Title: Linking Means of Egress Systems and Emergency Response Strategies

Author: Jake Pauls, Jake Pauls Consulting Services

Subject: Fire & Safety

Keyword: Fire Safety

Publication Date: 2005

Original Publication: CTBUH 2005 7th World Congress, New York

Paper Type: 1. Book chapter/Part chapter2. Journal paper3. Conference proceeding4. Unpublished conference paper5. Magazine article6. Unpublished

© Council on Tall Buildings and Urban Habitat / Jake Pauls

ctbuh.org/papers

http://ctbuh.org/papers

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Jake Pauls, CPEJake Pauls Consulting Services in Building Use and Safety

With 20 years at the National Research Council of Canada as part of 38 years of international experience inresearch, codes/standards development, public health advocacy, and consulting, Jake Pauls currently serveson about a dozen national committees in the United States involved with standards and model codes forbuilding design. He represents the American Public Health Association on nine committees, including theNFPA High-Rise Building Safety Advisory Committee.

Educated in architecture (after physics and engineering) and certified in ergonomics, Mr. Pauls is well knownfor bridging among ergonomics, public health, and development of codes and standards for building use andsafety. Much of this work focuses on stairway safety and usability, including stairway use in major evacuationssuch as the World Trade Center, for which he co-directed an international initiative on evacuation researchand serves on the Skyscraper Safety Campaign Professional Advisory Panel.

Professionally, Mr. Pauls is also interested in the behavior of crowds in emergencies, including egress fromassembly facilities of all sizes, which seems to have been for quite some time a focus of research; consulting;media attention; and standards/codes development, adoption, and enforcement. Additionally, beyond thework in relatively large buildings, he feels a growing area of work is in public health, particularly how it isimpacted by design and regulation — including regulatory politics — for all buildings, including private homes.

Linking Means of Egress Systems and Emergency Response StrategiesThe prime objective of the presentation will be to demonstrate key functional links between design of meansof egress (including more-or-less traditional exits and non-conventional elevators) and urban design incorpo-rating tall buildings.

A multifaceted record of international research and technological developments will be presented, begin-ning in 1967 and paralleling the life and aftermath of New York’s World Trade Center. Human behavior in firesand other emergencies, broadly-based concerns for life safety, and usability will be subsequently addressed incontexts of architecture, engineering, ergonomics (human factors), building codes/standards, and publichealth.

Technical understanding of the role and design of means of egress systems has improved dramatically overthe last few decades although there has been relatively limited relevant research. There has also beenrelatively limited interest — punctuated with occasional muted protests from design professionals andrelated building industry professionals — when relatively minor changes were made in codes and standardsdealing with means of egress. Much more substantive changes, along with further incremental changes, arenow needed to help restore or maintain real and perceived safety in tall buildings. Many of these changeswill affect stairways although there has recently been a dramatic shift, even a paradigm shift, in professionalthinking about the use of elevators in emergencies.

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Linking Egress and Emergency Strategies with Building and Urban Design

Jake Pauls

Jake Pauls Consulting Services in Building Use and Safety

Silver Spring, Maryland, USA Tel: 301-933-5275 Fax: 301-933-5541

E-mail: bldguse@aol.com Individual Member, CTBUH

Abstract A prime objective is to contribute to a discussion about key links between design of means of egress (including exit stairs and elevators) and tall building design functionally integrated in urban design. A multifaceted record of international research and technological developments is presented, beginning in 1967 and paralleling the life plus aftermath of New York’s World Trade Center. Beginning with a student project, “Responses to Emergencies in Buildings,” helping to start a new field of study—human behavior in fires, broadly-based concerns for life safety and usability were subsequently addressed in contexts of architecture, engineering, ergonomics (human factors), building codes/standards and public health. Despite relatively limited relevant research, technical understanding of means of egress systems has improved over the last few decades. Some of that technical understanding has led to relatively minor changes to safety requirements in model building codes and standards. More-substantive changes, along with further incremental changes, are now needed to help restore or maintain real and perceived safety in tall buildings. Many of these affect stairways although there has recently been a dramatic shift—indeed a paradigm shift—in professional thinking about occupant use of elevators in emergencies to augment the evacuation function of exit stairways. Keywords: Means of Egress, Human Behavior, Ergonomics, Design, Building Codes INTRODUCTION: HISTORICAL BACKGROUND A Canadian Contribution to Research on Means of Egress. Including some autobiographical elements, this paper is based on a 38-year history of concern for life safety in high-rise buildings which parallels the life and aftermath of New York’s World Trade Center. After being introduced, as an architecture student at the University of British Columbia, to certain safety problems of tall buildings by research architect Stirling Ferguson of the National Research Council of Canada, the author was invited to work at NRC Canada in 1967 as part of its summer student program. Within a new, long-term project titled “Building Use Studies,” this work addressed means of egress design issues and was done under the title, Geometry of Building Spaces. Despite this somewhat limiting title, the work focused on the performance of means of egress systems, beginning in mid 1969 with documentation and detailed analysis of evacuation drills held in tall office buildings. In other words, there was a focus on how people interacted with each other in an unusual crowd event and how well the exit stairway environment, as well as the evacuation procedure and its management, facilitated egress. Only years later would it be fully recognized that such work fell under the category of human factors or ergonomics research and that it helped to create a new field of study. In the mid 1970s this field became known as “Human Behavior in Fire” after an initial publication by the US National Bureau of Standards—now the National Institute of Standards and Technology, NIST (Rubin and Cohen, 1974). One account of the history of this field was published after several international meetings were held in the field (Pauls, 1998).

