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Methodology for Evacuation Drill Studies
Ser TH1 R427 no. 730 c. 2 BLDG
National Research Conseil national
Council Canada de recherches Canada
Institute for lnstitut de
Research in recherche en
Construction construction
-
K?CmCIWC
Methodology for Evacuation
Drill Studies
n t e r n a l r e p o r t ( I n s t i t u t e f+ I S T I / I C I S T N R C / C N K C ' ~ N A L Y S E J R C Ser
R e c e i v e d a n : 01-09-97 I n t e r n a l r e p o r t .
by GuyDne Proulx, Chantal Laroche and Joelle Pineau
Internal Report No. 730
Date of issue: November 1996
This is an internal reporl of the Institute for Research in Construction. Although not intended for general distribution, it may be cited as a reference in other publications.
ABSTRACT
Evacuation drills can be canied out as a means to educate the public about the evacuation procedure for a specific building. Drills can also be conducted to obtain data on the occupants' behaviour, movement and timing of escape. In the latter case the results of the drill can be used to develop computer models such as the National Research
Council of Canada's FiRECAWM which can assess the risk to life and the cost of different fire safety features. The methodology used in conducting evacuation drills is essential to obtain meaningful and reliable data.
The methodology discussed in this report has been used in a number of apartment and ofiice buildings to obtain data on occupant response during evacuations. The various steps to cany out a successful evacuation drill are presented. The initial planning
comprises some ethical considerations to be taken into account in developing the study protocol as well as the selection of a suitable building and the participation expected from the local fire department. Specific material to record the drill is necessary comprising video cameras and equipment to measure the audibility of the fire alarm. On the day of the drill, different actions should take place in a timely fashion to ensure the success of the exercise and the data-gathering activities. After the drill, all the information gathered is analyzed in a systematic manner and results are interpreted and documented.
It is important to use a sound methodology to study evacuation drills to be confident later in interpreting and generalizing the results. Each drill conducted can be costly since
many
people have to be involved, material has to be purchased and analysis requires a long time with trained analysts. Further, a drill in a building cannot be repeated if something goes wrong. For all these reasons, it is essential to use a dependablemethodology that will ensure the success of the study.
Les exercices d'evacuation peuvent 6tre realids pour eduquer les occupants d'un bitiment relativement aux mesures d'urgence en cas d'incendie. Les exercices peuvent aussi servir pour obtenir des donnees sur le comportements des occupants, l e s ~ ~ mouvements et les temps de dblacements pendant l'evacuation. Dans le demiers cas, les ri.sultats d'un exercice dcvacu~io~cpcuveni 6tre utiliscs dans lc dheloppement d'outils informatiaucs, tcl auc FiRECAM. , qui neut cvalucr les risques ct coiits dc diffirrcntes composanks de securite incendie d'hi b&iment. La methoddogie utilisee pour realiser un exercice d'evacuation est essentiel pour I'obtention de donnees significatives et fiables.
La m&odologie decrite dans ce rapport, a ete utilise dans certains edifice
a
bureaux et des immeubles a appartements dans le but d'obtenir des donnees sur le comportements des occupants pendant l'evacuation. Les differentes etapes pour mener une telle etude sont presentees. La planification initiale de l ' h d e suppose des
considerations d'ordre ethiques qui doivent 6 e integre au protocole de recherche. Aussi
il faut proceder a la sdection d'un bitiment acceptable et s'assurer de la participation des services d'incendie locaux.
Du
materiel specifique est necessaire pour la prise de donnees; entre autres, des cameras video et des appareils de mesure du son de l'alarme d'incendie.La journk m6me de I'exercice differentes activites doivent avoir lieu de maniere coordonnee pour assurer le succes de l'exercice et de la prise de donnees. Apres
l'exercice, toutes les donnees obtenues doivent h e analysees systematiquement puis les ksultats sont interpretes et documentes.
I1 est important d'utiliser une methodologie solide pour etudier les exercices d'evacuation afin d'gtre confiant dans l'interpretation et la generalisation des resultats. Chaque exercice d'evacuation peut etre tres coiiteuse etant donne le grand nombre de participants necessaire, du materiel a se procurer et du temps requis pour I'analyse des donnkes. De plus, il n'est pas possible de reprendre une evacuation ratee. Pour toutes ces raisons, il est essentiel de proceder avec une methodologie &prouvee qui va assurer le succes de l'ktude.
Le present rapport prbente une methodologie pour etudier les exercices d'evacuation. Ce rapport est disponible uniquement en anglais.
TABLE OF CONTENTS 1
.
INTRODUCTION...
1 2.
INITIAL PLANNING...
2 2.1 Type of Study...
2...
2.2 Ethical Considerations 2 2.3 Selection of the Building...
32.3.1 Building Attributes
...
42.3.2 Fire Safety Features
...
52.3.3 Occupant Characteristics
...
52.4 Permission to Cany Out an Evacuation Drill
...
52.5 Participation of the Local Fire Department
...
53
.
PREPARATION...
63.1 Necessary Equipment
...
63.2 Technical Preparation
...
73.3 Preparation of the Occupants
...
113.3.1 Occupants with Disabilities
...
1 1 3.3.2 Alarm Activator...
1 1 3.4 Preparation of the Memo and Questionnaire...
113.5 Alarm Measurements
...
1 2 4.
EVACUATION OF THE BUILDWG...
124.1 Set-up
...
124.2 Evacuation
...
134.3 Post-Evacuation Procedures
...
135
.
CODING DATA...
;...
145.1 Coding the Videotapes
...
14...
5.1.1 Assessing the Age 15 5.1.2 Assessing Limitation...
155.1.3 Identifying Groups
...
155.1.4 Variables Recorded
...
155.2 Coding the Questionnaires
...
165.3 Coding the Sound Samples
...
166
.
DATA ANALYSIS...
176.1 Calculations of the Evacuation Times
...
176.2 Analysis of the Speed on Stairs
...
17...
6.3 Comparisons According to Occupants' Characteristics 18 6.4 Direction of Movement...
196.5 Analysis of the Questionnaires
...
19...
6.6 Analysis of Alarm Measurements 19 7.
INTERPRETATION OF RESULTS...
20...
8.
SUMMARY 2 1 9.
REFERENCES...
22APPENDIX A: MEMO DISTRIBUTED TO OCCUPANTS
...
23 APPENDIX B: POST-EVACUATION QUESTIONNAIRE FORRESIDENTIAL BUILDINGS
...
