How to Choose a Cleanroom Laundry
By Susan English
Cleanroom laundry users can be taken for a ride if they`re not careful about their choice of laundry, their contract options, and the services provided. Understanding how the laundry functions, as well as your company`s needs–required level of cleanliness, the right garment system–all contribute to the choice of a laundry that`s right for your company.
Educating oneself as a potential laundry user means that both user and provider will enter into a contract with realistic expectations based on an accurate assessment of the processes and requirements and with a better chance at achieving profitable results. Customer knowledgeability, quality control, garment availability and turnaround, and redundancy–backup systems–are factors most laundries can agree upon as integral to the service they provide. According to Mission Clean Room Services` (Round Rock, TX) cleanroom/contamination consultant Bob Spector, “an informed user is the best kind of customer to work with.”
Sometimes informed users may not necessarily understand how the laundry works, but they definitely know what they want from a laundry. Affordability, high standards of cleanliness, technical support, or “rapid response,”–not necessarily in that order–are some of the things end-users look for in a cleanroom laundry system. For Joe Rauchet, a senior engineer with AT&T Microelectronics (Allentown, PA), the end-user/garment service relationship is an important one that includes continuous monitoring and information sharing. In addition to tests the laundry performs and which Rauchet monitors, his people examine garment fibers on scanning electron microscopy, sampling twice a year for fiber breakdown. Also, his team audits the laundry on a yearly basis.
He cites an example of the industry-wide benefits of close cooperation. “Years ago, when people were putting the antistat solutions in the cleanroom laundry, I was asking, `Why are they doing this?`–because we`re already wearing antistat material–so who really cares!” When AT&T began getting complaints from their other facilities where people were contracting skin rashes, he felt it was time to enlist the services of nearby Bell Labs (Murray Hill, NJ). After experimenting with garments laundered without the antistatic formula for a month, reports of rashes disappeared. Rauchet shared the formulation with the laundry`s technical people, and as a result, the antistat was dropped from their process. AT&T Microelectronics also called other laundries and shared the information with them.
The Role of Cleanroom Laundries
The role of cleanroom laundries is to eliminate the secondary release of particles/fibers, ESD, chemical or biological residues from cleanroom garments. Although the human operator seems to have been superseded by acids, gases and other process fluids as the major source of contamination in semiconductor processing– “environmental contamination” (the atmosphere within the cleanroom and the operator) contributes to less than 5 percent of defects, according to a fairly general consensus within the semiconductor processing industry–in the other industries that employ contamination-free manufacturing, operator-generated contaminants remain a major concern. The human operator also generates potentially destructive electrical charges that can seriously impact profit/yield margins in applications ranging from semiconductor wafer fabrication to parenteral drug and aseptic fill, from fiber optics to food processing, and from aerospace to automotive paint spray applications.
Often, cleanroom laundries began their existence as offshoots from industrial laundries. Industrial washers and dryers were reconfigured to prevent cross-contamination in the processing of hospital and surgical garments. These original “barrier” machines were loaded from one side of a wall–the “dirty side”–and unloaded into the clean side. Today`s cleanroom laundries operate on much the same principle, except that washers and dryers are sealed into the walls. Also, few function merely as “laundries,” but offer complete garment leasing and rental programs, and a few offer their own line of cleanroom garments for direct sale. As such, cleanroom laundry companies in reality comprise the major portion of the reusable garment industry. They operate entirely separate from the big industrial laundries or uniform rental companies that spawned them, usually as a division, if not a physically separate entity.
Cleanroom laundries process disposables as well as reusable garments. Even though never worn, disposable cleanroom garments must be prelaundered to prevent contamination of cleanroom environments from fibers from cut edges and sewing thread, lubricants from machinery, and the general dust and dirt from manufacturing and warehousing. Laundries use specialized equipment and specific processes and controls to clean garments to acceptable levels, as well as special testing methods to measure the effectiveness of the cleaning process itself. Cleanroom laundries operate under Federal Standard 209 and largely base their processes and procedures on the recommended practices (RPs) of the Institute of Environmental Sciences (IES), specifically IES-RP-CC003.2–“RP-3,” as it is known–and various Standard Operating Procedures (SOPs), Statistical Process Controls (SPCs) and Quality Control/Quality Assurance (QC/QA) guidelines.