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“Responses to Emergencies in Buildings” and Ensuing Tall Building Evacuation Studies Student Project on State of the Art. After being part of NRC Canada’s student program over a two-year period, the author completed studies in Architecture with a graduation project titled, “Responses to Emergencies in Buildings” with a subtitle, “A survey of fire problems in modern high-rise office buildings and proposal of design solutions.” Completed in May 1969, the thesis holds up well in the current context—especially in this post World Trade Center period with its deliberations about the post-9/11 design development of Ground Zero in New York and of high-rise buildings generally. The degree to which the thesis was prescient may be evident in reading its abstract (Pauls, 1969).

New buildings are designed to be fire-resistive; occupancy hazards are highly controlled; and safeguards and emergency facilities are provided to protect life and property. These facilities have been provided largely because of building and fire codes. In the face of technological and legal advances, the users of buildings have grown complacent about hazards which, while statistically reduced, nevertheless still exist—particularly in the case of uncontrolled smoke movement in high-rise and air-conditioned buildings. Also attitudes toward safety provisions are not conducive to their use in the event of emergency. Worse still, the safety features may be effectively nullified by abuse (or non-use) during normal conditions. How are these facilities to be designed so that they will not only perform effectively during emergencies but also become a useful part of the users’ normal working environment? In the graduation project, answers were sought to questions of this type. The results of the work fall into three areas:

(1) Introduction to fire problems in modern buildings, particularly in high ones used for office occupancies. (2) Survey of research on responses to and behaviour during emergency conditions. Concurrent with this were observations and experiments during campus fire drills and inspection of circulation routes in local office buildings. (3) Statement of three behavioural goals and examination of environmental and building implications for various emergency conditions. These goals are:

(a) Rapid egress (b) Emergency muster (c) Non-egress

The implications to building form are suggested in terms of gross and detailed features of circulation spaces. For example, the goal of rapid egress is manifested with provisions similar to those now required by codes and is applicable to lower or older buildings. Emergency muster applies to high-rise buildings in which there is presently much confusion, on the part of occupants (and fire officials), about the need to evacuate quickly. Emergency muster would provide a two-stage procedure more in keeping with the motivations of building users. The third goal, that of non-egress, is applied to building forms which are interconnected at several levels—a logical step from the problematic freestanding high-rise towers in vogue today. At a parametric level suggestions are made for environmental design to be in keeping with the perceptual responses of the building users.

A key reference for the third goal was a report from the Regional Plan Association (1969) in New York, Urban Design Manhattan, which included some suggestions for innovative urban design based on the concept called the Access Tree based on a new level of integration of buildings at, below and above grade. The graduation thesis drew upon this concept to suggest better ways of sharing means of egress among adjacent buildings which would reduce, if not obviate, the need for either rapid total evacuation or phased, partial evacuation utilizing only the exit system within an individual high-rise tower. (This concept is further discussed below.) Emergency Behavior of People. The thesis predated—if not spurred—research on behavior of people in fire emergencies beginning in North America in the early 1970s. Before this time, the most substantial