25 APPENDIX C: POST-EVACUATION QUESTIONNAIRE FORMETHODOLOGY FOR EVACUATION D R a L STUDIES by
Guylene Proulx, Chantal Laroche and Joelle Pineau
1. INTRODUCTION
The methodology presented in this report will enable researchers to collect
required data on times and occupant movement during evacuation drills in buildings. The methodology suggested is aimed at observing the impact of occupants' characteristics and building design on the evacuation outcome. Depending on the building attributes (e.g., its physical organization and components), the fire safety features and the nature of its
occupants, evacuation behaviour for a selected population can be observed.
The methodology presented was successfully used in a number of studies of residential and office buildings [I, 2,3]. Even though this methodology was developed to study multi-apartment residential buildings, it could be used, with some modifications, to study a large range of occupancies.
The main objective for the researchers at the National Fire Laborato~y of the National Research Council of Canada, is to conduct evacuation drill studies to obtain required data to validate computer models under development. Results of the studies are used to verify and modify models such as the Occupant Response Model and the
Evacuation Model, both part of FiRECAMTM [4]. The time occupants need to evacuate a building and their behaviour during such an event are necessary information to develop predictive models in fire safety. Such data are not readily available in statistics or in the literature, which explains the need to develop a comprehensive methodology to gather reliable and comparable data.
Studying and documenting evacuation drills in detail also allows for the
identification of oroblems associated with evacuations. This identification can heln in the development of design and architectural solutions that would increase safety for ail occupants. The results of such studies can be used as a basis for updates to fire safety regulations. In addition, information about the time required for the evacuation of a building may enable fire departments to be better prepared for fire fighting and thus reduce risk to life of occupants. Findings can also be used to draft evacuation procedures that take into account the capacity and limitations of the building users. The cumulative knowledge acquired through drills can lead to improved fire evacuation education and training programs. Areas requiring further research can also be identified through such field studies.
To conduct a successful evacuation study, it is essential to prepare carefully and to foresee eventual problems. The methodology presented proved successful in the study of a variety of buildings in Canada. It is not a guaranty, however, that applying this method without any change, to a different type of building or in a different cultural context would lead to the expected results. In any research involving human factors, it is important to have a well-planned methodology that is flexible enough to deal with unexpected situations.
This report details the different steps necessary to organize an evacuation drill study. It assumes that the necessary funding is available as well as staff and materials. The methodology presented concerns the study of residential buildings but it can be used, with some modifications, to study other types of occupancies. The initial planning of the
study starts with some ethical considerations, the selection of the building and obtaining permission and support from building managers and the local fire department. It then continues with the preparation of the drill itself, the equipment and documentation. The next step is to conduct the evacuation drill and the data gathering activities which include a post-evacuation questionnaire to be filled out by occupants. Finally, the analysis of the data obtained, and the interpretation of the results, complete the study.
2. INITlAL PLANNING
The initial planning of the study is an important step that will influence the rest of thc work. Prcparaiion of &c documentation on thc study objcctivcs, methodology and findinrs ex~ected has to be carcfdly produced. It is on thc basis of this documentation that th: pr4ect will receive acceptahie. It is often difficult to obtain permission to cany out an evacuation drill in a building, so meetings and discussions should be organized to present the study to administrators, managers and groups of occupants as well as the local fire department. Explanations of the project should be tailored to be understood by these different groups; benefits that can be gained in taking part in such a study should he well stressed to obtain their full participation.
2.1 Type of Study
Before deciding on the building or buildings to be studied, it is necessary to decide the type of study that will fulfil the objectives of the research [5]. A choice should be made between two main options: conducting a case study or a comparative study.
Depending on the objectives of the research, it may be decided to do a case study. A case study would be the observation of the evacuation of one specific building
presenting unusual characteristics, such as a complex architectural organization, or a building with occupants having distinct profiles (e.g., elderly occupants, occupants with disabilities). A case study gives a detailed account of a specific building with a specific group of occupants. One disadvantage of a case study is that it is difficult to generalize the results and apply them to other buildings.
The second option is a comparative study which requires the study of more than one similar building, following which the results &om each building can be compared and contrasted to the results of others. Performing a comparative study of building
evacuations can be difficult as it is usually impossible to ensure that all variables are exactly the same and that the buildings are virtually identical. If the buildings vary in more then one way, it becomes difficult to identify which variable caused the discrepancy in the results. The cumulative knowledge gathered through comparative studies is, however, paramount in this area of work which lacks data.
A third possible type of research is a representative study which is not practical for evacuation drill studies. In a representative study, a sample number of buildings with specific characteristics would be chosen, and the results from the sample could than be generalized to all other similar buildings. The cost, time and energy necesssuy to cany out a representative study of building evacuation drills would he phenomenal which explains why representative studies cannot be conducted in this field.
2.2 Ethical Considerations
Most research organizations will require that an ethics committee review the study ~rotocol because the study involves human subjects. If this is the case, the methodology ^should be submitted to thk ethics committee foi approval.
Even if there is no ethics committee to approve the methodology, some general ethical considerations need to be taken into account when conductinp. an evacuation field study. At no point should the occupants be subjected to unnecessa~risks. Any risks or discomfort to which human subjects may be exposed should be justified by the potential benefits of the study to science and to society.
Unlike many studies involving human subjects, occupants are not asked to give their consent to participate in the study before the drill is conducted; this is to obtain their genuine reactions to an unexpected fire alarm. To ensure the privacy of people who
participated
in the drill, any data gathcrcd during the study, such as pictuicsor videotapes of occupants where thcy could be recognizcd, must be kept confidcntial. Names of thc occupGts, their specific addresses or any specific description that could identify the participants should be avoided. During a residential drill, occupants are in their private home environment, and that fact should be respected. If the drill is held in a publicbuilding, such as a shopping mall, there is less concern about the issue of privacy since this is a public space. All apartment building areas should be considered private space,
especially when the access to the building is restricted by locked entrance doors. The National Research Council of Canada @RC) for instance, has very clear ethical guidelines on research involving human subjects [6]. The Ethics Review
Committee requires that a memo be sent to residential occupants to inform them of the up-coming drill and advise them of the presence of video cameras (see Appendix A). The memo must be sent to occupants one week before the drill, specifying that the drill will be held during the following week without indicating the exact date and time to keep some element of surprise. It is important not to be too precise about the time of the drill since bad weather or problems with the equipment could change the time unexpectedly. Being evasive about the time also keeps some surprise of the exact moment of the drill; it prevents eager occupants from waiting by their doors to rush outside and prevent those who would rather be out of the building during the drill from purposely being absent. The memo provides information about the purpose of the study, the presence of video cameras during the drill, and the name and telephone number of the principal researcher. This memo offers a compromise between formally asking for the occupants' consent to participate in the drill, and keeping the drill a complete surprise to replicate possible fire emergency conditions. If such action is not required, it must be decided whether or not to send a memo. During office drills, no memo was sent to workers. It is difficult to
measure the impact of the memo on the occupant response. In the residential and office buildings studied, each case had approximately 20% of the occupants mentioning in their post-evacuation questionnaires that upon hearing the fire alarm they thought it was a real fire [2,3].
