4m high and 3.6m wide.There is a window at one end 2.0m high and 3.0m long. A hotel room has a fire hazard categoryof 2. The New Zealand Acceptable Solutions [4] assume a design FLED of 800MJ/m2.

Running though the steps above

1. Total fuel load, E=AF ef=6.0� 3.6� 800=17280MJ2. Av=2.0� 3.0=6.0m2, H=2.0m3. Burning rate, Qv ¼ 1:5AV

ffiffiffiffiH

p¼ 1:5� 6:0�

ffiffiffiffiffiffiffi2:0

p¼ 12:7 MW

4. Burn time, tb=E/Qv=17280/12.7=1271 s (or 21min)5. time equivalent, te

ef ¼ 400 MJ=m2

kb ¼ 0:065 ðnormal concrete ceiling and floor; plasterboard wallsÞ

av ¼ Av=Af ¼ 6:0=ð6:0� 3:6Þ ¼ 0:28

ah ¼ Ah=Af ¼ 0=ð6:0� 3:6Þ ¼ 0

bv ¼ 12:5ð1þ 10av � a2vÞ ¼ 12:5ð1þ 10� 0:28� 0:282Þ ¼ 46:5

wf ¼6:0

H

� �0:3

0:62þ90ð0:4� avÞ

4

1þ bvah

� �¼

6:0

2:4

� �0:3

0:62þ90ð0:4� 0:28Þ4

1þ 46:5� 0

� �¼ 0:84

te ¼ efkbwf ¼ 800� 0:065� 0:84 ¼ 43:7 min or 2621 s

6. FRR is 25min for walls and 15min for the ceiling7. ASET ¼ FRR ðtb=teÞ ¼ 25� 1271=2621 ¼ 12 min ðwallsÞ

ASET ¼ FRR ðtb=teÞ ¼ 15� 1271=2621 ¼ 8 min ðceilingÞ



Although this design approach is very simple, this example shows that using the FRR of15min as ASET is unconservative. If a detector response time of 60 s is assumed, an occupantresponse time of 4min and a travel time of 1min for the upstairs occupants to exit the upperfloor there is a required safe egress time of 6.0min. Using the nominal FRR this gives a factor ofsafety of 15/6.0 or 2.4 for the ceiling and 25/6.0 or 4.2 for the walls. Using this method the factorof safety is 1.25 for the ceiling and 2.0 for the walls. The ceiling would need relining, but not thewalls. Using the nominal FRR would result in the ceiling not being relined, resulting in apotentially dangerous situation.

Obviously there are a number of assumptions in this method. The most critical is that theseverity of both the furnace test and the compartment fire is constant throughout both thefurnace test and the compartment fire, or that the severity varies throughout the duration of thefurnace test in the same manner that it varies throughout a compartment fire. This assumptionand the influence of the compartment size are tested using computer modelling of a range ofassemblies and one full scale compartment fire test.

3. VARIATION OF FIRE SEVERITY

The time to failure of an assembly is derived for a compartment fire curve for a range of openingfactors. The time-temperature curve used assumes an infinite fuel load, so the fire carries on untilthe boundary fails. We are attempting to find the failure time early in a fire and not themaximum fire severity for a given compartment, ventilation and fuel load.

Compartment fires are modelled using COMPF-2 [6]. The methodology is that usedby Thomas [7]. The time-temperature curve includes an additional growth phase at a rate of1008C/min added to the time-temperature curve. The growth phase makes little difference in thetime to failure [7]. A sample COMPF-2 input file is included in Appendix 1.

Failure is determined based on a temperature criterion. For timber walls and floor systemsthis is defined as the onset of charring at 3008C, at a depth of 10mm into the assembly. This is aconservative measure of structural failure [7]. For steel structural elements failure is assumed tooccur when any part of the steel reaches 5508C. Similarly in reinforced concrete structures,failure is deemed to occur when the reinforcing reaches 5508C. The time to failure is recorded.The actual time equivalent is calculated by comparing the same thermal model with that runwith an ISO834 time-temperature or test data where available. The value for the actual timeequivalent is at failure and is therefore the same as the FRR. The time equivalent is calculatedusing the BIA formula [4,5] and the burning time is calculated using the severity correlation. Theratio of the severity correlation to time equivalent is then compared with the ratio of the actualtime to failure to the FRR. If the methodology is perfectly accurate the value of the calculatedratio divided by the actual ratio should be 1.0. If it is less than 1.0 the method is unconservativeand if it is greater than 1.0 the method is conservative. This value can therefore be referred to asa factor of safety for the method.