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body of research into human behavior in emergencies was done within the context of large-scale, usually natural disasters as covered authoritatively from sociological and psychological perspectives in the book, Man and Society in Disaster (Baker and Chapman, 1962). (At this time Peter Wood,1972, was doing his pioneering study of the behavior of people in fire in the UK and the best North American examination of human behavior in a fire was study by John Bryan, 1957, of the Arundel Park Hall fire in 1956.) The “treatment of the problem” in the thesis was described by the first published review of the field (Rubin and Cohen, 1974) as “the most detailed and relevant account found.” Key to their perception was the effort to “explore how emergency provisions might be designed if the designer worked logically from clearly stated premises or principles through to design conclusions. . . .” In other words, a multiple strategy approach was advocated. Tall Building Evacuation Documentation. Moreover, beginning in 1969 with the first detailed documentation of a total evacuation of a tall office building (the BC Hydro Building in Vancouver), the thesis led directly to a major program of evacuation studies—at the invitation of the Fire Commissioner for Canada—that ran from 1969 to 1974. Although the most detailed treatments on these tall building evacuation studies were not published until the end of the 1970s (e.g., Pauls, 1980; Pauls and Jones, 1980) preliminary findings were being widely reported from the mid 1970s on, including in a book focused on tall buildings (Pauls, 1977a). Around this time the author was invited to join the Means of Egress Committee of the National Fire Protection Association (NFPA) to help update stairway and egress design requirements in the Life Safety Code (NFPA 101) beginning with the 1981 edition. Results of those studies are still having an impact on codes and standards requirements for building design internationally. Pedestrian Movement and Stairway Studies Conducted around 1970 People Movement Studies, Especially in New York. Significantly, the author’s work on crowd movement on exit stairways was being carried out as well known pedestrian movement authority, John Fruin, was completing his doctoral dissertation at the Polytechnic Institute of Brooklyn and publishing it as the much-used text, Pedestrian Planning and Design (Fruin, 1971, 1987). Notably he was then working for the Port Authority of New York and New Jersey Research Department as the World Trade Center was being constructed. Also, underlining just how fertile this period was for innovative studies of pedestrian movement and design, researchers at the Regional Plan Association were working on the book Urban Space for Pedestrians (Pushkarev and Zupan, 1975). (Not until three decades later did these researchers collaborate on a co-authored paper, Pauls, Fruin and Zupan, 2005.) Also, related to the critical role played by stairways in tall buildings’ means of egress, the early 1970s were the busiest years for major examinations of stairway safety, with John Templer completing his dissertation, Stair Shape and Human Movement, at Columbia University in 1974, later to be made into a two-volume book, The Staircase (Templer, 1992). Furthermore, John Archea and colleagues at the US National Bureau of Standards were examining stairway safety in detail for the US Consumer Product Safety Commission (Archea, Collins and Stahl, 1979). Underlining just how far behind the New York City has fallen with respect to stairway and means of egress design, only in 2005 has it begun to seriously update its building code requirements to take account, for example, of research done three decades earlier and widely adopted in model building codes in the US and, especially, NFPA’s Life Safety Code during the 1980s. In fairness, it should be noted that Chicago, the other major site for high-rise building innovation, has also been backward in bringing stairway and means of egress requirements up to date in its building code. As a result, many tall buildings in these cities have exit stairs that fall short in terms of effective, reasonably safe means of egress. Such deficiencies could last for decades in the existing stocks of many tall buildings. Reiterating the point made above, relative to both building design and environment/behavior research, the author’s 1969 thesis, “Responses to Emergencies in Buildings,” remains remarkably relevant in the current context—especially in this post World Trade Center period with its deliberations about the post-9/11 design development of Ground Zero in New York and of high-rise buildings generally. The remainder of this paper moves from the focus on the past to brief examination of how we might proceed today.

