2

Design of Sports Stand Buildings for Fire Safety by

I. D. Bennetts, K. W. Poh, S. L. Poon, G. Anderson

P. England, N. Kurban

I. R. Thomas Victoria University

Content page

Sports Stand Buildings................................................ 1 Parts of Modern Sport Stands Buildings ..................... 2 Historical Review......................................................... 4 Fire Safety Aspects..................................................... 5

! Occupant Avoidance ................................ 10 ! Smoke Development and Management ... 12 ! Fire Detection and Suppression

Brigade Communication and Response... 14 ! Fire Spread and Management.................. 16

Conclusions .............................................................. 18 References................................................................ 18

1 Modelling of Fire Characteristics 20

2 Application of BCA Access and Egress Requirements to a Building 21

3 Calculation of Evacuation Times 26

4 Exposed Surface Area to Mass Ratio of Steel Sections—ksm (m2/tonne) 29

5 Checking of Steel Member Size for Fire Adequacy 31

Acknowledgment: The assistance of Mr Gary Carter of Daryl Jackson Pty Ltd, with the supply of technical information used in this publication, is gratefully acknowledged.

ISBN 0 86769 106 9

Published by: OneSteel – Market Mills Ingal Street Newcastle NSW 2300 Australia

First published, June 1998 Reprint edition, September 2006

Scope

This publication applies to sports stand buildings in open stadia which fall outside the scope of the open spectator stands covered by clause C1.7 of the Building Code of Australia. However, it only applies to buildings which are of non-combustible construction.

Sydney Football Stadium

Melbourne Cricket Ground

Des

ign

App

endi

ces

1

SPORTS STAND BUILDINGS

In recent years, a number of impressive and largesports stand buildings have been constructed.This has certainly been the case in Australiawhere there is a demand for increased seatingcapacity—usually with multiple seating tiers, highquality corporate viewing and entertainingfacilities, and multi-function spaces within differentlevels beneath the seating tiers. These facilitiesare in addition to the traditional change rooms,sanitary facilities and storage areas.

Suncorp Stadium

Structural steel framing features prominently intheir construction providing such benefits as:

• fast speed of construction—especiallyimportant when critical sporting eventmilestones must be met

• lighter weight, long spanning ability whichsimplifies cranage, particularly on sites whichhave restricted access

• cost effectiveness• flexibility for future modification or upgrading• aesthetically pleasing structure having

minimal bulk and intrusion into the urbanfabric

The deemed-to-satisfy requirements of theBuilding Code of Australia (BCA) [1] (in cl C1.7)permit an open spectator stand to be constructedas Type C construction if it contains not more thanone tier of seating, is of non-combustibleconstruction, and has only change rooms, sanitaryfacilities, or the like, below the tiered seating. Inthe case of open spectator stands of Type Aconstruction, the BCA allows “concessions1” forsome building elements within the stand, such thatthese elements do not have to satisfy therequirements of Table 3 of Specification C1.1. Tobe specific, the roof and structural memberssupporting only the roof (ie. columns and

1 In attempting to determine how normal provisions may be

modified in the light of alternative solutions, the BCAfrequently makes use of the term “concessions”. As thesealternative requirements are permitted within the code, itfollows that they must be considered to correspond to anequivalent level of safety in certain situations—namely thesituations specified in the “concession”. The use of theword “concession” unfortunately implies a lower level ofsafety, which is not the case.

loadbearing walls) are not required to have a fire-resistance level (FRL) provided they are non-combustible; and non-loadbearing parts of anexternal wall may have a reduced FRL if they arewithin 3 m of a fire-source feature and are non-combustible.

The Brisbane Cricket Ground

Modern sports stand buildings usually providefacilities for corporate viewing, dining, and specialfunctions, in addition to change rooms andsanitary facilities. Several tiers of seating are oftenprovided. These buildings, therefore, may fall welloutside the scope of cl C1.7 of the BCA, yet theapplication of Table 3 in Spec C1.1 may not beappropriate due to the fact that many parts withinthese buildings cannot be easily classified interms of the classes of building given within theBCA.

The purpose of this publication is to consider thefire safety of these more complex buildings, and topresent design principles and procedures whichwill allow the fire-safety objectives and relevantperformance requirements of the BCA to besatisfied. The satisfaction of the performancerequirements depends on many factors, includingthe correct choice of materials of construction,appropriate egress requirements, adequate firesuppression, and appropriate structural fireresistance.

The design principles and procedures contained inthis document are drawn from recent Australianand overseas experience and state-of-the-art fireengineering knowledge, and have taken intoaccount the sub-systems and methodologiesgiven in the Fire Engineering Guidelines [2]prepared by the Fire Code Reform Centre.

PARTS OF MODERN SPORT STANDS BUILDINGS

SEATING TIERS

Construction: Usually constructed from reinforced orprestressed concrete plats which span between girders.Seating shells or benches are connected to the plats andhave been constructed from materials including steel,timber, aluminium and plastic (the most common).Combustibles: plastic seats, rubbish.

CONCOURSE AREAS

Construction: These areas are contained in the back-of-house construction, provide horizontal access to anadjacent seating tier and also to service areas such astoilets, food and beverage outlets. Designed for a largenumber of pedestrians as this is the primary means ofentrance to the seating tier.Combustibles: Incidental items such as chairs, tables andboxes.

TOILETS AND CHANGE ROOMS

Construction: These areas are accessed via theconcourses.Combustibles: Benches, chairs, rubbish.

FOOD AND BEVERAGE OUTLETS

Construction: Usually located adjacent to the concourseareas and typically have a substantial opening in the sideadjacent to the concourse to allow serving and access.The opening is generally protected with an open mesh orsolid screen when the facility is not in use. A ceiling isoften provided in these areas.Combustibles: Some furniture such as plastic chairs,tables, benches, cardboard boxes and packaging.

MEDIA AND CORPORATE SUITES

Construction: Generally fully glazed at the front but areseparated from the adjacent enclosures by walls offeringsubstantial sound proofing. Dry wall or block workconstruction is commonly used for this purpose. Theglazing at the front of these boxes is frequently extendedaround the sides for a short distance adjacent to theviewer’s seating area. (Food is rarely prepared in theseareas although it is commonly reheated and served.)Combustibles: Spectator seats, tables and chairs,benches, cupboards and carpet.

FUNCTION ROOMS

Construction: Often positioned to overlook the playingarea with full height glazing along one side. (Cooking isgenerally not undertaken in these areas.)

Combustibles: Tables, chairs, and furniture associatedwith the serving of food.

BISTRO AND DINING AREAS

Construction: Often positioned to overlook the playing areawith full height glazing along one side. (Cooking isgenerally not undertaken in these areas.)Combustibles: Tables, chairs, furniture, carpet.

KITCHENS

Construction: Normally occupied when cooking is beingundertaken. A continuous flush ceiling, such as aplasterboard ceiling, is normally required in these areas tosatisfy health requirements.Combustibles: Cooking oil, some packaging.

OFFICES

Combustibles: Tables, chairs, books, carpet, paper.

STORAGE AREAS AND PLANTROOMS

Construction: Storage areas are typically located at groundlevel and under the lower level of seating. Plantrooms areoften located at ground level.Combustibles: Storage areas may contain liquid fuelstored in drums, motorised equipment, and othercombustibles such as spare seating shells.

ROOF

Construction: Normally of steel construction.Combustibles: Nil.

2 3

4

HISTORICAL REVIEW

There have been many fires in older sports standbuildings where combustible construction hasbeen used (see for example [3]). Fortunately, withthe exception of the Bradford Stadium fire in theUnited Kingdom, there have been few deaths duemainly to the fact that these buildings were notoccupied at the time of the fire, or that there wassufficient time for evacuation.

Bradford Stadium Fire, UK, 1985 [4]

In this fire 56 people lost their lives and many wereinjured. The fire developed in an isolated (unoccupied)location—in the substantial volume below the seatingplats—before it was noticed by the occupants in thestand above. The combustibles below the seatingconsisted of rubbish that had accumulated over theyears from the disposal of materials via gaps betweenthe seating plats to the volume below. The fire locationand size made it almost impossible to fight with hosereels or fire hoses—even if they had been available. Asthe fire further developed, its rate of spread wasaccelerated through the involvement of combustibles inthe stand and roof covering materials. This fire resultedin high levels of radiation and the loss of life wouldhave been much higher, should escape on to theplaying field not been possible.

Following the Bradford fire and various incidentsinvolving crowd violence, the Home Office in theUnited Kingdom conducted an Inquiry into crowdsafety at sports grounds [4]. This was followed bya publication entitled “Guide to Safety at SportsGrounds” [5] which seeks to address all safetymatters associated with the design and operationof sports grounds and gives general guidance andprinciples for this purpose. Fire-safety issues areconsidered briefly.

In 1988, Hughes Associates [6] published a reportwhich reviewed fire safety incidents in sportsstadiums in the United States from 1971 to 1986.These buildings varied from combustible to non-combustible construction and were from 1-9

storeys in height. It was found that deaths wererare (3 deaths). The paper recommended the useof non-combustible construction; properseparation of storerooms used to storecombustible materials; wall linings usedthroughout construction to have a low flame-spread rating; sprinklers for such areas asstorerooms, shops, offices, restaurants, anddining areas; and a communication system forrelaying essential messages to all parts of theoccupied facility.

Texas Stadium Fire, USA, 1993 [7]

Reprinted with permission from NFPA Journal (July/August, Vol. 88, No. 4),Copyright ©1994, National Fire Protection Association, Quincy, MA 02269.

This fire commenced in a corporate suite, but the standwas not occupied at the time of the fire. The fire wasburning vigorously by the time an alarm was sent to thefire station. By the time the fire brigade arrived and setup (approx 8 minutes after the alarm was received) thefire had spread to five suites on the lower level, sevensuites on the upper level, and to the plastic seating atthe front of the lower level suites. The fire was almostextinguished after several minutes. However, due to afailure of the local water supply the fire flared up againand it finally took another 28 minutes for the fire to befinally extinguished. Firemen reported heavy smoke inthe corridors behind the suites even though the doorsinto the suites were closed.

It was established that fire initiated in one of the uppersuites and spread horizontally via the fronts of thesuites once the glazing had broken. The fronts of someof the suites had been clad in clear plastic and this fellburning onto the seats below, starting a fire amongstthis seating. This fire, in turn, spread to the lower suiteslocated above these seats. It appears that there was noaisle between the seats and the front of the suites.

In 1989, British Steel reviewed a number ofspecific examples where sports stand buildingshad been designed using fire-safety principles asopposed to complying with local regulations. Thepublication highlights examples whereunprotected structural steel has been used [8].

5

FIRE SAFETY ASPECTS

Introduction

A rational engineering approach which takes intoaccount the unique features of these buildings isessential to ensure cost-effective construction andhigh levels of fire safety. In this context the term“fire safety” should be taken as referring to both“life safety” and “property protection”. It is theopinion of the authors, that if the building isproperly designed for life safety (which is primarilythe concern of the BCA), then it will possess alevel of protection against property loss. Thismatter is further considered again later in thissection.

