Welcome to the Bird's Nest
(Photograph: AP/Wide World)
In August 2008, the Chinese are throwing a party and inviting the world, and they are determined that absolutely nothing will go wrong. This is a tall order for any country, but for one unused to such scrutiny and one that has to build or renovate 31 competing stadiums and gymnasiums and 43 training venues, that challenge becomes urgent.1 Now add to that challenge the threat of earthquakes.
NFPA Journal®, March/April 2008
By Lisa Nadile
In 1976, just 91 miles from Beijing, the world’s second most destructive earthquake on record, measuring 7.9 on the Richter Scale, hit Tangshan City.2 While China places the official death toll at 240,000, the U.S. Geological Survey reports that some estimates place the death toll closer to 655,000. More than 799,000 people were injured.
Workers relax atop the National Stadium, which is known as the "Bird's Nest" because of its distinctive shell of steel struts that appear to be interwoven. (Photograph: AP/Wide World)
A worker pauses in front of the Bird's Nest's unique open design, which was designed by Swiss architects Herzog & de Meuron. (Photograph: AP/Wide World)
The Beijing Fire Department runs a drill at the National Stadium. (Photograph: AP/Wide World)
When you consider that that earthquake occurred just 32 years ago, you can begin to understand why China would want to make safety—especially, but not only, earthquake safety—a top priority for the designers, engineers, and builders of the new Olympic facilities. From these buildings' very inception in 2003, the pressure was on the fire protection engineering division of Arup, Inc., which developed the fire protection design for the National Stadium and the National Aquatics Center, nicknamed the Bird’s Nest and the Water Cube, respectively.
There’s no "maybe" in "comply"
"In 2005, I was in Beijing when they had a 4 or 5 Richter [Scale] earthquake. We felt the building we were in moving up and down. This is when these two buildings [the Bird’s Nest and the Water Cube] were under construction," says Dr. Ming Chun Luo, technical director and team leader of Arup Fire in Hong Kong, who worked on both buildings in the early stages of their development.
The fact that Beijing is in an earthquake zone is just one of the reasons China stressed that life safety is the first priority for all Olympic venues, says Dr. Luo. Any company designing and building the fire protection for Olympic venues had to adhere to stringent requirements for withstanding seismic events.
"The requirements for seismic design in some respects help us in terms of fire," says Dr. Marianne Foley, senior associate for Arup Fire in Sydney, Australia, who helped create the Water Cube’s fire protection design. "The seismic design for the structure had to be so redundant to be able to take the loading that, in the event of fire separate from earthquake, we could afford to lose a lot of elements in the building to fire without any building collapse."
The over-designed fire protection that results from the seismic design is also true of the Bird’s Nest, which is divided into zones, each stabilized independently, says Luo.
Weaving the nest—prescriptive versus performance
The allegorical bird’s nest design won the hearts of the Chinese people who took part in the voting on several designs for the stadium. The stadium is elliptical in shape, and the Bird’s Nest’s open roof curves like a saddle. Designed to seat 80,000, the stadium in Olympic mode will have additional seating for 11,000.
According to Arup, its gross floor area is 309,000 square yards (258,000 square meters), the total site area is about 244,000 square yards (204,000 square meters), the height is 227 feet (69 meters) above the field, and the structure is composed of 43,056 square yards (36,000 square meters) of unwrapped steel.
Designed by Swiss architects Herzog de Meuron and working with the China Architectural Design and Research Group, which oversaw local construction, the stadium consists of a bowl with seven tiers, around which the nest-like façade of steel segments was connected. Some of these segments are also concourses people will use to gain access to the tiers and to ascend into the stadium.
The design looks as though it breaks quite a few rules—and it does. The design does not comply with the Chinese prescriptive-based National Code.
"China doesn’t have performance-based design, but they acknowledged early on that the Olympic venues were so special that a prescriptive code would not be adequate...for them. They agreed to a performance-based approach, so rather than changing their standards or using another country’s standards, they went straight to performance-based design," says Dr. Foley. "Where we didn’t comply with code, we had to prove, using fire protection engineering, that the design was safe."
"China has a commonly used, high-rise building code and a low-rise or normal building code called the China National Code. They do have a sports facility regulation, but that was issued before these two buildings were designed," says Dr. Luo.
Informally, Arup referred to United Kingdom standards, specifically the Guide to Safety at Sports Grounds, nicknamed the "green guide," and to NFPA standards that apply to stadiums and to fire protection for all-steel structures.