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EVACUATION PROCEDURES IN TALL BUILDINGS Phased, Partial Evacuation Procedure. To a large extent, evacuation procedures assumed (by designers, regulators and operators) for tall office buildings entail evacuation of only a few floors in case of fire; specifically the fire floor and one or two floors above and below the fire floor. This assumes that the effects of a fire can be reliably confined to one or two floors. This assumption has been shown to be faulty enough times in fires and other incidents to be worrying, especially to occupants who then “self evacuate”—the somewhat disparaging expression used by some people to describe occupants choosing a more conservative strategy for their personal life safety. Increasingly, in an age of apparently more frequent and better publicized terrorist attacks, building occupants are simply applying the old rule, “Of the thirty-six ways to escape danger, running away is best” (Quarantelli, 1973). Thus, in designing, regulating and managing tall buildings, we need to consider carefully the attitudes and perceptions of occupants; in some cases—such as the expeditious evacuation of World Trade Center Tower Two (WTC 2) —they will make the better decisions about their own safety than do management personnel. Of course, it would be helpful to have the benefits of adequate—and ongoing—research on the (changing) attitudes of typical tall building occupants to appropriate evacuation procedures. Unfortunately, this was not part of the post-9/11 research response to the WTC disaster of 2001, for example by the US National Institute of Standards and Technology (NIST). Reportedly, NIST requested $16 million for its WTC investigation and precious little of that—apparently about $1 million initially—was planned for occupant behavior aspects (although, reportedly, closer to $2 million was eventually spent by NIST for this topic). For official information on NIST’s WTC studies see http://wtc.nist.gov/. Exit Capacity and Redundancy in Relation to Egress Strategies and Demand Today we have an increasingly dangerous mismatch between the demand (by occupants in an emergency—real or perceived) for means of egress capacity when that capacity is based on a sometimes flawed assumption that only one or a few floors of a tall building will be simultaneously evacuated. Indeed, it is common for building code requirements for means of egress capacity of exit stairs to be based on the population of a single floor. Thus a three-story office building has exactly the same exit stair width—and egress capacity—as does one with a hundred or more stories. With only an occasional exception, the ever taller buildings—being erected in the competition to be the world’s highest—rely completely on two or three exit stairs contained within a single slender tower. One exception to this is the pair of (mid-height) bridge-connected towers in Kuala Lumpur, the Petronas Towers, which effectively doubles the redundancy and capacity of exits for many office floors without increasing the space devoted to stairs in a single tower. Figure 1 consists of three images taken from the author’s 1969 graduation project, “Responses to Emergencies in Buildings,” illustrating (from left to right):

(a) A pair of office towers, 56 and 46 stories in height, in the Toronto Dominion complex in downtown Toronto showing three hypothetical, connecting bridges.

(b) A schematic plan of multiple towers connected with bridges and sharing exits for greater redundancy.

(c) An isometric sketch modifying the Access Tree concept put forward in the report, “Urban Design Manhattan,” by the Regional Plan Association (1969) to illustrate vertical and horizontal means of egress for connected building floors.

Connected Buildings Depicted in Design Competition. Other conceptual examples of buildings connected at various heights were demonstrated with at least two of the nine proposed designs in the competition for new buildings for New York City’s Ground Zero site. The Meier and Partners plus United Architects proposed designs provided multiple horizontal connections at various heights connecting towers, thereby providing significant redundancies and capacities for means of egress. (For information on these competition proposals see the Lower Manhattan Development Corporation web site: http://www.renewnyc.org/plan_des_dev/wtc_site/new_design_plans/.)

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Figure 1 (a) (b) (c)

Urban Design Implications If Tall Buildings Designed in More Integrated Fashion. Capacity Issues. Exit capacity, occupant demand and resulting flow times—plus, ultimately, evacuation times—have been of particular interest to the author for decades and provision of egress capacity, at least, has been a major component of building codes for a long time. The author’s extensive studies of evacuation drills in tall office buildings—as well as larger-scale studies of crowd movement in major assembly facilities in events as large as the Olympic Games (particularly in the summer of 1976 and the winter of 1988)—are reflected in the technical literature on evacuation and design plus regulation of means of egress. (See, for example Pauls, 1980, 1988, 1989 and 1995.) Without going into great detail on the many aspects of egress capacity and means of egress width, two points need to be made. First, the author’s evacuation studies of three decades ago led to a substantial reduction in the expected egress flow as a function of stair width and the more-reasonable flow expectations resulting from the office building evacuation studies and assembly occupancy crowd movement studies were in line with flow-width relationships published by Fruin (1971, 1986). Occupant Fitness and Capability. Notably, in both the author’s studies in Canada and Fruin’s studies in the New York City area—both done a few decades ago, people were not as overweight and as physically unfit as is the case today, especially in the USA but, increasingly, in many other countries. Now there is a need for new studies that will establish reasonable flow expectations (as well as movement speeds) for the significantly less fit people using buildings today, especially tall buildings where evacuations will be especially arduous. Notably, the WTC studies by NIST (2005) estimated stair descent speeds and flows that were only about half of the conservative predictions based on the work of three decades ago. Thus the bottom line is that, three decades ago, studies led to an approximate halving of flow expectations because of errors made in traditional assumptions based on very limited studies. Now we face another halving of expectations and we need to determine to what extent this is fitness-related and to what extent it is a function of larger number of stories to traverse in total building evacuations. We simply cannot afford to build and operate large buildings with unrealistic expectations of occupant performance in conditions where efficient egress is crucial. Minimum Exit Stairway Width. As part of this needed new research on human performance when using stairways, work is needed on implications—for minimum stairway widths—of increased body size plus mass combined with reduced fitness. Increased lateral body sway, induced especially with larger bodies and slower movement speeds, exacerbates the growth in static dimensions of people. Now, new stairway design implications need to be empirically determined. The recent paper by Pauls, Fruin and Zupan (2005) addresses this subject specifically and includes extensive suggestions on how to pursue the needed research addressing coherent flow, overtaking movement and counterflow. Recent Codes/Standards Deliberations on Increased Minimum Stair Width. Over a four-year period