Working with a Laundry
Different companies have different ways of working with a laundry. Intel Corp. (Hillsboro, OR), for instance, uses a “partnering” rather than a vendor approach in working with its laundries. The company considers the laundry workers as much a “first line of defense” as its process equipment people and treats them accordingly, says Intel`s Dave Hope, microcontamination manager in the Facility Technology Group. As part of the corporate group that constructs new fabs and certifies them, Hope sits on a special “strategic cleanroom users group” comprised of all Intel microcontamination group leaders. When Hope goes shopping for a cleanroom laundry for one of Intel`s many facilities, he often finds his team must bring the laundry up to the company`s own standards.
Intel, which predominantly uses cleanroom garments fabricated of Gore-Tex from W.L. Gore Associates, (Elkton, MD) requires their local contract laundry/processor personnel to work onsite. Laundry personnel literally “live” in Intel`s gowning room, and are responsible for keeping stocks replenished, sending the garments to the laundry for cleaning, and also for helping visitors suit up.
Obviously, it is important for a laundry to be of the same class as the facility it services. Layout is also important. Says Intel`s Hope: “The last thing you want is somebody unloading dirty garments that have to be brought past a final drying/packaging area to go to the washers,– and I`ve seen that done.” Ideally, he says, garments should be loaded directly into washers from the outside, and then sent to a Class 10,000 or better pre-screen room to get ID`d and checked for damage and repaired or weeded out before washing. (Because Intel uses garments constructed of Gore-Tex fabric, they are washed and dried only with other Gore-Tex garments.) Hope has actually seen garments brought in through an airlock, past the dryer, to get to the washer. He has also seen dryer filters blowing air in upstream of the heater element. “So we look at this and the attitudes of the people and whether they`re cleanroom trained,” says Hope, who sends a team of Intel`s microcontamination people and buyers on a yearly inspection tour of each of the laundries contracted by Intel facilities.
Analog Devices (Wilmington, MA) was looking for a garment processor that could provide a very specialized system to make cleanroom personnel more responsible for their garments and treat them with better care, says Roger Diener, Analog`s materiel control manager. “When I put this out to bid to the laundry services, I defined that I wanted a personalized system and a `touchless` one for me. We found that over the years, people are not very careful with the garments–they may end up on the floor just as easily as hanging on the hook properly–so that when people come in, they can`t find their garments. And you ended up using a lot more laundry, so we were constantly running into problems of not having enough garments on supply.” Together, he and the garment processor devised a system of identifying garments with sewn-on logos. The garments were then packaged in a kit, and laundry personnel placed each kit in each worker`s own locker. The system helped Diener`s team control sizing and also saved the company valuable “real estate,” because gowning and storage did not need to be in the same area, and lockers vs. garment-covered walls are a more efficient use of space, he says.
While Analog Devices was searching for a personalized garment system, Dale Malzie, a process and facility engineer at optical fiber manufacturer Alcatel (Roanoke, VA) was handling his company`s first encounter with extra charges levied for “spotting” garments and for the barrels the laundry used to transport garments to and from the site–costs which were not included in the original contract. Also, when a garment did not come up to the laundry`s “standard,” the company found itself being automatically charged replacement costs. Originally, the laundry had “lowballed” the contract, but by three months before termination, Malzie says, Alcatel ended up spending double the amount they had originally signed a purchase requisition for. Trying its luck with a new laundry, Alcatel found it actually saved “in the neighborhood of about 58 percent” over its original investment.
Educating Potential Users
Prudential Overall`s (Irvine, CA) Bill Stoner offers some advice for potential laundry users: “This is a small industry. We bring a customer through our plant to find out what things they`re looking for–so it`s an education. Many times, we have to bring a potential customer up to speed on what`s involved in maintaining their garments and what they have to consider.”
