Mirroring medicine: Breathtaking architecture matches breakthrough medical technology at CHOP
After five years and $650 million, The Children’s Hospital of Philadelphia now shines as the city’s latest architectural jewel.
The three-phase project transformed CHOP from a dark, 1970s-era structure to a light and welcoming glazed expansion that tested technical and creative abilities of participants every step of the way.
The importance of the CHOP expansion and recladding, however, extends far beyond architectural magnitude, technical challenges and calendar days, says Kevin Whelan, ironworker foreman for contract glazier National Glass and Metal Co. in Horsham, Pa. The real significance comes from seeing the young patients and their families, and knowing the expansion will improve hospital visits for them, he says.
“Working this job is gratifying,” Whelan says, remembering in particular one young cancer patient named Tommy, whose father told construction workers that his son enjoyed watching them.
The guys wrote “shoot for the stars Tommy” on plywood and put it on the crane,” Whelan recalls. “One day after he had chemo, he was in bed, and they brought the plywood up for him to see.”
Architects from Kohn Pedersen Fox Associates PC in New York City kept those patients and their families in mind at every stage, resulting in a colorful kid-friendly building with numerous art-glass elements. The sleek, modern design also offers a representation of cutting-edge medical practices, something the bronze-clad original building failed to do, says David Zoolalian, project executive for construction management company L.F. Driscoll Co., Bala Cynwyd, Pa.
“This is creating a new identity for CHOP,” Zoolalian says. “It allows the exterior to match the technology of medicine going on inside.” Rankings from U.S. News and World Report and Child Magazine place CHOP at the top among pediatric hospitals.
Phases of construction
Construction on Phase I, the 11-story, glass-clad South Tower that extends over the emergency entrance, began in June 2001 and was completed in April 2003.
Construction began in May 2005 for Phase II, the West Tower that makes up the backside of the hospital and includes an expansion of the cardiac center and oncology departments. The tower has a scheduled completion of June 2008.
The hospital’s jewel-like image, however, comes from Phase III, the glassy reclad of the building’s front door. Phase III consists of a stunning point-supported-glass sleeve, a glass cantilevered entrance canopy, a nine-story custom unitized curtain wall with deep metal reveals at the spandrel line, and a four-sided structural glazed curtain wall called the northeast extension. Construction began in October 2003 and will be completed this month.
Zoolalian says project participants want the expansion, particularly the point-supported sleeve front door, to make the hospital an architectural icon of Philadelphia.
Participants say CHOP “will become a signature shot of Philadelphia—such as the Liberty Bell, Independence Hall, Boathouse Row—a picture that represents the city on Monday Night Football,” Zoolalian says.
The years of studies, planning, design and construction required to create CHOP’s glassy identity presented numerous obstacles, says Pamela O’Malley, CHOP senior project manager.
“Since the project was approved, I’ve lived with, pulled, coerced and cajoled. … It has just been really a hands-on, inch-by-inch thing,” O’Malley recalls. “But it’s really satisfying.”
Some construction delays and roadblocks grew out of completing a major renovation in a working hospital. Government mandates require environmental infection control in health-care facilities during construction. The Washington D.C.-based U.S. Department of Health and Human Services and the Joint Commission on the Accreditation of Healthcare Organizations of Oakbrook Terrace, Ill., follow strict guidelines outlined by the Centers for Disease Control and Protection of Atlanta. These guidelines require an infection control risk assessment prior to construction to determine the type and nature of barriers that must protect all occupied patient spaces from the active construction site.
Limiting dust and debris, in addition to noise pollution, to meet CDC requirements stalled progress and forced workers to come up with roundabout methods of installation.
The Phase III reclad, in particular, pushed many participants to their limits, O’Malley says. “There have only been two other hospitals that I know of in the nation that ever attempted to do a reclad while the wings were occupied,” she says, referring to Doylestown Hospital in Doylestown, Pa., and Miami Children’s Hospital.
