Cleanrooms are special environments but so are cleanroom laundries. Cleanroom operators send soiled garments to such places and expect such items to be returned ready for use.
Monique takes a behind the scenes look at cleanroom laundries and the quality control systems necessary to ensure that returned garments are up to standard.
Hopefully this insight will enable you to ask the 'right' questions when deciding where to place your cleaning order.
The basic requirement of the cleanroom laundry is that its clean facility should be equal to or better than the cleanrooms where the garments are used, e.g. garments that are used in a class 10 (Fed. standard 209E) should be treated in a class 10 cleanroom laundry facility.
For a cleanroom laundry this necessitates, therefor, a system for monitoring the major parameters as for any 'normal' cleanroom e.g.
In addition to this ,however,there are other important parameters e.g.
All of the instruments used must,of course, be validated and this information must be available.
The quality of the cleaned garments is so dependent on this initial set-up that cleanroom laundries should be moving towards,where possible, continuous and automatic monitoring of all important parameters. This data should be documented and available for scrutiny.
In addition to those validations that are done "automatically" there has to be a system in place to do microbiological controls. This is especially important for those laundries that decontaminate garments that are used in the medical and pharmaceutical cleanrooms, and also for garments used in the food industry.Important tests that monitor cross-contamination are:
Surface contamination: The critical spots where the garment will or can touch the surface like the door of the washer, the door of the dryer, transport material in the cleanroom, folding tables, door handles (if there are any).
Personal hygiene: In a cleanroom laundry there are still many manual actions necessary, like loading and unloading of washers and dryers, folding and packaging. Therefor it is important that the personnel are regularly checked for microbiological contamination on fingertips, hands and garments.
Beside these 'objective' checks the personnel have to be trained and checked on working in the right manner. They have to be dressed properly and behave to assure optimal conditions in the cleanroom and of the garment. A personnel education and training program has to be in place.
Even with an ideal laundry set-up,it is important to have appropriate procedures to monitor the final quality of the garments concerned.The exact nature of such monitoring should reflect customer needs but due consideration should be given to:
A major consideration of the final product is the particulate and microbial counts present.
(i) Particles
To determine the number of particles that are present after the laundry and decontamination process there are standard test methods available:
(i)ASTM F51-68; standard method for sizing and counting particulate contaminant in and on cleanroom garments.
(ii)IES-RP-CC003.2 Garment System considerations for cleanrooms and other controlled Environments. This includes a modified ASTM method and the Helmke drum test.
The ASTM F51-68 test method is simple but very time consuming. A section of the garment is placed over a gauze screen, one square foot in area, and is vacuumed using a filter paper holder.
The classification of surface cleanliness of the fabric as detailed in the standard is as follows:
Table 1 Particulate cleanliness classes(maximum counts per square foot)
|
Class |
Contamination per square foot |
|
A |
Less than 1,000 - 5 microns and greater particle length |
|
B |
Less than 5,000 - 5 microns and greater particle length |
|
C |
Less than 10,000 - 5 micron and greater particle length |
|
D |
Less than 15,000 - 5 microns and greater particle length |
|
E |
Less than 25,000 - 5 microns and greater particle length |
The Helmke Drum test method is very easy to perform. The garments to be tested are placed in a rotating drum that is open at one end and tumbled to release particles from the fabric. An automatic particle counter is used to sample the air within the drum to determine the particle density level.
Table 2 Helmke Classification Chart
|
Category |
Garment |
number of particles > 0.5 µm |
|
I |
1 coat |
< 1000 |
|
I |
1 coverall |
< 1200 |
|
I |
5 caps |
< 450 |
|
3 hoods |
< 450 |
|
|
II |
1 coat |
1000 - 10.000 |
|
1 coverall |
1.200 - 12.000 |
|
|
5 caps |
450 - 4.500 |
|
|
3 hoods |
450 - 4.500 |
|
|
III |
1 coat |
10.000 - 100.000 |
|
1 coverall |
12.000 - 120.000 |
|
|
5 caps |
4.500 - 45.000 |
|
|
3 hoods |
4.500 - 45.000 |
(ii) Micro-organisms
There are no national or international standards that describe how to test the level of micro-organisms on (cleanroom) garments. On the other hand, almost all standards and guidelines concerning the pharmaceutical, medical and food industries say that "micro-biological tests have to be done" on garments. They just do not explain how these tests have to be performed or what the acceptance criteria are. Other guidelines prefer sterilisation of the cleanroom garments by gamma or beta radiation or steam sterilisation.
Sterilisation always damages the garments. It shortens the lifetime of the garments by approximately 30% and is thus expensive. Further it is questionable if it is really necessary to sterilise garments, because they are not sterile anymore when removed from the package and worn. Some cleanroom laundries have developed a validated process of washing and decontamination of garments, including extensive microbiological controls. These controls are not performed on the garments themselves, but as mentioned earlier,but in the cleanroom itself, on the equipment, the personnel and the used wash and rinse water.
The actual microbiological tests are mainly done with dipslides. By making contact with a dipslide and the surface of the fabric of the cleanroom garment its microbiological status can be determined. Because there are no requirements formulated in standards, the acceptable levels of microbiological contamination have to be discussed and agreed between the laundry and the end-user. An example of such target levels can be as follows:
Table 3 Colony Forming Unit (CFU) Count
|
degree of hazard resp. risk level |
target level (CFU/100 cm²) |
|
4 |
< 1 (or sterile) |
|
3 |
< 5 |
|
2 |
< 50 |
|
1 |
< 500 |
Cleanroom laundries must have procedures that ensure product quality and these must be documented and be accessible to potential customers.
But for Cleanroom Laundries is it also important that their service level is optimal. Supplying the customers the right garments, the right amount of garments on the right time and at the right place.
It is also important that the garment 'history' is logged.Therefor the garments should be supplied with a unique number- a bar code or chip. These unique numbers are connected to a Garment Registration System.
The objective of this system is to achieve an optimal logistical process.
The following information is important:
This information is available for both the laundry and the customer. This makes it possible to create together an optimal service level with which the customers are assured of the right amount of garments with the requested Quality.
Another important advantage of such an automated system is that the system can help to control the logistical process. It is, for example, possible to program a "signal" when a piece of garments must be taken out of rotation, or must be tested after a certain number of washes. If garments are registered per person, all garments of one person can be taken out when he stops working for the company.
The chance of mistakes is seriously decreased, and thus the Quality of the service is guaranteed, as is the cost effectiveness.