Before choosing a laundry, it`s a good idea to make sure you have a list of questions for your laundry candidate. Says Dave Schedin division manager of UniClean, whose parent company, Unifirst–the U.S.`s third largest industrial laundry, according to the company–operates two cleanroom laundries, in Nashua, NH and Portland, OR: “Some customers very much look to us as the experts; others give an ultimatum. Every company has a different culture. All we can do as a potential supplier is give them all the options and they decide.” The “options” start with a basic package, which usually includes fabric selection–what features are appropriate, the ramifications of the different selections, frequency of change, etc. He says recommendations are based not just on what the company suggests, due to vested interest, but what independent professional societies or organizations support.
One way to learn about the cleaning process and keep up with important developments in the industry is to attend IES working groups. Mission Clean Room Services` Spector is chairman of Standards and Practices for the IES`s Contamination Control Division. His goal is to get more and more users involved in IES working groups. In addition, Chuck Berndt of C.W. Berndt Associates, Ltd. (Highland Park, IL) chairs IES Working Group 29, which in May, expects to issue nonmandatory Recommended Practices and guidelines for controlled paint spray environments and related operations, including but not limited to the automotive, avionics and aerospace industries.
Negotiating the Right Contract
Laundries generally offer three options for servicing cleanroom garments: Direct Purchase of Customer-Owned Garments (COG), Lease/Purchase, or Rental. With direct purchase, the user purchases outright the garments it needs and is responsible for managing inventory, including replacements, style/size exchanges, repairs, inventory increases/decreases. This approach requires an upfront cash investment and involves an additional charge for repairs and stain removal over and above normal processing charges.
In a lease/purchase arrangement, the garment processor buys the garments, spreading the purchase price in payments plus interest over a predefined and agreed upon time frame usually based on the expected life of the garment system.
In a rental arrangement, the charge to the user is generally on a per item/per week basis. Total garment system purchase cost is borne by the laundry, who owns the garments at the end of the rental term. (Rental payments are higher than lease/purchase payments if compared on a weekly charge basis.) Services include routine repairs and replacement of apparel at no charge due to normal wear and tear. The laundry controls the useful life of the garment system, is responsible for managing the inventory, and generally provides garment-related technical advisory and training support. There may be a small handling charge for style/size changes, inventory decreases, and replacements attributable to other than normal wear and tear, etc. Because of the significant investment in inventory made by the laundry, the rental contract will usually contain a “buy-out” clause in the event of early termination. The user may be charged on a weekly rental-plus-processing basis, or a flat rate, based on assigned inventory and minimum weekly inventory usage, may be assessed.
For those potential users with moderate to lower-use cleanrooms, there is the option of installing an in-house laundromat system like the one offered by cleanroom manufacturer Liberty Industries, Inc. (East Berlin, CT). Designed for Class 10,000 and other areas with laminar flow conditions, the system consists of a combination 15 lb. capacity washer and 120 Vac, front-loading, HEPA-filtered (to 0.3 mm) dryer that can process both reusable and disposable cleanroom apparel. The use of deionized water is not recommended, but water is filtered to one micron. Capacity is 12 pieces–double for disposables or nonwovens.
Garment Availability
Besides cleanliness, availability of garments is perceived as the highest user priority on the part of many industry suppliers. Being able to get garments quickly enough on a week-to-week basis is the biggest concern of customers, says Brian Webber of Aramark (La Grange, IL), whose cleanroom division exists within Aramark Uniform Services, the largest uniform company in the country. According to Webber: “The way I talk to our customers is, we`re here not just to provide them with garments, but to provide them with insurance. Because unlike our industrial uniform sister, if one of our customers doesn`t get a uniform in one day, it`s not going to shut them down; but if we don`t ship our customers their cleanroom garments in a timely fashion, we can literally shut down their facility and bring them to a screeching halt.”