The original layer-cake style façade of CHOP’s east side fronted offices at the north end and critical patient areas including the neonatal intensive care unit at the south end. To meet government guidelines and protect patients, KPF architects designed the point-supported glass sleeve to sit 16 feet in front of the original façade on the south end. The existing fixed and operable windows on the stepped façade were wet sealed from the exterior prior to repainting, recalls Walter Cichonski, director of exterior fenestration for L.F. Driscoll. “These 30-plus-year-old, stainless steel banded, insulating glass units still had more than 90 percent of the useable desiccant life left, and we were able to leave them in place,” Cichonski says.
The plan allowed for patient areas to remain functional during construction, since all building activity took place around the original structure, says Edward Cizek, senior project architect for Ballinger, the Philadelphia firm that executed Phase III.
“The theory was we wouldn’t have to go in at all—completely noninvasive,” Cizek says. “In reality, minimal intrusion into sleeve-area patient rooms was required.”
In the end, of the 66 patient rooms in the sleeve, only two had to be closed throughout the entire construction. The rest were closed in a phased sequence for one or two days each while workers replaced exterior panels. The unitized curtain-wall reclad on the north side presented a more disruptive and difficult scenario. About 125 CHOP employees were pushed out of their offices for three to four months at a time. In addition, contractors had to systematically install the curtain wall without contaminating the interior.
Glaziers and ironworkers from National Glass and Metal worked on an exterior scaffold enclosed entirely with reinforced plastic sheeting, and a temporary dustproof barrier was erected inside the façade to isolate the construction zone from hospital operations, explains Joseph Clabbers, National Glass’ president. L.F. Driscoll set up large portable fans and a hinged door at the top of the scaffold to provide air circulation in the sealed area.
Because workers had to complete the installation in a tightly sealed area, they developed a meticulous system of completing one row at a time of the preassembled curtain-wall units, Clabbers says.
“The curtain wall had to be temporarily enclosed to maintain the building envelope,” he says. With the help of a 120-ton crane, workers would “slip one panel at a time through a trap door at the roof, with our men guiding the 500-pound glazed panel down six floors inside a 2-foot-wide space.”
At every stage, construction productivity ranked second priority to patient health and comfort, Clabbers says.
“[The nurses or doctors] could shut it down just like that, and the guys are all aware that the needs of the patients take precedence,” he says. “As soon as you get started on something, they might say it’s too loud, and we’d sometimes have to stop in that area until a patient could be relocated.”
The difficult design demands of the sleeve and entrance canopy forced L.F. Driscoll officials to search locally and internationally for materials. With steel from Poland, a point-supported system from Germany and glass from China, Phase III of CHOP truly represents a worldwide effort, Cichonski says.
The point-supported façade design from Dewhurst Macfarlane and Partners Inc. of New York City is a six-story, three-sided sleeve consisting of 13-foot-4-inch-by-4-foot-6-inch clear laminated glass lites. The large lites match the height of the stepped floors in the original building, visible through the sleeve.
Germany’s Josef Gartner GmbH won the bid for the point-supported system, providing the “complete package” through an international system of suppliers, Cichonski says.
Gartner officials looked to a relative novice in the architectural arena, Poland’s Mostostal Siedlce S.A., for the steel in the canopy and sleeve, most notably 12 pre-made 86-foot trusses, he says. “This was the first big architectural project for them,” Cichonski says.
“Gartner wanted the best of quality, and they got it. … These trusses really were finished to a very high-end architectural level, body filled and sanded twice. Visually, they have a smooth, fine level of finish.”
For the 446 large laminated lites, Gartner sought assistance from local Philadelphia fabricator J.E. Berkowitz LP, where managers gathered a team of companies at home and abroad. Berkowitz chose to get glass from China Southern Glass of China, but the interlayers posed a greater challenge, Cichonski says.
Mock-up tests revealed that polyvinyl butyral interlayers would not sufficiently support the load of the large lites during the hotter summer months. The project required instead a product such as SentryGlas Plus structural interlayer from DuPont Glass Laminating Solutions in Wilmington, Del.
“At the time, you couldn’t buy the DuPont sheets that large,” Cichonski recalls. “But DuPont custom-produced the sheets, and China Southern fabricated the glass with holes, did edging and married the pieces in an autoclave. … We were impressed with the level of quality.”
