Glass Curtain Walls From China - Limited life

Window washers on the 60-story, glass-walled JW Marriott Hotel Shanghai.

Glass-covered towers nearing critical age: China's first buildings to feature glass curtain walls will reach the end of their design life in the next few years, prompting experts to call for better maintenance of the structures to prevent accidents. Glass curtain walls, in which a building's facade is made of sheet glass held in place by framework, began to appear in Chinese blueprints in 1984, and have an average design life of 25 years.

The durability of supporting parts, such as bolts and sealant, is generally 10 to 15 years. In Shanghai, about 900 of at least 4,000 such buildings are more than 15 years old. "But that doesn't mean they should be replaced by new ones or demolished immediately," said Lu Jinlong, deputy director of the Shanghai Research Institute of Building Science. "They can be used for some time if regular maintenance is done well."

China builds 70 million square meters of glass curtain walls each year, according to the China Architectural and Industrial Glass Association. The cost of replacing these could be enormous. "Who should be responsible for the large sum? The developers or the maintenance companies?" said Li Dexiang, a professor at Tsinghua University's School of Architecture. "The problem is there, but there's no efficient solution yet."

Some buildings with glass facades overseas are still in good condition after 50 or 60 years, thanks to timely maintenance. But there have been many cases in China of glass curtain walls in high-rises bursting without warning. In Hangzhou, Zhejiang province, a 20-year-old woman was hit by shards of glass from a window that burst in a glass facade as she walked down the street on July 8. Part of her left leg had to be amputated.

A month later in Yiwu, Zhejiang province, a 20-meter-high glass ceiling in a garment market came crashing down, injuring several children, one seriously. Shanghai enacted a management regulation for glass curtain wall construction on Feb 1, establishing a fund collected from developers and owners of such properties for maintaining and repairing glass curtain walls.

"However, there's a long way to go between setting up the fund and using it to have the glass curtains in good condition in Shanghai," said Lu, of the building research institute. "Let alone in other cities, which don't have such a regulation or plans."

China released a building code for glass curtain walls in 2003, but no guidelines have been issued on who is responsible for the maintenance. According to Motian City magazine, there were 350 buildings higher than 152 meters, and another 287 under construction on the Chinese mainland in March. "The number of completed super high-rises may increase by 10 percent this year," said Wu Chengtao, the magazine's editor-in-chief.

"But the construction of many glass curtain wall buildings takes only the charming exterior into account," he said. "First, they invest more than hundreds of millions in the construction. The cost for later repair and maintenance comes to no small sum," Wu said.

On July 8, when a 19-year-old girl named Zhu Yiyi was walking past a 23-storied building in Hangzhou, a glass curtain wall fell from the 21st floor and hit her, leaving a 20-cm laceration on her left lower limb, severing the arteries in her left thigh, and fracturing her thighbone. Her vessels, muscles and tissues in the left lower leg were also severely damaged, which means amputation at the knee would have been the only viable treatment.

19 year old Zhu Yiyi faces amputation after her leg was virtually severed by a shard of falling glass from a commercial building in Hangzhou, the capital of eastern China's Zhejiang Province on July 8. Zhu is now in a Shanghai hospital for surgery in hopes of preserving most of her leg. Though in stable condition, Zhu must sleep in a corridor because the hospital has no beds available. A sheet of glass, measuring 1 meter in length, dropped from the 21st floor and hit Zhu from behind on her knee as she walked near the 23 story Qingchun Development Building on her way to work. "At that time, I felt extremely painful and I was bleeding seriously. I was very weak and just wanted to be alive," said Zhu Yiyi.
Witnesses said her left leg was almost cut off beneath her knee. Doctors in the Hangzhou hospital said that due to the severe damage to the blood vessels and nerves, Zhu might lose her leg. In order to keep her leg, Zhu's parents, farmers from a village in Jiangxi Province, took her to Shanghai right away to receive better treatment. The father said they hoped the hospital could save her knee so that she could walk with an artificial limb after surgery. A doctor said the hospital would try to move Zhu into a ward from the corridor soon, and promised to let the best doctor perform the amputation. "Amputation is necessary for her and we are concerned where to conduct the amputation. We are trying to conduct it on a lower place of her leg. If we conduct the amputation under her knee, the artificial limb will be functioning in a better way," said Zhang Tao, Executive Director of Orthopaedic Department of Shanghai No. 8 People's Hospital.
Zhu's family is not wealthy and she gave up her education after high school to work in an architectural design company in Hangzhou. Though the sudden disaster has challenged her in an arduous way, she remains positive about her future. "I believe that I will be like a normal person once I have my artificial limbs on. I can do nothing but to face and accept the situation now," said Zhu. "I blame no one, but hope similar tragedies will never happen to others. I still feel optimistic about my future. For example, I can be a senior architectural designer. I can earn more money. I can also find my Mr. Right to love for the entire life," Zhu also said.
The building's property management company issued a written guarantee to Zhu to cover all her medical expenses. Zhu Meilong, the father of Zhu Yiyi, explained that the company initially refused to take full responsibility and gave Zhu only 30,000 yuan in compensation, which was less than the 40,000 yuan needed for medical expenses. He also said the company agreed to pay more after a Hangzhou law firm helped Zhu negotiate with the company voluntarily. Hangzhou police were still investigating who was liable, but Dai Heping, the head lawyer of the law firm who is helping Zhu Yiyi free of charge, said both the property management company and the tenant of the floor, a paper-making company, should be held responsible. 

Tempered glass breakage: A frequent misconception about tempered glass regards its resistance to breakages. Many consider it "unbreakable" or "nearly unbreakable". Such is not the case. As with every other type of glass, also tempered glass can break. Glass breaks when it is exposed to stresses that it cannot withstand. To increase its strength and heat resistance annealed glass can be subjected to a thermal treatment or chemical process. Tempered glass is obtained using this process, and its final form is four to five times as strong as annealed glass of the same type and thickness. When broken, it shatters into many small fragments, which prevent major injuries. Due to these characteristics tempered glass is used traditionally in applications requiring increased strength and reduced likelihood of injury in the event of breakage.
Tempered glass should receive the same care as annealed glass. Unfortunately, the perception of "unbreakable" characteristics of tempered glass may mislead people to provide less care while handling it. Careless handling and improper installation sometimes produce damage, which leads to "spontaneous breakage" or "delayed breakage." This means that occasionally a sheet will not shatter immediately at the time of damage, but perhaps weeks later. Inclusions in glass such as NiS can also trigger a delayed breakage effect. Nickel sulphide inclusion, also known as NiS, occurs during the manufacturing process for float glass. In a glass batch, nickel-rich contaminants such as stainless steel might be present, and then combine with sulphur to form nickel sulphide inclusions. To minimize the risk of NiS breakages, a heat soak test is performed. Although some spontaneous breakages occur due to the above-mentioned factors, much breakage is called "spontaneous" just because there is no easily visible cause.

Window Cleaners Smile - Glass Walls Trending In New & Old Homes

Growing Panes: Homeowners Go Big on Glass Walls - Anita and Bob Dethlefs wanted the new Portland, Ore. home they were building to really let the sunshine in. So, the couple installed 2,700 square feet of Marvin windows—about $300,000 worth—on nearly every wall of the property. And then they put up 12 security cameras. "We're getting about as much light as you can in the Northwest but with so many windows, safety was the No. 1 concern for me as a mommy with kids running around the house," says 43-year-old Ms. Dethlefs, who has five children. Her husband started a leadership conference business, Evanta Inc., in 2003 and later sold it. Their 13,000-square-foot, $5 million Frank Lloyd Wright-inspired home even has a glass front door, letting visitors on the front stoop see through the family's living room out to Mount Hood.

Forget about a room with a view. Today, homeowners want views from every room. As large expanses of glass have become architecturally acceptable for modern and traditional homes, new technology is making living in a fishbowl more practical—albeit sometimes challenging. Homeowners' desire for more open floor plans with combined kitchen and living-room spaces has paved the way structurally for bigger spreads of glass. A growing appetite for more energy-efficient windows and associated tax incentives and rebates have also supported the trend.  "The open floor plan is predominant in almost everyone's design now," says builder Tim Wilkinson of Great Falls, Mont. "They want more light and bigger windows to take advantage of views."

Today, thanks to technological advances, nearly all windows installed in new homes have special, invisible coatings that block heat and keep ultraviolet rays from fading furniture. Many also use double or triple-panes with argon or krypton gas sandwiched in between, which helps insulate in cold climates. Now standard on Andersen Windows glass: a titanium dioxide coating the company says sheds dirt and virtually eliminates water spots. Some glass makers are even marketing windows for residences that can tint and untint with the push of a button.

And for those put off by the prospect of raising and lowering so many blinds, companies such as Lutron Electronics sell window shades that can be controlled with an iPhone app. "Across the board, people want more light," says Mike Rogers, senior vice president of GreenHomes America Inc., a company specializing in energy-efficient home renovations, which has been incorporating more glass in its projects. Beyond privacy and safety—Ms. Dethlefs's chief worries—there are maintenance issues, such as how to keep so much glass spotless. (The couple pay $850 to $950 for professional cleaning at least three times a year.) And despite technological improvements, glass still doesn't typically insulate as well as a wall packed with insulation.

Then there is the bird problem: Anywhere from 100 million to 1 billion are killed in window collisions every year, according to the U.S. Fish and Wildlife Service. While manufacturers such as Andersen Corp. and Marvin Windows and Doors say overall window sales have slowed amid a sluggish new-house market, the companies say they are seeing more and larger windows going into new homes. In modern homes, "they are filling space between floor and ceiling with as much glass as they can," says Jay Sandgren, an architectural representative for Andersen. He says builders are being "a lot smarter" about positioning a home and the roof overhang to capture the most sunlight in winter and to block much of the heat from the sun in summer.

