READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE. https://nrc-publications.canada.ca/eng/copyright
Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.
Questions? Contact the NRC Publications Archive team at
PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information.
NRC Publications Archive
Archives des publications du CNRC
This publication could be one of several versions: author’s original, accepted manuscript or the publisher’s version. / La version de cette publication peut être l’une des suivantes : la version prépublication de l’auteur, la version acceptée du manuscrit ou la version de l’éditeur.
Access and use of this website and the material on it are subject to the Terms and Conditions set forth at
Building use studies to solve building regulation problems: some
Canadian examples
Henning, D. N.; Pauls, J. L.
https://publications-cnrc.canada.ca/fra/droits
L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site
LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.
NRC Publications Record / Notice d'Archives des publications de CNRC:
https://nrc-publications.canada.ca/eng/view/object/?id=20e0707b-15b1-4bdf-a2b2-ed23adc01a23 https://publications-cnrc.canada.ca/fra/voir/objet/?id=20e0707b-15b1-4bdf-a2b2-ed23adc01a23Building
use studies
to
solve
building
regulation
problems: some
Canadian
examples
D.
IV.
HEIVNING,
J.
L.
PAUlLS
Division of Building Research
National Research Council
Ottawa, Canada
Summary
This paper &scribes some Canadian sturlies of the use o f buildings that were undertaken because of information needs in t h e preparation of codes and standards dealing with health and safety, including fire safety. Results provided information which is useful in rationalizing the design and operation of' buildings. O n e major study included detailed observations of the movement of building occupants and t h e mechanism cont- rolling this n~ovcmcrlt in normal and simulated fireemergency conditions. Particular types of human activity in buildings were studied, as well as key occupancy characteristics, such as the distribution of people in automobile parking garages and enclosed shopping plazas. These da ta are used in conjunc- tion with information provided by studies of frequency and duration of use t o determine requirements for exits and sani- tary facilities. Another complementary aspect of these studies concerns t h e problems encountered by certain building users, movement of people in wheelchairs and emergency egress via stretcher being t w o examples. S o m e implications of such stu- dies f o r building design, operation and regulation are discus- sed.
The use of buildings is an area of research that is beco- ming increasingly important in a technological appro- ach t o building design. As the activities in buildings change and new combinations of activities encourage non-traditional building forms, a sound basis is neces- sary t o predict the adequacy of those building facili- ties provided for the safety and well-being of building occupants.
This paper tlescribes a few building use studies
undcr thrce main hcadir~gs: occupancy characteristics,
special needs o f particular building users, and facility
r e q u i r e ~ ~ e n t s for activities cornmon t o a variety ol'
building types.
l n f o r l l ~ a t i o l ~ obtained fro111 these studies is dircctly
applied to building regulations. In Canada, there is a fortunate relationship between the National Researcll Council's Divisior~ of Buildirlg Research and the Natio- nal Committees which prepare the model Codes known as the National Building Code of Canada and the Na- tional Fire Codes of Canada. One aspect of this close relationship is that DBR Research Officers, including
those in the Building Use Section, are technical advi- sors t o Code Committees. This facilitates a two-way exhange so that up-to-date information is made avaible t o Committees and new research areas are readily indentified. When t h e information from research stu- dies becomes more comprehensive, detailed design control may b e exercised, not through legal regula- tions but through separate standards or design guides which are t h e responsibility of design professionals.
A s there are generally few precedents for these studies, a variety of field observation techniques, in- cluding photography, video recording and audio re- cording, were developed t o record transitory events involving t h e simultaneous behaviour of thousands o f people. More conventional surveys of statistical re- cords or published literature were also used.
Occupancy Characteristics
Population density is an important occupancy charac- teristic used in the regulation of buildings. T h e d e n - sity figures given in the National Building Code o f Canada are used t o determine t h e provision of buil- ding facilitiessuch as exits and sanitary fixtures. These Code figures are largely based on traditionally accep- ted estimates which d o not account for changing pat-
terns of building use. In order t o improve these d e n -
sity estirnatcs, surveys have bcen conducted in large, cnclosed, shopping centres and underground a u t o m o bile parking garagcs.