Many pcoplc suggcstcd that the prcscncc of artificially-generated, non-toxic smoke would add a realistic dimension to thc drill. Othcrs argucd that tbc presence of smoke could increase the risk to occupants as it might introdGce an elemeni of stress and affect their behaviour. Smoke has not been used in any evacuation drills so far, conducted by the National Fire Laboratory researchers, but the possibility has not been entirely discarded.
2.3 Selection of the Building
When conducting a case study, the selection of the building is made easier since a building with unique characteristics is identified. The selection of buildings for a
comparative study is more complicated since each building should have similar characteristics to be comparable.
As shown in Table 1, three major aspects of a building must be considered during the selection process: the building attributes, the building's fire safety features and the occupants' characteristics.
Table 1: Residential Building Selection Check-list
Many buildings may be considered before one or more are selected for an evacuation drill. Basic information on each candidate building should be gathered and compared before the selection is made. The check-list presented in Table 1, can be used to collect the necessary information for a residential building. All elements listed can affect occupants' evacuation behaviour.
2.3.1 Building Amibutes
The building attributes include a number of details that could affect the evacuation behaviour of occupants. Some elements are easy to gather such as the number of units, floors, elevators, staircases and fire exits. Other elements may need a few visits to the building and some observations. For example, it is important to know the location of the daily entrance-exits that most occupants use, since it can be expected that some will move
in that direction even if it is not planned as the evacuation route. Further, if there is ~ a r h g , in the basement, it is possible that some occupants will move to this location in brder
6
remove their cars and leave the premises. A building with multi-occupancy, suchas a residential building with ofices on the first floor, will influence the evacuation outcome since occupants in different types of settings do not necessarily react the same.
2.3.2 Fire Safety Features
The fire safety features offer indications of which systems are in place and how they could influence the occupants' evacuation behaviour. For example, if there are areas of rehge and the evacuation procedure specifies that these areas should be used as an alternative to the traditional complete evacuation, this will affect the evacuation drill. Researchers should also obtain information concerning the number of false alarms and alarm tests in the recent past. Frequent unwanted alarms dampen occupants' response to fire alarms. It is also important to know if the alarm is monitored by a company who is responsible for calling the fire department when the alarm is activated, otherwise an occupant of the building will have to call to notify the fire department.
2.3.3 Occupant Characteristics
Obtaining information on the occupants' characteristics provides an indication of what to expect in terms of occupants' evacuation behaviour. The first point to note is the number of occupants in the building. Occupant characteristics should also be examined. Population characteristics vary between buildings; some apartment buildings house a large number of families with young children, while others contain a majority of seniors. Also, occupants with disabilities could have an important impact on the evacuation timing if they have to be moved to safety by rescuers; their numbers and the type of disabilities should be taken into account. In the case of occupants of multi-cultural backgrounds, it is possible that some of them may not know the evacuation procedure if it was not presented in their
own language or they may not know what to do when hearing the fire alarm.
When selecting a building, its physical location must be considered. It is important to ensure that there is sufficient space for the occupants to wait outside following the
evacuation. It would be inappropriate, for example, to choose a building situated directly on a major intersection that would endanger the occupants standing outside and would disrupt the traffic in the event of an evacuation drill. The travel distance for the fire department should also be considered and the disruption firefighters will cause when aniving at the building with their trucks and equipment.
2.4 Permission to Carry Out an Evacuation Drill
Once a building has been selected, a number of parties need to be contacted to obtain the necessary permission and authorization to study an evacuation drill. If management conducts annual evacuation drills, it is usually easy to obtain permission to observe the yearly drill. If there is no annual drill planned, permission to perform the drill should be asked of the building management, explaining in detail the procedures and the purpose of the study. The building management should provide a copy of the evacuation plan, if one exists. This plan should be considered and respected when conducting the drill. If no plan exists, the building management might be able to provide details about the fire safety information that occupants were given.
If there is a tenants' association in the building, it should be contacted. The members might also be able to provide details concerning the evacuation plan, or the fire safety information distributed to tenants. Ifmembers of the tenants' association have any concerns about the evacuation drill, these can be addressed before the final planning is set.
2.5 Participation of the Local F i e Department
The participation
of
the local fire department adds an invaluable dimension to the evacuation. The fire chief or the person in charge of fire prevention in the municipality ofthe chosen building should be contacted. A meeting should be arranged to explain the purpose of the study, to examine the evacuation procedures for the building and to identify any potential problems. In some cases, the fire department personnel might be under the impression that the purpose of the evacuation drill is to study their performance and might accordingly be reluctant to participate. It is important to clearly explain that the purpose of the study is essentially to obtain data on the evacuation behaviour of occupants. It should be pointed out that the participation of the fire department will add an essential component of realism to the study, which strongly affects the results.
If the fire department agrees to participate in the evacuation, a person from the local fire department is designated to coordinate the efforts and participate in the drill. A
date and time for the evacuation is then chosen. For example, in a residential building, it may be planned to conduct the evacuation during the evening instead of the day, in a way to ensure a maximum of people in the building. Different time and weather conditions may yield different evacuation results. An appropriate date and time should be agreed on, based on the study objectives and the local fire department's availability.
The number of firefighters and the extent of their involvement should also be discussed. During past evacuation drills, the arrival of fire trucks using sirens and firefighters in fullgear appeared to prompt the evacuation of the occupants remaining in the building. The fire department participation adds a dimension of reality to the cxcrcisc. Some occ@ants may n& hear the fire al&m from within their apartment;, but the sound of the truck siren could alert them If possible, the firefighters' response should be exactly
-
as if they were answering a fire call foi this building. A
The location of the hypothetical fire in the building is discussed with the
firefighters to determine a strategy for evacuating occupants. The firefighters' role is to assist occupants with limitations and to ensure that occupants on the designated fire floor, the
two
floors directly above and the floor immediately below, have evacuated thebuilding. The drill can end when the firefighters judge that all these occupants have reached a safe location. The fire captain can then give the "all clear", the alarm is re-set and occupants are allowed to return to their apartments.
