There are a lot of numbers, but the math doesn’t work.
The minimum width for an exit stairwell in a New York high-rise is 44 inches. That has been the width since the 1938 building code. That was the width of the stairwells in the World Trade Center (WTC), and that is the width required in the 2008 building code. And in between, there are a lot of other numbers.
The current New York City Building code has been in effect since 1968. When the WTC towers collapsed after the attacks on September 11, 2001, new scrutiny was focused on the standards, and the Buildings Department began an overhaul of the code.
In 2002, Congress asked the National Institute for Standards and Technology (NIST) to analyze the structural and building evacuation failures in the WTC collapse. The final NIST report, which cost over $30 million, was released in 2005 and included over 10,000 pages and 30 specific recommendations about how high-rise buildings might be stronger, safer, and easier to get out of. In turn, the Buildings Department, according to a 2005 press release, “requested NIST’s input and expertise in five specific areas: impact resistance, open web steel joists, progressive collapse, stair widths and fuel oil storage.”
Some of the WTC lessons are reflected in the new building codes for high-rises. These include requirements for impact-resistant stair and elevator enclosures and full sprinkler protection. However, the recommendation that stairwells be made wider to accommodate a full building evacuation was not included.
In a high-rise, as in most multi-story buildings, emergency evacuation means stairs. But for the evacuation to work, everyone in the building has to be able to get to the stairs and get down them before fire, smoke or structural collapse block their escape.
The number of exit, or egress, staircases required for a building is figured based on the number of occupants and the width of the stairs. Building codes include formulas to determine the appropriate number of stairways. However in most high-rises the number and width of the stairs is based on the assumption that they would only be needed for a partial evacuation – as if there were a fire that only affected a few floors.
During the September 11 evacuation, when the WTC was less than half full, 15,400 people escaped from the north and south WTC towers. That event demonstrated how the building code calculations translated into real-life – and the results were not good. People took twice as long as previously estimated to get down the stairs and NIST investigators concluded that if the towers had been fully occupied, up to 14,000 people would have died before they could escape.
John Labriola, a WTC survivor who used the stairs to escape from the 71st floor of the north tower, contributed his recollections of that day to the Smithsonian Museum’s 2002 exhibit, September 11: Bearing Witness to History. “We walked down two by two,” Labriola said in his statement. “Whenever necessary we would press ourselves into a single file line to let [injured] people get by… Around the 35th floor we started meeting a steady stream of firefighters walking up and had to press into single file again.”
Labriola also took photographs during the evacuation. One of the most famous, taken within the stairwell, shows civilians flattened against the wall as firefighters pass. NIST investigators cited Labriola’s photographs and testimony from him and other survivors in recommending that high-rise buildings use wider stairwells. The idea that incoming firefighters might have to share the stairs with evacuees had not been factored into evacuation scenarios, but a former WTC director told the 9/11 Commission in 2004 that the stairwells should have been wider for faster evacuation.
To Glenn Corbett, a fire sciences professor at Manhattan’s John Jay College of Criminal Justice and a consultant to the New York Department of Buildings, the message was clear. "Out of all the issues, one of the no-brainers was the issue of stairway width," said Corbett.
The NIST report concluded that building standards should reassess their calculations based on the WTC experience. “To achieve a significantly faster total evacuation at full capacity would have required increases in egress capacity (number and width of exits and stairways),” lead NIST investigator Shyam Sunder said in 2005.
Jake Pauls, an internationally recognized fire safety specialist from Silver Springs, Maryland, has also scrutinized the WTC and other high-rise evacuations and concluded that wider stairwells are needed. In a 2005 report, Pauls said that the 44-inch minimum width “was flawed, and known to be flawed a few decades ago.” Indeed, a report sponsored by NIST in 1995 found evidence that the assumptions about how long it takes people to get out of a skyscraper were wrong. That assessment was based on a different high-profile evacuation: the escape from the World Trade Center after it was bombed in 1993.
Based on multiple studies and the NIST evidence, Pauls proposed that the new requirements for exit stairs in high-rise buildings be changed to a minimum 56-inch width. His proposal was adopted by the National Fire Protection Administration and has been supported by building safety experts and firefighters’ groups as overdue. As Corbett explained, "56 inches gives you the ability for counterflow, the ability for people to pass. It's an obvious solution. Any four-year-old can figure that out."
The Buildings Department agreed – for a while. As late as May 2007, the proposed code revisions included wider stairwells, but the final version returned to the old, narrow 44-inch standard. What happened? This is where the numbers change from inches and people to square footage and cash.