The glass was transported to the United States ready to install. Shipment took about three weeks. Gartner ordered additional lites in the event of breakage to prevent any possible time delays, he says.
Permasteelisa Cladding Technologies Ltd. of Windsor, Conn., executed the installation.
L.F. Driscoll also relied on overseas suppliers for elements of the 72-foot-long, nearly all-glass cantilever entrance canopy. The glass-topped canopy extends 32 feet and, aside from three steel trusses, features an all-glass support system by Shanghai Glass in China, Cichonski says.
Six 24-foot-long, 21⁄8-inch-thick beams of four-ply laminated glass run lengthwise, connecting the steel trusses. Three of the beams are 36 inches high, and the rest 18 inches.
“We’re literally using glass as a structural element,” Cichonski describes. Where glass meets trusses, “we filled the entire shoe with caulk silicone, so the receiving sleeve’s members of stainless steel never touch the glass,” he says.
Thinner laminated decorative glass support purlins also run parallel to the steel trusses.
Art of healing
Reappearing themes of color and decorative glass fill the interior spaces of CHOP—themes KPF architects expressed in the reclad design and associates from Ballinger made sure to execute in the construction.
In addition, the colorful art displays provide a welcoming atmosphere for children.
KPF designers chose a red, green and purple color combination to carry throughout several art-glass elements in Phase III, Cichonski says.
Colored laminated glass fins hang in the sleeve interior, creating a sine wave pattern of each individual shade, Cichonski says. “The fins float about 10 feet from the existing wall,” he says. “Children in their rooms look through the multicolor panes of glass, and it becomes a magical place for them.”
St. Louis-based Solutia Inc. provided its Vanceva interlayer for the fins.
Melissa Mather, Ballinger associate, says challenges arose when choosing each specific shade. When a lite of one color crossed sightlines with a lite of another color, the mixed color needed to complement the rest. “We had samples created of at least 40 different reds just to try to find that one red that, when overlaid on the green, creates a beautiful secondary color and not a brownish hue,” she recalls.
The United Kingdom’s Macalloy Ltd. supplied the cables and fittings to support the glass fins.
The colorful sine wave pattern is expressed horizontally in the canopy structural glass purlins. Ballinger chose DuPont’s SentryGlas Expressions for this application. The product allowed for an exact color split on one laminated film, and the colors developed with DuPont match those from Vanceva, Mather explains.
Lastly, the color trio is featured throughout a series of custom designed and fabricated light sconces lining the east and south elevations, with some fixtures measuring 5 feet in height, and the rest 13 feet. This decorative element posed a creative and technical challenge for Ballinger’s architects, who had to find glass that could span the desired lengths with 90-degree return legs and be self supporting. In addition, they had to incorporate color into that glass. “It was critical that the color was perceived saturated in both the daytime sunlight as well as while illuminated in the night sky,” Mather says.
After numerous trials of several glass types combined with varieties of films and interlayers, Ballinger and L.F. Driscoll associates chose single pieces of channel glass from Bendheim Wall Systems in Passaic, N.J., lined with a colored interior film from 3M of St. Paul, Minn.
“These are real pieces of jewelry,” Mather says.
A final decorative glass element in Phase III included translucent patterned glass in the arcade storefronts. National Glass fabricated and installed the decorative unitized storefront systems using glass from Goldray Industries Inc. in Calgary, Alberta.
Goldray applied its standard Cloud Dragon ceramic frit pattern over another standard frit pattern on the interior lite of an insulating glass unit to create a translucent effect, while maintaining the rice-paper texture of the pattern, Mather says.
“The glass glows,” she says. “It allows light into the space while maintaining the highest level of privacy into the patient areas on the ground floor.”
While participants see completion on the horizon of KPF’s three-phase marathon reclad, construction continues at CHOP, Zoolalian says. And L.F. Driscoll continues to inhabit its permanent office at the hospital as renovation and expansion of Philadelphia’s newest gem and its surrounding buildings take place through ongoing improvement.
“The growth of this institution is phenomenal. We no sooner complete a new addition, and they are out of space,” Zoolalian says.