3. PREPARATION
On-site preparation for the evacuation can be undertaken during the week preceding the drill. Access to the building will be necessary a few days prior to the evacuation to become familiarized with the architecture and some of the occupants of the building. Information such as the type of alarm system, the location of the alarm bells, staircase and corridor measurements, the number of exits and general demographic information about the occupants will be gathered on site.
It is useful in most cases to obtain access keys from the building management to have easy access to common areas of the building. All members of the team conducting the study should have identification papers with them, in case an occupant asks about their presence in the building. Members of the team should agree beforehand on the
explanation to give to occupants who inquire about their activities in the building. Explanations should be truthful without giving too many details on the up-coming evacuation drill.
3.1 Necessary Equipment
A number of video cameras are needed to record the movement and evacuation times of the occupants. In previous evacuation drills, over 30 portable cameras were
used, each equipped with a two-hour rechargeable battery and two-hour tape. These cameras are mounted and fixed to the walls in the staircases and corridors with specially- designed brackets. They record the sound of the alarm and the evacuation movements of the occupants as well as providing precise time measurements.
As an alternative to video cameras, human observers can be posted in the building to record occupant movement. There are advantages and disadvantages to both methods. Observers with limited training can adequately note pre-determined specific items such as time and characteristics. The observer method, however, limits the information that can be gathered and does not provide a record of the full situation. Observers usually fill in a grid with pre-determined information, which can be quite limiting, both in time and in content. Video cameras will record the integral evacuation behaviour allowing for
extensive quantities of data to be collected. The presence of the observers during the drill could interfere with the evacuation, and could influence the occupants, while cameras are more discrete and are often unnoticed by occupants. The use of cameras can result in minor building damage, as the camera brackets must be fixed to the walls.
When analyzing the results of an observer-only drill, researchers cannot verify information, and only have access to the written accounts taken during the drill. Since many observers are needed, it is likely that there will be variations of what is recorded among observers. When using cameras, one person can watch all the tapes and record all results, minimizing variation in the data collection. The coding of the results from the videotapes can be a long and tedious process as one person must watch all tapes from beginning to end, and transcribe occupants' movement. It ensures, however, that all information needed is recorded, and the tapes can be reviewed any number of times to add or confirm information.
The most important factor to consider in many cases is the costs associated with the drill. The initial cost is significantly higher when using video cameras, however, they can be re-used for numerous drills, while observers must be paid for each study. Unless cost is a problem, video cameras should be used to record the drill. It is unlikely that any number of observers can capture the wealth of information recorded by video cameras.
Sound samples of the ambient noise and of the alarm should also be taken throughout the building. The recordings are taken using a Type 1 microphone (Cirrus
MK 224*) plugged into a digital audio tape recorder (TEAC DM-209. The audio
recordings are analyzed later with a software package, such as dBFETE*, installed on a computer equipped with an analog-digital card. It is also possible to use a sound level meter to measure the sound pressure level in A-weighted decibels. Such a tool, however, will not provide a complete analysis of the sound spectnun which is required to properly assess the perception of the alarm in an environment with background noises.
3.2
Technical PreparationBefore starting the technical preparation, it is important to become familiar with
the evacuation plan for the building. If occupants are familiar with and understand the evacuation plan, they are likely to follow it. Studying the evacuation plan and the building layout provides ideas of how occupants are likely to behave, which are indictors for the ' Certain commercial products are identified in this paper in order to adequately specify the experimental procedure. In no case does such identification imply recommendations or endorsement by the National Research Council, nor does it imply that the product or material identified is the best available for the purl"==.
placement of the video cameras (or observers), and the locations to be used for sound measurements.
Measurements of the building dimensions should be taken. For drills in apartment buildings, measurements are usually taken only in public areas, such as staircases,
comdors and entrances. If scaled plans of the floors are available, they can be very useful since dirncnsions can be obtained that way, rather than through actual mcasurcrncnts. Table 2 can serve as a chcck-list of measurements of a residential building that will be - needed for further analysis of the results.
Table 2: Residential Building Measurements Check-list
. . . . .. .. . . . . . . . ..
easummlits:
::.; : . ,i':::'':':
,: : .,.. . . . . . .. . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .. . . Corridor length Corridor width Corridor height Staircase door width #of steps per flight of stairs Step height Stw width Step nosing Handrail (yp) Landing length Landing width Ffoor height Exit door widthDimensions of areas of refuge
Dimensions of other common areas (e.g., lobbies)
For speed calculations, the most important measurements are those of the wmdors and staircases. Figure 1 shows a schematic of a typical staircase. The precise dimensions of the stairs must be measured so that, during the analysis stage, the travelling speed of the occupants in the stairs can be calculated based on their measured evacuation times. Necessary measurements include the height, length and width of a typical step, as well as the dimensions of the floor landings, and the total height of one floor. The number of steps between each landing must also be recorded. These measurements must be canied out in each staircase of the building.
Plans and elevations of the building can be drawn if they are not readily available. Scaled floor plans with apartment numbers are needed to identify the initial locations of occupants and the distance travelled.
Figure 1: Schematic of a Typical Staircase
Cameras should be placed in each staircase. A well-positioned camera can usually view two sets of stairs; cameras can thus be placed at every second flight of stairs between landings. Ideally, a camera in a staircase should have a view of the door leading from the conidor to the staircase. This allows the recording of the occupants' specific times of entry into the staircase. Figure 2 shows a typical view from a camera installed in a
staircase. It should be noted that part of the doors leading to comdors on both floors are visible from the camera. Other cameras should be placed in each corridor, to record the precise time at which occupants leave their units. It is important that apartments can be differentiated when viewing the videos; the viewer should ideally be able to identify the occupants' apartment numbers. A camera must be placed at each ground exit and at the entrance of areas of refuge to record the precise time at which occupants reach safety.
Figure 2: Typical Video Camem View of Staimase
A thorough howledge of the b ~evacuation plan can help optimize the use ~ g of cameras. For example, if occupmts are ~ ~ c t e d in the evacuation plan wt to use a specitic staircase, it might not be worthwhile to put as many cameras in that staircase as in others. Accorhg Po some b d h g evacuation procedwes, balconies are identfied as areas of refuge. To capture the tifne at which occupants seek rehge on their balconies, outside cameras should be positioned to film balcony movement.
