Schering-Plough beats the odds in the shadow of a volcano
Earthquakes, volcano posed building challenges for new facility, which houses the company`s 52,000-square foot cleanroom
By Hank Hogan
For Schering-Plough Corp., the company`s latest clean manufacturing facility in Mexico was both an opportunity and a challenge. The opportunity was to build a large state-of-the-art pharmaceutical manufacturing facility utilizing the latest ideas of the clean core concept. The challenge was how to pull this off. The new factory, located adjacent to an older one in Xochimilco, Mexico D. F., just southwest of Mexico City, had some basic environmental hurdles to overcome.
“It is an earthquake area, a little more severe than California,” notes William Cokeley, P. E., project director for Schering Laboratories, a division of Schering-Plough. Cokeley was actively involved in the planning and construction of the new facility, which was dedicated by the president of Mexico in February 1997 and certified by Mexican health authorities in September of the same year.
The volcano factor
Besides earthquakes, Mexico has something California doesn`t: volcanoes. With numerous minor venting eruptions in 1997, the volcano Popocatepeti has been at its most active since reawakening in 1994. Those eruptions have dumped ash on Mexico City, which is less than 50 miles away. But there`s no need to tell anyone at the Schering-Plough plant this; they can check on Popocatepeti`s current mood for themselves.
“You can stand in the plant and look at the volcano,” says Jim Hayes, director of operations for Clestra Cleanroom. Clestra supplied the modular cleanroom facilities used inside the factory as well as the HVAC system. The Jacobs Engineering Group (Philadelphia, PA) was the architect/engineer for the facility while the general contractor was Bufete Industriál S.A. de C.V., a leading Mexican firm.
In designing and constructing the new plant, there were several objectives. Schering-Plough, which had $5.7 billion in worldwide sales in 1996, has been active in Mexico for 50 years. Indeed about 10 percent of the corporation`s total sales come from its Latin American operations. The company needed to replace its existing Mexican facility with one built to a higher standard of cleanliness and more stringent health regulations. While none of the pharmaceuticals produced in Mexico would be shipped back to the United States, the NAFTA treaties and procedures followed by Mexican health authorities meant that U.S. health standards would essentially be adhered to.
At the same time, Schering-Plough needed a factory that was more efficient and had a greater capacity to serve the growing Mexican economy. Furthermore, once completed the new plant would have to take over production from the old facility without disrupting the steady flow of goods needed to supply the Mexican market. For these reasons, the new facility was constructed on the same site as the older one.
The new three-story plant has 30,000 square feet of space on each floor. Of that, some 20,000 square feet can be built as cleanrooms. The rest is taken up by utilities, maintenance areas, and other uses. At present, the first and third floors are completely finished, while on the second, some space is reserved for future expansion. The total cleanroom area at the moment is 52,000 square feet. It`s a Class 100,000 facility throughout with modular enamel-coated steel panels for ceilings and walls, and epoxy-coated concrete flooring. The walls can be moved and rearranged for equipment move-in or maintenance. They can also be moved to accommodate changing manufacturing needs.
An earthquake-proof building
Building in an active earthquake zone presented some challenges, which are all the more severe because the Mexico City region sits on top of a dry lake bed. To firm up the foundation, 300 piles were driven 131.33 feet into the ground. Since the building is 80 feet high, there`s more of the structure below the ground than above it.
“You can visualize the building as a hair brush sitting on mud,” explains Schering-Plough`s Cokeley. “The building, in essence, floats. So, if there is a vibrational impact you`ll notice it, but you don`t get the contortion or twisting or floor drops that you get with a typical building.”
Internal fixtures, such as air handlers, piping, and the modular cleanroom ceilings and walls, had to be braced back to the structure. In some cases, these internal fixtures had to be strengthened, particularly if they covered long otherwise unsupported spans. To make sure there wouldn`t be a failure in its modules, Clestra ran a seismic analysis of the cleanroom components.
The overall idea has to be sound. Cokeley was at the site when southwest Mexico was rocked by a 7.2 magnitude earthquake in September 1997. The tremor injured dozens of people and flattened numerous homes along the country`s Pacific coast. It was also felt in the nation`s capital, Mexico City. Although the 90-plus percent complete Schering-Plough building swayed there was no damage to the facility. This was after the floors had been coated with epoxy, and yet there were no cracks.
Volcanic ash, dust, and other particulate air pollutants are handled through a series of filters. There are three banks of filters — 30, 80, and 95 percent efficient — for the building as a whole. In addition, there are individual air handling units with 85 percent efficient filters. This is in each one of the nearly 100 individual production rooms. The final filter is a ceiling-mounted HEPA filter that`s 99.99 percent efficient. Most of the brunt of any volcanic ash would be borne by the first building filter, and during eruptions those filters would have to be changed more frequently. Just how often that would have to be done would depend upon the amount of ash and other airborne contaminants.
Changing filters in the cleanrooms themselves is made easier because the ceilings are three-inch-thick galvanized steel panels. Although not load bearing, the panels can support people and their tools.
“It`s walkable to where maintenance personnel can go up there. And, if you`ve got top access lights, you can change light bulbs or you can change filters from the top without disrupting the cleanroom operation and still maintain cleanroom integrity,” comments Clestra`s Hayes. Within the building this filtered air flows through once, with no recirculation in any of the critical production areas. As a result, the air exiting the building is much cleaner than the entering air.