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there have been extensive deliberations about proposed changes to NFPA 101 (Life Safety Code) and NFPA 5000 (Building Construction and Safety Code) about increasing minimum required exit stair width from the traditional 44 in (1120 mm) to 56 in (1420 mm) to account for errors in the original misconception about “units of exit width” based on 22 in (560 mm) and the inability of people to move effectively within the 44-in (1120 mm) nominal width (which provides clear width between handrails of only about 36 in, 910 mm). The 56-in (1420 mm) proposed new minimum exit stair width—being adopted only for especially high-occupancy stairs, serving an accumulative occupant load of over 2,000 persons—provides a clear width of 48 in (1220 mm) between handrails and, as such, is similar to widths already being required in USA codes for assembly aisles as well as for certain exit stairways on which people will have to be carried in wheelchairs. Incidentally, the 2,000-person criterion is based on the high likelihood of counterflow of evacuees and emergency responders, notably heavily clothed and equipment-laden firefighters. However, there are benefits also for coherent flow and for overtaking, bypassing behavior on stairs. For relatively large floor area buildings, the stair widths below 14 fully occupied office floors would need to be the new, wider minimum width according to the proposals being finalized by NFPA during 2005. The opposition to increasing minimum exit stair width, even with the scoping limited to high-population exits, has been led by the US General Services Administration with support from the Building Owners and Managers Association, BOMA. Wider Exit Stairways Already Being Designed into Major High-Rise Buildings. One of the three exit stairways (designated as B) in each WTC tower had the 56-in (1420 mm) nominal width. Notably, designers of major new office buildings—including WTC 7 and the Freedom Tower at Ground Zero in New York City— are reportedly already designing exit stairways to be much wider than the traditional 44 in (1120 mm), even significantly wider than the 56 in (1420 mm) proposed for NFPA documents. Designers are cautioned, however, not to make clear widths between handrails larger than about 60 in (1525 mm) as extensive crowd use of greater widths puts people in the middle of the stair beyond reach of a handrail. Thus 68 in (1725 mm) is the largest nominal width that exit stairways should generally have. Also, relative to expected flow performance as a function of width, it should be kept in mind that, while not recognized in the simplified formulas used by building codes in the USA, flow performance is a function of a stair’s effective width which is the nominal width less 12 in (300 mm). Thus wide stairs—up to the 68-in (1725 mm) limit provide more flow per width than do narrower stairs. For example, a 56-in (1420 mm) nominal width stair performs about 38 percent more effectively—for flow—than does a traditional 44-in (1120 mm) nominal stair even thought the former is only 27 percent wider. (See Pauls, 1980, 1988, 1995 for details on the effective-width model for evacuation flow.)

Figure 2. Floor plan of WTC 1, floor 96. with superimposed circles connecting and enclosing the three exit stairways, designated as A, B and C.

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Exit Remoteness and Redundancies on Individual Tower Floors Figure 2 shows the floor plan for WTC1, 96th floor (derived from WTC draft final report, Figure 1-5, by NIST, 2005). One of the problems in the World Trade Center towers was the close proximity of all three of the exit stairs on almost all floors and particularly on the impact floors for WTC 1, including the floor illustrated in Figure 2. On these floors the direct-line distance separating exit shafts was, at best, only about 20 ft (6 m). If a triangle were drawn connecting the three exit shafts, it would have an area of only about 200 sq ft. (19 sq m). This would be relative to an overall floor plan dimension of about 200 feet (61 m) per side (about 280 ft or 85 m in diagonal dimension) and an area of about 40,000 sq ft (3,716 sq m). Superimposed on the plan in Figure 2 are two circles. The smaller circle, touching the closest walls of the three exit stairways (A, B, and C), has a diameter of about 21 ft (6 m) and an area of 360 sq ft (33 sq m); the larger circle encompasses all three stairways and has a diameter of about 66 ft (20 m) and an area of about 3,400 sq ft (316 sq m). In other words, an event impacting as little as a 360 sq ft (33 sq m) circle area could damage a portion of the shaft walls of all three exit stairways while an event destroying as little as a 3,400 sq ft (316 sq m) circular area could eliminate all three exit stairways. Relative to the overall floor area, these circular areas are respectively only about 1 percent and 9 percent of the floor area. Note that the core area, within the major interior columns, measured about 80 ft by 125 ft (24 m by 38 m), making an area of about 10,000 sq ft. (930 sq m) or about 25 percent of the floor area overall. Surely it cannot be reasonably argued that the exits, especially on upper floors such as floor 96, were as far apart as was practicable nor that reasonable redundancy was provided. Subchapter 6, Means of Egress, of the 1968 NYC Building Code, Section 27-363, had the following requirements.

