Perl's Architecture Weblog 2008 Fall

Perl's Architecture Weblog
2008 Fall Semester
Associate Professor Robert D. Perl, AIA
Freshest postings at top. Go to the bottom of the page for links to 1000+ earlier Weblog entries.

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Texas Tech University College of Architecture Robert D. Perl

updated 12/19/2008

September 11 Special Edition
A Note from the Editor: Just a few days after September 11th 2001, I began to collect links to webpages about the World Trade Center and the Pentagon that I believed were relevant to architecture and architectural education. I updated the page as I saw important articles, and maintained it as a separate page for some time. For the last few years, I have included heavy coverage of the WTC in this weblog. The re-re-redesigns and construction delays continue, however the 2008 International Code Council Annual Conference, Business Meeting & Final Action Hearings, September 14–23 may have the most significant long-term effect on architecture. -RDP

Perl's September 11 Page from Fall Semester 2001.

There Should Be No More Excuses At Ground Zero
Wall Street Journal September 10
By MICHAEL R. BLOOMBERG
"Progress on the redevelopment of the World Trade Center has been frustratingly slow, owing in large part to a multilayered governance structure that has undermined accountability from the get-go. The city does not own or control the site, but we do control the streets around it. For those who widen their gaze, the rebirth of Lower Manhattan is impossible to miss.
We will now push the Port Authority to make two concrete commitments. Most important, the memorial must be completed by the 10th anniversary. No more excuses, no more delays. New York Gov. David Paterson and I are in complete agreement on this subject, and it's time for the PA to formally commit to the same goal.
In addition, the PATH station's design, including the underground hall, is too complicated to build and threatens to delay the memorial and the entire project. It must be scaled back."

Bloomberg Shakes Up Trade Center Planning
New York Times blog September 10
"Because the transportation hub mezzanine lies directly under a part of the memorial plaza, its framework must be completed nearly to street level by July 2010 to guarantee that the memorial opens on Sept. 11, 2011, said Joseph C. Daniels, the president of the memorial and museum."

"Mayor Michael R. Bloomberg all but declared the death on Tuesday of a four-year-old plan to build an underground transportation center and PATH terminal at the World Trade Center site, designed by the Spanish architect Santiago Calatrava, which was meant to rival Grand Central Terminal.
It has grown clear in recent weeks that Mr. Calatrava’s plan to construct a virtually column-free underground mezzanine — one of the most arresting facets of his design for the transportation center — was in serious jeopardy. Even Mr. Calatrava’s client, the Port Authority of New York and New Jersey, had commissioned the study of an alternative approach using traditional column-and-beam construction. The changes to the mezzanine would not necessarily affect the distinctive birdlike roof Mr. Calatrava has designed for the entrance hall."

New York's 9/11 Site Needed Not a Moses but a Logue
Wall Street Journal August 27
By ADA LOUISE HUXTABLE
"As we approach the seventh anniversary of 9/11, it is clear that the rebuilding of Ground Zero has failed. A recent editorial column in this newspaper by Daniel Henninger made the sad and insightful observation that even the coming together inspired by that awful event came apart as the process itself unraveled. He called the rebuilding arguably the greatest political and bureaucratic fiasco in the history of the world.
I would carry that indictment further. I would say that this has probably been the greatest planning fiasco in the history of the world. Daniel Libeskind's prize-winning design, a flexible, schematic concept that established a framework of achievable, creative possibilities, has been progressively purged by political pandering and economic pragmatism. The Port Authority's own brutally detailed report earlier this year gave some cogent reasons why a strong, unified vision of civic and urban renewal on a plane worthy of a great city could not survive. These ranged from jurisdictional conflicts of the multiple agencies involved to the project's sheer logistical complexity.
The only reference to the idea of planning was made by occasionally invoking the name of Robert Moses as the man who "got things done." Although it is impossible to overstate the complexity of the problems involved at Ground Zero, what was needed there was not a Robert Moses breaking heads and eggs, but someone more in the mold of Edward J. Logue, the planner who successfully rebuilt New Haven and Boston in the downbeat decades of the 1950s and 60s, and brought Roosevelt Island through conception to completion in New York in the 1970s. After presidents and public officials had walked the smoking ruins of the South Bronx, it was Logue who brought hope and an ultimately successful housing model to the ashes of the infamous Charlotte Street. Logue was the kind of smart, tough, dedicated professional who would have provided the leadership that Ground Zero needed desperately and never had. Unlike the autocratic Moses, he was a remarkable human being who cared about people as much as he revered the quality of the environment. A practical visionary, he knew how to implement a plan without rolling over to every political constituency and special interest. And he got things done. After decades of turning dreams into reality, he knew a lot about what made cities good places to live and work. He operated under rules we might not sanction now, using the draconian slum clearance of the 1960s as a tool to revitalize dying cities, but he did it with style and sensitivity. His belief in the future and his willingness to gamble on it was ultimately undone by New York state's "full faith and credit" bonds -- with their risky guarantees backed by the state's word rather than its money; his affordable housing programs, which he believed in and actually built, were the victim of the 1970s recession when he stretched his credit too far. Logue died in 2000 at the age of 78, and I don't know if we even have his counterpart today. Mention his name to most people and you draw a blank, that is how completely he has been forgotten. It is unlikely that anyone in the city's power structure would recognize his capabilities if they were to meet him now. They wouldn't care; it's not their game.
It was never inevitable that the greatest opportunity growing out of the greatest disaster in the city's history should be so badly squandered. The critical factor that did Ground Zero in was the denial of the professional planning role essential to coordinate and execute an effort of this magnitude, while keeping its priorities and promises alive. Its greatest failure may be the fact that no one appeared to be aware that such a role, person, or process, ever existed. We know all about deals, and that is what we got in the end."