In the case of p:~~king garages, an 883-car garage
urltler a 3600-seat theatre corl~plex was chosen t o
represent a situation where near I T I ~ X ~ I I I L I I I I population
densitieswould occur; a 175-car garage under an apart- ment building was chosen t o represent near niinirnurn population densities. The lnaximurn density observed following theatre performances when there was a large influx of people t o the garage was 0.026 persons p e r square meter. This density was about 5 0 per c e n t
parking garages. In the apartment garage the maximum density observed was only 0.0022 persons per square meter. The results o f these studies were reviewed by Code Committees and changes made in the National Building Code.
A survey o f enclosed shopping centres showed that the over-all average population densities in stores va- ried considerably from one store t o another. The po- pulation density o f 0.36 persons per square meter, gi- ven in the Code, appeared reasonable as a conservative single-figure approximation f o r the maximum den- sity over a large sales area. The central mall area had population densities up t o 0.54 persons per square meter during busy shopping periods and u p t o 5.5 persons per square meter in portions of the mall dur- ing special sales promotions. Both t h e shopping centre figures were inadequate t o represent design population densities for broad occupancy classes.
Special Needs of Particular Building Users
Persons with physical disabilities find buildings awk- ward, frustrating and hazardous t o use. Attempts t o bring about design improvements by approaching designers and owners have n o t been very successful.
The current Canadian activity in enacting Building
Code requirements t o ensure t h a t buildings are usable by disabled people is expected t o bring about desired improvements. The standards involved in this legisla- tion are based on the results o f research conducted in Europe and the United States.
An cxaniple of original research t o develop infor- matior1 on the needs of special groups is a survey be- gun recently on the problems faced b y ambulance attendants in carrying stretcher patients from buil- dings. The survey, initiated by the Building Use Sec-
t i o l ~ , is bcil~g co~lducted by tlic O l ~ t a r i o Ariibularicc
Services I r ~ f i ) r l i i a l i o ~ ~ Service, using cxtcrisive colnpu-
tcrizctl records of' every ;~lilbularicc (rip riiadc iri tlic
l'rovi~lcc 01'Orit;lrio. Tlic rcsults will be useful i r ~ dcsc-
rihirig tlic cxtcrlt of difl'icultics such as ad~iiinistcring
o x y g c ~ i or kccpir~g patielits iri a Iiorizorit:~l position
w l ~ c r c tlic diriicrisioris o l ' c o r r i d o r s , s t ; ~ i r w ~ ~ s a i d eleva-
tor cabs arc i~i;~dcquatc. T l ~ c nature o f tlic difficultics
and t l ~ c cffcct 0 1 1 tlic paticnt will bc analyzcd. Tlic
survcy iliforr~i;ltior~, togcthcr witli iriforriiution or1 thc
critic;ll diliicrisiorisof tlie space rcquircd by the stretch- cr a r ~ d attcridants in action, rnay form the basis of Buildi~ig Codc requirenxnts.
Facility Requirements for Common
Activities in Buildings
Washroom Use
T h e use o f washroom facilities was studied at a shop- ping centre and a theatre complex. In t h e shopping centre it was found that a similar percentage of men and women used the washroom facilities. The mean duration o f elimination fixture use in t h e washrooms was 9 0 seconds f o r m e n and 9 2 seconds for women. T h e current Code requirements neither provide for this level of use nor d o they reflect findings o n the ratio o f water closet t o urinal use.
Preliminary results from the study o f a theatre complex indicate that the percentage o f population
using t h e washrooms is between 15 and 3 0 per cent;
t h e percentage o f men using the washroom is higher than the percentage of women. Although women out- number rnen in the audience, t h e mean duration o f cli~iiination fixture use is much lower f o r men. These findings suggest that the current requirements for twice as many fixtures for women as f o r men is in line with the use patterns o f the washroom facilities in this
theatre, although the number o f fixtures suggested
on t h e building population basis may b e insufficient. Information from these washroom studies is a t pre- sent being considered b y the Code Committee con- cerned.