Remote location - When more than one exit is required from a floor of a building, each exit shall be placed as remote from the others as is practicable. Door openings to scissor stairs shall be*(6) at least fifteen feet distant from each other. In all other buildings, the minimum distance between such doors shall be the greater of thirty feet or one-third the maximum travel distance of the floor, provided, however, that where such distance will result in travel distances exceeding those authorized in section 27-357 additional vertical exits shall be provided.

Even by the relatively lax, badly drafted rule based on travel distance, the NYC code would have required at least 66 ft (20 m) between exit entry doors; the impact floors of Tower One provided only about 45 ft (14 m). Notably, the third- and half-diagonal rules in current model building codes in the USA would require the distance between exit doors to be a minimum of about 93 ft or 140 ft (28 m or 43 m), depending on whether the sprinkler-based relaxation of the rule applies. Notably, when initially constructed, the WTC towers were not sprinklered and, on 9/11, sprinklers were not operational. Thus by all measures, there was not reasonable redundancy—due to exit remoteness—provided on critical floors of the WTC and many people above impact areas were trapped. The draft final report on the WTC disaster by NIST (2005) plays down this design defect. Benefit of Increased Remoteness of Exit Stairways. It is well documented that, due to an unusual more-remote positioning of exit stairway A in WTC Tower Two—in the vicinity of its impact zone, several people were able to descend through the impact zone shortly after impact. There is a possibility that, later, exit stairway A was once again usable because evacuees were reported coming down—below the impact zone—just prior to collapse. Thus the largest “what if” question about 9/11 (at least for this author) is about the possibility of fewer trapped occupants if the exits had been located for greater redundancy—even if still located in the core column area, let alone outside the core area. Moreover, both at building scale and urban scale, it is worthwhile assessing the relative merits—the pros and the cons—of locating one of more of a building’s exit stairways at a building perimeter location to maximize remoteness as well as potentially gain other advantages including easy access to outside air and natural lighting. Here it should be noted that, as part of his early duties at NRC Canada around 1970, the author spent some considerable time investigating various criteria for exit remoteness. Although the