If garments are not in stock, companies may have to “go calling around the marketplace,” says Karry Jones, cleanroom general manager of Cintas Corp. (Gilroy, CA), which means there may have to be compromises in the consistency of quality or sizing, as well as cutting and sewing, because Jones says, each garment company has its own sizing lasts. Cintas is a startup operation catering to small and intermediate size operations in the semiconductor industry.
Quality control is taken very seriously by good laundry companies, and a few–particularly those who service users in pharmaceutical applications–boast in-house laboratories to test and monitor quality. At Servitex Cleanroom Services (Durham, NC), in-house laboratory personnel perform bioburden tests, as well as surface resistivity, Helmke Drum and the various other ASTM methods. Also, quality control at Servitex includes continuous inspection of all equipment and regular recalibration and certification of instruments, says General Manager Jay Valentine. Garment testing and research also help laundries keep abreast of new fabric technology. Canadian high tech processing firm Cleanroom Garments (North York, Ontario) services the automotive paint spray, as well as micromanufacturing and pharmaceutical industries, specializing in “absolute particulate control” for removal of one-component, two-component and waterborne paints. The company is presently doing comparative research on cleanroom processing of ESD twill polyester automotive garments, both in a cleanroom and an industrial laundry setting. Particulate loading and fabric degradation are being measured using cleanroom vs. industrial laundry methods, according to company President Rob Nightingale.
Static testing for “tribo-charging” and resistivity, integral to the semiconductor industry, is something Alltex Uniform Rental Service (Manchester, NH) specializes in. In 1985, vice president Dick Buechsenschuetz developed a device that measures the potential (voltage discharge) to ground of a human body. As a result, he has built special patterns for grounding the body through cleanroom boots and a standard for boot measurements. Antistatic coatings on garments do work, he says, but the challenge is to get the right amount, so that the fabric itself does not give off a gas.
Most laundries/processors seem to be aware of the importance of service as a component of good working relationships with users, especially the smaller laundries. Companies like J & G Cleanroom Laundry (Greenville, SC), a Class 1 certified operation with its own QA program and in-house laboratory, offer a flexible program. Greg Shawber, who used to operate cleanroom laundries for one of the largest companies in the country, says, “The name of the game is “service”–and that`s what we do: We`re in the service business.”
Understanding “Clean”
Laundries do clean garments, but to determine if the process is done correctly, laundries must also test their cleaning methods. In order to test the effectiveness of the cleaning process, a percentage of each lot is sampled. Laundries use a variety of test methods to check such garment factors as chemical-residue levels, electrostatic discharging (ESD) and bioburden. Fiber and particle measurement are of primary importance to the users of open-weave fabrics, which tend to trap particles measuring 5 mm or larger. (Fibers are defined as particles with a length/width ratio of 10:1.) For industries concerned about submicron particles, these tests are useful as a tool for checking on the integrity of the garment-processing (laundry) system and determining if a garment is breaking down. They are unsuitable for evaluating more advanced barrier-type materials such as those used in the pharmaceutical and biotech industries, which require sterilization.
Two test methods of non-destructive particle count testing of garments published by the American Society of Testing and Materials (ASTM) are recommended in IES-RP-CC003-87T. ASTM F51-68 (R89) Alternate Method employs small area (0.093 m2) sampling. A garment is vacuumed for one minute, using an air flow of 20 liters per minute. Performed on a clean bench, particles are collected on a 0.8 mm membrane filter, and microscopically counted and characterized as particles and fibers up to 5 mm in size. The preferred and most widely used test method is the Helmke Drum Test, which measures the number of particles per minute released from the surface of a garment, quantifying particles from 0.5 mm to 0.3 mm or less for Class 1 wafer fabrication applications. A folded garment is placed in a rotating, stainless steel drum and tumbled at 10 rpm. Either an optical or a laser particle counter can be used to sample the air in the drum and measure the size and quantity of particles present. Connected to the particle counter is an air-sampling tube, inserted into the opening of the drum. First, the number of particles present inside the rotating drum is measured to establish a background count. Then, average particle density is measured during the first 10 minutes of the test, the background count subtracted out, and the results compared to a classification chart.