Exit Stairway Use
The use of exit stairways in simulated emergency con- ditions is a major area o f study. The design of fire emergency facilities, such as exit stairways, is largely based o n what appears t o have worked well in exist- ing buildings. T h e use o f such facilities in emergencies is, howcvcr, difticult to obscrvc, rccord and evaluate. T o provide a rcliablc basis for uriderstanding thc criic@ericy use o f bxit stairways, nearly 4 0 building cvacuatior~ excrciscs Iiavc bccri observed since 1969.
'l'hcsc obscrvatiol~s were rii:~dc i l l coopcr;~tion with
thc Office of the Doriiiriio~i Fire Cornmissioncr of Cariad:~, in office buildings ranging in heiglit from 8 t o 29 storcys. In somc of thcsc cxcrciscs, building occu- parits bclicvcd they were evacuating because o f a gcnuinc emcrgency. This factor, as well as the de- tailed level o f observation and a n a l y s ~ s used in the
study, made the findings relevant t o t h e design
of
D. N . H E N N I N G - J. L . PAULS
2
8
as well. T o complement these office building observa- tions and a concurrent study of existing literature o n the movement of people,anew series ofobservations of typical crowd movements in large theatres, arenas and stadia was begun in 1973. The resulting broad data base will permit better predictions of human movement in a variety of emergency and non-emer- gency situations.
Most of the preliminary findings concern the rela- tionships between stairway geometry and evacuation flows down stairways in high office buildings. Relati- onstlips between niovement speed, density and flow have been investigated in relation t o building popula- tion, doorway and stairway widths, as well as other physical factors.
The most important finding was that the conventi- onally-accepted formula relating evacuation flow and stairway width appears t o b e too optimistic. The North American practice is t o assume an evacuation flow of 4 5 persons per minute for each 0.56 meter increment of stairway width(22 inches or one "unit exit width"). Based both on observations of stairways under conditions of large flow and o n more theoreti- cal analyses o f crowd movements down stairways, it appears unreasonable t o assume that a flow as large as 4 5 persons per minute will be sustained b y normal p e pulations during an entire evacuation which could take 5 t o 30 o r more minutes t o complete. A flow of
less than 30 persons per minute per 0.56 meter of
stairway width appears t o be a more reasonable esti- mate both for designing stairways for use in large-scale
evacuations and f o r predicting evacuation times for buildings.
In current building code practice, only whole o r half increments of unit exit widht are considered when determining t h e capacity of exit stairways. T h s practice is based o n the simplistic assumption that t h e movement of crowds down exit stairways occurs ei- ther in fairly distinct streams about 0.56 meter wide or in staggered files where an additional 0 . 3 0 meter of stairway width is provided. Observations indicate, however, that evacuees space themselves in a fairly informal arrangement on stairs with each person oc- cupying about 0.3 t o 1.0 square meter o f stairway area, depending o n factors such as the number of per- sons waiting t o enter the exit stairway. These obser- vations aswell ascounts of evacuation flow for various stairway widths suggest that the width of exits stair- ways can be designed t o b e in proportion t o the n u m - ber of evacuees expected t o use t h e stairways during the time available for evacuation (Fig. 1).
These findings are particulary timely because major changes are now being made in Building and Fire C o - des in North America t o deal w i t h the problems of fire in high buildings. One important aspect of t h s is the reassessment o f the role o f evacuation as a life-safe- ty measure. The studies of actual evacuations are valuable n o t only in helping t o establish the practl- cable limits o f total building evacuation b u t in propos- ing alternative controlled partial evacuation procedu- res for large buildings where smoke control and emer- gency communication systems are provided.
29
SUH.IECT - T H E M E II
I
I
-
a SUSTAINED FOR PERIOD
OF LESS THAN 15 SECONDS
b SUSTAINED FOR PERIOD
-
OF AT LEAST 3 MINUTES-
-
-
-
-
1
I
-
EXIT STAIRWAY WIDTH, METERS
Exit stairway flows in evacuatiao~ of high of* build-
