Fab 25`s world-class, on-site laundry
Fab 25`s Class 1 cleanroom laundry is designed to service the needs of between 400 and 500 employees a day. Particle-loading was a major concern to project leader Bob Woods, who was hired last March to get the laundry up and running. “At the outset, I was very interested in what an acceptable standard of cleanliness would be. We did a lot of testing of the garments coming back from our vendors offsite. To me, it just didn`t seem acceptable that the industry standard was 50 particles at 0.5 µm. I generated the first load of laundry in April of last year, and we`ve had no failures yet at 50 particles at 0.16 µm.” To further reduce costs, and since they will not be leaving the fab, garments are not poly-bagged as in independent laundries, but stored in containers for dispensing. Woods feels an additional source of ESD contamination has been eliminated by not using the bags.
Wood concedes there were major challenges and setbacks in building an in-house laundry facility from the ground up. “I checked into the industry and found that independent laundries of this nature generally fail, and I wanted to know why. The reason is that it`s pretty difficult to maintain a standard of excellence if you lose control of your standards or lose sight of what you`re there for.” Woods developed a training program for the fab`s laundry personnel and documented standards and processing. “From Day 1,” he says, “I tried to instill in the people working in the laundry that a world-class operation is going to take everybody`s support and efforts.” Laundry employees receive training from nurses in a local health care facility in the use of gloves, facemasks and goggles when handling garments.
The laundry consists of two classified areas–a Class 10, or “building suit” area where washing and folding of laundry takes place, and a Class 1 gowning area–supplied by five different air supply zones. No street clothes are admitted into the fab, and jumpsuits and building suits are not to be worn outside the fab`s controlled environment. Two 240-lb. barrier-type washers and four 150-lb. HEPA-filtered dryers operate two loads a day at each tool– a total of four loads a day. Process cycles are over an hour long, and DI water is used throughout. The industry standard, says Woods, has always been “street” water–clean or filtered–with the last two rinses “UPW” or DI water. At Fab 25, he says, “we have no street water in the laundry at all. It`s expensive, but you pay for what you get, and the accomplishments we`ve had with that are worth the expense.”
The use of ultrapure water for all wash/rinse cycles in the fab`s laundry presented its own problems. A special stainless steel tank had to be constructed to allow the UPW water to be degraded before it could be safely drained through piping and sewer systems. UPW engineer Marcel Montalvo says ultrapure water is used because “we don`t want any sodium content being released into the fab. We also want to make sure that all our garments are clean and don`t hold any residual sodium content.” Steps are also being taken to conserve water, since the fab currently uses 300-400 gallons a minute, says Montalvo, which will expand to 800 gallons at full build-out. Flow rates have been reduced, and methods for recovering some of the water throughout the UPW systems have been developed. Quantity of soap was also an issue, according to Woods, because of the ultrapure water. “By using the UPW, we`ve reduced our chemical consumption drastically. We were expecting to go through a 55-gallon drum every quarter: I`m still on the same 55-gal. drum almost a year later. So I`ve cut it by a third or a fourth.” As to cost factors, at this point in time, he says, the staff is still collecting data because procedures are still changing.–SE