Laundering for cleanrooms

15th of May 2015
Laundering for cleanrooms
Laundering for cleanrooms

CWS-boco is one of the leading international service providers of washroom hygiene, matting, workwear and textile solutions. The company’s headquarters is in Germany and it has facilities in 18 countries. In September of last year it opened its latest cleanroom laundry in Heidenheim, Germany and ECJ editor Michelle Marshall visited the facility to find out about the very demanding requirements of running such a service for clients.

In many of today’s high-tech industries – pharmaceuticals and electronics for example – goods can only be produced under very special conditions, cleanroom conditions. A cleanroom is a controlled environment that has a low level of pollutants such as dust, airborne microbes, aerosol particles and chemical vapours. The controlled level of contamination is specified by the number of particles per cubic metre at a specified particle size.

Those people working in cleanrooms must wear specific workwear, often made from particular fabrics. For example, no cotton is used and often garments are made of 98 per cent polyester and two per cent anti-static material.

CWS-boco offers all aspects of the workwear service to this and many other industries – through this side of the business the company is involved in the development of fabrics and garments, it owns them all and rents them out to the customer. All clothes regularly come back to one of the company’s own laundries for washing and drying, before being delivered back to the wearer.

At the Heidenheim site, where the most recent cleanroom laundry was built, 25,000 garments of all kinds are laundered every day. Those that must be handled under cleanroom conditions are collected by CWS vans and brought back to the facility in aluminium boxes – all clothes are put inside them immediately after leaving the cleanroom.

Jan Ulrich, who is responsible for the Heidenheim laundry, explains why conditions are so tightly controlled. “Bodies shed skin particles continuously and cleanroom clothes keep those in – so protecting the product and the cleanroom. Those clothes must be washed under cleanroom conditions because every time it is worn, that garment is contaminated.”

Each piece of clothing is scanned as it arrives and a batch number assigned to it so it can be traced at every stage of the process. Automatic counting of each batch means the CWS operative does not have to do it – preventing machine overload. The CWS software also gives a cycle count because some garments can be laundered more times than others.

A sticker is attached to each batch and the operative then checks for particular customer requirements in terms of ISO standard required (the recognised system for levels of cleanroom and associated controlled environments), washing, packaging and sorting.

Garment separation

The trolley is then taken to the 80 kg machine, which is loaded to 70 per cent of capacity. The stainless steel drum is divided in order to enable separation of garments. “We never mix customer loads,” Ulrich explains. “Even if one load is only 10 kg it goes into the machine alone.”

The water used in the cleanroom washing machines is always fresh, there is no water recovery in this area, and it has been treated in advance to ensure it has low particulate levels. After treating it is softened and deionised.

A main wash is done at 60°C, with four rinses to remove all detergents and particles. “Large amounts of water are needed for this part of the process,” points out Ulrich. And sometimes a 40°C pre-wash is required. Only specially filtered chemicals can be used in these washes, and the detergent used within the cleanroom is also an approved formulation.

The washing machine is unloaded at the back, where cleanroom conditions are in place and the airflow is stringently controlled. Ulrich explains: “Cleanrooms must incorporate over-air pressure – which is air flow from above – because as people move they still shed particles and some particles will inevitably come out of the garment. Cleanroom air presses those particles down so they cannot contaminate the room.”

CWS employees enter the cleanroom over special mats before going into the changing room, which is a controlled area. Here they put on cleanroom under-garments and clogs. Then they wash, dry and disinfect their hands and enter the second room, where they get fully dressed for the cleanroom. “They use single use gloves, hood, coverall, face mask, overboots, goggles and a second pair of gloves. Then they disinfect again,” Ulrich continues.

The third chamber which staff enter is like a sluice, an air shower to remove any remaining particles on their body. Only then are they ready to go into the cleanroom and start work.
Each cycle takes 15-20 minutes and in each room there are clearly displayed instructions on the steps to follow, just to remind them of the routine. Each batch number is recorded at all stages of the process, with note taken if it’s been disinfected for example.

Firstly the operatives unload the washing machine and load the dryer – the air in the dryer unit must be filtered and 30 per cent of it is recycled. Because the staff are always working in such a confined space at all times the cleanroom laundry area has been designed with many windows in order for it to not be too claustrophobic.

When dry, clothes are folded according to individual customer requirements, with the barcode visible. Large items are then placed into the automatic packaging machine (for small items there is a manual machine) and out-scanned again when packed. This takes place in the last room of the cleanroom complex, and the bagged garments are conveyed through a plastic door to the outside environment. They are then put back into their aluminium boxes for delivery back to customers.

For garments that require sterilising CWS has its own autoclaving machine, however this is carried out only when necessary as the process halves garment life.

At the end of laundering one garment from each batch is tested using the Helmke Drum Test , a method that simulates particle shedding of clothing under movement. The garment under test is tumbled in a rotating drum to release particles from the surface of the cleanroom garment in a controlled manner. An automatic particle counter is used to sample the air within the drum to determine the average particle concentration of the air during the first 10 minutes of the test.

“This allows us to document particle levels, along with data on how long garments were washed for, at what temperature, and dried for,” Ulrich explains. “This is absolutely crucial because it allows us to trace discrepancies and monitor all stages of the laundering process. And there is an online tool enabling customers to track and trace their workwear at all times.

“When we are serving customers in such precise and demanding industries, this level of trust in our procedures is key,” he emphasises.

Cleaning the cleanroom

So how is the cleanroom itself actually cleaned? As expected, this too is a tightly controlled procedure - it must be cleaned daily and everything that has come into contact with people or garments must be done. Floors, door handles, conveyors, walls, ceilings are also cleaned at least once a week with an approved disinfectant and each room in the facility has its own cleaning plan with separate equipment/chemical specifications.

Ulrich explains the cleanroom laundry staff clean the facility themselves. “They know best the critical places because they are in there every day, so they clean at the beginning of their shift - then they start with a completely disinfected area.”

Unlike conventional laundry and cleaning situations, a cleanroom laundry like the new CWS-boco one at Heidenheim is operating at high stakes, and mistakes can result in significant penalties and potentially serious consequences. Only the very highest of standards are good enough – not only that, CWS-boco must offer complete transparency and documentation of all its processes.


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