Previous work by Thomas [7] used the heat transfer model TASEF [8] for thermal analysis oftimber walls, floors, insulated steel beams and concrete slab walls and floors. These data havebeen reanalysed and are based on a small compartment (Figure 1). (Table I)

The following ventilation parameters are used. The restriction of window size being not morethan 25% of the floor area in the BIA ventilation factor calculation has been taken into accountby using the value for the ventilation factor when the window area is 25% of the floor area.



The first structural member considered is a 360mm deep steel universal beam section(360UB57) in a compartment lined with 100mm concrete all round. The UB is directly underthe ceiling slab and is protected on three sides with 16mm Fyreline Gib gypsum plasterboard [9]in a box profile. The time to failure for the various ventilation parameters and ratios of actualand calculated burn times and time equivalents is shown in Table II. When calculating the burntime and time equivalent, only the ratio between them is of significance, so both values arenormalized with respect to fuel load energy density (FLED). The value of both calculated burntime and calculated time equivalent is directly proportional to fuel load, so in the ratio betweenthe two calculated values the fuel load cancels out. The FRR rating is taken as being that for thethermal model exposed to the ISO834 time-temperature curve and not the actual furnace testresult. (Table III)

The factor of safety in Table II for the method varies from 0.86 to 1.27. The method isunconservative for three opening sizes, however, if the FRR time had been used directly as anestimate of time to failure the answers would be unconservative by 51% and 93% of the FRR.The design method is highly conservative when the openings are large, however, this is outsidethe range of the BIA formula and it is conservative, whereas using the FRR directly would beunconservative.

Analysis was also carried out on the following structural elements and compartments:

(i) a 150mm concrete floor slab in a concrete compartment with a D20 reinforcing bar with20mm cover

(ii) a light timber frame stud wall with 90� 45mm studs and a 9.5mm Fyreline Gib gypsumplasterboard lining

Figure 1. Compartment used for initial analysis.

Table I. Ventilation parameters.

WindowBurning rate Ventilation factor BIA

Height (m) Width (m) Area (m2) (MW) (Dimensionless)

1.0 2.75 2.75 4.125 1.5441.5 3.00 4.50 8.267 1.0202.0 3.00 6.00 12.728 0.8332.0 4.00 8.00 16.971 0.8162.0 5.00 10.00 21.213 0.8162.0 6.00 12.00 25.456 0.816



TableII.Resultsforanalysisof360UB57,lined

with16mm

GIB

inconcretecompartment.

Window

area

(m2)

Actual

timeto

failure

(min)

FRR

(min)

FRR/actual

fail.time

Calc.burn

time/fuel

load

(min

m2/M

J)

Calc.timeequivalent/

fuel

load

(min

m2/M

J)Calc.time

equiv./calc.burn

time

FoS

Calc./actualratios

2.75

88.5

84

0.95

0.10

0.10

0.99

1.05

4.50

55.5

84

1.51

0.05

0.07

1.31

0.87

6.00

43.5

84

1.93

0.03

0.05412

1.65

0.86

8.00

37.5

84

2.24

0.02

0.05305

2.16

0.96

10.00

34.5

84

2.44

0.02

0.05305

2.70

1.11

12.00

33.0

84

2.54

0.02

0.05

3.24

1.27



(iii) a light timber frame joist floor with 240� 45mm joists(iv) a 16mm GIB Fyreline lining and a 250mm square steel universal column section

(250UC73) lined with 16mm Fyreline Gib gypsum plasterboard in box profile.

The compartment for the last three structural elements had light timber frame boundingsurfaces and therefore the calculated time equivalent changes as the value for the conversionfactor kb in the time equivalence formula changes to 0.09.

The factor of safety for the method varies from 0.74 to 1.92. When only the range of validityof the BIA formula is considered, the maximum value is 1.15. Again the design method appearsto be unconservative in some instances, in this case for the insulated steel column in a lighttimber framed lined room. However, it is safer than using the FRR directly, which isunconservative by 26% compared with an FRR that is up to 2.9 times the time to failure.

This analysis uses a crude method to determine time to failure that is in most instancesconservative. Further analysis using detailed structural modelling may show that this method ismore conservative.

4. EFFECT OF COMPARTMENT SIZE

The effect of compartment size was analysed by running the COMPF2 fire model with twolarger compartments. The second compartment was 8m long, 10m wide and 4m high. Thecompartment is intended to represent a small shop in a larger building such as a mall, or a shopunder a hotel or crowd space. It was assumed to have concrete boundaries and the structuralelement being considered is the 150mm reinforced floor slab described previously. Windowheights were 1m, 1m, 1.5m and 2.5m, respectively, for the four runs respectively shown inTable IV.