The ASTM procedure is considered tedious and laborious and is usually only employed to satisfy statistical test requirements or specific customer requests. While the Helmke Tumble Test has a few drawbacks (it does not distinguish fibers nor allow visual inspection of contaminating materials), it is fast, relatively fail-safe, and easy to administer. By virtue of its simplicity, it is probably the most widely used test by state-of-the-art precision laundries. n
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(Below, top left) A “body box” test is performed at Mission Clean Room Services. (Top right) Garment testing at Cleanroom Garments, Inc. (Bottom right) PFG`s line of Aegis fabric is antistatic and splash resistant. (Bottom left) A Helmke drum test measures the number of particles per minute.
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Garments are loaded into large capacity (200 lb.) barrier pass-thru washers, washed with a solution of purified water and special non-ionic surfactants, and loaded into large capacity dryers fed with HEPA-filtered air, powered by steam, gas or electrical resistance. For low to moderate cleanroom usage, an on-site cleanroom laundromat system like the one from Liberty Industries (near right) could be a cost effective options.
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After drying, garments are inspected for defects, then folded, packed and sealed in polyethylene bags, placed in a pass-thru and sent out of the cleanroom to the shipping area.
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Garment turnaround time, a major component of service, is one of the highest user priorities. Being able to get garments quickly enough on a week-to-week basis is the biggest concern of customers, says an Aramark company spokesperson.
How are Garments Cleaned?
Even before the cleaning process, pre-processing in the laundry`s cleanroom wash preparation area is a vital step.
Some laundries have an ID-system using barcoding or microwave tagging. Soiled garments are inspected before being sorted into groups of similar items for washing, and damaged garments are weeded out for repair or replacement. Here, garments no longer meeting a contamination-containment standard should be removed and returned to the customer. Most processors separate heavily soiled garments from more lightly soiled ones during processing to avoid cross-contaminant burdening. Cleanroom boots should always be washed separately from other cleanroom apparel. The washload is made up, weighed and logged into the machine. A solution of purified water and chemicals is added to a large capacity (200 lb.) barrier pass-thru washer to overcome the forces that attach particles to the garment– the London/Van Der Waals, electrostatic, and capillary condensation forces–and wash away any chemicals and contaminants present. A typical water system combines several phases of purification, including carbon filtration and mixed-bed ionization, which prevents the ionic residues left by cleaning solvents, surfactants, and water or organic solvents, such as perchlorethylene.
All phases of the process are tightly controlled. Instead of commercial detergents, special non-ionic surfactants are used. Water is passed through a pre-treatment cycle, a reverse osmosis system, a deionization system, and a final sub-micron filter ranging from 0.5 to 0.2 mm. For medical or pharmaceutical applications, the washload will undergo a series of ultraviolet sterilizers. At this point, process water will usually have a resistivity of anywhere from 5 to 18 megohms. The water is then mixed with a surfactant in special washer extractors for initial cleaning. Many companies have microprocessor-controlled wash formulas programmed into the memory of the equipment–properly metered, controlled and alarmed. The initial wash is followed by several rinses with DI water, and then often passed through UV filters to kill and remove any bacteria present.
Garments are dried in large capacity dryers fed with either HEPA- or ULPA-filtered air, powered by steam, gas or electrical resistance. Drying temperatures must be high enough to dry garments in the shortest possible time but not so high as to reach the glass transition point of the material. Drying is followed by a cool-down phase to minimize wrinkling. Drying temperatures, drying times, cool-down times, wash formulas, etc., vary according to the type of application and are invariably considered proprietary. After drying, garments are inspected for defects such as split seams and broken zippers or snaps, and then folded, packed and sealed in polyethylene bags. Once sealed, the garments are placed in a pass-thru and sent out of the cleanroom to the shipping area, which is itself often Class 100. Inspection, folding and packaging–as well as washing and drying–of cleanroom garments should be performed in a well-controlled cleanroom environment.–SE