Factors Important for Fire Safety

There are many factors thathave an influence on thelevel of fire safety offered bya building. Some of the moresignificant factors are listedbelow:

• numbers and types of fire starts• likelihood of fire suppression by the occupants• reliability and effectiveness of the detection

and alarm systems• communication systems• emergency procedures and staff training• reliability and effectiveness of the sprinkler

system• fire characteristics (flames and smoke)—rate

of spread, size, severity• means of evacuation• number of occupants and their behaviour• reliability and effectiveness of the smoke

control system• the action of the fire brigade• performance of the building structure

Modern sports stand buildings, because of theirvolume and openness, generally offer efficientmechanisms for venting smoke in the event of afire. Also their form of construction means thatthey are, from a structural viewpoint, highlyredundant and therefore overall building failure isalmost inconceivable given any credible fire. Inaddition, practical egress requirements associatedwith the need to efficiently move people out of thebuilding after a sporting event mean thatevacuation times are short.

A fire-engineering approach to the design of thesebuildings requires systematic consideration ofsuch aspects as smoke management (smokecontrol and occupant evacuation), fireextinguishment and fire fighting, and the structuraladequacy of the building as it relates to occupantsafety. The above aspects are particularlydependent on the choice of design fire and this, inturn, must be determined from the range ofpossible fire scenarios.

Fire Initiation and Development

Fires may occur in many parts of thesebuildings including the seating tiers. Asthe seating shells are usually plastic(typically polypropylene) it is possiblethat a substantial fire could develop

within the seating but this would require asignificant ignition source and sufficient time. Theignition source will need to be substantial (as withrubbish burning below several seats) if the fire isto spread beyond one seating shell due to theseparation between seating shells and betweenrows of seats. It is unlikely that sufficient rubbishwill be allowed to accumulate below the seats, andmore importantly, the occupants within the stand(assuming it is occupied) will most likelyextinguish any fire while it is small. Firesassociated with the spectator seating of publicviewing areas (other than that associated withcorporate suites) are therefore considered not topresent a hazard, given the presence of adequatecontrols (eg. housekeeping to avoid rubbish build-up).

Areas such as concourses (excluding food andbeverage outlets which open into the concourses),toilets and change rooms, generally present a lowfire hazard due to their low level of combustibles.

However, all other areas within the sports standbuilding should be considered as potential sitesfor fire starts. An estimate of the averageprobability of fire starts in these latter areas canbe obtained by using the rate identified for retailbuildings [9] and multiplying by the total floor areaof these areas. This rate is 2.5×10-4/yr/m2 andincludes the fire starts which are not reported tothe fire brigade. These latter fire starts representthe majority and have been deduced frominsurance records and other sources. It isconsidered that it is reasonable to apply this firestart rate to these buildings because many of theareas where there are combustibles areassociated with retail activities (food andbeverage)—although they are areas of relativelylow fire load. Furthermore, fires can be dividedinto those that occur when the building is occupiedand those that occur when the building isunoccupied. These buildings are large publicbuildings which are used for functions other thanmajor sporting competitions and the servicesassociated with the building must be operated toallow for this. It is known from retail fire statisticsthat about 70% of fires occur during the occupiedhours. Thus the number of fires occurring duringoccupied hours can be estimated by multiplyingthe above number by 0.70.

Although it is possible to estimate the number offire starts associated with a particular buildingduring the occupied hours, it is necessary todetermine the range (and correspondingseverities) of the resulting fires. Again, it is known

6

from overseas fire statistics [9], that at least 80%of these fires will be so small that they will notresult in the attendance of the fire brigade. Of theremaining 20% of fires that will be attended by thefire brigade, more than 85% will be confined to theobject or area of fire origin through the action ofthe occupants and/or the fire brigade. These latterfires are likely to have little impact on either theoccupants or the structure of the building. Thus, insummary, 97% (100-20×0.15) of fires, duringoccupied hours, will be small and not require adetailed fire engineering assessment. Theprovision of adequate fire-fighting facilities,emergency procedures, staff training, and the like,can be considered to constitute an adequateresponse to these fires. It is the remaining 3% offires that have the potential to become large andwhich may extend beyond the room of fire origin,and it is these which may pose, by far, thegreatest threat to the occupants of the building.

fire starts

attended by fire brigade

not attended by fire brigade

occupied hours

unoccupied hours

small fire (confined to

object or area of fire origin)

significant fire (not confined to object or area of

fire origin)

20%80%

30% 70%

85% 15%

The population within these building is low most ofthe time and it is only during major events that theit reaches the maximum number. If it is assumedthat this occurs for only one afternoon or eveningper week and occasionally more frequently, thenthe average probability of having a significant fireduring a time when the building is occupied closeto full capacity can be taken as 1/10 of theprobability of having a significant fire duringoccupied hours.

It is also not common for these buildings to befitted with sprinklers. However, if sprinklers areincorporated they will further reduce the likelihoodof a major fire. In the context of this document, asprinklered building should be understood as abuilding where sprinklers are provided throughoutall areas with the exception of concourses, toiletsand change rooms. It is considered that it is not

necessary to sprinkler such areas. A sprinklereffectiveness2 of at least 98% can be assumed.

The above observations on the occurrence of asignificant fire are summarised in the table below.The resultant rate in the table of 5.25×10-6/yr/m2 isderived from 2.5×10-4×0.7×0.03 and the variable A(m2) in is the total area associated with storageareas, shops, offices, corporate and media suites,function rooms and bistro and dining areas.

Estimated Average Number of Significant Firesper Year during Occupied Hours

OccupantSituation

Sprinklers notPresent

SprinklersPresent

Normal 5.25×10-6×A 5.25×10-6×0.02×A

Major Event 5.25×10-6×A ÷10 5.25×10-6×0.02×A÷10

Substitution of typical values for A into the aboveexpressions gives an estimate of the averageprobability of having a significant fire in a year.

Example:Probability of occurrence of a significant fireduring a major event.

Assume A = 2000 m2

Average number of fires per year if sprinklersnot present = 5.25×10-6×2000÷10 = 0.00105,ie.• a significant fire can be expected to occur

during a major event once in 952 years ifthe occupancies are not sprinklered

• a significant fire can be expected to occurduring a major event once in 47,619 yearsif the occupancies are sprinklered

Design Fires

A fire-engineering approach to thedesign of these buildings requiresthe adoption of appropriate designfires. In this regard, it is importantto understand that the same designfire must be used whenconsidering each element of thefire-safety system whether it

influences occupant evacuation, management ofthe smoke, or the structural stability of thebuilding, etc.

Building without Sprinklers

In this case it is proposed that the design firesmust include those flashover fires which mayoccur within any one of the relevant parts of thebuilding such as: storage areas, shops, offices,

2 Sprinkler effectiveness refers to the combination of

efficacy (ability to control or extinguish a fire) and reliability(whether the system will deliver water in the first place)and has been estimated from statistical data for NSWretail buildings as being 98%. It is likely that the systemsin these buildings will be even more effective due to thelesser levels of combustibles and the fact that isolation ofthe sprinklers will be extremely rare given soundmanagement of the system.

7

corporate and media suites, function rooms andbistro and dining areas.

The following observations may be made for thesebuildings:

i. From the above probability calculations fornon-sprinklered buildings, it will be found thatthe likelihood of having a significant fire is verysmall.

ii. the areas within these buildings that have asignificant fire load are generally broken intosmall enclosures due to the need to maintainexclusive use or security of these areas andthe passages needed for access and egress.In the event of a fire, this will reduce the rateat which the fire spreads, the probability of firespread and the severity of the fire at any time.

Fire characteristics such as the time-temperaturerelationship may be determined directly fromrelevant tests or by means of an appropriatemodel (see Appendix 1). These should take intoaccount the fire load and ventilation relevant to theenclosure.

The fire load densities given in the table belowmay be considered to apply to various parts ofthese buildings. These fire loads have beenderived from [10] or from calculations based ondirect observation of combustibles in suchenclosures. Some sports stand buildingsincorporate gaming machine areas. The fire loadin such areas can be taken as being equivalent tothat associated with offices.

Fire Load(kg of wood equivalent

per m 2 of floor area)Storage Areas < 80

Offices < 40

Function Rooms < 30

Bistro and Dining Areas < 25

Media Suites < 25

Food and Beverage Outlets < 20

Corporate Suites < 18

Gymnasium < 5

Concourse Areas < 5

Kitchens < 5

Toilets and Change Rooms < 5

Building with Sprinklers

In the case of sprinklered buildings it is proposedthat the design fire is a sprinklered fire. This isconsidered to be appropriate since the likelihoodof having a significant non-sprinklered fire is verylow, and the addition of a sprinkler system, whichhas been properly designed, commissioned andmaintained, will further dramatically reduce thislikelihood.

In this regard, it is important to note that there willbe very little reason for the sprinkler system to be

isolated (very few tenancy alterations3) and this,combined with the fact that the ceilings are lowand the fire load is generally not in racking, wouldbe expected to give very high levels of sprinklereffectiveness.

Nevertheless, the consequences of a non-sprinklered fire should be considered but balancedagainst the extremely low probability of such anoccurrence. The presence of practical measuressuch as a sound fire-safety management strategyat the venue and a redundant building structure(see later discussion) can be taken as providingsufficient assurance against the effects of asignificant non-sprinklered fire and to guardagainst the possibility of catastrophic failure.

In the context of this document, it is assumed thata sprinkler system, if provided, will becommissioned, maintained and managed tomaximise its effectiveness. A formal managementsystem to ensure that this is the case will benecessary.

Smoke Development and Management

It is known that a primarycause of death in fire is due tothe exposure of the occupantsto the products ofcombustion—smoke; although

burns are also commonly noted as a contributingfactor. Smoke is generated by combustion andcontains, in addition to toxic gases, small particlesof matter suspended in air. It is these particles thatindicate the presence of potentially toxic gasesand assist in the containment of heat within asmoke layer. The temperature of a hot smokelayer can also present a threat to the occupants.

In the event of a fire, because it is hotter than theambient air, smoke will tend to rise and movethrough a building including enclosures andpathways used by the occupants—thereby puttingthem at risk. Smoke management, whenunderstood in the broadest sense, is concernedwith managing smoke within the building such thatthe likelihood of exposure of the occupants todebilitating smoke is minimised. Other objectivesinclude assisting the activities of fire fightingthrough maintaining visibility and minimising theproperty damage associated with smoke.Strategies for achieving these objectives include:

• keeping the fire small—such fires generatesmall quantities of smoke

• providing adequate egress paths andevacuation strategies—to quickly movepeople away from the smoke-affected areas

3 The major source of a loss of reliability of a sprinkler

system is associated with the system being isolated forbuilding upgrade.

8

• providing adequate venting/extraction whereappropriate—removing smoke from thebuilding and away from the occupants

• providing barriers to minimise the spread ofsmoke

Thus, smoke management is about managing thesmoke in relation to the building occupants. Theterm debilitating smoke was used above toemphasise the fact that not all exposures tosmoke will lead to serious injury or death. Injuriescan vary from minor irritation to serious injury anddeath—the seriousness of the injury being afunction of the density and content of the smokeand the length of exposure to it.

As noted previously, the population in thesebuildings is only likely to be a maximum for aboutone half a day per week. During the remainingpart of the week various parts of the building willbe used to differing extents. Certainly, this will bethe case if the sports stand has function roomsand there are various social clubs. The maximumnumber of people in these buildings is related tothe seating capacity.

The people within the building will behave similarlyto people in other buildings where the occupantsare awake and aware, and the presence of densesmoke will serve to reinforce the need foroccupants in the vicinity of the fire to move awayfrom the fire-affected part of the building. In theevent of a major fire there almost certainly will beinteraction between people attempting to moveinto the concourse areas from the seating and theback-of-house construction. Thus queuing willoccur and this must be taken into account whenconsidering evacuation of part of the building.

