Six weeks flat

Chip filtration and separation firm coverts ISO Class 6 cleanroom to ISO Class 5 in tight timeframe

by Mark A. DeSorbo

To transform a 1,000-square-foot ISO Class 6 cleanroom into ISO Class 5 environment in just six weeks may sound like tall order, but Pall Portsmouth Ltd. (Hampshire, England) managed to pull it off.

“We did it in a manufacturing window,” says Stuart Wells, general manager. “We built up a stockpile of products in order to satisfy customers and shut down for six weeks for the upgrade.”

The game plan, however, had a two-pronged strategy; the second part of which was to make cleaner filters for high purity process fluids, gases and water systems used in semiconductor and microelectronics manufacturing environments.

“The filters are very small. You can hold two or three of them in each hand,” says Derek Morse, industrial engineering manager. “Producing them in a cleaner environment was a strategic need to meet product demands. We needed the ability to show that the filters are made in this type of environment in order to supply that market.”

Small structure, bigger problems
With the help of the same contractor who built and installed the ISO Class 6 environment, Clean Room Construction (Kent, England), the upgrade was completed a week ahead schedule, despite tight quarters in a three-story building that required some fancy redesign work to provide a vertical laminar flow that an ISO Class 5 demands.

“The major problem we had was with the very low ceiling on the first-floor,” Morse says. “When it was Class 6, we were just blowing air in from the sides, but the upgrade required a vertical laminar flow and the norm would have been to duct air to the ceiling level.”

The greatest challenge to overcome were the low ceilings in the existing ISO Class 6 cleanroom. The upgrade to ISO Class 5 required the flooring of the second level to be sealed for pressurize plenum that feeds through 36 HEPA filters.
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Because the ceiling space wasn't there for ductwork, the floor above, a biological lab that is part of Pall's testing facility, had to be sealed to prevent cross contamination. “We changed the whole second-floor for a pressurized plenum, which feeds through 36 HEPA filters,” Morse adds.

“It is small, we keep it fairly tight, but by specification, it's as good as you can get,” Wells says.

“Apart from that, there were no real problems,” Morse adds. “It was a turn-key project and it complies with ISO 14644-1.”

Filters in the making
Pall's Portsmouth facility also has an ISO Class 6 cleanroom for research and development that's less than a quarter of the size of the newly upgraded environs.

Wells and Morse, however, are quick to point out one particular special feature of the newly upgraded facility, a degreasing station.

“It will degrease the components in an automatic cycle,” Morse says. “It will put them through two de-ionized water rinse tanks, and then the components go into a drying oven. A conveyor then brings the components into the cleanroom.”

When it was all said and done, the project was within budget and took just six weeks to complete, one week ahead of schedule.
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All stainless steel parts enter the cleanroom through the degreasing station, while the filter medium enters the cleanroom through two airlocks, one near the degreaser and one on the other side of the cleanroom

“We are encapsulating the filter medium inside a stainless steel housing,” Morse adds. “Welding is done in a glovebox in the cleanroom. It uses HEPA filters and is positively pressurized like the cleanroom.”

That means environmental monitoring is an absolute must, and Pall regularly checks flow testing and particle counts down to the nanometer.

“We have laser etching and helium leak detecting as well as bagging and sealing systems, which incorporates helium into the bag to ensure the product is kept in an inert environment,” Morse says.

The temperature of the ISO Class 5 environment is maintained at 68 degrees Fahrenheit (20 degrees Centigrade) +/- 2 degrees. There are no humidity controls, Morse adds, because it is not really an issue “in this part of the country.”

Air is predominately re-circulated with a percentage of constant fresh-air make-up that keeps the environment fresh and replaces lost air. Cleanroom personnel wear full bunny suits, booties, gloves, facemasks, and head covers.

“The market for these filters goes up and down and is subjected to global demand,” Wells adds. “It is in a downturn now, and we are using this time to make an investment so that when the market takes off, we can provide our customers with the product the industry is demanding. We're upgrading because they demand a cleaner product.”

The upgrade at the Portsmouth facility was not the only project Pall has recently completed.

In mid-April, Pall Corp. (Hauppauge, NY) announced the opening of a 75,000-square-foot life sciences facility, where filtration systems will be manufactured for biotechnology, pharmaceuticals and blooding banking.

The filtration systems, including tangential flow filtration (TFF) membranes and cassettes, aim at improving quality and lowering the cost of development of biopharmaceutical products.

“Pall's customers will gain from our streamlined manufacturing and improved process control,” says Leonard L. Krakauer, president of the Hauppauge facility. “Our operations meet the strictest quality standards and qualify for use in the most rigorous biopharmaceutical current good manufacturing (cGMP) applications.”

Key Facts  
Size of facility: 1,000 square feet ISO Class 6 cleanroom that was upgraded to ISO Class 5.
Purpose of facility: Manufacture filtration and separation technologies for the semiconductor and microelectronics environments.
Contractor: Clean Room Construction (Kent, England)


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