The Building Owners and Managers Association (BOMA) and the Real Estate Board of New York lobbied the Building Commission task force to keep the old width rather than give up floor space for stairs. Patricia Lancaster, the city’s former Building Commissioner, explained the developers’ position in a Sept. 9, 2006 article in the New York Times: “If you increase a stairwell by one inch at the top of a 90-story building, you are giving up dozens and dozens of square feet of rentable space."
And that rentable space is worth a lot. A check of available offices in Wall Street high-rises shows luxury buildings renting at several hundred thousand dollars to as high as $1,080,000 per square foot per year. That may explain why an advocacy memo to BOMA members encourages them to keep “abreast of legislative and regulatory action at the state and local level to ensure that the NIST recommendations are not used as justification for introducing unnecessary new requirements in state and local building codes.”
The fight about square footage in stairwells in New York is just a skirmish in the national battle between the NFPA, which is made up largely of fire safety advocates, and a rival code-making body, the International Code Council (ICC), which is supported primarily by developers and real estate managers - including BOMA.
[TK: para about ICC and NFPA fight - New York City adopted ICC standards]
Members of BOMA and the Real Estate Board of New York served on city committees that approved the egress requirements for the new building code and, according to Corbett, who served as an advisor to the Buildings Department, “they blocked every attempt” to raise the minimum stair width. “BOMA and the Real Estate Board [of New York] resisted anything that’s going to impact their bottom line,” he said.
Rick Arbeb, the legislative director for New York City Councilman Erik Martin Dilan, who chairs the City Council’s Housing and Buildings Committee, agreed. “ There was an issue with the size of the stairs; basically if the stairs were wider, the rooms would be smaller.”
[TK: summary of change to require additional stairwell, including WTC history]
Frederic Schwarz, a Manhattan-based architect and who designs high-rises, said, "There's nothing preventing wider stairs and concrete stairs, except money." He was one of the leaders of the early efforts to rebuild the WTC site designs and is familiar with the challenges of balancing safety and revenue.
So the new building code going into effect on July 1 will ask only 44 inches for egress stairs. While developers can allocate more space if they want, Schwarz said he doesn’t even try to propose anything wider. "Forget it,” he said. “That's not even a conversation. You're fighting for every inch."
###
Sources named:
- Glenn Corbett: c: 201-993-2814; gcorbett1@ix.network.com
- Jake Pauls: w: 301-933-5275; bldguse@aol.com
- Frederic Schwarz: 212-741-3021; fschwartz@schwartzarch.com
- Rick Arbeb @ Councilman Dilan’s legislative office: 212-788-7284
Additional sources:
- Steve Scotford, Bluerock Real Estate, c:917-340-1187
- Councilman Erik Martin-Dilan’s district office: 718-642-8664
Documents cited:
- New York Times, “9/11 Has Spurred Only Modest Changes in New York City and National Building Codes,” by Sewell Chan, September 6, 2006
- “Minimum Stair Width for Evacuation, Overtaking Movement and Counterflow Technical Bases and Suggestions for the Past, Present and Future,” by Jake L. Pauls, John J. Fruin, and Jeffrey M. Zupan, June 2005
- 2008 New York City Building Codes, Chapter 10, “Means of Egress”
- Gotham Gazette, “Reconstructing New York’s Building Code Overhaul,” by Mark Berkey-Guard, May 14, 2007
- “Statement from John Labriola, World Trade Center, September 11, 2001,” by John Labriola, courtesy of the Smithsonian Museum of American History, September 2002
- Statement by NYC Building Commissioner Patricia J. Lancaster, regarding NIST’s Recommendations, June 23, 2005
- The Study of Occupant Behavior During the [1993] World Trade Center Evacuation, by Rita Fahey, September, 1995
- NIST NCSTAR 1: Federal Building and Fire Safety Investigation of the World Trade Center Disaster: Final Report of the National Construction Safety Team on the Collapses of the World Trade Center Tower, September, 2005
- NIST NCSTAR 1-7: Occupant Behavior, Egress, and Emergency Communication, September 2005
Web sites consulted:
- http://www.boma.org - Building Owners and Managers Association (Advocacy, Codes & Standards, and back issues of "Up to Code" magazine)
- http://www.bomany.org - Building Owners and Managers Association of New York
- http://www.nist.gov - National Institute of Standards and Technology
- http://www.nfpa.org - National Fire Protection Association
- http://americanhistory.si.edu/september11/collection - Smithsonian Museum of American History, September 11 special collection
- http://www.iccsafe.org - International Code Council
- http://www.nyc.gov/html/dob - New York City Department of Buildings
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment