What are some crucial behavioural errors frequently observed in airlocks and cleanrooms? Katrin Hoessler from German cleanroom wear provider CWS explains
A cleanroom creates special conditions for highly demanding processes and products. Employees are the decisive factor for the hygiene status of cleanrooms – and the most common cause of contamination.
Therefore, correct behaviour in and around the cleanroom is particularly important and strict rules of conduct must be observed at work. If the background is known, the understanding and thus the willingness to comply with these rules increases.
All persons entering a cleanroom are subject to strict hygiene rules in order to reduce the risk of contamination as far as possible. This importance of personal hygiene should therefore be clearly communicated and put into practice. Here, the contribution of each individual counts, because in the end, a sum effect takes place in the cleanroom. Thus, working in the cleanroom is always a team effort.
One behavioural error that should be applied to all activities in airlocks and cleanrooms is the so-called first-air effect
In terms of personal hygiene, the focus is on body hygiene, and especially hand hygiene. If possible, no body care products, cosmetics, etc. should be applied before cleanroom work. Drugstore articles should be applied before cleanroom work. This applies to both hair and skin.
The guiding principle here is clearly: less is more! After all, working in the cleanroom is not about looking good. Consequently, the following applies to hands and faces: pure nature. The trend towards nail design and eyelash extensions must be resisted.
Consistency also pays off when it comes to banning visible jewellery, because particles and microorganisms adhere to it. In addition, movement causes friction and thus material and skin abrasion. This also applies to jewellery worn under the glove. There is also the question of whether the finger ring might damage the glove. Another issue is occupational safety at this point. All this clearly speaks against wearing jewellery in the cleanroom.
For the cleanliness requirements in the cleanroom, the cleanroom clothing, including the correct handling and the associated gowning, plays an important role.
After all, cleanroom clothing is the only barrier between the human particle and germ sling and the cleanroom. In practice, correct dressing is always a challenge, especially for the cleanroom overall and sterile gloves.
Intensive training and practice are therefore required. If even one leg of the overall falls to the floor because the fabric can be very slippery, it is a case for the laundry and a new overall is needed. In the right size, of course, because otherwise there is a risk of the so-called pump effect.
This is an uncontrolled release of contaminants from the collar area during a rapid downward movement, so that the overall tightens around the body.
This brings us to these mnemonics: Please move slowly and in a controlled manner. Avoid fast and hectic movements. This applies to all cleanroom activities, including cleaning. Stress or haste and the cleanroom are a big no.
Consistency also pays off when it comes to banning visible jewellery, because particles and microorganisms adhere to it
This is due to the special airflow in the cleanroom. Ideally, the maximum amount of clean air enters the room via the ceiling and leaves it as close to the floor as possible. As a result, contaminants of any kind are always pushed down to the floor and accumulate there. If cleanroom personnel now walk too fast, these contaminants are stirred up again. This also has a negative effect on the airflow in the room.
The designed airflow of the cleanroom and airlock should be influenced as little as possible by the activities and machines in the cleanroom. A common mistake is when exhaust air openings are partially or even completely obstructed. After all, a trolley or other cleanroom interior, such as a table, must be placed somewhere.
There is usually space in front of the exhaust air opening to put things down. However, this is not a good idea for the reasons described.
For optimal removal of all airborne contaminants, there should also be no horizontal surface above the exhaust vent. Trash cans or similar should not be placed right next to it.
The subject of coughing and sneezing in the cleanroom is often the subject of controversial discussions. Is it permissible to prohibit these physiological reactions to chemical or physical stimuli? Should they be suppressed? The regulations on this are up to the cleanroom operator. In any case, it makes sense to consider possible solutions to both problems, even though in practice people very rarely cough or sneeze in the cleanroom - provided they are healthy.
One option would be to take cleanroom wipes and hold them quickly in front of the mouth and nose. All droplets should be trapped in the wipes at the latest, so it makes most sense to remove these wipes from the face and dispose of them only in the personnel airlock. All cleanroom clothing, in particular face masks, possibly eye slit hoods and gloves, must be changed after this action. This is followed by renewed gowning in accordance with the specifications of the relevant cleanliness class.
The subject of coughing and sneezing in the cleanroom is often the subject of controversial discussions. Is it permissible to prohibit these physiological reactions to chemical or physical stimuli?
However, you may have just entered the cleanroom and can return to the personnel airlock by a short route to finish coughing and/or sneezing. Thus, your aerosol does not enter the cleanroom at all. If left unchecked or without a mouthguard or similar, the ejecta consisting of glycoproteins, cell debris, minerals, bacteria and viruses would be distributed over a distance of approx. 5 - 8 metres.
Not suitable for the cleanroom is the widespread rule of coughing or sneezing into the crook of the arm due to the coronavirus. If you sneeze or cough into your armpit, aerosol will get past the top and bottom of your arm and into the room. In addition, the sputum would subsequently be on the outside of the cleanroom clothing. Microorganisms and particles would then be blithely carried through the cleanroom - even if you went directly to the personnel airlock after coughing and sneezing.
A common behavioural mistake is also scratching.
One must not do this.
The first hurdle to become aware of at this point is the conscious awareness of this automatism of the body. The second hurdle is self-control. If one cannot or does not want to oppose this stimulus, one goes by the shortest route to the personnel lock. There you can scratch.
This procedure is also recommended for corrections that have to be made to the cleanroom clothing for various reasons. This also includes a brief tug on the mouth guard or safety goggles.
Skin particles and hair do not belong in the cleanroom. However, anyone familiar with cleanroom cleaning will certainly have already found and removed the hair in the cleanroom. And with it, of course, particles and microorganisms.
One behavioural error that should be applied to all activities in airlocks and cleanrooms is the so-called first-air effect. The rule is: Do not lean over the process/product/cleaned or disinfected surfaces.
Otherwise, the specific airflow in the premises will cause contamination to be blown off by the cleanroom personnel and travel directly to where it is not supposed to go, thus posing a hazard to the product.
It always becomes especially critical when there is a human being at the end of the value chain who wants to get well.
The question also arises as to how many people may be in the airlock and cleanroom at the same time.
Do the cleanroom personnel know these numbers? Where are these figures written down or, in the simplest case, can they be read on site? Are there language barriers among the personnel or is everyone able to read and understand German texts?
This is usually determined by the cleanroom manager and regularly monitored by particle measuring devices and must be communicated and known to the employees.