News Air Lock Concepts
Here you will find answers to the following questions:
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Air locks are rooms of a particular cleanliness grade that enable the passage of persons or materials into an area of a lower or higher grade. Air locks must correspond to the same cleanliness grade as the adjoining work area. They are subject to the same building and air filter requirements as all other rooms of the same cleanliness grade (see chapter 3 Premises).
The use of different air lock concepts depends largely on the layout of the building, the machine facilities, and the direction of any air flow channels. Regardless of the resulting design, the air lock must always fulfil the relevant requirements in terms of minimising microbiological and particulate contamination. The following is an explanation of the different air lock concepts.
12.B.1 Personnel locks in the clean area
A personnel lock is usually a relatively small or medium-sized room in which activities of a certain cleanliness grade are permitted to take place. In the air lock, the cleanliness grades of adjoining areas come into contact with each other.
The concept of a "sit-over-system" has proven easily manageable from an airflow perspective; it can provide an air flow suitable for two cleanliness grades with use of the appropriate filters, and can logically be integrated into activities by the persons using the air lock. Doors are only required to maintain pressure levels in the operating areas.
Cupboards used for the storage of clean and worn clean-room clothing (for short-term absences from the work area) should be ventilated or equipped with UV light in accordance with the cleanliness grade. Clothing that has been worn in cleanliness grade B must be stored in a cupboard that complies with at-rest cleanliness grade B (cleanliness grade B, ventilated), in the case of short-term absence from the cleanliness grade B area. Clothing that has been worn in cleanliness grade C must be stored in a cupboard that complies with at-rest cleanliness grade C (cleanliness grade C, ventilated).
12.B.1.1 Air locks in cleanliness grade F/E
Air locks that lead to undefined areas with respect to particles (cleanliness grade F/E, for example labs, offices), are ventilated only by an air current from E to F or into the uncontrolled area via doors that are not locked on both sides or secured with indicators.
Required clothing: none prescribed
However, clothing regulations are recommended, for example, lab coat, shoes and possibly a head covering in a standard colour to provide physical protection (laboratory) or to indicate that the employee is assigned to cleanliness grade E/F (see chapter 11.B.1 Clothing).
12.B.1.2 Air locks in cleanliness grade E/D
Starting from cleanliness grade E, the air lock to cleanliness grade D should be entered through a door with a lock (with an emergency exit mechanism) or at least an indicator (lit "Do Not Enter" sign), in order to prevent uncontrolled air flow through the air lock.
Layout: the air lock should be divided into two sections by a sit-over (see figure 12.B-1).
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Cleanliness grade E section: wardrobe cupboards for cleanliness grade E clothing/private clothing, washing facilities, storage area for cleanliness grade D clothing.
Cleanliness grade D section: wardrobe cupboards for grade D clothing, washing facilities, disinfectant for hand disinfection.
Ventilation: the air current in accordance with cleanliness grade D (microbiological particulates) should flow in the direction of the sit-over diagonally from ceiling to floor towards the "unclean" grade E side, where it is extracted. The flow conditions should be verified using smoke tubes.
Personnel: change of clothing from cleanliness grade E to D as described in figure 12.B-2.
| Change of clothing from cleanliness grade E to cleanliness grade D |
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12.B.1.3 Air locks in cleanliness grade D/C
Starting from cleanliness grade D, the air lock to cleanliness grade C should be entered through a door with a lock (with an emergency exit mechanism) or at least an indicator (lit "Do Not Enter" sign), in order to prevent uncontrolled air flow through the air lock.
Layout: The air lock should be divided into two sections by a sit-over (see figure 12.B-3).
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Cleanliness grade D section: Wardrobe for storing grade D clothing, shelf for shoe storage, washing facilities for hands, dryer, disinfectant dispenser.
Cleanliness grade C section: Wardrobe for grade C overalls, shelf for grade C shoes, sock dispenser, supply of gloves and face masks next to sit-over, disinfectant dispenser.
Ventilation: The air current in accordance with cleanliness grade C should flow in the direction of the sit-over from ceiling to floor towards the grade D area, where it is removed. Flow conditions should be verified.
Personnel: Change of clothing from cleanliness grade D to C as described in figure 12.B-4.
| Changing clothing between cleanliness grade D and cleanliness grade C |
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12.B.1.4 Air locks in cleanliness grade C/B
Starting from cleanliness grade D, the grade D "pre-lock" should be entered through a door that is equipped with a lock with an emergency exit mechanism or at least an indicator (lit "Do Not Enter" sign), in order to prevent uncontrolled air flow through the air lock.
A second door shuts off this "prelock". Behind this door is the "main lock" with the two sections cleanliness grades C and B, separated by a sit-over. The air lock is exited via a door to the grade B work area (see figure 12.B-5).
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Layout: This area is divided into three sections, with a grade C/grade B sit-over in the second section.
Cleanliness grade D section: wardrobe for storing grade D clothing, shelf for shoe storage, pool shoes for transition to section C, washing facilities for hands, dryer, disinfectant dispenser.
Cleanliness grade C section: wardrobe for optional particle-free underclothes, shelf for storing pool shoes, sock dispenser, washing facilities for hands, dryer, supply of gloves and face masks next to sit-over, disinfectant dispenser, disinfectant spray bottle.
Cleanliness grade B section: storage of grade B shoes under the sit-over or on designated shelf or optional overshoes, cupboard for sterilised cleanliness grade B clothing, cupboard for reusable grade B clothing (overall, hood), safety glasses case, disinfectant dispenser, disinfectant spray bottle.
Ventilation: the air current in accordance with cleanliness grade B should flow in the direction of the sit-over from ceiling to floor towards the grade C area, where it is removed. Flow conditions should be verified.
Personnel: change of clothing from cleanliness grade D to B as described in figure 12.B-6.
| Change of clothing from cleanliness grade D to cleanliness grade B |
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12.B.2 Material locks
Material locks are rooms through which larger pieces of equipment (vessels, bins, magazines, machine accessories, etc.) can be transferred from one cleanliness grade to another, higher, cleanliness grade. The requirements comply with the cleanliness grade of the work area that can be reached through the air locks. Only one door can be opened at a time. The material lock is generally a room that separates the cleanliness grades by two doors.
Layout: the facilities usually consist only of a store for disinfectant used in spray disinfection.
Ventilation: in single-room air locks often none, since the air is refreshed by the higher air pressure from the clean area.
Figure 12.B-7 and figure 12.B-8 show examples of material locks from cleanliness grade D to C and from cleanliness grade D to B.
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In double locks, the higher grade room can be actively ventilated, and apertures (lamellae) in the door enable the cleaner air to disperse into the pre-lock, so that a pressure difference is maintained to the rest of the environment.
Materials: all objects that enter a higher cleanliness grade via the air lock must be cleaned and disinfected appropriately. A residence time in the lock following disinfection must be established.
Summary The different cleanliness grades are separated by air locks, in which personnel change into the prescribed clean room clothing and materials are disinfected. The personnel lock is generally divided by a sit-over bench that separates the areas corresponding to the adjacent cleanliness grades. Staff change clothing in accordance with a written, defined plan (standard operating procedure, SOP). |