Each camera, battery and videotape should be numbered before the
drill rand
their precise locations should be identitied on a building p k It is important to consistently number the equipment because, after dismmting the cameras, it is possible to find that a tape has not functioned properly.In
this case, it would be possible to re-trace the camera md battery used with that tape, conduct a thorough check-up of the components and identify which element was responsible for the failme.It
is
important lo testdl
the equipment before eachdrill
because an evacuation c m o t be rmeated. Things to check include: how to deactivate the automatic system that terminates r & o r b g on some video cameras if there is no movement after 10&
md testthe
exact Me of two-hour batteries that magr last only 1:15. To avoid surprises, all equipment must be thoroughly checked.3.3 Preparation of the Occupants
Sending a memo prior to the evacuation can have a mixed effect on the occupants. It can be a disadvantage to warn occupants in advance as some of them might decide to leave the building prior to the drill to avoid taking part in the exercise or to decide to stay in but not to evacuate at all, based on the fact that this is simply an exercise and not a real emergency. Conversely, the memo may encourage occupants to participate as some might welcome the chance to review evacuation procedures as preparation for a possible real fue. The decision of whether or not to distribute the memo may also depend on the type
of occupants in the building. If most of the occupants are college students used to frequent false alarms, the memo might do little to change their behaviour. If most of the occupants are seniors who are prone to anxiety, it might be better to warn them that it is an exercise, that there is no need to wony, and that they should simply follow evacuation procedures.
3.3.1 Occupants with Disabilities
Regardless of whether a memo is sent, meetings should take place with occupants with limitations prior to the exercise. This is suggested since there are no specifc plans for the evacuation of occupants with disabilities in most buildings. The building
management or some key occupants should be able to help with the identification of occupants who have limitations such as health problems, mobility impairments or perceptual limitations. Meetings with these people should be organized to discuss the study and their ability to participate. Each should decide whether or not he or she wants to participate in the drill; for those who wish to participate, the best evacuation procedures for them should be determined. These meetings provide information for the fuefighters and ease occupants' concerns about the drill.
3.3.2 Alarm Activator
One occupant must be selected as the alarm activator. It must be agreed that, at a given time following a phone call from the principal researcher, the occupant is to leave his or her apartment and proceed to the corridor to activate the alarm pull-station. The designated occupant then evacuates the building. This person may have to call the f i e department from the ground floor, if the building is not linked to a monitoring service.
3.4 Preparation of the Memo and Questionnaire
A memo, if needed, and a questionnaire have to be developed or customized for each evacuation drill. Both the memo and the questionnaire should be tailored to the building studied and the occupants targeted. The memo example provided in Appendix A was designed for Canadian residential buildings, the terminology used may not be
appropriate in other countries. Furthermore, some of the aspects explored may not apply to a specific building and will require modifications. For example, the name and the number and location of staircases mentioned in the questionnaire must reflect the building studied.
A post-evacuation questionnaire should be distributed to occupants immediately after the drill. A sample of two questionnaires used in previous evacuations is provided in Appendices B and C . Each questionnaire gathers information regarding the ability of occupants to hear the alann and understand P.A. messages, the types of activities they engaged in while preparing to evacuate, their age, gender and limitations, and their evacuation route.
The memo and questionnaire provide the name and phone number of a person to contact for further information. In all buildings studied, some occupants telephoned the contact person to voice their concerns or to get some information and advice on what they were expected to do. It is important to allow occupants to contact the person in charge of the exercise to give them confidence in the study and to reassure them of the authenticity and need for the study.
3.5 Alarm Measurements
A first series of sound recordings should be conducted one hour before the drill to measure ambient noise levels. The recording procedure should follow the requirements of CSA Standard 2-107.56 [9]. Different samples of approximately 15 to 20 s duration are recorded in different locations. Samples are taken in public areas such as the lobby and on different levels of the corridors and the staircases, as well as offices and washrooms in office buildings.
If possible, in residential buildings, sound samples should also be taken in some apartments. The apartments are selected in order to give a good representation of the different apartment locations in the buildings; within an apartment, sound samples can be taken in different rooms with the main door open or closed, the windows open or closed and a fan or air-conditioning system on or off. In each apartment visited, sound samples of the ambient noise are taken in the living room, kitchen, bedroom and bathroom. In a bedroom, the sound measurements are taken at the centre of the room at 1 m from any obstacle, with the bedroom door open and closed. The position of the person taking the samples and the conditions in the room should be carefully noted. During the drill, when the alarm
is
ringing, a second series of measurements is taken in the same rooms with the same room conditions and at the same locations.Since some of the occupants with limitations will most likely opt to stay in their apartments during the drill, these apartments are good locations to take measurements. When meeting with these people, researchers can inquire about whether they could take measurements inside the apartments before and during the drill.
Only a limited number of samples can be taken, as the alarm will be functioning for only a short time. Typical drills in apartment buildings last approximately 15 to 20 min. During that period, it should be possible to collect about 25 samples. Once the sample locations have been established, they must be indicated on a building plan. A path that minimizes distance travelled from one sampling site to the next should be planned and rehearsed by the person taking the samples.
4. EVACUATION OF THE BUILDIh'G
On the day of the evacuation, the person in charge of the study should go to the
fire hall to review the evacuation procedure with the firefighters who will participate in the
drill. Other members of the research team can set up the equipment and verify that all is in place.
The internal clock of each camera should be set to the exact same time (tenth of a second). Occupants travelling down the stairs will be seen f i t by one camera, then by another one and so on. To calculate the speed of movement and to obtain times that are comparable, it is vital that
all
the clocks be perfectly synchronized.AU cameras should be installed at their pre-determined locations. The view from
each camera should be adjusted to capture exactly what is needed for the analysis, which is
generally the doors leading to corridors, staircases and exit doors.
Ambient noise sound samples at each of the pre-determined locations should be taken about one hour before the drill. Prior to taking a sample, the person in charge of the sound measurements should clearly identify the location at which the sample is taken by speaking into the microphone. This minimizes possible confusion during later analysis among the many samples taken. Ideally, two people should be assigned to the sound sampling task. One person is responsible for the actual sound sampling, while the other serves as a guide from one location to the next. This team must work efficiently; there will be no second chance and all the samples must be obtained within the short period during the alarm sounding. The second person can carry a second complete set of sound sampling instruments; if the battery or another component fails during the drill, the sound sampling could then continue uninterrupted.
