Dedicated cleanroom cleaning equipment and products account for a large proportion of cleanroom running costs and this spend is steadily increasing year on year. The challenge is reducing consumable costs while upholding environmental standards that maintain yield levels and do not create final product issues: invariably, the higher the cost, the lower the number of particles and fibres a wipe will generate. One cost reduction strategy is to move from single use to reusable items that can be laundered or resterilised or both. Another is to change to a supplier that promote itself as either a manufacturers selling direct or as a distributor handling large volumes of product at lower selling prices
Wipes are used at all stages of cleanroom production processes
Dedicated cleanroorm cleaning equipment and products account for a large proportion of cleanroom running costs and will readily continue rising if selection and practice goes unchecked. Karen Rossington, marketing consultant for Contec Inc, looks at how to implement the most cost-effective selection of cleanroom wipes and mops.
In today’s current economic climate, pressure to minimise costs, increase bottom line profits or meet budget targets is more acute than ever. Even with the most innovative of products, manufacturers will not succeed unless the products are appropriately priced, which usually means minimising production costs – including consumables.
Even the smallest cleanroom facility will spend tens of thousands of pounds on cleanroom consumables in a year; in a large facility the consumables spend will run into hundreds of thousands of pounds. McIlvaine’s Cleanroom World Market report put the revenue for cleanroom consumables at US$10.3bn (€8bn) in 2011. This spend is steadily increasing year on year. Gloves are the single biggest consumable purchase, closely followed by wipes.
Taking into consideration all the areas of the cleanroom where wipes are used, it is easy to see why they form such a significant part of the consumables budget. The global spend on cleanroom wipes is currently estimated at $776m (€600m). Wipes are a very visible cleanroom consumable used for cleaning and disinfecting equipment and work surfaces, residue removal, wiping operator gloves, transfer disinfection and the final wipe down of product in pharmaceutical cleanrooms. In semiconductor Fabs wipes are frequently used for the removal of surface contaminants and molecular condensables, to pick up liquid spills, and to clean equipment, load ports and process chambers during preventative maintenance.
Mops can equally be regarded as a special form of wipe used for cleaning large areas and are usually manufactured from similar fabrics but with the addition of foam or lining to make them more sorbent. The addition of mop costs to the figures raises the consumable spend even higher.
The large demand for wiping products throughout a clean facility means that today there are numerous wipe fabrics to choose from.1 These can range from heavyweight, double ply, laundered, knitted polyester, sealed edge wipes through to rayon and cellulose blends manufactured with binders. Invariably, the higher the cost, the lower the number of particles and fibres a wipe will generate. The options that are available specifically for cleanroom use are also numerous (see Table 1).
|Table 1: Options for cleanroom wipes|
|Choice of fabric||100% polyester, polypropylene, polyester microfibre, microfibre blends, polyester/cellulose blends, rayon, cotton, PU foam|
|Weight per m2||Can range from 22g/m2 to 300g/m2|
|Construction||Knitted, hydroentangled, meltblown, chemical binders|
|Conversion||Sealed border, heat sealed (laser, thermal), knife cut|
|Size||Can range from 10cm x 10cm up to mop wipes 30cm x 60cm|
|Format||Bulk packed, flat stacked, bulk half fold, individual fold, C fold, Z fold, dry or presaturated|
|Packaging||Pouch, tub, resealable, number of wipes per pack|
The majority of fabrics mentioned in Table 1 can also be used to produce mop covers. Mops adapted for cleanroom use include string or edgeless mops manufactured from low particulate materials. Flat mops are used in many cleanroom facilities and mop heads are available both sterile and non-sterile manufactured from polyester/cellulose, 100% knitted polyester, looped polyester, polyester-covered foam, microfibre and looped microfibre. Unique flat mops based on hydrophilic polyurethane (PU) foam coated with polyester have also been developed for cleanroom use.
A reduction in consumable quality that leads to contamination of a final product or reduction in yields could end up being dramatically more costly than the immediate savings
As consumables form such a significant part of the running costs of a facility it is an area that many facilities are looking at, with a view to reducing costs. However, careful consideration needs to be given as to where these consumables cuts should happen. A reduction in consumable quality that leads to contamination of a final product or reduction in yields could end up being dramatically more costly than the immediate savings. So the challenge is reducing consumable costs while upholding environmental standards that maintain yield levels and do not create final product issues.