Fire Fighting

Occupant Fire Fighting

As previously observed, a highproportion of fires in buildings areextinguished without the fire brigadebeing called, and even when they arecalled, more than 80% of these firesare confined to the object and area offire origin. These facts suggest thatthe occupants of the building have an

important role in early fire fighting, or in controllingthe fire until the fire brigade arrives. Thisemphasises the importance of adequate fire-fighting facilities and staff training.

Brigade Fire Fighting

The fire brigade’s charterrelates not only to safety of theoccupants of the building butalso to the protection ofproperty—including the buildingin which the fire originates. They

are not expected, however, to take unnecessaryrisks. The BCA, on the other hand, is primarily

concerned with maintaining a high level of lifesafety, although it is concerned with minimisingthe damage to adjacent properties and buildings.The latter objective is less relevant for thesebuildings as they are generally well separatedfrom adjacent properties.

The fire brigade is an important part of the firesafety system, and in the event of an alarm, maybe considered to have the following specificfunctions:

i. where there is no other evidence of fire,investigate the situation and the probablecause of the alarm

ii. extinguish fires that are small or that arebeing controlled by the occupants or asprinkler system

iii. participate in evacuation of the occupants inthe event of a significant fire—if that has notalready occurred

iv. undertake any reasonable measures tocontrol, and finally extinguish, a significantunsprinklered fire

v. limit fire spread to other parts of the buildingor other buildings

Factors which can have an important influence onthe ability of the fire brigade to fulfil the abovefunctions include: receiving an alarm; activitiesand timing including travel and setting-up times;fire-brigade facilities; and the size of fireconfronted.

In considering the role of the fire brigade inattacking a fire in a non-sprinklered building, it isimportant to estimate the time at which they will beeffective in limiting the spread of the fire andreducing its heat output (ie. impacting the fire) inthe enclosure of fire origin. Such action isconsidered to be feasible in these buildings due tothe fact that easy access can be obtained to mostparts of the building and that it is broken into manyenclosures. Thus, after a certain period of time itcan be assumed that the fire will be impacted bythe fire brigade. This time is variable and is afunction of the time at which the alarm is receivedat the fire station, the travel time to the building,the setting-up time once the fire brigade hasarrived and the time to impact the fire.Conservative estimates have been made for eachof these times4.

The time for detection of a fire and for calling thefire brigade is likely to be fairly short if the buildingis occupied. Also, in this case, it is very unlikelythat the fire will have reached flashover before thealarm is given. It is conservative therefore, toassume that the brigade has been notified by thetime flashover occurs.

The time for arrival of the fire brigade to a majorsports stand is estimated as 10 minutes, and in

4 Estimated times for setting up and travel time are based

on advice from various fire brigades [11].

9

practice, is likely to be considerably less. Thesetting-up time for the brigade, prior to supplyingwater to the fire, is estimated as 10 minutes. Thistiming assumes that there is little interferencebetween persons evacuating the building and thebrigade who are trying to gain access to the seatof the fire. If this is not the case then the set-uptime may be considerably longer and the firespread may be considerably greater, and in thissituation, one has to question the value of brigadeintervention.

It is therefore important to manage the evacuationprocess to minimise the brigade/occupantinterference and/or to provide independent accessfor the brigade to various locations. If this cannotbe achieved then consideration should be given tosprinklering the building from a property protectionviewpoint.

The supply of water to the fire will result inreducing air and structure temperatures in theenclosure of fire origin. Given the size of flashoverfires possible in these buildings, it is likely thatapplication of water for a period of about 10minutes will be required before the air andstructure temperatures reduce significantly.

In summary, the fire brigade is an important partof the fire-safety system, and for the fires likely tobe encountered in a modern sports stand, can beassumed to be effective in influencing a fire within30 minutes of flashover for most areas withinthese buildings—subject to an evacuation plan oralternative paths which minimise interference tobrigade activities. Of course, it is likely that the firewill have exhausted itself in less than 30 minutes.

The effect of the fire brigade in reducing fireseverity is taken into account in determining thelevel of protection required to maintain structuraladequacy.

Structural Adequacy

Section C (Fire Resistance) of theBCA gives a series of performancerequirements, some of which relateto the building structure. A carefulstudy of these requirementsreveals that the building must be

designed to provide safety for the occupants andfire fighters, and so that fire does not spread toother properties. The latter matter is rarely anissue with these buildings due to the fact that theyare generally well separated from adjacentbuildings; whilst the former is achieved bydesigning for the appropriate design fire and

through recognition that these buildings offer ahigh level of structural redundancy.

Property Protection

The issue of property protection is of importanceto both owners and operators of sports standbuildings. From overseas statistics [12] theaverage costs associated with fires in buildingsare divided as follows:

building structure building

contents

consequentiallosses

21%

36%

43%

Consequential losses include those associatedwith the loss of business, and in the case of sportsstand buildings, it is likely that these will be muchhigher than the above proportion. In any case, itcan be seen that the building structure losses area small part of the total losses.

The most effective way that a property can beprotected against fire is to not have a fire start inthe first place. This cannot always be achieved inthese buildings but routine surveillance andhousekeeping audits will be effective in reducingfire incidents. These activities therefore offer valuewith respect to property protection.

If a fire start cannot be prevented, the next bestaction is to confine the fire to the object or area offire origin through the action of staff or theoccupants. The majority of fire starts (70%) occurduring the hours that the building is occupied andare associated with the demand for services andelectricity and the activities of the occupants.However, during occupied hours, the presence ofpeople will result in the fire being mostlyextinguished before the sprinklers are able toactivate. This is less so during the “unoccupied”times when only a skeletal staff occupies thebuilding; but even then, it appears that many ofthese fires will not go beyond the area of fireorigin. Housekeeping, the establishment of fire-response procedures, and the training of staff insuch procedures can provide additional levels ofproperty protection.

A soundly-managed sprinkler system is theremaining way of restricting a fire to the area offire origin—although activation of sprinkler headsmay result in water damage. Nevertheless, thisdamage will be substantially less than thatexperienced if the sprinklers are not present orfunctioning.

High levels of structural fire resistance will notnecessarily provide high levels of propertyprotection. If property protection is a majorconcern, then the building should be sprinklered.

10

OCCUPANT AVOIDANCE

Design Strategy

To provide means for safe egress ofoccupants put at risk by a fire.

Design Principles

i. All enclosures5 and areas within the buildingshall be designed to avoid entrapment.

ii. All enclosures and areas shall have sufficientegress paths to allow staged (progressive)evacuation to a safer place, open space, orroadway, prior to the achievement ofuntenable conditions.

iii. A plan to assist the staged evacuation of thebuilding shall be developed and implemented.

Details

In designing these buildings for evacuation, it isimportant that entrapment is avoided as this hasbeen found to be one of the major sources ofdeaths in buildings. This is normally achievedthrough the provision of sufficient alternativeegress paths from each enclosure or area of thebuilding. This is the purpose of the first principle.Egress paths are those parts of the building thatare intended to be used by the occupants whenevacuating the building. They may include suchareas as concourses, walkways, corridors,doorways, stairways, ramps, etc. Smoke may flowthrough corridors and concourses and up rampsor stairs and care should be taken to ensure thatin such cases adequate alternative means ofegress are available from all areas and enclosuresthat may be affected.

The first principle may mean that egress pathswill, at least, be provided at each end of anenclosure or area. This is not practical for allenclosures and the BCA and current experiencesuggest that this principle need not apply toenclosures with a maximum plan dimension of20 m or less. However, each situation needs to becarefully evaluated. For example, in anunsprinklered building, corporate suites where theonly means of egress is via a narrow corridor atthe back of the suites may represent one situationwhere entrapment could occur—especially if thecorridor at the rear could become smoke loggeddue to a fire in an adjacent part of the buildingbefore the occupants of the suites become awareof the fire.

5 The term enclosure refers to a part of the building which is

surrounded by wall construction which may be fire-resistant and which may contain significant voids.Concourses are not considered as enclosures in thispublication.

For the purpose of this publication, well-ventilatedconcourses are regarded as areas, notenclosures, as their principal purpose is to provideaccess to an adjacent seating tier and also toareas such as toilets and food and beverageoutlets. These areas are also designed to providean efficient means of egress for occupants as theyleave the building at the end of a sporting event.Similarly, in the event of a fire, the occupants willseek to move into the concourses as they movetowards the exit stairs and/or ramps. Thus themovement of evacuees through these areas is ofcritical importance and will have a significantimpact on the overall evacuation time for theseparts of the building.

Similarly, the passageways which provideexclusive access to and from corporate viewingand other private areas must be designed toensure timely evacuation.

Part D of the BCA specifies the aggregate width ofexits or path of travel to exits and distances oftravel to these exits. An example of the applicationof this part to a sports stand building is given inAppendix 2.

The exit width requirements in the BCA appear tohave worked well with respect to facilitating thesafe movement (absence of panic, crowdpressure) of large numbers of people throughthese buildings under non-fire conditions.Designers need to be cautious in varying fromthese width requirements. However, variation ofthe travel distances and exit spacings may beappropriate.

Some egress paths will be preferred over others.Preferred paths are those that are used mostcommonly by the occupants—as opposed to fire-isolated stairways which are rarely used, andwhich are only likely to be used for evacuationwhen there is no alternative means of egress.

11

Efficient, staged (progressive) evacuation ofsignificant parts of these buildings will be assistedby the existence and implementation of anevacuation plan. Those occupants closest to thefire (vertically and horizontally) should beevacuated first, with those further away beingevacuated later, should this be necessary. Theevacuation plan should consider various firelocations and scenarios and be developedaccordingly.

Efficient, staged evacuation will be assisted by theuse of a public address system, in combinationwith direct guidance from staff positioned withinthe part of the building to be evacuated.

In the event of a significant fire it is recommendedthat the game or event is stopped to ensure thatpeople will take any instructions seriously.

Although it is not generally permitted, it may bepossible to evacuate some of the occupants fromthe lowest seating tier on to the playing field in theevent of an emergency. However, it is notrecommended that this is taken into account incalculating times for evacuation.

Times for evacuation of various enclosures andareas may need to be calculated irrespective ofwhether the exit spacings comply with Part D ofthe BCA. These times must be less than the timeto untenable conditions in those areas (seesection on Smoke Development andManagement). However, it should be noted thatcalculations of evacuation times or of the time tountenable conditions will not be necessary if thebuilding is sprinklered, or if the enclosures orareas in an unsprinklered building are sufficientlysmall or well ventilated. Further details on thesituations where such calculations are notrequired is given in the section on SmokeDevelopment and Management.

Methodology

EXIT Evacuation

The time for evacuation of the occupants from aparticular enclosure or area within the buildingshall be taken as:

te = tpm +tm

where tpm is the pre-movement time and includesall of the events required to make the decision toevacuation, and tm is the total movement time forthe occupants to move to a safer place.

Pre-movement Time

Within the enclosure of fire origin it can beassumed that the decision to evacuate will bemade well before flashover—probably at thepoint that it is recognised that occupant firefighting is not effective. In reality, the majorityof occupants will have left the enclosure wellbefore this point and it will only be thoseattempting to extinguish the fire that mustescape as the fire continues to grow. It isestimated from the observation of firedevelopment that this time period is likely tobe at least two minutes from fire initiation andseveral minutes before “flashover”.