4.2 Evacuation
When everything is ready, 5 to 10 min before the beginning of the
drill,
all the cameras can be started or the observers can take their positions. If video cameras are used, the evacuation can be carried out without any intervention from the research team; ideally, all the members should stay outside the building. The only exception to that is the people in charge of the alarm audibility measurements, who should be at the fnstmeasurement location, waiting for the alarm to start. Once everythmg is in place, the principal researcher calls the alarm activator. That person leaves his or her apartment and activates the closest alarm pull-station to start the drill.
During the drill, pictures can be taken, but this activity should not at any time interfere in the exercise. The
fm
department will arrive on location usually 3 to 8 min after receiving the call, depending on the location of the fire hall. Upon arrival, the fmfighters will proceed with their normal search and rescue activities as if they were responding to a genuine call. When the firefighters judge that everyone has reached safety, the fue chief gives the "allclear" signal, the alarm is re-set and occupants can return to the building.4.3 Post-Evacuation Procedures
Once the evacuation is terminated, all cameras are turned off and the tapes are rewound. The cameras and brackets are dismantled and any damage must be repaired; it is important to leave the building in the same condition as before the drill.
A post-evacuation questionnaire is distributed to each door. As each questionnaire
is distributed, the unit number is written down on the front page. It is essential for later analysis to know the initial location of people reporting any action or behaviour during the
drill. A
questionnaire without a unit number cannot be used in the analysis. A clearly visible collection box or boxes should be left in a public area of the building, such as the lobby. Completed questionnaires are to be placed in this box before a specifed day. The location of the collection box and the deadline for returns should be indicated on the questionnaires. Periodic visits to the building every few days for a period ofa
week to retrieve the questionnaires will be necessary.5. CODING DATA
All the data collected is coded using a spreadsheet, or database tool. NRC uses SPSS, Version 6.01, which is a comprehensive software package for statistical data analysis [S]. This program is used to store information in a database format and to perform simple arithmetic as well as complex statistical calculations. It is used to
determine if significant differences exist between occupants of different genders, ages and levels of ability when examining their times to start the evacuation, exit the building, and move from start to finish.
A
l
l
the evacuation data is collected from the three media. The videotapes providefactual information on occupants' behaviour and evacuation movement. The
questionnaires contain the respondents' perception of the evacuation drill. Finally, the sound sample recordings give a detailed representation of the sound level of the alarm throughout the building. All the information must be coded to extract the details needed to generate results.
5.1 Coding the Videotapes
The videotapes must becarefully viewed and the resulting data F i n t o a
transcript. The transcript identifies the unit number from which each occupant started to evacuate, the exact time to leave that unit as well
as
the time speed in the corridor(s) and staircase(s),as
wellas
general behaviour during the evacuation.When viewing the tapes, it is vital to ensure that there is consistency in the time stamps. The best way to do this is to take the frst tape, starting with the top floor of the building, assume that this one is correct and note the time at which the alarm can first be heard on that tape. For each subsequent tape, if the alarm starts at a time that is different than that of the fust tape,
all
times reported on that later tape must be adjusted by that difference. The fact that all the camera clocks were set at the same time should prevent any discrepancy between tapes, but it is possible to encounter variations of a few seconds that should be taken into accountIdeally, all the coding should be done by the same person over a short period of time to ensure consistency. The age of the occupant is judged by the person viewing the video. It is important that the same person make all of these age estimates. It is also important to be consistent when coding the time of specific actions. The viewer should set some rules; for example, a person is recorded as entering the staircase when one foot touches the landing. Subsequently, this rule is systematically used throughout the coding of the videotapes, which will guarantee comparable results.
Each videotape must be watched individually. The easiest way is to start with the tapes from the cameras placed on the highest floor, and proceed down to the ground floor.
This way, on the fust tape viewed, only people from the highest floor can be seen. Each person seen in the tapes should be given an identification number. For each person seen, the unit number is recorded from which he or she emerged, the direction of movement, the time at which the occupant appears on the tape and a brief description including gender, age category, limitatiou if observed, whether the person is moving alone or with a group, specific behaviour and obvious characteristics such as clothing. The gender, age and limitation will be used for further analysis, while the physical and clothing characteristics will allow for recognition of the person from one tape to the next Whenever a person is seen on another
tape,
the same identification number should be used, and the time and behaviour should be noted. The other descriptive details need not be recorded again.5.1.1 Assessing the Age
The evacuees should be placed in one of seven age categories. Category 1 defines children 1-2 years old who have to be carried down the stairs. Category 2 is for c h i i e n 3-5 years old. These children may be able to walk down the stairs but often need
assistance from an adult Category 3 consists of children 6-12 years old. These children have no difficulty travelling without assistance. Category 4 is for teenagers 13-19 years old. Teenagers may travel without adults and have no problems with the stairs.
Category 5 is for adults between the ages of 20 and 39. These adults travel quickly without problems. Category 6 is for older adults, between the ages of 40 and 64. These adults may be a bit slower than the younger adults, but they still have a relatively easy time with the stairs. Category 7 is for seniors, aged 65 and up. These people often experience some difficulty with the stairs due to their age or other limitations. Comparisons with the questionnaire results can confirm some occupants' age estimates in cases when the
occupant's unit number is known both from the questionnaire and from the tapes. 5.1.2 Assessing Limitation
Limitations are factors which may hinder an occupant's ability to travel with ease, particularly in the staircase. In this study, people with limitations should include: slow elderly people; people carrying children, pets, or objects; toddlers and the adults helping them down the stairs; and people using a cane, walker, or other aid to move. The presence of a limitation can be judged by the videotape viewer. Only those limitations which are visible and obvious are noted. The presence of limitations such as hearing problems, heart problems and respiratory problems cannot be inferred from the videotapes, although they may have had an effect on occupants' movement times and behaviour. If the viewer has been made aware of these limitations, then the movement of affected occupants wiU be coded carefully with the specific note of their limitation. 5.1.3 Identifying Groups
In past evacuations, many people were seen evacuating in groups of two or more. When a number of people travel in a group, the speed of the group is generally that of its slowest member. If there was a group of occupants travelling together, the group was assigned an identification letter, starting with A for the first group, B for the second, etc. 5.1.4 Variables Recorded
Once the tapes of all the corridors have been coded, a staircase tape is chosen and the procedure is repeated, starting with the highest placed camera and working down. The same people should be seen from one tape to the other, with new people joining on each floor. For each person, the time at which the person enters the stairs is recorded and the time at which the person appears at each floor landing. The corridor tapes wiU
provide each occupant number.