Table III. Results for other structural elements.

Description Window area (m2) 2.75 4.50 6.00 8.00 10.00 12.00

100mm Actual failure time 92.4 66.6 58.2 55.2 54.0 52.8concrete FRR (min) 89 89 89 89 89 89slab FRR/actual 0.96 1.34 1.53 1.61 1.65 1.69Conc. Compt FoS (calc/actual ratios) 1.03 0.98 1.08 1.34 1.64 1.9290mm stud Actual failure time 25.6 20.4 19.2 19.1 19.0 16.2LTF wall FRR (min) 38 38 38 38 38 389.5 GIB FRR/actual 1.48 1.86 1.98 1.99 2.00 2.34LTF Compt Calc. burn time/fuel load 0.10 0.05 0.03 0.02 0.02 0.02

Calc. time equiv./fuel load 0.14 0.09 0.07 0.07 0.07 0.07Calc. time equiv./calc. burn time 1.38 1.82 2.29 2.99 3.74 4.49FoS (calc/actual ratios) 0.93 0.98 1.15 1.50 1.87 1.92

240mm joist Actual failure time 37.0 28.3 26.2 25.5 25.3 25.2LTF Floor FRR (min) 55 55 55 55 55 5516mm GIB FRR/actual 1.49 1.95 2.10 2.16 2.17 2.18LTF Compt FoS (calc/actual ratios) 0.93 0.94 0.79 1.00 1.24 1.48250UC73 Actual failure time 46.0 35.0 30.0 29.0 28.0 28.0Column FRR (min) 86 86 86 86 86 8616mm GIB FRR/actual 1.87 2.46 2.87 2.97 3.07 3.07LTF Compt FoS (calc/actual ratios) 0.74 0.74 0.80 1.01 1.22 1.46



TableIV

.Resultsforconcretefloorslabin

concretelined

8.0m

by10.0m

by4.0m

highcompartment.

Window

area

(m2)

Actual

timeto

failure

(min)

FRR

(min)

FRR/actual

fail.time

Calc.burn

time/fuel

load

(min

m2/M

J)

Calc.timeequivalent/

fuel

load

(min

m2/M

J)Calc.time

equiv./calc.burn

time

FoS

Calc./actualratios

2.00

315.0

89

0.28

0.44

0.18

0.40

1.40

8.00

87.0

89

1.02

0.11

0.10

0.89

0.87

12.00

66.0

89

1.35

0.06

0.07

1.18

0.87

20.00

54.6

89

1.63

0.03

0.05

1.74

1.07

TableV.Resultsforfire

ratedsteelbeam

inGIB

lined

30.0m

by30.0m

by6.0m

highcompartment.

Window

area

(m2)

Actualtime

tofailure

(min)

FRR

(min)

FRR/actual

fail.time

Calc.burn

time/

fuel

load

(min

m2/M

J)

Calc.timeequiva-

lent/fuel

load

(min

m2/M

J)Calc.timeequiv./

calc.burn

time

FoSCalc./actual

ratios

22.50

33.0

84

2.55

0.63

0.22

0.34

0.13

55.00

33.0

84

2.55

0.26

0.16

0.63

0.25

110.00

28.5

84

2.95

0.09

0.10

1.14

0.39

220.00

25.5

84

3.29

0.03

0.06

1.88

0.57



Again the correlation between the design method and computer modelling is good. The timesto failure are very long, hence egress time may not be an issue, unless the compartment is locatedunder a large residential or crowd occupancy with long escape times.

The third compartment used was 30m by 30m with a ceiling height of 6.0m. It was assumedto have light timber frame boundaries and the structural element being considered was a360UB57 fire rated with 16mm GIB Fyreline described previously.

In this very large compartment the results are poor with the factor of safety ranging from 0.13to 0.57. This is not surprising as the size of the compartment is such that it is outside the range ofboth the BIA time equivalent formula and the assumption of a well-mixed compartment inCOMPF2. This method should not be used for large compartments with a volume greater thanabout 1000m3.

5. HOUSE FIRE TEST

In 1995 a compartment in a derelict house in Christchurch was used for testing a standardWinstones wall system. The compartment was 3.9 by 3.8m and 3.12m high. The windowopening was approximately 1.8m square. The wall system had a nominal FRR of 30min [9].Using the design method adopted in this paper the wall was predicted to fail in 14.6min. Thewall failed in the test approximately 15min after flashover.

6. DISCUSSION

The analysis shows that the assumption that the proportionality constant, k is equal to 1.0 isvalid.