The Towers of Memory, Before and After
New York Times September 10

"In the contemporary view, the Woolworth Building still dominates the southern end of City Hall Park. The glass tower to the right of Woolworth is 7 World Trade Center, the first new tower built near ground zero. On the other side of Woolworth is Barclay Tower, one of a growing number of residential projects that attest to Lower Manhattan’s changing character. Dwarfed among these giants is the little steeple of the 18th-century St. Paul’s Chapel, whose survival on 9/11 seemed nearly miraculous."
"In its current state, the Brooklyn Bridge has an American flag and a dividing line to separate pedestrians and bicyclists on what remains one of the most popular and crowded promenades in the city. The silhouette of the financial district is almost the same with a few prominent exceptions, underscoring downtown’s perpetual runner-up role to mid-Manhattan."

Latest Design Is Unveiled for 9/11 Museum
New York Times blog September 9
"A design shows the World Trade Center memorial museum pavilion, upper left corner, at night, with two trident columns from the original twin towers housed in its corner atrium. In the foreground and center background are the waterfalls and pools marking the towers’ location."

"The architect Craig Dykers has been working since 2004 on the design of a museum building for the World Trade Center site. In the end, he realized there could be no more powerful a centerpiece than something Minoru Yamasaki designed 45 years ago. To an otherwise Spartan design for the twin towers, Mr. Yamasaki, the original architect, added one instantly recognizable flourish: trident shaped columns at the base of the buildings, which created an arcade of almost Gothic proportion. Enough of these enormous steel tridents survived the terrorist attack of Sept. 11, 2001, that their familiar silhouettes came to symbolize endurance in the face of catastrophe.
Two surviving tridents from the north face of the north tower, each almost 90 feet tall, will return to ground zero to be incorporated in the atrium of the museum pavilion designed by Mr. Dykers and his colleagues in the firm Snohetta, which is based in Oslo and New York.
“The two tridents placed side by side will create an immediate visual reference to the distinctive ‘Gothic arch’ motif of the twin towers,” Snohetta said in a statement of its architectural intentions, “and, in their re-erection at the site, will convey strength, fortitude, resilience, survival and hope.”
Though the broad outlines of the design have been known for some time, the unveiling on Tuesday provided and confirmed some key details about the $80 million pavilion, which is being financed by New York State. The polygonal pavilion will range in height from 57 to 72 feet (roughly equal to a six-story office building). It will contain 47,499 square feet of floor area; 34,834 square feet devoted to public programs and museum functions...
The current plans call for the pavilion to be clad largely in metal panels — stainless steel, if the budget permits; aluminum if not. The panels will be angled and striated, with alternating bands of polished and matte finish. The design is intended, in part, to add visual interest, especially to the south facade of the building, which would otherwise be a blank wall punctuated by ventilating louvers, since so much mechanical equipment is on that side.