The procedure is then repeated for each staircase. Finally, the pertinent times for any tapes left is recorded, such as tapes of the ground floor exit doors or tapes of the outside of the building. All the information recorded should be coded on a spreadsheet,
with each person being treated as a case, and all the different types of data treated as variables. Following, in Table 3, is a list of variables included in a typical evacuation study database.
16
Table 3: Suggested List of Database Variables
A number of actions are not quantifiable in terms of time but they can, nonetheless, reveal much about occupants' evacuation behaviour. For example, it is interesting to note details such as: people trying to use the elevators, people looking in the comdor but returning to their apartments instead of evacuating, people knocking on their neighbours' doors, people stopping to chat and people turning back. The description, time and location for these actions should be recorded in the "Specific behaviour" section.
. . .. ... . ~ . ~ .... ..* :...: . . . . ..., :.:::*
a r O c ~ p ~ f i : & & a Y ? ~ & ~ / i ; f ...
Personal Characteristics
Evacuation Movement
5.2 Coding the Quesliomaires
;:.*:>$ ~;x~::>*: s.<:xs: :*s;Ez,;$:,;;yFy :.:::: .. ::: ... !.$a$. . .:: .:*.... .: .:..:...::.>:~>::.:...:.:.:.:.~;~~:~::.;.:.:.:::.~::~:~::;:.~$~$::.~;.::;.:::.~<;~.;~~
&
$s82Ea<:::~:~v~~;-::I:~,:,:j~i/~,.~~~~:~~~::~~~~b~~~i~i~~i~ij~:~:::~~~ji:'~~;~:;~~~~~~~~:.:.:.::.:
.>.: ...Identification number Sex Age group L i t a t i o n
.
Group identification.
Spccific behaviour.
Apamnent number.
Floor of origin T i e to start.
Comdor(s) used-
Stairca.se(s) usedT i e seen in staircase X on floor Y Ourside exit chosen
.
T i e to exitT i e of arrival on balcony
.
T i e of leaving balcony T i e of arrival in safe areaTime of leaving safe area
The questionnaire data should also be recorded in a spreadsheet, using a different database from the one used for the videotapes. Each questionnaire is considered as a case, and each question as a variable. When the unit number of both an evacuee and a
questionnaire respondent are known to be the same, the information in the questionnaire can be used to validate videotaped observations, such as the occupant's age, unit number and the route chosen to evacuate.
5.3 Coding the Sound Samples
Data gathered can be analyzed using a Toshiba T-5200* computer equipped with a digital-to-analogue board and two specialized software packages. The fust software package, dBFETE*, gives the 113 octave band levels (80-8000 Hz) and the overall level in
dBA of each samole. The second software nacka~e. DetectsoundTM*. can be used to analyx the audibGity and recognition of theLalarm"fJr different background noises
xcorded in thc d~fferent locations. In past evacuations, the audibility was assessed taking into account the hearing status of a group of 55 year old men with normal hearing
according to age and a group of 55 year old men with a mild to severe hearing loss. These age groups give an interesting picture of the alarm audibility for those with and without hearing limitations and were representative of the occupants in the buildings under study.
Detectsoundm is a software package developed by the University of Montreal Grouve d'Acoustiaue to evaluate and h e l ~ in the selection of warnine sounds 191. The software analyzes ihe audibilitv and recobition of the alarm considgrine the backnound noise, the he&ing status of thcreceivers and, if appropriate, the use of gearing pr6tectors. Different algorithms, based on scientific literature and experimental studies, are included in the software. They allow comparisons to be made between: a) the spectral content of an alarm measured at a specific location, and b) the audibility "design window" calculated according to the background characteristics and the hearing status of the receivers. The hearing status of the receiver refers to the hearing thresholds and the frequency selectivity of the ear. Hearing thresholds in noise
are
computed for each 113 octave band and 10 to 25 dB are added to these values in order to make sure that the alarm will not only be detected but also attract attention and be recognized. The design window goes from 125 to 3000 Hz, and takes into account that spectral elements over 3000 Hz can be missed by people suffering from different kinds of hearing losses; for example, older people or workers exposed to noise.6. DATA ANALYSIS
Data analysis involves taking all the raw information collected and proceeding with calculations to generate results that summarize the situation. Statistical tests are used to yield comparative results
[lo].
6.1 Calculations of the Evacuation Times
Obtaining descriptive summary statistics of the evacuation times is the first step in the analysis of the data. From the videotape database, it is possible to calculate times of interest. Three different evacuation times are calculated for the analysis: a) Time to Start, b) Time to Exit, and c) Time to Move. The Time to Start represents the amount of time elapsed between the start of the alarm and the moment the person initially leaves his or her apartment, desk or office. The Time to Exit represents the amount of time elapsed
between the start of the alann and the moment that the person reaches safety. The T i e to Move is the difference between these two times; it represents the time taken by
occupants to travel from start to finish, regardless of when and where they started their evacuation. All these times are calculated for each occupant. Those who appear but do not leave the building (e.g., balcony users, people entering the building from outside during the drill) are not used to calculate these times.
The Times to Start, Exit and Move can be reported as averages for all the occupants and can also be divided into intervals. For example, tables can show the distribution in terms of the frequency of people starting, exiting or moving in 1 min time intervals, or in 15 s time intervals if a more precise representation of the evacuation times is desired.
6.2 Analysis of the Speed on Stairs
The use of videotapes makes it possible to accurately calculate the speed of the occupants travelling down the stairs. For each person, it is possible to determine the time at which the occupant first appears in the staircase and the time at which he or she reaches the ground floor landing. These times are used to calculate the total time each person travels in the staircase. The travelling time includes the time elapsed when occupants slow down to chat with neighbours or to let newcomers enter the staircase. The travelling time is stopped only if an occupant leaves the staircase or starts moving upward on the stairs. It is also possible to determine how many flights of stairs the person has travelled. These
two calculations are used to determine the average time for a person to descend one flight of stairs. Measurements of the staircase are taken prior to the drill to determine the distance in metres that the occupants travelled. This makes it possible to calculate for each person, a speed in metres per second. Table 4 indicates how to calculate evacuation speeds.