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half-diagonal rule held some promise as a rough guide to exit remoteness—and ultimately, exit redundancy, the author rejected long-term use of simplistic geometric bases for exit remoteness recognizing that, ultimately more-performance-based criteria were needed and work on their development would be helpful. As a 38-year veteran of the model code making process in the USA and Canada, the author has seen little or nothing approaching a risk evaluation addressing the exit remoteness issue. One current exception, affecting egress, is discussed next. Use of Elevators for Occupant Evacuation and for Firefighters During the last two years there has been a genuine paradigm shift in the thinking of elevator industry professionals, and some related fire safety and codes/standards professionals, regarding use of elevators for firefighters and for occupant egress during fire emergencies. The shift occurred in conjunction with an international workshop held in March 2004 in Atlanta, Georgia. Useful information about the workshop is available at http://www.asme.org/cns/elevators/postworkact.shtml. Use of elevators for egress has been discussed for decades; indeed the author’s first foray into this topic—particularly on the combined use of exit stairways and elevators—dates back nearly three decades (Pauls, 1977) with an update to that paper being given at the March 2004 workshop and subsequently reprinted in the trade magazine, Elevator World (Pauls, 2004). Over the last year, thanks to the initiative of the American Society of Mechanical Engineers and other organizations, there have been productive workshops held to closely examine both firefighter use and occupant use of elevators during fires. In these workshops a systematic risk assessment method is used to establish the strategies and specific tactics that will be needed to use the elevators with reasonable safety. Incidentally, predating the paradigm shift—and perhaps encouraging it, at the last major conference on tall buildings there was a presentation on the work by NIST researchers addressing the potentials and challenges with use of elevators for egress (Kuligowski, E. D., 2003). Urban-Scale Considerations With increasingly large, taller buildings in urban settings—where economics are more likely to favor them, emergency events and evacuations in one building will affect its neighbors. For example, where are large crowds, with on the order of 10,000 evacuees, supposed to go for their own safety as well as to keep clear of vehicular traffic, debris, secondary events, emergency responders, etc? Such questions as well as the exit capacity and redundancy issues, touched on in this paper, deserve serious, detailed consideration. For example, what are the safety plus security pros and cons of connecting individual buildings at certain above-grade floors? What about structural considerations with connected buildings; for example, how can the different dynamic responses of individual buildings be accommodated by bridges or other connecting structures? Are there structural advantages to increasing lateral support? Drawing on the innovative and responsive concepts such as the “Access Tree” described in the Regional Plan Association (1969) report, the author addressed the life safety advantages in his 1969 graduation project. Now the time has come to brush the proverbial dust off both documents and reconsider the role —in relation to occupant safety—of tall buildings in the urban fabric. Clearly, this would mean reassessing the long-established pattern of free-standing, individualistic, iconic towers—often erected for dubious economic reasons just to gain a world record, no matter how briefly that record stands. It is this author’s personal and professional opinion—as a long established authority in building safety issues, now deeply immersed in public health aspects of building codes and standards—that we need to get away from the competition to be taller only for the sake of the ego(s) of some developer and/or designer. The fundamental problems of transporting people large vertical distances, via a small number of not very redundant systems, are being exacerbated in the race to be taller, especially in the form of free-standing towers. Providing movement options and diversity of paths helps to make urban settings attractive and more functional. Why should we continue to insert, into those settings, such large buildings that severely limit—rather than enhance—our movement options? CONCLUDING COMMENTS Architects typically do not get excited in a positive fashion with means of egress. They tend to view the facilities as disruptive to planning, to be hidden as much as possible, and not to be considered in a first-

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principles fashion where human factors (ergonomics) are addressed. Building code requirements are often seen as adding cost as well as limiting artistic freedom. Facilities dictated by codes are not considered in an operational sense by the designers; thus the facilities often function poorly simply because the needs of occupants have not been addressed well. Even many consulting engineers, who assist architects with large building design, share a flawed assumption that code requirements for means of egress are based on a complete assessment of the safety and usability needs of occupants. This is hardly the case. All involved with the design, construction, regulation and management of means of egress should get involved with a more thorough look at how means of egress actually function and how they can work better. Society has done a relatively poor job with stairways in the means of egress system; adding elevators now to that system raises even more complex ergonomic and management issues in our task of making sure our emergency preparedness and responses truly address human needs and capabilities. Just as the addition of elevators to means of egress systems is a paradigm shift, we need a paradigm shift in our overall approach to means of egress especially in very tall buildings. REFERENCES Archea, J.C., Collins, B.L. and Stahl, F.I., 1979 GUIDELINES FOR STAIR SAFETY, NBS-BSS 120, National Bureau of Standards, Gaithersburg, MD. Baker, G.W. and Chapman, D.W. (eds.), 1962 MAN AND SOCIETY IN DISASTER, Basic Books, New York. Bryan, J.L., 1957 A STUDY OF THE SURVIVORS REPORTS ON THE PANIC IN THE FIRE AT THE ARUNDEL PARK HALL, BROOKLYN, MARYLAND, ON JANUARY 29, 1956, University of Maryland, College Park, MD. Fruin, J.J., 1971 PEDESTRIAN PLANNING AND DESIGN, Metropolitan Association of Urban Designers and Environmental Planners, Inc., New York. Kuligowski, E. D., 2003 ELEVATORS FOR OCCUPANT EVACUATION AND FIRE DEPARTMENT ACCESS. STRATEGIES FOR PERFORMANCE IN THE AFTERMATH OF THE WORLD TRADE CENTER. Proceedings of CIB-CTBUH Conference on Tall Buildings. Task Group on Tall Buildings: CIB TG50. CIB Publication No. 290. October 20-23, 2003, Kuala Lumpur, Shafii, F.; Bukowski, R.; Klemencic, R. (Eds.), pp. 193-200. Fruin, J.J., 1987 PEDESTRIAN PLANNING AND DESIGN, Revised Edition, Elevator World, Inc. Mobile, Alabama. NIST, 2005 FINAL REPORT OF THE NATIONAL CONSTRUCTION SAFETY TEAM ON THE COLLAPSES OF THE WORLD TRADE CENTER (DRAFT), National Institute of Standards and Technology, Gaithersburg, MD, Report NIST NCSTAR 1 (Draft). (Accessible at http://wtc.nist.gov/) Pauls, J.,1969 RESPONSES TO EMERGENCIES IN BUILDINGS, Undergraduate Thesis for the Bachelor of Architecture Degree, University of British Columbia, Vancouver, 154 pp. Pauls, J., 1977a MOVEMENT OF PEOPLE IN BUILDING EVACUATIONS, Human Response to Tall Buildings, (Edited by D. Conway), Stroudsburg, PA, Dowden, Hutchinson and Ross, pp. 281-292. Pauls, J., 1977b MANAGEMENT AND MOVEMENT OF BUILDING OCCUPANTS IN EMERGENCIES, Proceedings of Second Conference on Designing to Survive Severe Hazards, IIT Research Institute, pp. 103-130.