However, in areas or enclosures away from theenclosure of fire origin, the occupants may notmove away until flashover within the enclosureof fire origin occurs. As this occurrence will beaccompanied by large quantities of denseblack smoke and considerable heat, it isreasonable to assume that those closest to thefire will begin to move first and that this willtake place shortly after flashover. Evacuationof other parts, further from the fire, will onlycommence as smoke begins to threaten orwhen the occupants are directed to evacuateby management. As noted above, if asignificant fire develops in the building, thegame should be stopped.

Total Movement Time

The total movement time shall be determinedtaking into account:

• the available tenable egress paths• the speed of travel• queuing within the egress path• the evacuation plan

The population of each area of the buildingshall be based on the seating capacity. It is notnecessary to consider additional occupantssuch as staff unless special circumstancesarise where the additional occupants make upa significant proportion of the total population.

Movement time calculations are consideredfurther in Appendix 3 which also presentsexamples based on the building presented inAppendix 2.

Des

ign

12

SMOKE DEVELOPMENT AND MANAGEMENT

Design Strategy

To provide means for the safe egress ofoccupants put at risk by a fire.

Design Principles

The building shall be designed so that:i. areas and enclosures shall remain tenable for

a period sufficient to allow evacuation fromthe area or enclosure

ii. egress paths from each area and enclosureshall remain tenable for the expected durationof evacuation from that area or enclosure

Details

The above design principles mean that for anyenclosure or area, the time to untenableconditions must be greater than the time forevacuation of that part of the building. The time forevacuation must be determined in accordancewith the section “Occupant Avoidance”.

It may not be necessary to consider the times forevacuation or tenability in those small enclosureswhere it is obvious that awake and awareoccupants can evacuate quickly enough to avoid afire. The BCA implies that this is the case forenclosures with a plan area less than 500 m2. Inthe case of sprinklered buildings it is unlikely thatany detailed consideration of evacuation ortenability will be necessary since there is a verylow probability of the occurrence of a significantnon-sprinklered fire.

Similarly, where more-than-sufficient naturalventilation (see Methodology) is provided, littleanalysis of smoke flows and smoke layer depthsis required.

The majority of the occupants in sports standbuildings will normally be in open areas and thusat little risk due to smoke from a fire. Occupants inenclosed areas and in partially-closedconcourses, etc, will be at greater risk from a firethat introduces smoke into those areas and theegress paths from them. Due to the nature ofthese buildings the evacuation time from mostareas of the building is short provided all or mostegress paths are useable.

In the areas of these buildings open to the generalpublic (ie. the majority of the occupants), thepossible locations of fires are limited (eg.concessions or food and beverage outlets) andare naturally separated by concourses, stairwaysand ramps, and enclosures such as toilets.Therefore the spread of fires in these areas islikely to be limited to a very small proportion of thebuilding. The concourses in such areas can bedesigned for smoke tenability using naturalventilation (openings in the sides) with suitably

placed barriers or curtains. Other paths such asramps and stairways at the rear of the concoursewill allow venting of smoke provided they havesufficient natural openings. In these public areas,the judicious use of natural ventilation will limit theeffect of the smoke from fires in these areas tothose in the immediate vicinity of the fire.

Any ventilation system, whether natural ormechanical, should be designed such that smokefrom a fire will be spilled to the outside of thebuilding (that is, on the side away from the playingfield) except perhaps in the most adverse weatherconditions or where this is unavoidable.

In many cases, enclosures such as corporatesuites will have glazing only on the playing side,and in the event of a fire, the glazing may breakand the smoke be largely vented outwards into theopen air rather than into the adjacent passagewayfrom which the corporate suites are entered.Untenable conditions may still be achieved in theadjacent passageway (see Texas Stadiumexample) even if the doors to such enclosures areclosed, due to gaps around the doors. This spacecould also be rendered untenable by fires fromother enclosures opening directly into thispassageway.

corporate suite passageway

minimun smokeif doors closed

venting outwards

doorglazing

ceiling

Food and beverage outlets generally have theirmain opening (often completely open) ontoconcourses. However, provided these areas havemore-than-sufficient ventilation, this should notpresent a problem.

Function rooms may have glazing on both theplaying side and the passageway (opposite) side.In such cases smoke may be vented in bothdirections and attention to adequate venting,particularly of the passageway, may be required.

function room passageway

ventinginwards

venting outwards

glazingglazing

ceiling

Smoke Reservoirs

Areas and enclosures may be designed takinginto account available reservoirs for smoke(formed naturally by walls and ceilings, etc, and byplacement of smoke barriers or curtains) providedthat smoke will be able to fill these areas underthe range of weather conditions (particularly wind)expected for the building location.

13

Mechanical Smoke Control System

Large contiguous enclosed areas of the buildingmay require a mechanical smoke control system.The design of such systems should be appropriateto the size and usage of the area. Alternatively, ifsprinklers are installed, it is unlikely thatmechanical smoke control will be required.

Natural Ventilation

It is expected that in many buildings of this typenatural ventilation will be acceptable and sufficientto satisfy the above design principles for all ormost areas of the building.

Methodology

2 m Tenability

Tenable conditions may be considered to exist inan enclosure or area if the smoke layer in thatenclosure or area is greater than 2 m from thefloor. This criterion is considered to be sufficientlyconservative that detailed consideration of thesmoke hazard is not necessary. If a lower smokelayer height is used, then detailed consideration ofthe smoke hazard (temperature, toxic properties,etc) should be undertaken.

The rate of smoke production from a fire dependson such factors as the fire size, the height towhich the smoke rises before hitting anobstruction (such as a ceiling, floor, upper deck,etc), the plan area of the enclosure and the heightof the bottom of the smoke layer. Formulae forestimating the smoke production rate and theheight of the bottom of the smoke layer for thesecases and cases involving balcony spill andwindow plumes or confined flows are given insuch publications as NFPA 92B [13], Klote andMilke [14] and CIBSE [15]. Zone models may alsobe used to estimate these quantities withadequate accuracy in many instances.

As noted previously, if more-than-sufficient naturalventing is provided, little analysis of smoke flowsand smoke layer depths may be required.

The design of more-than-sufficient ventilation willdepend on the details of individual designs but thefollowing principles may be of assistance:

i. Such ventilation should be designed to takeadvantage of the natural tendency of smoke torise. Thus pathways for smoke from possiblefire locations should not incorporatedecreasing elevations of the roof or ceilingtowards the vents to the open air. Preferably,the elevations of the roof or ceiling shouldgradually increase towards the vents.

ii. Concourses, stairways, ramps, etc that havemore than 20% of the total external wall areaopen at the top of the walls may be consideredto be equivalent to being in the open airprovided that the openings are not separatedby more than 10 m.

iii. Concourses, stairways, ramps, etc, innaturally-ventilated areas should notincorporate doors or other impediments tosmoke flow unless at least 70% of their area isopen and such openings are located at the topof the potential barrier. Concourses, stairways,ramps, etc in such areas and with more-than-sufficient ventilation need not be considered asenclosures.

iv. The roof or ceilings in concourses, stairways,ramps, etc, should be at least 3 m high andpreferably 4 m.

If more-than-sufficient natural venting is notprovided to a large enclosure (ie. > 500 m2) then itwill be necessary to assess the tenability of thatenclosure by, for example, using either therelevant equations for smoke production or zonemodelling (some details are given in Appendix 1),as described above. This must be doneconsidering a local fire within the enclosure underconsideration, and then a “flashover” fire in anyadjacent enclosure (assuming a flashover fire canoccur). In the latter case, the smoke from a fire inan adjacent enclosure will spill into the enclosureunder consideration and the modelling must takethis into account.

Des

ign

14

FIRE DETECTION AND SUPPRESSIONBRIGADE COMMUNICATION AND RESPONSE

Design Strategy

To provide sufficient means of detection andfire fighting for the occupants and the firebrigade.

Design Principles

i. Sufficient means of detection shall beprovided.

ii. Sufficient means of alerting staff and firebrigade shall be provided.

iii. Sufficient portable extinguishers shall beprovided and suitably located within thebuilding to enable occupant fire fighting.

iv. Sufficient hose reels shall be provided andsuitably located within the building to enableoccupant fire fighting.

v. A training program for staff in fire awarenessand the use of portable extinguishers andhose reels shall be developed andimplemented.

vi. Sufficient fire brigade access shall beprovided.

vii. Sufficient hydrants shall be provided andsuitably located to facilitate brigade firefighting.

Notes on Design Principles

The occupants of the building will be mosteffective in detecting fire in occupied areas. Inunoccupied areas, detection must be by othermeans (eg. smoke detectors). This is likely to beparticularly important from a property protectionviewpoint. However, in the case of a sprinkleredbuilding, it is not considered necessary toincorporate alternative detectors.

If a fire is detected in an occupied area, it is verylikely that the fire will be extinguished by theoccupants. Should a fire develop in an unoccupiedarea, it will be necessary to alert the ground staffand the fire brigade. This will be achieved bydetectors via the Fire Indicator Panel.

Portable extinguishers provide animportant means of firesuppression for occupants andare more likely to be used as animmediate response to a fire startthan a hose reel. Therefore theplacement of such equipmentclose to areas where fires aremore likely to start is important.

Hose reels can alsohave an important (butlesser) role inoccupant fire fightingand should beprovided throughoutthe building. In manyof the open publicareas, these may beused for otherpurposes such ascleaning, and in thiscase, will beconnected to thedomestic watersupply. The use of such equipment for thispurpose is considered as an acceptable practiceas it provides a check on the operational status ofthe equipment.

Adequate access to (and into) the building mustbe provided if the fire brigade is to be effective inimpacting a spreading fire. Vehicular access tohydrant boosters and major entrances into thestand is therefore important. The speed with whichthe brigade can reach areas within the building isa function of the number of people (moving in theopposite direction), the distance from the entrypoint, the means of access into certain areas (eg.lifts, ramps or stairs), and their knowledge of thebuilding layout. As far as the latter factor isconcerned, the brigade will need to be guided tothe fire-affected area by ground staff. The use ofstaged evacuation will minimise interference withthe brigade. The presence of a sprinkler systemwill reduce the urgency of brigade response.

Hydrants may beexternal or internal andprovide a source of waterfor the fire brigade toconnect hose lines.Typically, the fire brigadewill connect a fire-fightingappliance (ie. truck) tothe hydrant booster andconnect hose lines to therelevant hydrants.However, it is knownfrom statistics collectedby the fire brigade thatinternal hydrants are veryrarely used, with workingfrom an appliance being the preferred approach. Itappears that an internal hydrant will only be usedwhere there is no other equivalent means ofproviding water (via hose lines) to a particularlocation within the building.

15

Details

Detection System

If the building is not sprinklered, a smokedetection system in accordance with AS1670 [16]shall be provided. However, in kitchens andsimilar areas heat detectors may be installed inlieu of smoke detectors.

Communication

Detector or sprinkler activation shall result in analarm to ground staff and the fire brigade via theFire Indicator Panel.

Access

In the case of a building that is not sprinklered,access to various parts of the building shall beprovided to ensure that the brigade can reachnecessary locations within the required timeinterval, taking into account the assistance ofground staff and staged evacuation. A joint groundstaff/fire brigade action plan to facilitate access tonecessary locations shall be developed andimplemented.