In the northwest corner will be an atrium, running the height of the building and enclosed in an angular framework of glass and steel. This will house the tridents, which are currently stored in a hangar at Kennedy International Airport, and allow them to be seen from within the museum and from around the plaza — especially after dark, when they will be illuminated. “When they’re lit at night, they will guard the site,” Ms. Greenwald said. “They’re like sentries.”
The large glass enclosure had to be robust enough structurally to withstand the effects of a blast. The framework had to be supported on irregularly spaced columns below ground. And Mr. Dykers said he did not want the window wall to have purely vertical elements, which would come into conflict visually with the upright tridents. A computer was harnessed to plot the most efficient locations for the structural members of the framework. The result, designed by Snohetta and the engineers of Buro Happold, is a pattern that looks organic and weblike, reminiscent of some of the earliest designs for the trade center site by Daniel Liebeskind. From certain perspectives, it might also suggest an explosion, with random, irregular shapes that could be seen as flying shards. No such imagery was consciously intended by the architects, Mr. Dykers said, though he added that the design is not meant to shy away from the “dualities” inherent in the new trade center, which will be a place both of mourning and of hope."

Fire, Not Explosives, Felled 3rd Tower on 9/11, Report Says
New York Times August 21
"Fires in the 47-story office tower at the edge of the World Trade Center site undermined floor beams and a critical structural column, federal investigators concluded on Thursday, as they attempted to curb still-rampant speculation that explosives caused the building’s collapse on Sept. 11, 2001."

"No one died when the tower, 7 World Trade Center, tumbled, as the estimated 4,000 office workers there at the time had evacuated before it gave way, nearly seven hours after the second of the twin towers came down. But the collapse of 7 World Trade Center — home at the time to branch offices of the Central Intelligence Agency, the Secret Service and the Giuliani administration’s emergency operations center — is cited in hundreds of Web sites and books as perhaps the most compelling evidence that an insider secretly planted explosives, intentionally destroying the tower."

"A separate, preliminary report issued in 2002 by the Federal Emergency Management Agency questioned whether diesel fuel tanks installed in the tower to supply backup generators — including one that powered the Giuliani administration’s emergency “bunker” — might have been to blame. But S. Shyam Sunder, the lead investigator from the National Institute of Standards and Technology, based here in the suburbs of Washington, also rejected that theory on Thursday, even as he acknowledged that the collapse had been something of a puzzle. “Our take-home message today is the reason for the collapse of World Trade Center 7 is no longer a mystery,” Dr. Sunder said at a news conference at the institute’s headquarters. “It did not collapse from explosives or fuel oil fires.” The institute’s findings were released on Thursday as part of a 915-page report resulting from the work of more than 50 federal investigators and a dozen contractors over three years.
During the last four decades, other towers in New York, Philadelphia and Los Angeles have remained standing through catastrophic blazes that burned out of control for hours because of malfunctioning or nonexistent sprinkler systems. But 7 World Trade Center, which was not struck by a plane, is the first skyscraper in modern times to collapse primarily as a result of a fire. Adding to the suspicion is the fact that in the rush to clean up the site, almost all of the steel remains of the tower were disposed of, leaving investigators in later years with little forensic evidence. Using videos, photographs and building design documents, the investigators at the National Institute spent the last three years building an elaborate computer model of 7 World Trade Center that they used to test various chains of events to figure out what caused the collapse, Dr. Sunder said. The investigators determined that debris from the falling twin towers damaged structural columns and ignited fires on at least 10 floors at 7 World Trade Center, which stood about 400 feet north of the twin towers. But the structural damage from the falling debris was not significant enough to threaten the tower’s stability, Dr. Sunder said. The fires on six of the lower floors burned with particular intensity because the water supply for the sprinkler system had been cut off — the upper floors had a backup water supply — and the Fire Department, devastated by the collapse of the twin towers, stopped trying to fight the blaze.