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Pauls, J., 1980 BUILDING EVACUATION: RESEARCH FINDINGS AND RECOMMENDATIONS, Fires and Human Behaviour, (Edited by D. Canter) John Wiley and Sons, pp. 251-275. Pauls, J. and Jones, B., 1980 BUILDING EVACUATION: RESEARCH METHODS AND CASE STUDIES, Fires and Human Behaviour, (Edited by D. Canter) John Wiley and Sons, pp. 227-250. Pauls, J., 1988 MOVEMENT OF PEOPLE, The SFPE Handbook of Fire Protection Engineering, National Fire Protection Association, Quincy, MA, Section 1, Chapter 15, pp. 246-268. Pauls, J., 1989 HOW UNIFORM ARE BUILDING CODE REQUIREMENTS FOR EXIT STAIR CAPACITY? Building Standards, September-October, pp. 13-15. Pauls, J., 1995 MOVEMENT OF PEOPLE, The SFPE Handbook of Fire Protection Engineering Second Edition, Society of Fire Protection Engineers and National Fire Protection Association, Sec. 3, Ch. 13, pp. 3-263—3-285. Pauls, J., 1998 A PERSONAL PERSPECTIVE ON RESEARCH, CONSULTING AND CODES/STANDARDS DEVELOPMENT IN FIRE-RELATED HUMAN BEHAVIOUR, 1969-1997 WITH AN EMPHASIS ON SPACE AND TIME FACTORS, Human Behaviour in Fire: Proceedings of the First International Symposium, University of Ulster, August 1998, pp. 71-82. Subsequently published in Fire and Materials, Vol. 23, 1999, pp. 265-272. Pauls, J., 2004 ELEVATORS AND STAIRS FOR EVACUATION: COMPARISONS AND COMBINATIONS. Proceedings of Workshop on Use of Elevators in Fires and Other Emergencies, American Society of Mechanical Engineers. Also in Elevator World, Vol. LIII, No. 1, January 2005, pp. 69-74. Pauls, J., Fruin, J.J. and Zupan, J.M., 2005 MINIMUM STAIR WIDTH FOR EVACUATION, OVERTAKING MOVEMENT AND COUNTERFLOW: TECHNICAL BASES AND SUGGESTIONS FOR THE PAST, PRESENT AND FUTURE, Proceedings of Pedestrian and Evacuation Dynamics 2005, Vienna, September 2005. Pushkarev, B.S. and Zupan, J.M., 1975 URBAN SPACE FOR PEDESTRIANS, Regional Plan Association, MIT Press. Quarantelli, E.L., 1973 HUMAN BEHAVIOUR IN DISASTER, Proceedings of Conference, Designing to Survive Disaster, IIT Research Institute, Chicago, pp. 53-73. Regional Plan Association, 1969 URBAN DESIGN MANHATTAN, A Studio Book, The Viking Press, New York. Rubin, A.I., and Cohen, A., 1974 OCCUPANT BEHAVIOR IN BUILDING FIRES, NBS Technical Note 818, U.S. Department of Commerce, National Bureau of Standards. Templer, J.A. 1992 THE STAIRCASE: STUDIES OF HAZARDS, FALLS, AND SAFER DESIGN, MIT Press, Cambridge, MA. Wood, P., 1972 THE BEHAVIOUR OF PEOPLE IN FIRES, Fire Research Note No. 953, Building Research Establishment, Fire Research Station, Borehamwood, Herts, England.

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