Analysis results suggest that this design method is reasonably accurate, normally conservativeand when unconservative, not significantly so. Further analysis is required to determine itsadequacy when unprotected steel structures are used. The method should be analysed usingstructural modelling rather than the simple thermal criteria used here. Testing against othercompartment fire models and real fire time-temperatures curves is also necessary.

This method has been used to calculate actual factors of safety for egress for two room sizesand various window geometries. This analysis assumes a nominal factor of safety (FRR/RSET)of 2.0 and then calculates an actual factor of safety using this burn time/time equivalent method.A sensitivity study has been carried out varying the compartment height, compartment area,window height and window width for the two smaller compartments described previously.Varying the size (height or width) of vents has far more effect than varying the compartmentheight or area. Values of the actual factor of safety for both compartments for reasonable valuesof the various parameters were about 0.9 compared with a nominal value of 2.0.

7. CONCLUSION

The method described is suitable for use in fire engineering design for compartments up to about1000m3 in volume. It is simple to use and utilizes simple calculations that practising fireengineers are already familiar with. It appears to be slightly unconservative in some cases, but is



far more conservative than using a fire resistance rating as the available safe egress time for thecase where escape routes are protected by fire rated assemblies from the compartment where thefire has occurred. The fire resistance rating is typically between one and two times actual failuretime, but can be as much three times the actual failure time of a structural element.

APPENDIX 1

Sample COMPF2 Input FilePESSIMIZED PYROLYSIS FIRE FOR CONCRETE WALL V=.025, FLOAD=100

ADIA=.FALSE. pvAFLOOR=25.0 pvAWALL=85.0 pvAWDOW=2.2 pvBPF=0.9 pvCD=0.68 0.68

CFLPC=44.4 44.4CPPYR1=.1127 pvCPPYR2=1010.0 pvCVGROS=18.7E6 pvDENSW=2400. pvDHP=0.0 pv

DTIME=10.0 pvEF=1.0 pv

EISCAN=.FALSE. FALSEEITA=1.00 pvFLOAD=3.333333 pv

FLSPEC=.FALSE. FALSEHFLPC=5.40 pvHWDOW=1.0 pvIRUN=1 sequentialIX=10 pv

KTRACE=0 0MTIME=14400.0 pvMWPYR=28.97 pv

NEWPRP=.TRUE. FALSENFLPC=0. pvOFLPC=38.2 pv

PLFUEL=.FALSE. FALSEPRNT= 10.0 pv

REGRES=1.0E�05 pvRPSPEC=.FALSE. FALSE

SH=0 pvSHAPE=2. pvSIZE=4.00E�02 pv

STEADY=.FALSE. FALSE



STOICH=.FALSE. FALSETBOLIC=390.0 pvTHICKW=0.115 pvTINPT=0.0 0.0

VTSPEC=.TRUE. FALSEWFLPC=12.0 0.0

5,10,1,0,00. 1.8 25. 1.8 388. 1.28 107.3 0.8 1473. 0.520. 909.09 373. 909.09 373.01 3878.79 388. 3878.79 388.01 737.97393. 737.97 413. 737.97 453. 737.97 473. 1030. 4273. 1030.0.0 0.9000

REFERENCES

1. Jones WW, Forney GP, Peacock RD, Reneke PA. Technical Reference for CFAST: An Engineering Tool forEstimating Fire and Smoke Transport. NIST TN 1431. National Institute of Standards and Technology:Gaithersburg, MD, 2000.

2. ISO-834. Fire Resistance Tests-Elements of Construction. International Standards Organisation; Geneva, 1975.3. Buchanan AH. Structural Design for Fire Safety. John Wiley and Sons: Chichester, 2001.4. Building Industry Authority. Approved Document for New Zealand Building Code Fire Safety Clauses. Wellington,

2000.5. Buchanan AH (ed.). Fire Engineering Design Guide, 2nd edn. Centre for Advanced Engineering: Christchurch, 2000.6. Babrauskas V. COMPF2, A Program for Calculating Post-Flashover Fire Temperatures. NBS Technical Note 991,

U.S. Department of Commerce/National Bureau of Standards: Gaithersburg, 1979.7. Thomas GC. Fire Resistance of Light Timber Framed Walls and Floors. Fire Engineering Research Report 97/7.

University of Canterbury: Christchurch, 1997.8. Sterner E, Wickstrom U. TASEF-Temperature Analysis of Structures Exposed to Fire. Fire Technology SP Report

1990:05. Swedish National Testing Institute, 1990.9. Winstones. Gib Fire Rated Systems. Winstone Wallboards Limited: Wellington, New Zealand, 2001.



Fire resistance of structural components protecting escape routes

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