Normally, fireproofing on a skyscraper should have been sufficient to allow such a blaze to burn itself out and leave the building damaged but still standing. But investigators determined that the heat from the fire caused girders in the steel floor of 7 World Trade Center to expand. As a result, steel beams underneath the floors that provided lateral support for the tower’s structural columns began to buckle or put pressure against the vertical structural columns. These fires might have been fed partly by the diesel from tanks and a pressurized fuel line, which were on the fifth to the ninth floors, Dr. Sunder said. But the analysis showed that even in the worst case, the diesel fuel-fed fire would not have burned hot enough or long enough to have played a major role in weakening the structure. The investigators determined that the fire that day was fed mainly by office paper and furnishings. The collapse started when a girder on the 13th floor disconnected from a critical column — listed as Column 79 — that supported a long open floor span, the report said. Once that floor gave way, the floors below it down to the fifth floor also collapsed, although this was not visible from the building’s exterior. Without lateral support for nine stories, Column 79 buckled, and the floors above gave way all the way up to the roof. Only then did the collapse become visible from the exterior with a penthouse area on the roof first falling in, followed by what looked like the sudden implosion of the tower, Dr. Sunder said. “The physics is consistent, it is sound, it has been analyzed,” he said.
Dr. Sunder said there were no apparent flaws in 7 World Trade Center’s design that contributed to its collapse and that it met New York City codes. But there are some important lessons for other skyscrapers, he said, as engineers and architects should consider how the heat from fires can weaken structural elements, potentially causing a so-called progressive collapse.
A new, substantially different 7 World Trade Center — now 52 stories — reopened at roughly the same site in 2006. The new building has extra safety features, including wider emergency stairwells and a fire-resistant refuge area on each floor.
Within moments after the news conference ended, leaders of a group called Architects and Engineers for 9/11 Truth held their own telephone conference briefing, dismissing the investigation as flawed."

Architects, Engineers, and Scientists Analyze Failings of NIST's WTC 7 Final Report
Architects & Engineers for 9/11 Truth August 29
"For the first time in history, normal office fires have created a total progressive collapse if the report from the National Institute of Standards and Technology (NIST) can be believed, said Richard Gage, AIA. Office fires can not melt steel, Gage claims, and NIST has neither explained the mystery of molten iron at the World Trade Center site nor considered other evidence that also suggests the use of thermate incendiary charges to cut the steel framework of 47-story Building 7. NIST's vaguely worded presentation was "absurd on its face," contended Kevin Ryan, and differed completely from the story they had previously told Popular Mechanics. Though NIST claimed to hold scientific attitudes about alternative theories, they never responded to multiple invitations to discuss them, Ryan complained."
Table of 216 high resolution World Trade Center Drawings

Agency Fights Building Code Born of 9/11
New York Times September 7
"A federal agency has joined some of the nation’s biggest landlords in trying to repeal stronger safety requirements for new skyscrapers that were added to the country’s most widely used building code last year, arguing that they would be too expensive to meet.
The new provisions, which include requiring tall office buildings to have more robust fireproofing and an extra emergency stairwell, were enacted as a result of an exhaustive federal study into the collapse of the twin towers at the World Trade Center seven years ago this week. The General Services Administration, which serves as the federal government’s property manager, is now opposing the tougher standards, even though they were based on a report by the National Institute of Standards and Technology, which issues recommendations for safety standards after investigating fires and other building catastrophes. “It does not take a NIST report or a rocket scientist to figure out that requiring additional exit stairs will improve overall occupant evacuation times,” David Frable, a General Services Administration fire safety engineer, wrote in a petition asking the International Code Council to rescind the changes, which go to a vote next week. “The bigger question that needs to be answered is at what economic cost to society?” The dispute reflects a debate among safety officials and real estate executives nationwide as to how to respond adequately to the 2001 attacks. The fireproofing and stairwell requirements alone could cost real estate developers $13 million for a 42-story office building, as well as perhaps $600,000 a year in lost rent because of decreased floor space, real estate industry officials estimated.
The challenges raised by Mr. Frable and building owners and architects focus on three safety standards drawn up by a code council committee that were based on recommendations in the final NIST report from 2005. Under the new rules, any nonresidential skyscraper over 420 feet tall, or about 40 stories, must have a third stairwell and fireproofing capable of staying in place even if hit with 1,000 pounds per square foot of force, provisions that Mr. Frable and a real estate industry group, the Building Owners and Managers Association, want repealed. As an alternative, Mr. Frable is urging that skyscrapers include specially designed elevators that can reliably operate even during a fire. Separately, the building owners’ group has asked the organization to repeal a requirement that buildings taller than 75 feet apply glow-in-the-dark markings on stairwells as a backup if the lights go out. Such markings are credited with saving many lives on Sept. 11; they had been installed at the twin towers after the first terror attack there in 1993, even though the enhancement was not yet required by city code. Only a small number of new towers would be subject to all three of the contested changes. Since 2000, about 10 nonresidential towers taller than 420 feet have been completed each year in the United States, according to Emporis, a German-based database of tall buildings, compared with about 750 such buildings currently standing nationwide.
Historically, tall buildings have not been designed to anticipate a complete evacuation, because even during an office fire generally only the several floors immediately near it are cleared. Fireproofing was also not traditionally designed with enough adhesive strength to ensure that it would stick to steel in the event of an explosion or another unexpected stress. But dislodged fireproofing was blamed in part by federal investigators for the collapse of the twin towers. And the flow of firefighters climbing the stairs as office workers were leaving created traffic jams, the investigators found.
... statistics from the National Fire Protection Association that show an average of one civilian a year died in office building fires nationwide from 2000 to 2004, excluding the Sept. 11 attacks.
S. Shyam Sunder, who led the $16 million investigation into the World Trade Center collapse for the standards institute, said he would be in Minneapolis urging the council to honor the recommendations in his report. “Everything is more complicated when an emergency happens in a skyscraper,” he said. “So you want to have more safeguards in taller buildings.”
The federal government itself is technically exempt from local building codes. But the General Services Administration, which has 352 million rentable square feet in 8,600 properties nationwide, generally requires that buildings it rents or buys honor building codes.
New York has demonstrated mixed emotions over tougher building standards. After the Sept. 11 attacks, city officials declined to require wider stairwells in skyscrapers, as some safety advocates had urged. But at several of the towers built since 2001, including the Bank of America building near Times Square and 7 World Trade Center near where the twin towers stood, the developers have decided on their own to include either additional stairwells or wider ones."