Fire Extinguishers

Portable extinguishers to AS2444 [17] shall beprovided in all enclosures where there is powerdistribution equipment, the cooking of food (eg.kitchens, dining rooms, food and beverageoutlets), or the storage of hazardous goods orflammable liquids, or any enclosure which cannotbe practically reached with a hose reel—ie. anenclosure where the hose must pass through aself-closing door.

Hose Reels

Hose reels to AS2441 [18] shall be locatedthroughout the building such that the nozzle end ofthe fully extended fire hose fitted to a reel, and laidto avoid any partitions or other physical barriers,will reach every part of the building.

Hydrants

The water supply shall have adequate flow andpressure characteristics and any occasionalisolation shall be properly managed.

Hydrants shall be provided generally inaccordance with the requirements of AS2419.1[19] and each part of the building shall be able tobe reached from an external or internal hydrant.

An internal hydrant need only be provided wherewater cannot be delivered efficiently from anappliance or external hydrant, taking into accountthe likely direction of attack. Efficient delivery ofwater is dependent on the number of lengths ofhose line that must be laid, and the height abovean external hydrant/appliance. It is considered thatthe limiting number of lengths of hose line thatmay be laid from an external hydrant or applianceis two (60 m), and the limiting height (beyondwhich it will be difficult to drag hose lines) is twostoreys above the external hydrant/appliancelocation. The length of the hose stream may betaken as 10 m in accordance with AS2419.1.

Spacing of internal hydrants shall be based on theassumption that one length of hose line (30 m)only can be laid from each hydrant. In this casethe length of the hose stream may be taken as 6m.

In the case of a sports stand building which issprinklered, it is considered that generalconcessions may be sensible with respect to thenumber and location of internal hydrants. Onepossible concession is that only external hydrantsneed be provided on the condition that the totalhose length does not exceed 120 m or the heightabove the hydrant is not greater than 4 storeys.Such allowances are possible due to the fact thatthe probability of having a significant non-sprinklered fire is very low.

Deemed-to-Satisfy Solutions

BCA Part E1

Des

ign

16

FIRE SPREAD AND MANAGEMENT

Design Strategies

To minimise the number of occupants put atrisk by a fire.

To allow safe egress of occupants put at riskby a fire.

To provide an adequate level of safety for firefighters.

Design Principles

The building shall be designed so that:i. there is little risk of spread of fire from the

area or enclosure of fire origin

ii. the risk of fire spread from an area orenclosure to another area, enclosure oregress path is not such that the safe egress ofoccupants having to evacuate is threatened

iii. there is no likelihood of combustible materialsbuilding up in cavities or concealed spaces

Details

In the areas of these buildings open to the generalpublic (the majority of the occupants) the possiblelocations of fires (concession areas, etc.) arenaturally separated by concourses, stairways,ramps, etc. Therefore the spread of fires in theseareas is likely to be limited to a very smallproportion of the building by the separation ofcombustible materials, provided non-combustibleconstruction is used. Combustible cladding andconstruction has in the past led to extensive firespread through buildings of this type.

The roof structure over the major spectator areasof these buildings is very unlikely to be subjectedto a significant fire. Therefore these roofstructures need not be designed for fireresistance.

The seating tiers usually consist of reinforced orprestressed concrete plats supported on girders.The plats are normally not required to be designedfor fire resistance unless they directly form theroof of an enclosure (below). If this is the casethen they should be designed as a floor.

Achievement of the design principles will beassisted by designing the relevant buildingelements to have sufficient fire resistance. In thisregard, floors (floor slabs, beams, and in somecases, seating plats), columns, and loadbearingwalls shall be designed to maintain structuraladequacy, integrity and insulation (as relevant forthe member) for the duration of the design firewith an appropriate level of safety, or 30 minutesfrom flashover, whichever is the least. Theresultant time is referred as the design duration.

The above duration of 30 minutes is dependent onlittle interference between evacuees and firefighters attempting to reach the fire. As indicatedpreviously, this can be achieved with a soundevacuation plan or by providing alternative accessfor fire fighters. If such is not provided, and thebuilding is not sprinklered, the duration associatedwith the impact of the fire brigade should beextended to 60 minutes. This will have an impacton the design duration.

A comprehensive assessment has beenundertaken of the above building elements whensubject to the relevant design fires correspondingto various locations within the building. In eachcase, the range of possible geometries andenclosure characteristics associated with theparticular location have been taken into account indetermining the protection requirements (if any)for structural steel and other members. Theseanalyses have been used to develop solutionswhich cover a wide range of situations and whichcan be conservatively adopted for designpurposes. These solutions are given in theDeemed-to-Satisfy part of this section and applieswhen the design duration is up to 30 minutes.

Buildings of this type are composed of manystructural members which are connected togetherto form a complex and continuous structure. Theremoval of one or even several members will notimpair the overall stability of the building. It followstherefore, that the presence of a localised intensefire which severely reduces the strength of severalstructural members, is unlikely to effect the overallstability of the building or the ability of theoccupants to move away from the fire.

Design principle iii stems from fires such as theBradford Stadium fire where accumulated rubbishin such a space was set alight with disastrousconsequences.

Bradford Stadium: combustibles burning inspace below seats

17

Methodology

Fire Resistance

The fire resistance of a member may bedetermined using the following procedure:

i. Obtain or estimate the time-temperaturerelationship for the relevant design fire. Thismay be based upon test data or calculation(see Appendix 1). In the case of a sprinkleredfire, the air temperature within the vicinity ofthe structural member may be taken as lessthan 100°C and no further analysis of fireresistance is required.

ii. Identify the relevant design criteria for themember.

If the member is loadbearing then it will benecessary to demonstrate structuraladequacy. However, if the member is either awall or a floor slab it will also be necessary toconsider integrity and thermal insulation.

iii. Estimate, using a transient heat-flow analysis,the temperatures throughout the memberincluding unexposed surface temperatures ifthermal insulation is a relevant criterion.

iv. Determine the load on the member (if any)The level of load applied to the member in thefire situation is defined by AS1170.1 [20] as:

wf = 1.1G + 0.4Q where G is the dead load and Q the live load.

v. Undertake appropriate structural analysis ofthe member if loadbearing.

Analysis of the structural member will need totake into account the effect of temperature onthe mechanical properties of structural steel,reinforcing and prestressing steel, andconcrete. In this regard the properties given inAS4100 (steel structures) [21] and AS3600(concrete structures) [22] may be used.The normal assumptions of structuralmechanics may be considered to apply in theanalysis.

vi. Check compliance with design criteria.

If the design criterion is structural adequacy,then it is necessary to show that the appliedload can be supported by the member for thedesign duration. If the criterion is thermalinsulation, then the temperature of theunexposed face will need to be calculated andfound to be less than 140°C above theambient temperature.

Deemed-to-Satisfy Solutions

i. For members (eg. floor slabs, walls, beamsand columns) required to have a fireresistance, and in the absence of fire-engineering calculations or other deemed-to-satisfy solutions, an FRL of 60 minutes.

ii. Based on fire-engineering calculations, thefollowing solutions apply for steel beams andcolumns. The exposed surface area to massratio (ksm) is the key parameter in determiningthe temperature of a steel member whenexposed to fire. The lower the value, the lowerwill be the temperature achieved.

TABLE A: Steel beams and columns withinenclosuremaximum ksm (m2/tonne)

no sprinklers: beam columngymnasiums 30 30concourses & walkways 30 30change rooms & toilets 30 30corporate suites- depth <7.5 m & 10 min ceiling†- depth ≥7.5 m & 20 min ceiling†

3030

26‡26‡

function rooms- depth <7.5 m & 20 min ceiling†- depth ≥7.5 m & 30+min ceiling†

3030

26‡26‡

Dining rooms (30+min ceiling†) 30 26‡food & beverage outlets (10 minceiling†)

30 26‡

storage areas & offices (60 minFRL)

(60 minFRL)

with sprinklers: beam column(all areas) 30 26

† ceiling systems:10 min = plaster tiles on steel runners20 min = 13 mm plasterboard screw-fixed to steel runners30+min= 13 mm fire-resistant plasterboard screw-fixed to

steel runnersNote that openings within a ceiling (eg. for lights) should bepositioned such that they are not closer, in plan, than 1 mfrom a beam.

‡ clad with 16 mm plasterboard wrapped around column andpenetrating the relevant ceiling. ksm values are those basedon the profile area (see Appendix 4).

TABLE B: Steel beams and columns outsideenclosuremaximum ksm (m2/tonne)

no sprinklers in enclosure: beam columnfood & beverage outlets:

>2 m from opening 30 30

≤2 m from opening 18.5 18.5

(other areas) § §

with sprinklers in enclosure: beam column(all areas) no req no req

§ Columns and beams should be positioned so that themembers are not located adjacent to openings. Otherwise, themembers should be protected as if they were within theadjacent enclosure.

The ksm for BHP steel sections can be found inAppendix 4. Only members which have a ksm

value less than or equal to the relevant valuegiven in the above tables are acceptable.Worked examples of checking the adequacy ofsteelwork are contained in Appendix 5.

Des

ign

18

CONCLUSIONS

This publication gives design principles and detailswhich address the fire-safety objectives of theBCA. By implication, the performancerequirements of the BCA are also considered. Thedesign approach described herein will lead togreater flexibility and economy of construction—

and in many situations, a greater level of safety.Sructural steel with little or no fire protection canbe used in these buildings and offers advantageswith respect to speed of construction, reducedcosts, and flexibility for future buildingmodifications.

REFERENCES

1. “Building Code of Australia Class 2 to 9Buildings”, Australian Building Codes Board,1996.

2. “Fire Engineering Guidelines”, Fire CodeReform Centre Ltd, Sydney, Australia, March1996.

3. Anon, Fire Journal, September 1978, pp 78.

4. “Committee of Inquiry into Crowd Safety andControl at Sports Grounds: Interim Report”,HMSO, London, UK, 1985.

5. “Guide to Safety at Sports Grounds”, HMSO,London, UK.

6. Hughes Associates, “Fire Safety Survey ofLarge Outdoor Stadiums”, May 1988.

7. Isner, M. S., “Stadium Fires DemonstrateUnique Protection Problems” NFPA Journal,Vol. 88., No. 4, July/August 1994.

8. Kirby, R. B., “Recent Developments andApplications in Structural Fire EngineeringDesign—A Review”, Fire Safety Journal, Vol.11, No. 3, 1986.

9. Bennetts, I. D., Poh, K. W., Poon, S. L.,Thomas, I. R., Lee, A. C., Beever, P. F.,Ramsay, G. C. and Timms, G. R., “Fire Safetyin Shopping Centres”, Fire Code ReformCentre, Project 6, BHPR/SM/R/G/073, August1977.

10. Société Suisse des Ingénieurs et desArchitectes, “Evaluation du risque d’incendie:Méthode de calcul”, SIA Dokumentation 81,1984.

11. “Fire Brigade Intervention Model” (version 2.1)Australian Fire Authorities Council, Nov. 1997.

12. Favre, J. P., “Design of Buildings for FireSafety in Switzerland”, Design of SteelBuildings for Fire Safety—European andAustralian Perspective, Seminar Proceedings,1996.

13. “NFPA 92B, Smoke Management Systems inMalls, Atria, and Large Areas”, 1991 Edition,National Fire Protection Association, USA,1991.

14. Klote, J. H. and Milke, J. A., “ Design ofSmoke Management Systems”, AmericanSociety of Heating, Refrigerating and Air-Conditioning Engineers Inc., USA, 1992.

15. “Relationships for Smoke ControlCalculations”, The Chartered Institution ofBuilding Services Engineers, TechnicalMemoranda TM19:1995, 1995.

16. AS1670, “Automatic Fire Detection and AlarmSystems—System Design, Installation andCommissioning”, Standards Australia, 1986.

17. AS2444, “Portable Fire Extinguishers—Selection and Location”, Standards Australia,1988.

18. AS2441, “Installation of Fire Hose Reels”,Standards Australia, 1988.

19. AS 2419.1, “Fire Hydrant Installations Part 1:System Design, Installation andCommissioning”, Standards Australia, 1996.

20. AS1170.1, “Minimum Design Loads onStructures Part 1: Dead and Live Loads andLoad Combinations”, 1989.

21. AS4100, “Steel Structures”, StandardsAustralia, 1990.

22. AS3600, “Concrete Structures”, StandardsAustralia, 1994.

23. Peacock, R. D., Forney, G. P., Reneke, P.,Portier, R. and Jones, W. W., “CFAST, theConsolidated Model of Fire Growth andSmoke Transport”, NIST Technical Note1299, Nat. Inst. Stand. Tech., Gaithersburg,MD 20899, 1993.

24. Tanaka, T. and Nakamura, K. “A Model forPredicting Smoke Transport in Buildings—Based on Two Layers Zone Concept”, Reportof the Building Research Institute, No. 123,Published by the Building Research Institute,Ministry of Construction (in Japanese),October, 1989.

19

25. Poon, S. L., “A Design Fire for Use inPredicting the Performance of ExposedStructural Steel Members”, 4th PacificStructural Steel Conference, Singapore,October 1995.

26. Bennetts, I. D., Poon, S. L. and Poh, K. W.,“Innovative Design of Steel Buildings for FireSafety”, Design of Steel Buildings for FireSafety—European and AustralianPerspective, 1996 Seminar Proceedings,Australian Institute of Steel Construction.

27. Nelson, H. E. and MacLennan, H. A.,“Emergency Movement”, SFPE Handbook ofFire Protection Engineering, 2nd Edition,National Fire Protection Association, Quincy,Massachusetts, 1995.

28. Nelson, H. E., “FPETOOL: Fire ProtectionEngineering Tools for Hazard Estimation”,NISTIR 4380, National Institute of Standardsand Technology, Gaithersburg, MD, 1990.

29. Kisko, T. M., Francis, R. L. and Noble, C. R.,“Evacnet+ User's Guide”, Department ofIndustrial and Systems Engineering,University of Florida, Gainesville, Florida, April1984.

30. Poon, S. L., “EvacSim: A Simulation Model ofOccupants with Behavioural Attributes inEmergency Evacuation of High-Rise BuildingFires”, Fire Safety Science—Proceedings ofthe Fourth International Symposium, Ottawa,Canada, June 1994.

31. Thompson, P., Wu, J., Marchant, E., “Simulex3.0: Modelling Evacuation in Multi-StoreyBuildings”, Fire Safety Science—Proceedingsof the Fifth International Symposium, 3-7March, Melbourne, Australia, Hasemi Y. (Ed),International Association for Fire SafetyScience, 1997.

32. Galea, E. R., Galparsoro, J. M. P, “EXODUS:An Evacuation Model for Mass TransportVehicles”, UK CAA Paper 93006 ISBN086039 543X, Pub by CAA London, 1993.

33. Owen, M., Galea, E. R. and Lawrence, P.,“The EXODUS Evacuation Model Applied toBuilding Evacuation Scenarios”, Journal ofFire Protection Engineering, 8: 2, 1996, pp665-86.

20

APPENDIX 1 Modelling of Fire Characteristics

\

Introduction

The characteristics of flashover fires are afunction of the likely combustibles, the ventilationavailable to the fire, and the geometry of theenclosure. Fire load is expressed in terms of thecalorific value of the combustibles per unit floorarea (typically wood equivalent expressed in kg/m2

of floor area); whilst the area of ventilationavailable to the fire is taken as the total area ofwindows and openings that are associated with anenclosure—it being generally assumed that anyglazing will break and form an opening throughwhich air can enter and through which smoke andheat will be exhausted. Values of fire load relevantto each of the types of enclosures within a sportsstand building are given earlier (see Fire SafetyAspects).

Other factors which have an influence on thedevelopment of the fire are the nature of thecombustible contents and the thermalcharacteristics of the materials lining the walls andceilings.

Computer modelling

There are essentially two approaches (models) tocalculating the air temperatures associated with afire. These are field models and zone models.Neither approach models the fire itself (ie. thecombustion process) and it is necessary to inputthe heat release characteristics of the fire. Themodels allow the air temperatures throughout anenclosure to be estimated based on different setsof assumptions.

Field models

Field models divide an enclosure into a grid ofsmall elemental volumes and solve equationsof mass, momentum and energy for eachelemental volume. They generally requiresubstantial computer resources.

Zone models

Zone models, in contrast, solve theconservation equations for relatively largeelemental volumes, usually considering theenclosure to be broken into only one or twovolumes. Each volume is assumed to haveuniform properties. A one-zone modelassumes that the entire enclosure has uniformtemperatures. Two-zone models are morecommon and they divide the enclosure into a

hot upper layer and a cool lower layer. Unlikefield models with fixed unit volumes, the size ofeach zone in a two-zone model changes toreflect the transfer of mass and energybetween the layers. The interface between thelayers usually provides a good indication of thesmoke layer height. The two most advancedzone models that are presently available areCFAST [23] and BRI2 [24].

Time

FLAS

HO

VER

IGROWTH

IIDEVELOPED

IIIDECAY

Qp

pt

Hea

t rel

ease

rate

∆Idealised stages in an enclosure fire

For both field and zone models, the fire is usuallymodelled based on a specified rate of heatrelease. A methodology for determining the heatrelease rate for such a purpose has beendeveloped [25]. This methodology has beencompared with four full-scale real fire tests ofenclosures ranging from floor sizes of 4 m × 4 mto 12 m × 12 m and appears to give an adequateprediction of the air temperature as a function oftime. Three of the tests used office type furnitureas fuel and one used wood cribs. When used withCFAST, the heat release rate given by themethodology tends to produce time-temperaturepredictions which are conservative (ie. airtemperature on the high side and a longerduration at air temperatures above 500°C) andeven more so for high fire loads. This is partly dueto the limitations of semi-empirical equationswithin CFAST. It is also due to the methodologywhich, because it is based on the burning of woodcribs, uses a more efficient burning characteristicthan may be encountered with real furniture. Inaddition, due to the limited validation mentionedabove, the methodology may not be appropriatefor enclosures beyond the tested range or forexcessive fire loads (> 60 kg/m² wood equivalent).

Within its tested range, the methodology generallygives reliable predictions for most enclosures andfire load situations.

21

APPENDIX 2 Application of BCA Access and EgressRequirements to a Building

Introduction

This Appendix illustrates the application of theBCA access and egress requirements to a two-tiersports stand.

Cross-sections through the stand and plan viewsat various levels are shown by the attacheddrawings. It will be noted that fire-isolated exits arehighlighted in yellow and open space in blue ateach level. The distance travelled by occupantsfrom the extreme position on the seating tiers toan exit is traced with a red dotted arrow. The exitsat each level are indicated on these drawings.

In the BCA, the following definitions apply:Open Spectator Stand means a tiered standsubstantially open at the front.Exit means -(a) Any, or any combination, of the following if

they provide egress to a road or openspace:(i) An internal or external stairway(ii) A ramp(iii) A fire-isolated passageway(iv) A doorway opening to a road or open

space(b) A horizontal exit or a fire-isolated

passageway leading to a horizontal exit.Horizontal Exit means a required doorwaybetween two parts of a building separated fromeach other by a fire wall.Open Space means a space on the allotment,or a roof or similar part of a building adequatelyprotected from fire, open to the sky andconnected directly with a public road.

No. of paths of travels and no. of exits

BCA cl D1.2 states:

(f) Exits in open spectator stands - In an openspectator stand containing more than one tier ofseating, every tier must have not less than 2stairways or ramps, each forming part of the pathof travel to not less than 2 exits.

Example: It will be noted from the drawings thatthe upper seating tier (see Plan—Level 4) hasmany stairs leading to a concourse that iscompletely open at the rear and which allowsdirect movement to two sets of open stairs to theroad and two fire-isolated stairways. In the case ofthe lower tier of seating (Plan -Level 3) there areagain many stairs down to the lower concoursewhich then provides (see dotted blue line onPlan—Level 2) many paths of travel to externalstairs or open space.

Do the exits need to be fire-isolated?

BCA cl D1.3 states:

(b) Class 5 to 9 buildings—Every required exit mustbe fire-isolated unless-(ii) it is part of an open spectator stand

Example: As will be noted from Plan—Levels 2-4, some fire-isolated exits have been provided inthis building. As the building is an open spectatorstand none of the exits are required to be fire-isolated. However, as will be found later, the totaldistances of travel to an open space or roadwayvia non fire-isolated exits exceeds the limits givenin the BCA at several points in the building. Thusfire-isolated exits were incorporated.

Exit travel distances

BCA cl D1.4 states:

(e) Open spectator stands—The distance of travel toan exit in a Class 9b building used as an openspectator stand must be not be more than 60 m.

Example:

Lower seating tierThe maximum distance of travel from thefarthest point on the lower seating tier to a pathof travel = 28 m (see Plan—Levels 2, 3). Themaximum distance along a path of travel to anexit = 31 m.Therefore maximum distance of travel to anexit = 59 m which is < 60 m.

Corporate suitesNote that Level 3 (ie. corporate facilities)comprises two fire compartments, with thegross floor area of the larger compartmentbeing less than 2000 m2 in order to meet thesmoke hazard management requirements ofthe BCA, Table E2.2b.The maximum distance of travel from thefarthest point on Level 3 to an exit from thebuilding is calculated as:

the maximum distance of travel from thefarthest point on Level 3 (playing field side ofcorporate suites) to a path of travel = 10 m(see Plan—Level 2); plusdistance along path of travel (ie. corridor andfoyer) to exit = 32 m. Therefore, themaximum distance of travel to an exit = 42 mwhich is < 60 m.

App

endi

x

22

Therefore, the maximum distance of travel toan exit = 42 m which is < 60 m.

Upper seating tierNote that the Level 4 concourse is completelyopen on the road side, has openings(vomitories) on the playing field side, and issubstantially open to the sky. It is also directlyconnected to the road. The concourse may beregarded as open space. Open stairwaysprovide a direct link between the open spaceand the road.The maximum distance of travel from the mostextreme point on the upper seating tier to anexit from this tier is (see Plan—Level 4):

distance from the back of upper seating tierto the start of the stairs (or vomitory) = 18 m< 60 m

Travel by an exit

BCA cl D1.9 states:

(a) A non fire-isolated stairway or non fire-isolatedramp serving as a required exit must provide acontinuous means of travel by its own flights ofstairs and landings from every storey served tothe level at which egress to a road or open spaceis provided.

(c) In a Class 5 to 9 building, the distance from anypoint on a floor to a point of egress to a road oropen space by way of a required non fire-isolatedstairway or non fire-isolated ramp must notexceed 80 m.

(e) In a Class 5 to 8 or 9b building, a required nonfire-isolated stairway or non fire-isolated rampmust discharge at a point not more than-(i) 20 m from a doorway providing egress to a

road or open space or from a fire-isolatedpassageway leading to a road or openspace; or

(ii) 40 m from one of 2 such doorways orpassageways if travel to each of them fromthe non fire-isolated stairway or non fire-isolated ramp is in opposite or approximatelyopposite directions.

Example:In accordance with BCA cl D1.8 an externalstairway has been incorporated at the end of thebuilding.The maximum distance of travel to the start ofthese stairs is 38 m (see Plan—Level 3), and thedistance of travel down the stairs (ie. to the pointof egress to open space) is 7 m. The totaldistance of travel is 45 m < 80 m.

Discharge from exits

BCA cl D1.10 states:

(a) An exit must not be blocked at the point ofdischarge and where necessary, suitable barriersmust be provided to prevent vehicles fromblocking the exit, or access to it.

(b) If a required exit leads to an open space, the pathof travel to the road must have an unobstructedwidth throughout of not less than-(i) the minimum width of the required exit; or(ii) 1 mwhichever is the greater.

(c) If an exit discharges to open space that is at adifferent level than the public road to which it isconnected, the path of travel to the road must beby-(i) a ramp or other incline having a gradient not

steeper than 1:8 at any part, or not steeperthan 1:14 if required by the deemed-to-satisfyprovisions of Part D3; or

(ii) except if the exit is from a Class 9a building, astairway complying with the deemed-to-satisfyprovisions of the BCA.

(d) The discharge point of alternative exits must belocated as far apart as practical.

(e) In a Class 9b building which is an open spectatorstand that accommodates more than 500persons, a required stairway or required rampmust not discharge to the ground in front of thestand.

Example: Exits from the building are clear ofobstructions and are each greater than 1 m inwidth. They are also well distributed and provideegress to the road or open space.

Exit dimensions

BCA cl D1.6 states:

In a required exit or path of travel to an exit-(a) the unobstructed height throughout must not be

less than 2 m; except the unobstructed height ofany doorway may be reduced to not less than1980 mm; and

(b) if the storey or mezzanine accommodates notmore than 100 persons, the unobstructed widthexcept for doorways must not be less than-(i) 1 m; or(ii) ………..

(c) if the storey or mezzanine accommodates morethan 100 persons but not more than 200 persons,the aggregate width, except for doorways mustnot be less than-(i) 1 m plus 250 mm for each 25 persons (or part)

in excess of 100; or(ii) ………..

23

(d) If the storey or mezzanine accommodates morethan 200 people, the aggregate width, except fordoorways, must be increased to-D1.6(i) 2 m plus 500 mm for every 60 persons (or

part) in excess of 200 persons if egressinvolves a change in floor level by a stairwayor ramp with a gradient steeper than 1 in 12;or

(ii) in any other case, 2 m plus 500 mm forevery 75 persons (or part) in excess of 200;and

(e) in an open spectator stand which accommodatesmore than 2000 persons, the aggregate width,except for doorways, must be increased to 17 mplus a width (in metres) equal to the number inexcess of 2000 divided by 600; and

(f) the width of a doorway must not be less than-(iii) the width of each exit provided to comply with (b),

(c), (d) minus 250 mm.

Example: The upper seating tier holds 5500persons. The lower seating tier holds 4000persons including 400 in corporate (open) boxes.The Level 3 corporate suites, media rooms,members dining room, function room and stafffacilities hold an additional 840 persons. Noallowance is made for concourses orpassageways (see cl D1.13(a))

Lower seating tierAggregate width of exits or path of travel toexits associated with travel from lower seating

tier and corporate boxes to road or openspace:

4000 persons ∴ aggregate width required is17+ (4000-2000)÷600 = 20.3 m (see D1.6(e))

Ten exits approximately evenly spaced providean aggregate width of 28 m (>20.3 m)Also has more than one exit (see D1.2(f)).

Corporate facilitiesAggregate width of exits or path of travel toexits associated with travel from Level 3 toroad or open space:

840 persons ∴ aggregate width required is(840-200)÷75 = 8.5 ⇒ 9 ∴ 2+9×0.5 = 6.5 m(see D1.6(d)(ii))

Nine exits at an aggregate width of 11 m areprovided (>6.5 m). More than one exit isprovided (see D1.2(f)).

Upper seating tierAggregate width of exits or path of travel toexits associated with travel from upper seatingtier to open space (Level 4 concourse):

5500 persons ∴ aggregate width 17+(5500-2000)÷600 = 22.8 m (see D1.6(e))

Ten exits approximately evenly spaced at2.5 m width = 25 m (>22.8 m). More than oneexit is provided (see D1.2(f)).

LEGENDopen space

fire-isolated stairway

exit

path of travel

distance travelled to path of travel or exit

typical accessto lower tier via vomitory

(2.5 m wide)

externalstairs

discharge(from Level 3)

discharge(from Level 3)ROAD

max distance travelled fromlower seating tier (see Plan -LEVEL 3) to a path of travel

total 28 m

31 m

A

B

C

PLAN—LEVEL 2

App

endi

x

24

LEGEND

open space

fire-isolated stairway

exit

path of travel

distance travelled to path of travel or exit

fire compartment separation(2000 m2 max GFA compartment)

max distance travelled fromlower seating tier to a path oftravel on Level 2 (see Plan -LEVEL 2)

ROAD

horizontal exit

total 28 m

10 m

32 m

9.5

m

aver

age

140 m

D

10 m

28 m

(open)(enclosed)

PLAN—LEVEL 3

to road

to road

typical access toupper tier via vomitory

ROAD

18 m

LEGEND

open space

fire-isolated stairway

exit

path of travel

distance travelled to path of travel or exit

max distance travelled fromupper seating tier to an exit

E

F

PLAN—LEVEL 4

25

upper seating tier(capacity 5,500)

lower seating tier(capacity 3,600)

vomitory

SECTION—BAY 1

upper seating tier

lower seating tier

road

SECTION—BAY 14

App

endi

x

26

APPENDIX 3 Calculation of Evacuation Times

Introduction

There are a number of means by which theevacuation times for a building may be calculated.For buildings with relatively simple layouts, simplehand calculations based on initial travel distancesand flow through openings would suffice. Thismethod is adequate provided the occupant flowrate is uninterrupted and the direction of travel isstraightforward.

As the layout increases in complexity, merging offlows or decisions on the choice of egress pathsmay affect the continuity of flow. When the flowrate varies, the density of occupant flow fluctuatesand affects the travel speed. Because thevariation of travel speed with occupant density isnon-linear, the effects of congestion and queuingon the overall flow become harder to determine. Infact, queuing approaches a stochastic process inthat its occurrence and duration is probabilisticand varies with time.

Travelspeed (m/s)

Vmax

Populationdensity

(persons/m²)3.80.5

Hand calculations which demonstrate the effectsof variation of occupant flow on travel speed canbe found in [27]. Despite the fact that the exampleconsidered is a nine-storey building with simplifiedfloor layout and flow assumptions, the calculationsare tedious. In situations where occupant flow isuninterrupted and is only affected by the rate offlow through the final point of egress, thecalculations are significantly simplified byassuming constant travel speed and flow rates[9],[28].

c

1.2 m/s 1.3 persons/s.m

0.9 m/s ~0.9 m/s for unprolonged travel

Constant free-flow rate assumptions

Computer calculations for evacuation haveevolved to facilitate the calculation of evacuationtimes in building situations where the flows andpaths are complex. There are many such models.These range from simple travel-time models [28]to network models [29] and more recently thosewhich allow a detailed representation of humandecision making [30-33].

Simplified calculations (as per hand calculations)can provide quick estimates of the time for agroup of people to evacuate a given space. Thesemodels assume free flow to the points of egressfrom the space and are therefore not suitable forspaces where movement to these points of egressmay be impeded by crowdedness or obstacles inthe flow.

Evacnet+ [29] is a networking optimisation modelwhich produces the minimum evacuation time forthe building being analysed. It associates a travelspeed between nodes and an average flowvolume which corresponds to a specified “level ofservice”6 which does not vary with populationdensity or time. Occupants are assumed to alwaystake the shortest route possible. It isrepresentative of the “hydraulic model” which isbased on the following assumptions [27]:

• All persons start to evacuate at the same time

• Occupant flow is unaffected by decisions of theindividuals involved

• Persons evacuating will move at the assumedspeed of the group. That is, it is not possible totake account of the movement characteristicsof individuals

EvacSim [30] is a discrete-event simulation modelfor building evacuation which has been developedto accommodate the complex behaviouralactivities of occupants during the evacuationprocess in a fire. It models the travel speed ofoccupants as a function of occupant density andincludes various decision-making attributes on thechoice of egress path. The choice of egress pathis a function of a number of factors includingqueue length, distance to point of egress,familiarity with egress paths and environmentalconditions (eg. smoke levels). It also allows for theimpact of a warden system for controlling theevacuation of the building in accordance with aprescribed evacuation management plan.

This appendix further considers the use andlimitations of simplified calculations. Themovement times associated with the evacuationof various parts of the building described inAppendix 2 are analysed using EvacSim.

6 The level of service may be interpreted as the maximum

flow rate through a node per unit effective width.

27

Although one of the main features of EvacSim isthe ability to model the dynamic interaction ofoccupants with the social and physicalenvironments during evacuation, this is notundertaken in the following example. Instead, onlythe inherent occupant movement features areutilised. These are the dynamic travel speed,based on occupant density, and the exit choicebehaviour as described previously less theenvironmental factors.

Worked Example

In the case of the sports stand building presentedin Appendix 2, the egress routes for the upper andlower seating tiers and Level 3 are allindependent.

The egress routes for each part of the building areassumed to be those with which the occupantsare likely to be familiar. These do not include thefire-isolated stairway or external stairs, and are asfollows:

Lower seating tierAll occupants in the lower seating tier areassumed to evacuate via Level 2 (see Plan-Level 2) as follows:

The public uses the doors at the end of theconcourse (3×1.6 m) (location A) and the mainentrance (1×5 m) (location B). Members willonly use the doors at location C (3×1.6 m).

Corporate facilities (Level 3)All occupants in Level 3 (see Plan-Level 3) areassumed to evacuate as follows:

Members and staff evacuate via the foyerthrough two double doors (2×1.6 m) and twosingle doors (2×0.8 m) at location D. Note thatthe main access into Level 3 is by lifts.

Upper seating tierAll occupants in the upper seating tier exit areassumed to evacuate via the Level 4concourse (see Plan-Level 4) to the stairs(2×6 m) at location E and at location F(2×4 m).

For both the lower and upper seating tiers, tenvomitories, each measuring 2.5 m wide, connectthe seating areas to the concourses.

The following populations are assumed for thepurpose of calculation:

Lower seating tier = 4000 (during game)Level 3 = 220 (during game)

= 840 (pre-game)Upper seating tier = 5500 (during game)

The pre-game population for Level 3 includesoccupants in the corporate suites (220), diningroom (210), function rooms (330) plus about 10percent allowance for kitchen/service staff andmedia. The population in Level 3 is less during thegame because the occupants of the function room

and dining room are assumed to move to theseating areas.

Simplified Calculations

As mentioned above, simplified calculations aresuitable for occupant flows which areuninterrupted and impeded only at points ofegress. This will be the case when small numbersof people are to be evacuated from a fire-affectedarea—as will often be the case with managed orstaged evacuation. However, such calculationsmay be questionable when considering theevacuation of large numbers of people such asthe whole building or an entire seating tier.

In the case of the evacuation of the seating tiers,the total movement time is a function of the timeof travel to the points of egress and the level ofqueuing. The time for movement of the occupantsto the points of egress is relatively difficult todetermine as several movements are involved—horizontal, stepping up and stepping down—andthese are different depending on the position ofthe occupants within the seating tier. Suchcalculations are best done using a computerprogram such as EvacSim.

The total movement time associated with theevacuation of the occupants of the corporatesuites during a game is now considered. For thepurpose of this example, it is assumed that asignificant fire develops within the corporate suitedirectly adjacent to the fire compartment wall. Thismeans that the horizontal exit through this wallcannot be used and that evacuation must be viathe fire-isolated stairway and the external stairs. Itis assumed that the occupants will be distributedequally between these points of egress.

As the external stairs have the narrowest width,this point of egress will govern the total movementtime. The effective width7 of the external stair canbe taken as 1 m and the maximum distance thatmust be travelled to the stair as 50 m. Using amaximum specific flow of 1.3 persons/s⋅m, thetime to pass through the external stair is220÷2÷(1.0×1.3) = 85 s. The travel time to thestairs can be taken as 50÷1.2 = 42 s. If thesetimes are added (this overestimates the totalmovement time) then the total time for theoccupants to move to safety can be taken asbeing between two, and two and one-half minutes.This is not the evacuation time as that mustinclude some allowance for pre-movementactivities. In this case it is suggested that the pre-movement time will be low—probably no morethan 2 minutes after it has been recognised thatthe fire within the suite cannot be extinguished bythe occupants.

7 The effective width is the nominal width of the opening

less the width occupied by hardware such as handrails orthat due to the partial obstruction from doors.

App

endi

x

28

EvacSim Calculations

EvacSim has been used to model the sports standby defining the layout of the building as closely aspossible to the layouts shown in Appendix 2.Nodes are used to define the outline of eachspace and walls are specified as links betweennominated nodes. Openings are defined within thewalls and connectivity between the spaces isworked out internally by the program. Movementof the occupants is continuously calculated as afunction of occupant density within each space. Ithas been assumed, for this example, that alloccupants within the seating tiers and Level 3must be evacuated.

Results of the simulations are shown in the figuresbelow. For the purpose of these calculations it hasbeen assumed that the fire is located such that thepreferred egress paths (ie. those used mostcommonly used by occupants within the building)are used for evacuation rather than the fire-isolated stairways or external stairs.

The egress routes for the seating tiers and Level 3are independent of one another. The followinggraphs plot the population (ie. number of peopleremaining) within these areas of the building afterevacuation has commenced.

The total movement times are summarised asfollows:

Lower seating tier: 411 s (6.9 mins)Level 3: 660 s (11 mins)Upper seating tier: 735 s (12.2 mins)

In the case of Level 3 it has been assumed that alloccupants evacuate via the horizontal exit andthen through the 2×1.6 m and 2×0.8 m doorsbeyond the fire wall. No account has been takenof the fire-isolated stairway or external stair at thislevel. This assumption results in the totalmovement time associated with Level 3 beingsignificantly longer than for the two seating tiers.

It takes 494 s (8.2 mins) to clear the upper seatingtier to the Level 4 concourse and a further 241 s(4.0 mins) to clear the concourse via the stairsfrom the concourse to the road.

The above calculations determine the totalmovement times associated with the evacuationof various parts of this sports stand. They take noaccount of pre-movement activities and theassociated times must be added. However, theseare expected to be short.

0

1000

2000

3000

4000

5000

6000

Population

0 60 120 180 240 300 360 420 480 540 600 660 720 780

Time (s)

0

1000

2000

3000

4000

5000

6000Population

0 60 120 180 240 300 360 420 480 540 600 660 720 780

Time (s)

Lower Seating Tier Population Corporate Facilities (Level 3) Population

0

1000

2000

3000

4000

5000

6000

Population

0 60 120 180 240 300 360 420 480 540 600 660 720 780

Time (s)

concourse

upper seating tier

Upper Seating Tier Population

29

APPENDIX 4 Exposed Surface Area to Mass Ratioof Steel Sections—ksm (m

2/tonne)

Beams

welded-plate sections

section ksm section ksm

1200WB455 8.51 500WC440 5.41423 9.10 414 5.78392 9.79 383 6.21342 10.4 340 7.30317 11.1 290 8.51278 12.1 267 9.22249 12.6 228 10.7

1000WB322 10.0 400WC361 5.48296 10.8 328 6.11258 11.8 303 6.56215 13.4 270 7.34

900WB282 10.7 212 9.25257 11.7 181 10.7218 13.0 144 13.4175 15.3 350WC280 6.08

800WB192 13.1 258 6.54168 14.5 230 7.30146 16.5 197 8.49122 18.9

700WB173 13.0150 14.3130 16.3115 18.4

hot-rolled sections

section ksm section ksm

610UB125 14.9 310UC158 9.66113 16.3 137 11.0101 18.1 118 12.7

530UB 92.4 17.8 97 15.382.0 19.9 250UC 89.5 13.9

460UB 82.1 17.7 72.9 16.874.6 19.4 200UC 59.5 16.867.1 21.4 52.2 18.9

410UB 59.7 21.9 46.2 21.253.7 24.1 150UC 37.2 20.3

360UB 56.7 21.1 30.0 24.650.7 23.444.7 26.3

310UB 46.2 23.240.4 26.2

250UB 37.3 24.731.4 29.0

200UB 29.8 26.3180UB 22.2 27.1150UB 18.0 28.3

App

endi

x

30

Columns

welded-plate sections

section ksm section ksm

1200WB455 9.61 500WC440 6.55423 10.3 414 6.99392 11.1 383 7.52342 11.5 340 8.77317 12.4 290 10.2278 13.3 267 11.1249 13.7 228 12.9

1000WB322 11.2 400WC361 6.59296 12.1 328 7.33258 13.1 303 7.88215 14.8 270 8.82

900WB282 12.1 212 11.1257 13.3 181 13.0218 14.6 144 16.1175 17.0 350WC280 7.33

800WB192 14.7 258 7.89168 16.1 230 8.82146 18.4 197 10.3122 20.9

700WB173 14.5150 16.0130 18.3115 20.6

hot-rolled sections

section ksm section ksm

610UB125 16.7 310UC158 11.6113 18.3 137 13.3101 20.3 118 15.3

530UB 92.4 20.0 96.8 18.482.0 22.4 250UC 89.5 16.8

460UB 82.1 20.0 72.9 20.374.6 21.9 200UC 59.5 20.267.1 24.2 52.2 22.8

410UB 659.7 24.8 46.2 25.653.7 27.4 150UC 37.2 24.4

360UB 56.7 24.1 30.0 29.750.7 26.8

310UB 46.2 26.8250UB 37.3 28.6

hollow sections

section ksm section ksm

457.0×12.7CHS 10.3 250×250×9.0SHS 14.69.5CHS 13.7 6.0SHS 21.76.4CHS 20.2 200×200×9.0SHS 14.7

406.4×12.7CHS 10.4 6.0SHS 21.89.5CHS 13.7 5.0SHS 26.06.4CHS 20.2 150×150×9.0SHS 14.9

355.6×12.7CHS 10.4 6.0SHS 22.09.5CHS 13.8 5.0SHS 26.26.4CHS 20.3 125×125×9.0SHS 15.1

323.9×12.7CHS 10.4 6.0SHS 22.19.5CHS 13.8 5.0SHS 26.36.4CHS 20.3 100×100×9.0SHS 15.4

273.1×9.3CHS 14.2 6.0SHS 22.46.4CHS 20.4 5.0SHS 26.64.8CHS 27.0 89×89×6.0SHS 22.5

219.1×8.2CHS 16.1 5.0SHS 26.76.4CHS 20.5 75×75×6.0SHS 22.84.8CHS 27.1 5.0SHS 27.0

168.3×7.1CHS 18.76.4CHS 20.74.8CHS 27.3

114.3×6CHS 22.44.8CHS 27.7

88.9×5.5CHS 24.74.8CHS 28.1

31

APPENDIX 5 Checking of Steel Members forFire Adequacy

The purpose of this appendix is to illustrate theprocedure for the checking (and selection) ofstructural steel members using the Deemed-to-Satisfy Solutions for Fire Spread andManagement.

Two cases are considered, for both sprinkleredand non-sprinklered options.

Case 1—Food and Beverage Outlet

PLAN

ELEVATION

food and beverage outlet

steel beam800WB122grade 300

ceilingsteel column219.1x6.4CHS

grade 350

food and beverage outlet

concourse

concourse

opening

steel column

steel column(alternative location)

2.1 m

open

ing

Steel Beam within Enclosure(see Table A, page 17)

From Appendix 4, ksm of the steel beam(800WB122) = 18.9 m2/tonne.Option 1: No sprinklers within enclosure

Maximum acceptable ksm = 30 m2/tonne(require a 10 min ceiling system)

ksm of the steel beam = 18.9 < 30 ∴ OKOption 2: With sprinklers within enclosure

Maximum acceptable ksm = 30 m2/tonne (noceiling required)

ksm of the steel beam = 18.9 < 30 ∴ OK

Steel Column outside Enclosure(see Table B, page 17)

From Appendix 4, ksm of the steel column(219.1x6.4CHS) = 20.5 m2/tonne.Option 1: No sprinklers within enclosure

Column located at > 2.0 m ∴ maximumacceptable ksm = 30 m2/tonne

ksm of the steel column =20.5 < 30 ∴ OK

In some situations, the column may be locatedat the edge of the opening (see “alternativelocation” in the above figure. In this case, thecolumn will not get as hot and a greater ksm

may be permitted. The use of a greater ksm

value will need to be justified by fire-engineering calculations.

Option 2: With sprinklers within enclosure No limit is set for the maximum ksm (ie. anysize steel column will suffice for fire adequacypurpose).

Case 2—Corporate Suite

corporatesuite

ceiling

6 m

steel beam610UB125grade 300

passagewaysteel column310UC118grade 300

Steel Beam within Enclosure(see Table A, page 17)

From Appendix 4, ksm of the steel beam(610UB125) = 14.9 m2/tonne.Option 1: No sprinklers within enclosure

Depth of enclosure < 7.5 m, ∴ maximumacceptable ksm = 30 m2/tonne (require a 10min ceiling system).

ksm of steel beam = 14.9 < 30 ∴ OK

Option 2: With sprinklers within enclosure Maximum acceptable ksm = 30 m2/tonne (noceiling required)

ksm of the steel beam = 14.9 < 30 ∴ OK

Steel Column within Enclosure(see Table A, page 17)

From Appendix 4, ksm of the steel column(310UC118) = 15.3 m2/tonne.Option 1: No sprinklers within enclosure

Depth of enclosure < 7.5 m, ∴ maximumacceptable ksm = 26 m2/tonne (require a 10min ceiling system and protection of columnby cladding it with 16 mm plasterboard,penetrating ceiling).

ksm of steel column = 15.3 < 26 ∴ OKOption 2: With sprinklers within enclosure

Maximum acceptable ksm = 26 m2/tonne (noceiling and no protection of column arerequired)

ksm of the steel column = 15.3 < 26 ∴ OK

App

endi

x