Two examples of cost reduction strategies highlight the benefits and risks of these efforts. The first is moving from single use items to ones that are reusable either through relaundering, or resterilisation or both. This tactic is economically and environmentally appealing. However, as detailed below, it is difficult for a relaundering operation to provide the same level of quality assurance as an OEM manufacturer. Obviously, the more critical the application, the greater the risk.
Another cost reduction strategy is to utilise new, alternative suppliers that promote themselves as either manufacturers selling direct or as distributors handling large volumes of product at lower selling prices. This strategy can be appealing based on the initial purchase price of the product, however, there can be hidden costs in this approach that are not obvious at first glance.
The option of relaundering versus disposable single use requires careful consideration
The option of relaundering versus disposable single use requires careful consideration. Best practice for both wipes and mops in a cleanroom environment is to employ single-use disposable products. This reduces the risk of cross contamination and ensures that contamination is physically removed from the cleanroom environment at the end of a session. The surface area per mop or wipe is determined by the sampling of critical metrics and validated if the area is sterile.
The alternative of laundering and re-use of mops or wipes may arguably be a cost-effective alternative to single use disposable products. Laundering typically involves a contract with an industrial laundry and, if a sterile product is required, either an autoclave process or an irradiation provider needs to be included.
A customer may purchase or rent mops at a negotiated rate from a commercial laundry. An immediate issue can result if the mops are not barcoded with the customer’s own details – only in this way is the customer sure it is its own mops that are being returned. Barcoding will enable tracking and control through the laundering (and potential sterilisation) process to ensure a customer receives the same mops through repeated processing.
As with a disposable mop or wipe, the reusable version requires the same initial testing and validation to ensure it meets the application and environmental require-ments. Since disposable mops are made from new materials to a validated process, they provide a consistent and predictable performance and result. This result remains constant even over a long period of time as a new mop or wipe with the same parameters is used every time.
With a reusable product, there must be serious concerns as to whether the product continues to perform as specified over the period of relaundering
With a reusable product, there must be serious concerns as to whether the product continues to perform as specified over the period of relaundering. With laundered reusable mops, unless the customer has enough mops of their own to fill a washer, the mops from multiple customers are processed together.
While the laundry makes every attempt to sort mops into wash loads by application, customers’ cleaning solutions, or by industry, there is no way for the laundry to know or control fully the conditions and contaminants to which mops from various customers have been exposed.
Non-sterile mops may even be processed in a less controlled industrial laundry process rather than a cleanroom laundry process, resulting in a wider range of potential cross-contamination sources.
A wide selection of different mops are available suitable for use in cleanrooms
This becomes more critical for sterile products where the irradiation parameters are also set and validated for virgin materials. Repeated use of gamma irradiation, for example, has the ability to render materials brittle and to accelerate ageing. The use of virgin materials that are less likely to have been exposed to unknown or potentially variable conditions and contaminants simplifies the validation process.
In the case of laundered reusable mops or wipes, the performance and quality of the product would need to be validated to ensure that it is not changing over time due to the inevitable degradation of the reused fabric.
During the evaluation of reusable products, it is necessary to project the performance and quality over time to estimate the life cycle and related costs of the product. Because conditions (surfaces, solutions, protocols, frequency, etc.) for each customer are different, these projections cannot be any more than “guesstimates” of actual product performance and life.
As a result, the actual quality, contamination profile and performance of reusable products will deviate over time from what was initially evaluated and predicted. Such deviation can certainly result in unintended and potentially unacceptable risk to the customer’s environment and processes.
Understanding the real risk of using reusable products can be accomplished only through repeated periodic revalidation. So the decision whether to use disposable or laundered may not be as simple a cost-down exercise as originally thought.
In today’s global age products can be easily sourced worldwide at the click of a button. The Far East is recognised as a hot spot for all kinds of fabric manufacture including wipe fabrics. A simple Google search returned results for 182 suppliers in the medical/healthcare sector within a matter of minutes offering a range of 100% polyester, microfibre and hydroentangled wipes. It is very tempting to cut out the middle man and buy a cheaper wipe directly from a converter. However, there are some factors to consider about what you are actually buying:
When purchasing from a specialised cleanroom wipes supplier you are also investing in companies with a high degree of technical support and research and development skill. Consider how much testing has been carried out on the product both through the process and on the final product before it reaches the market. Wipes that are manufactured in facilities without these controls in place, and with variable sources for the raw material are unlikely to deliver wipes that always meet the expected specification.