The clean core
To meet upgraded standards, the building is built around the core concept. The clean area is in the center of each floor, with a corridor running around the outside. Inside that clean area is the equipment used to manufacture the plant`s production of liquids, ointments, creams and solid dosage forms. All of these are non-sterile products. The building`s utilities which support manufacturing, such as chillers, boilers, dust collectors, air handlers, electrical panels, and the like, are located outside of this clean space. All the major utilities are located either on the roof or in a perimeter mechanical ring that encircles each floor. The utilities are brought into the building through an exterior tower.
To connect this mechanical support ring to the clean areas themselves Clestra constructed special wall panels so that Schering-Plough`s production equipment could get access to water, dust collection, and power inside the cleanroom.
“We provided utility panels and electrical panels that were fabricated into our wall systems that they connected their equipment to,” says John Sugar, field services manager for Clestra.
For cleanup, each floor has a single wash room and hence there is only one drain per floor. Equipment that can`t be moved to the washroom has the means to do clean-in-place. For these pieces of gear there are mobile cleaning units that can be wheeled into place, used to clean the equipment, and then taken to the wash room. This restriction on drains not only cuts down on particulate but also eliminates a potential point source for microbial growth.
Through the use of dampers and individual room air handlers, air pressure both suppresses particulate and eliminates cross contamination. Within the clean area, there is a central clean corridor. That corridor is positive pressure to the outside gray area and the production rooms as well, something that`s assured by the Clestra central building air management control system.
“There`s no possibility then of non-HEPA filtered air coming through doors or anything like that into the clean area, and there`s no possibility of any one production room basically pushing air out into the corridor which could then go to another production room,” says Schering-Plough`s Cokeley.
Because the new facility is a clean area, there are special plant clothes that are worn in gray areas inside the factory. In the clean production rooms, workers wear special floor-specific color-coded outfits. There is a gowning area so that employees can change clothes. All of this is quite different from the older factory which shares a site and personnel with the newer one. These differences are one of the reasons why only about 30 percent of the 120 different products made by Schering-Plough in Mexico had been transferred from the old factory to the new by the end of 1997.
“It`s really very difficult to transfer products from the old to the new,” comments Ricardo Cabrera, manufacturing director of the Schering-Plough facility. “In the new [building] we are going to use completely different technology, manufacturing technology, than the technology used in the existing facility.”
Once transferred, however, products will benefit from being manufactured in a much cleaner facility. Manufacturing should also be much more efficient. The old facility was only a single story and as a result is much smaller than the new. The smaller older facility could only house smaller production machinery and that combined with the need to produce a great many products lead to the creation of small batch runs. With the extra room in the new facility the equipment is larger, which means that each batch can be bigger, and that improves the overall manufacturing efficiency.
Meeting international standards
Building the facility in Mexico while using a supplier in the U.S. also involved some aspects that had to be planned and accounted for. Clestra fabricated the wall and ceiling panels and then shipped them into Mexico. Although there were some shipment and customs delays, the company had already done several projects in Mexico and knew what to expect and how much time to allow. Packing the wall panels had to be carefully done since they were uncrated and inspected by customs. Following that the panels then had to be recrated again for shipment to Mexico City itself.
Because the facility is state-of-the-art, Schering-Plough brought teams from the general contractor to the United States for training in clean construction and to show them existing manufacturing factories so that it would be clear what was expected. The sheet metal contractor responsible for the ducting outside of the cleanroom was also brought in and, partly as a result, bought special duct fabricating equipment to meet the facility`s specifications. This upfront education and training paid off, as Cokeley reports that the work on the final product, the plant itself, was of the highest quality.
As for the future, the plant should continue to ramp up as more and more products are transferred from the old to the new. There is the chance that Schering-Plough will use the facility to export to other Latin American countries, although at present there are no plans to do so. Construction of the new factory was justified primarily on the demand within the Mexican market itself. While the plant currently does not produce any sterile products, it is essentially a sterile facility. Indeed some of the reserved space on the second floor could be used for sterile manufacturing. Whether that happens or not will depend upon a number of factors including market conditions. In any case, the factory will continue to exist in the shadow of the volcano, but that isn`t the only reason why it`s noteworthy.
“It`s the most impressive facility because there`s no other one in Mexico similar to this,” says Schering-Plough`s Cabrera. “In Mexico I would say this is the only one with almost perfect environmental controls.”
Hank Hogan is a freelance editor based in Austin, TX.
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Clestra walkable ceiling and 20-foot high demountable walls in processing area. There is no limit to the size, shape, or number of process equipment penetrations in the Clestra ceiling system. Photo courtesy Clestra Cleanroom Inc.
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Equipment wash area. Wash panels are of all stainless steel fabrication, and incorporate numerous technical access panels for electrical and other process support services. Photo courtesy Clestra Cleanroom Inc.
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Processing room featuring Flush Glazing and technical access panels for electrical and process support services. Wall and walkable ceiling panels are electrozine galvanized steel featuring a durable factory baked-on epoxy paint finish. Photo courtesy Clestra Cleanroom Inc.
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Clean core area corridor. Each individual processing room is on its own dedicated AdvancAir unit to eliminate cross contamination and maximize production flexibility. Wall panels are demountable to permit rapid production equipment move in. Photo courtesy Clestra Cleanroom Inc.