NIST and the World Trade Center
"The collapse of New York City’s World Trade Center structures following the terrorist attacks of Sept. 11, 2001, was the worst building disaster in recorded history, killing some 2,800 people. More than 350 fire and emergency responders were among those killed, the largest loss of life for this group in a single incident.
In response to the WTC tragedy, the National Institute of Standards and Technology conducted a 3-year building and fire safety investigation to study the factors contributing to the probable cause (or causes) of post-impact collapse of the WTC Towers (WTC 1 and 2) and WTC 7; expanded its research in areas of high-priority need such as prevention of progressive collapse, fire resistance design and retrofit of structures, and fire resistive coatings for structural steel; and is reaching out to the building and fire safety communities to pave the way for timely, expedited considerations of recommendations stemming from the investigation."

NIST Video: The Collapse of World Trade Center 7:
Why the Building Fell

Questions and Answers about the NIST WTC 7 Investigation
NIST August 21
"When did WTC 7 collapse? On Sept. 11, 2001, WTC 7 endured fires for almost seven hours, from the time of the collapse of the north WTC tower (WTC 1) at 10:28:22 a.m. until 5:20:52 p.m., when WTC 7 collapsed.
What caused the fires in WTC 7? Debris from the collapse of WTC 1, which was 370 feet to the south, ignited fires on at least 10 floors in the building at its south and west faces. However, only the fires on some of the lower floors—7 through 9 and 11 through 13—burned out of control. These lower-floor fires—which spread and grew because the water supply to the automatic sprinkler system for these floors had failed—were similar to building fires experienced in other tall buildings.
How did the fires cause WTC 7 to collapse? The heat from the uncontrolled fires caused steel floor beams and girders to thermally expand, leading to a chain of events that caused a key structural column to fail. The failure of this structural column then initiated a fire-induced progressive collapse of the entire building. According to the report’s probable collapse sequence, heat from the uncontrolled fires caused thermal expansion of the steel beams on the lower floors of the east side of WTC 7, damaging the floor framing on multiple floors. Eventually, a girder on Floor 13 lost its connection to a critical column, Column 79, that provided support for the long floor spans on the east side of the building. The displaced girder and other local fire-induced damage caused Floor 13 to collapse, beginning a cascade of floor failures down to the 5th floor.
How did the collapse of WTC 7 differ from the collapses of WTC 1 and WTC 2? WTC 7 was unlike the WTC towers in many respects. WTC 7 was a more typical tall building in the design of its structural system. It was not struck by an aircraft. The collapse of WTC 7 was caused by a single initiating event—the failure of a northeast building column brought on by fire-induced damage to the adjacent flooring system and connections—which stands in contrast to the WTC 1 and WTC 2 failures, which were brought on by multiple factors, including structural damage caused by the aircraft impact, extensive dislodgement of the sprayed fire-resistive materials or fireproofing in the impacted region, and a weakening of the steel structures created by the fires. The fires in WTC 7 were quite different from the fires in the WTC towers. Since WTC 7 was not doused with thousands of gallons of jet fuel, large areas of any floor were not ignited simultaneously as they were in the WTC towers. Instead, separate fires in WTC 7 broke out on different floors, most notably on Floors 7 to 9 and 11 to 13. The WTC 7 fires were similar to building contents fires that have occurred in several tall buildings where the automatic sprinklers did not function or were not present.
Why did WTC 7 collapse, while no other known building in history has collapsed due to fires alone? The collapse of WTC 7 is the first known instance of a tall building brought down primarily by uncontrolled fires. The fires in WTC 7 were similar to those that have occurred in several tall buildings where the automatic sprinklers did not function or were not present. Factors contributing to WTC 7’s collapse included: the thermal expansion of building elements such as floor beams and girders, which occurred at temperatures hundreds of degrees below those typically considered in current practice for fire-resistance ratings; significant magnification of thermal expansion effects due to the long-span floors in the building; connections between structural elements that were designed to resist the vertical forces of gravity, not the thermally induced horizontal or lateral loads; and an overall structural system not designed to prevent fire-induced progressive collapse.
Why were there no fatalities from the collapse of WTC 7? Several factors contributed to the outcome of no loss of life—or serious injuries—in WTC 7. The building had only half the number of occupants on a typical day—with approximately 4,000 occupants—at the times the airplanes struck the towers. Occupants had recently participated in fire drills. The occupants, alerted by the attacks on WTC 1, WTC 2, and the Pentagon, began evacuating promptly. Evacuation of the building took just over an hour, and the process was complete before the collapse of the first WTC tower (WTC 2). Emergency responders provided evacuation assistance to occupants. No emergency responders were harmed in the collapse of WTC 7 because the decision to abandon all efforts to save WTC 7 was made nearly three hours before the building fell.

The following images are from the 115 page Final Report on the Collapse of the World Trade Center Building 7
(pdf) 7.7MB

What specific code changes based on recommendations from NIST’s investigation of the WTC towers have been approved for inclusion in the International Building Code? The eight specific code changes adopted in the International Building Code based on recommendations from NIST’s investigation of the WTC towers include:
1. An additional exit stairway for buildings more than 420 feet in height.
2. A minimum of one fire service access elevator for buildings more than 120 feet in height.
3. Increased bond strength for fireproofing (nearly three times greater than currently required for buildings 75-420 feet in height and seven times greater for buildings more than 420 feet in height).
4. Field installation requirements for fireproofing to ensure that: installation complies with the manufacturer’s instructions; the substrates (surfaces being fireproofed) are clean and free of any condition that prevents adhesion; testing is conducted to demonstrate that required adhesion is maintained for primed, painted or encapsulated steel surfaces; and the finished condition of the installed fireproofing, upon complete drying or curing, does not exhibit cracks, voids, spalls, delamination or any exposure of the substrate.
5. Special field inspections of fireproofing to ensure that its as-installed thickness, density and bond strength meet specified requirements, and that a bonding agent is applied when the bond strength is less than required due to the effect of a primed, painted or encapsulated steel surface. The inspections are to be performed after the rough installation of mechanical, electrical, plumbing, sprinkler and ceiling systems.
6. Increasing by one hour the fire-resistance rating of structural components and assemblies in buildings 420 feet and higher. (This change was approved in a prior edition of the code.)
7. Explicit adoption of the “structural frame” approach to fire resistance ratings that requires all members of the primary structural frame to have the higher fire resistance rating commonly required for columns. The primary structural frame includes the columns, other structural members including the girders, beams, trusses, and spandrels having direct connections to the columns, and bracing members designed to carry gravity loads.
8. Luminous markings delineating the exit path (including vertical exit enclosures and passageways) in buildings more than 75 feet in height to facilitate rapid egress and full building evacuation."

Texas Tech University College of Architecture Robert D. Perl

Associate Professor Robert D. Perl, AIA
AH 1002D Office Hours: TTh 1:30-3:00 pm or by appointment
(806) 742-3169 x248 robert.perl@ttu.edu