One of the most effective ways of reducing consumables spend without compromising on contamination control is to carry out an in depth product review. For example, Contec will support customers with expert on-site advice on whether they are using the most suitable product in each area of the cleanroom. Table 2 shows some real cost-saving examples from product application reviews carried out at biotech, pharma and semiconductor facilities.
|Table 2: Real life examples of product reviews leading to cost reductions|
|Cleanroom class||Application||Current product||Recommendation||Discussion|
|ISO 6 or 7||Wiping fused quartz||Heat sealed laundered 100% polyester knit 12”x12” wipe||Heat sealed, laundered 100% polyester knit 9” x 9” wipe||The PNHS-99 is the same as the wipe currently in use, except it is 9” x 9”. This ensures the same performance with the cost-saving associated with a smaller wipe. The wipe can be folded in half and used 4 times, similar to the current protocol|
|ISO 7 or 8||Work surface cleaning||100% knitted laundered polyester with thermal sealed edges 9” x 9” wipe||Meltblown polypropylene presaturated with 70% IPA 9” x11” wipe||This is a lower cost alternative to the wipes currently in use. They provide an adequate level of IPA with a clean wipe substrate to keep work surfaces clean. This substrate is clean enough for the grade of room|
|ISO 5||Cleaning product contact surfaces||100% sealed-edge, two-ply, laundered knitted polyester 9” x 9” wipe||100% sealed edge, single-ply, laundered, knitted polyester/microfibre 9” x 9” wipe||Combining cleanliness and performance, the Goldsorb wipe contains 30% round microfibre yarn, providing exceptional surface cleaning performance, high sorbency and excellent durability without the added bulk and expense of a two-ply wipe. The Goldsorb would be a very suitable alternative to the two-ply wipe providing improved performance, cost reduction and SKU consolidation|
This may seem a simplistic approach to cost saving, but it is surprising how many products have potentially been over- specified over time. In addition, advances in product development could lead to alternative substrates or packaging formats becoming available that better suit an application at a lower cost.
Very often the wipe that is used in the product contact areas or closest to the intended product (i.e. a wafer or a drug capsule) gets used throughout the rest of the cleanroom to minimise supplier inventory or reduce consumable SKUs. These wipes will invariably be the “gold standard” wipes, 100% laundered polyester with sealed edges and low numbers of fibres, which are not needed further away from the critical zone.
There are numerous life science facilities where sterile wipes and mops are used in Grade C and D cleanrooms because they are purchased for the Grade A and B zones as required by GMP2 and it is easier not to have another wipe or mop cover on site so as to avoid any potential mix ups in where the wipes are used.
There are substantial savings to be made by not using sterile wipes where they are not needed. Verification that the correct wipe is being used in the correct area can be easily achieved by using different shaped or coloured wipes and mops. This gives a quick visual indicator as to whether an operator has the correct wipe for the grade of room.
The use of coloured or differently shaped wipes can help ensure the correct product is used in the right area
A product application review would always take place on site, allowing observation of the cleanroom operations, the environmental classification required and the consumable products used. The scope should include all process consumables in the cleanroom and supporting areas. The goal is to identify product suitability for specific cleaning processes. Based on the observations, recommendations can then be made as to product suitability and cost-cutting opportunities that do not affect the overall levels of contamination.
Considerations for cost-cutting would include:
In summary, cleanroom consumable costs are a significant part of a cleanroom facility’s running costs that must be controlled if budgets and profit targets are to be met. Support from specialist cleanroom consumable manufacturers can help to identify cost-cutting measures with no loss of quality or increased risk of contamination.
Any cost-saving measures should be carefully considered with a long term view to ensure it is not a false economy or likely to compromise the consistency and repeatability of a product, which in turn could impact the production process or yields.
1. K. Rossington, Cleanroom Technology, Vol. 12, pp20–22 2011
2. EudraLex. The Rules Governing Medicinal Products in the European Union Volume 4 EU Guidelines to Good Manufacturing Practices for Medicinal Products for Human and Veterinary Use. Annexe 1
The author would like to acknowledge the assistance of Dave Nobile, Don Batts and Jack McBride in the compiling of this article.