Building with glass isn't cheap. Mr. Wilkinson the Montana builder estimates the price is about double the cost of installing regular walls packed with insulation. His own 4,800-square-foot home that he completed last year has $85,000 worth of Andersen glass, giving him a 240-degree view of three mountain ranges and the Missouri River. Even the deck railings are glass panels.

Tempered safety glass is installed according to local building codes in areas of homes where breakage might be of particular concern, such as windows and doors close to the floor or near a stairway or landing. Glass can sometimes attract vandals in the construction phase, a headache for builders, Mr. Wilkinson says. But breakage for homeowners "is rarely a problem," he says, although he cautions that people mowing the lawn should look out for rocks that the mower can kick out to crack a pane.

Architect Thomas Roszak took the fishbowl aesthetic to the extreme in his own Northfield, Ill. home, which features commercial curtain-wall glass around the entire building.The walls are constructed from two argon-filled glass panes covered with what's called low-emissivity, or "low-e," metallic coating to block heat flow through the window, keeping the home cooler in the summer and warmer in winter.

With little traditional wall space, art is suspended in front of windows from a floor-to-ceiling, museum-type wire hanging system, Mr. Roszak says. For privacy, he planted trees around his one-acre property and installed $60,000 worth of electronically operated blinds. One low point of glass-house design: The day his 8-year-old son spied a dead bird that had hit home's glass siding, likely mistaking the trees' reflection for safe habitat. "He said, 'Daddy, I don't think that bird is sleeping, I think it's broken,'" Mr. Roszak says.

Glass homeowners must be mindful of clutter, since the view goes both ways. When Beata and Brad Peters built their 3,900-square-foot brick home in Hawthorn Woods, Ill., they incorporated large panels of glass symmetrically throughout. While most windows have wood blinds, the family tends to leave them open for aesthetics. "I don't put a lot of stuff in front of the windows," Ms. Peters says. In the kitchen, appliances like toasters get packed along a wall with no glass.

Window-treatment companies are pushing to make shade operation less of a chore. Rotterdam-based Hunter Douglas this spring added a "Solar Energy Sensor" that raises and lowers blinds based on the amount of sun detected. Despite the slump in the housing market, the company's North American sales rose almost 5% last year. An electronically controlled Lutron shade sells for about $900 more than manual ones and can be controlled via remote control or an app for Apple Inc. or Android devices.

Some glass companies now make windows that reduce the need for blinds altogether. One is Sage Electrochromics Inc. of Faribault, Minn., whose product consists of clear panes that morph to a grayish-blue tint when a user flips a switch to send a low-voltage current across the window. The tint reduces glare and heat but not visibility. Sage began selling the glass for residential applications around 2005, though they are typically found in high-end homes due to cost. An installed window costs between one-and-a-half to two times as much as one with typical low-e glass. "If you're on the West Coast facing the ocean when the sun is beating on the glass, what people do is pull their blinds and shades to block the glare," says Helen Sanders, Sage's vice president of technical business development. "What that means is you've just lost your view you paid a huge amount of money for."

Modern architect’s glass is half full: In 1921, German architect Mies van der Rohe designed an all-glass skyscraper which, while never built, foreshadowed the countless glass-clad skyscrapers that would rise in cities around the world during the 20th century. As demonstrated by KGP’s Bikestation, iconic architecture in glass doesn’t have to be high or huge in scale. One of architect Philip Johnson’s most notable works is his one-story, modestly-sized but very elegant all-glass house built in 1949 in New Canaan, Conn. A simple rectangle in plan and elevation, Johnson’s transparent, minimalist house is enclosed entirely with large glass panels. Only the interior bathroom is opaquely clad. On a large landscaped parcel with no close neighbors, Johnson’s house needed no curtains or shades.

Of course, Johnson was not averse to grandiosity. Perhaps inspired by Paxton’s Crystal Palace, Johnson designed the daylight-filled Crystal Cathedral in Orange County, Calif., completed in 1980. An enormous religious sanctuary seating more than 2,700 worshipers, the Crystal Cathedral’s skin was constructed using 10,000 rectangular panes of glass. Today the building is for sale. A few years ago, the city of Seattle built a new library with a faceted skin composed only of diamond-shaped glass panels, some clear and some opaque. Designed by Dutch architect Rem Koolhaas, the 11-story library is an abstractly shaped, dramatically angular form covering an entire downtown block. Equally dramatic interior spaces are brightly suffused with daylight, even when it rains, a benefit much appreciated in Seattle.

State-of-the-art curtain wall technology allows architects to wrap buildings with increasingly large sheets of glass, to support glass with ever-thinner framing elements and hardware and to construct ever more complex glass skins. Glass can be manufactured using permanent coatings, surface etching and laminations to create artistic patterns, modulate light transmission, block solar radiation or sustain high impact forces. Energy-efficient glass, resisting conduction and radiation of heat, has made all-glass facades increasingly feasible. And by optimizing the amount of daylight reaching building interiors, a glass skin significantly reduces electric lighting needs and energy consumption. Now viewed as a relatively “green” building material, today’s glass is indeed not your father’s glass.

Roger K. Lewis is a practicing architect and a professor emeritus of architecture at the University of Maryland.