For example, Chinese regulations require that certain building columns and beams be able to resist fire exposure for a number of hours, but because the stadium is a very large space with a very high ceiling, "we didn’t need to have that in some areas," he says.
"We do refer to NFPA regulations at the same time we do the performance-based design to justify which areas need the fire protection," says Dr. Luo.
Flying outside the comfort zone
To make performance-based design in these venues a reality, Arup Fire began a global design and review process that extended from Beijing and Shanghai to Sydney to Manchester, England.
At each stage of this design process, even during the initial competitive design bidding phase, Arup was required to report to the Chinese authorities and to a peer-review panel to ensure that its work met its fire protection goals.
"We always have a forward and backward [discussion] with the architects and our colleagues internally. So after we finished all this design, the process of negotiating with the Chinese authorities started," says Dr. Luo.
This was a complex process that required Arup to detail its work completely.
"We had a complicated analysis that we needed to report to the Chinese authority, so we organized an expert panel," he says. "We presented the design and the solutions to the expert panel, which would then hold a Q&A. After the Q &A session, the panel would agree with some of our answers and not with others, and for those we went back to analyzing again. Then we would again present the results [of that latest analysis] to the committee, so there was a kind of a back and forth.
"For the stadium, we had two or three times back and forth, and for the Water Cube we had a couple of meetings, as well," he says.
One area in which Arup had to rely on performance- based design was evacuation.
"Egress is always the major issue for the firesafety design. In China, the sports facility regulation has the whole stadium divided into zones. Each zone must have its own egress route and must also make sure the evacuation time is limited to the regulation 4 or 5 minutes," said Dr Luo.
A venue the size of the Bird’s Nest would need a large number of exits, so Arup used British standards as a guide.
"After the 1985 [Bradford City football stadium] fire in the U.K., there was some extensive research. They found they have an 8-minute rule: if people are in an evacuation situation, they become unstable after 8 minutes, and people won’t get out of the area," he says.
"We used this estimate and worked out what was the smallest number of exits required and what [the stadium staff would need to do] to make sure the evacuation process would be smooth," Dr. Luo says. The same analysis was completed for the Water Cube.
Fighting fire in the Bird’s Nest
The size and design of the stadium meant that Arup also had to rethink the usual practices of sprinklering the venue. Originally, the stadium was to have a retractable roof, but that feature was dropped to reduce the cost of the project. When the design included the roof, however, Arup introduced additional fire suppression.
"The height meant the normal sprinkler would generally not work in this area, so sprinklers were not provided, and in China, they have a special fire suppression system called a water cannon. The [stadium had] a detection system that can scan the whole area and if it detects any fire, then that system would have automatically shot water to the fire," says Dr. Luo.
The water cannon can flow water 98 feet (30 meters) to 197 feet (60 meters) from the water source. It is an automated system that can also be operated manually. There would have been quite a large number of these cannons if the stadium had been built with the retractable roof, he says.
"The maximum coverage of the water cannon is 250 feet (75 meters), but that requires too high a water pressure, so normally the water cannons are used at a power for a 98- or 131-foot (30- or 40-meter) radius. You need a lot of this equipment for the whole stadium," says Dr. Luo.
The cannon are manufactured by a Chinese manufacturer and are also used in Germany and Japan, he says.
The areas of the facility other than those designated for the public, such as offices and training areas, are all built to code as normally required. They include firewalls, sprinklers, and other typical fire protection solutions.
"Behind the seating area is a two- or three-level concourse. That area has a shopping area. We recommended a special fire separation in these areas, and we have normal sprinkler systems and normal smoke control systems to make sure that if anything happen in that area, the fire will be controlled locally," says Dr. Luo.
The open design of the stadium gives spectators a clear view of exit routes, which are the same routes people will use to enter the facility.
"The concourse is also a means of escape from which the people can evacuate the area rapidly. [Spectators leaving the seating area] pass through the door into the concourse, through the concourse, and then use stairs to go to the ground floor. Only one level is below ground, but even below ground, one side of the stadium is entirely open to the air so that people can evacuate from the concourse easily," he says.
The underground level consists of storage, training, office areas, and a car park. During the Olympic games, the underground level will not be open to the public.
Much thought has been given to making the Olympic venues safe for people with physical disabilities, as the Bird’s Nest will also host the 2008 Paralympic Games in September. The concourses are handicapped-accessible, and there is a special elevator for people to reach upper-level areas. The stadium also has special zones for spectators who are disabled.
Beijing Fire Department — the sentinels
One important member of the expert panel review committee was the Beijing Fire Department. But it did more than just sit in on these meetings; it was a key player.
"We talked with the Beijing Fire Department a lot because they were part of the approval process. They were the main approval body, and we needed to convince them that our design was okay. So we talked with them quite a bit about how they would fight fires, what they would do, how they would want to get to the building, and where they would get their information," says Dr. Foley.
For example, Australian firefighters like to take control of smoke control systems, so they like to have a panel that gives them manual control for such tasks as turning on fans and opening doors. The Beijing Fire Department prefers these functions be automatic.
"We tailored the design to meet their operations," she says.
This meant rethinking basic concepts such as how firefighters would enter the stadium, says Dr. Luo.
"For the stadium, they actually have an emergency access road underground by the stadium seating tiers that allows them to run vehicles into the stadium to the sports ground if needed," he says.
Rethinking the protection of hundreds of thousands of people in town for the Olympics also meant the Beijing Fire Service had to develop a definitive emergency plan. Those operations combine computer-based predictive modeling tools and old-fashioned firefighting know-how.
Known as the Digital Fire Emergency Response Plan, or DFERP, the plan "consists of basic information, prediction and simulation and [risk] analysis, emergency response decision, and action," says Staff Officer Chen Bin, secretariat of the general office of the Beijing Fire Bureau. DFERP gathers data from many emergency systems, such as computer-based fluid dynamics fire and smoke analysis, 3D crowd evacuation simulation, basic geographic information, structural information, firefighting staff information, and emergency command response plans, to develop a digital fire plan and real-world training system.
DFERP is useful in two modes.
"The system can be used as the browsing, inquiring, demonstrating, and execution tools for the [staff executing the] fire emergency response plan of the Olympic sites, as well as advanced measures for the training in firefighting tactics, technique, and psychology," says Officer Chen.
The use of DFERP has allowed Beijing to organize its fire- and life-safety resources, Chen says.
The Beijing Fire Bureau has four divisions: Headquarters of the Staff, the Political Division, the Logistics Division, and the Fire Prevention and Supervision Division. The Bureau has more than 6,000 professional firefighters, and the city has been able to organize additional resources, drawing an additional 3,300 firefighters from 118 government fire services and 109 corporate fire services.
The Beijing Fire-Protection Direction Association helps advocate fire- and life-safety issues and organize citizen fire prevention and fire watch groups.
"Management measures will be introduced to strengthen the fire brigades and intensify the efforts to guide [communities] to offer specialized fire cover for the Olympic Games [by setting] voluntary fire brigades according to their needs and forming a self-rescue team with tactical ability," Chen says.
With the Olympics and its international constituency come basic language barriers that can render ineffective even the most carefully developed fire protection plan. So Beijing is training point staff and firefighters foreign language skills, as well.
"Through going abroad for advanced studies, training, distance learning, studying independently, and so on, we strive to train advanced firefighters, and then have them undertake [specific] tasks, such as venue-operation management, on-the-spot fire duty, emergency rescue direction, etc.," he says.
The fire response plan ensures that firefighters will be on the scene of any fire in five minutes. To make this possible, the city is building 26 temporary fire stations next to the Olympic stadiums and gymnasiums, according to the China Daily newspaper.3
Last summer, Beijing emergency response teams, including firefighters and fire brigades, trained in disaster drills, simulating responses to fires, earthquakes, and even a nuclear attack, reports the official Beijing 2008 website.4
The website also describes the firefighting communications network, which integrates the communications network of the 119 fire alarm platform (the Chinese version of 911) with that used by the new firefighting stations, firefighters based at the Olympic venues, and those in other temporary positions.5
The key to the Beijing Fire Department’s strategy is to stand close by, guarding buildings it is extremely familiar with and helped shepherd from concept through construction. While the stadium and the Water Cube are cutting-edge designs, not one element of their fire protection engineering is unfamiliar, thanks to the diligence of Arup and the close attention of the fire service.
source: Beijing Fire Bureau.
http://earthquake.usgs.gov/regional/world/most_destructive.php. See also “Table 1.1.17 World’s Deadliest Earthquakes on Record,” Fire Protection Handbook, 20th edition, NFPA (Quincy, Massachusetts), 2008.
Lisa Nadile is associate editor of NFPA Journal. Her email is firstname.lastname@example.org. The author would like to thank the Beijing Fire Department for its assistance.