Table 4: Evacuation Speed Calculations
When calculating an average speed for all occupants, it is important to do it by taking the average of
all
the occupants' average speeds. Another way to calculate an average speed would be to divide the distance travelled per floor by the average of all occupants' mean time per floor, however, this method can introduce an error in the results, especially when dimensions vary between staircases.6.3 Comparisons According to Occupants' Characteristics
The statistical analysis tools included in SPSS are numerous, and can be quite complex. The analysis of the evacuation drill results should be kept relatively simple, and only two types of test are needed: Analysis of Variance (ANOVA) and chi-square Cross- tabulations. The ANOVA compares the scores of groups and determines the differences between them by producing a probability level (p-level).
There are two distinctive types of variables: nominal and interval [lo]. In the case of a nominal variable, each numeric value represents a category (e.g., 1 = yes and 2 = no).
In an interval variable, a unit increase in numeric value represents the same change in quantity regardless of where it occurs on the scale (e.g., time). The ANOVA test is used when the independent variable is nominal and when the dependent variable is an interval. The chi-square test is similar to the ANOVA, in that it also determines the similarity of groups, but it is used when both the dependent and independent variables are nominal. Research in social sciences usually uses a p-level less than p=0.05 to indicate that a significant difference exists between the G o groups. This means that there is less than a 5% probability that the results occurred by chance; there is a 95% confidence level that the differences between the two groups are real differences that would occur again if the same experiment was repeated.
The tests are used to compare the effects of an occupant's characteristics on the occupant's behaviour. For example, tests can be used to determine if the speed of men in the stairs is different from that of women. Characteristics that can be compared are gender, age, limitations, and effect of travelling in a group. Average Time to Start, Exit and Move as well as Mean T i e per Floor and Average Speed in Stairs are used to determine if any differences exist between occupants with different characteristics.
6.4 Direction of Movement
Using the building plan in parallel with the evacuation plan, it is interesting to assess if each occupant has used the closest exit and the shortest evacuation route. Since the staircase used by each occupant is noted, it is easy to determine if each occupant chose the staircase that was closest to his or her initial location or used a different route.
6.5 Analysis of the Questionnaires
Summary statistics can be obtained from the questionnaires. The results for each question are represented as a percentage of people choosing each option, such
as
the percentage of people who heard the alarm.Statistical tests can also be performed, similar to those used to compare evacuation times and speeds for occupants with different characteristics. Questionnaire respondents are asked to provide their sex and age, and indicate if they have a limitation. Comparisons can be done to determine such things as whether people from different locations or of different age groups are significantly more or less likely to hear the f i e alarm or to use the staircases. The results obtained from the questionnaire analysis are an important part of the study and allow a more extensive understanding of evacuation behaviour, as the video cameras only offer one perspective.
6.6 Analysis of Alarm Measurements
Shown in Figure 3 are typical results obtained with Detectsoundm for the f ~ e alarm analysis of a sound sample taken in a comdor [I I]. The x-axis represents the frequency content in hertz (Hz). The y-axis gives the sound pressure level (dBSPL). Measurements of the spectral content of the background noise are represented by the continuous horizontal line and the alarm level by the vertical lines for each 113 octave band. The diagonal hatched area represents the audibility design window into which the alarm should have a minimum of three spectral elements in order to meet the requirements of audibility. The spectral elements that reach the audibility design window are
represented by a thicker vertical line. Figure 3 shows that the alarm met the audibility requirements in the comdor with four spectral elements reaching the audibility design window. There are, however, eleven spectral elements which exceed the design window and a series of high levellhigh frequency elements. These two factors c o n f i the intense sound pressure at that location.
Building B
-
Corridor 5th FloorMan 55 Years Old with Normal Hearing
1
m
100 80 ibili Design Wbndcm 2% s o
%
40m
0 Frequency (Hz)Figure 3: Audibility Design Window for a 55 Year Old Man
with Normal Hearing
7.0 INTERPRETATION OF RESULTS
Evacuation drills described in this methodology are observational rather than experimental studies. This implies that there is not a specifc element introduced in the environment to be tested. The drills are field studies which implies limited control over the subjects or the environment. In fact, it is only possible to control the time of the drill and the location of the equipment; there is little control over most of the variables
affecting the occupants' behaviour. For instance, the population studied is essentially that which is in the building at the time of the drill and who decides to evacuate the building.
Because of the observational nature of the evacuation drills, the interpretation of the results must be performed carefully. It should not be assumed that because results for one building show a relationship between some occupant characteristics and a specific behaviour, it will always be the case. The behaviour could be caused by a third factor which was not controlled and was not taken into account during the analysis.
This does not imply, however, that results from one building are useless outside of that building, and that evacuation studies must be carried out in every building to have an indication of occupants' evacuation behaviour. One thing is certain, the greater the
number of buildings studied, the stronger the conclusions, and the greater the possibilities for generalization.
Once the results for a building are compiled and analyzed, they must be explained. Whenever results obtained differ significantly from expected results, researchers must find explanations for the discrepancies. In many cases, a few variables can explain the results. For example, details such as the recent occurrence of a false alarm could help explain a particularly low participation rate.
Results from an evacuation study should also be compared to results obtained during other drill studies. Comparing them to drills both from the same research team and from others can be valuable. If there are differences between the results, it is important to determine the cause. Differences in the methodology, occupants or building
characteristics could explain variance in the results.
Finally, results from an evacuation study can be compared to case study results from actual fires. Many occupants' behaviour and characteristics can be observed in both types of studies and can be compared to highlight differences and similarities.
Pre-evacuation behaviour such as perception of the alarm, looking for information, getting dressed or gathering valuables or pets can
all
be observed in the two types of studies. Other behaviour, such as the use of the elevators and the tendency to evacuate in groups, can also occur in both situations. Some of the other results obtained from an actual fm,however, will differ from those obtained in an observed evacuation drill. For example, in the case of a fire, very little can be done to obtain precise evacuation times and speeds, only the account and estimates of occupants are available. Such assessments
are
rarely precise and can be compared with caution to the evacuation times measured during drills.8. SUMMARY
The methodology presented has been tested and used in a number of evacuations held in different types of buildings and under different conditions. They may need to be modified to accommodate specfic buildings, however, any modifications to them should be noted and considered throughout the study as they may have unanticipated effects.
The evacuation of more than one building will yield a greater range of information. A comparison ofdiffcrent buildings, with rcspcct to evacuation timcs and spccds can he performed using thc ANOVA test. Lfeach building evacuated is chosen carefully, and if ihe same evacuation procedures are respected eve6 time, the results from all the buildings can then be compared and significant conclusions can be drawn.
Findings can be further used to develop predictive models and to improve code and requirements as well as occupant training to ensure enhanced fue safety in buildings.
