Every one of us who has ever worked there in the pharma industry will be familiar with the concept of achieving & maintaining the status of clean rooms or classified rooms.There are different types of cleanroom classifications in pharma where different types of dosage forms are manufactured according to the standards to meet regulatory requirements.
What Is A Cleanroom?
A clean room is an area which has a controlled number of viable & non-viable particles and is protected from contamination & cross-contamination.
 What Is A Pas Box?
As the name indicates a pass box is a box which is used to transfer or pass the materials from one area to another.
Pas box is an installation which is used to transfer materials from a less classified area to a highly classified area or from a higher clean room grade to a low grade cleanroom.
Pas box is a box used to transfer materials within the same cleanroom classes but from one area to another area.
Pas Box acts as a barrier between clean room grades & helps to prevent contamination & cross-contamination.
The doors of the pass box have an interlocking system so both doors cant be opened at the same time.
Other Names Of Pas Box
Pas boxes are also known as,
- Transfer Box
- Transfer Hatch
- Pass-Through Box
Why Do We Use Pass Boxes?
A common question is asked, why do we use pass boxes despite having an airlock system in cleanrooms?
The simple and sweet answer to the above question is that Airlocks are better suited for the entry of personnel and pas boxes are for material movement.
Explanation
Pass boxes restrict the personnel movement to get out from a specific cleanroom area to another area,whenever you need any material. Multiple exit & entries from airlocks may disturb the cleanroom status due to particulates which may be carried by the material or personnel but in the case of the pass box personnel movement is restricted & eradication from material is done during transfer through the pass box.
What Is The Purpose Of A Pass Box?
Pass boxes in pharma are used for the following purposes,
- Pass Box in pharma is used to prevent Contamination.
- Pass Box in pharma is used to Prevent Cross Contamination.
- Pass box in pharma is used as a barrier between cleaned & uncleaned areas.
- Pass box in pharma is used to transfer materials from one area to otherÂ
- Pass box in pharma is also used to transfer some equipment parts.
- Construction Of Pas Box
Pass Boxes are made of Stainless steel and the following grades of steel may be used,
- SS 304
- SS 316
- SS 316L
Types Of Pas Box
There are following two main types of pas boxes which are used in pharma.
- Dynamic Pass Box
- Static Pas Box
Dynamic Pass Box
The Dynamic Pass box is the box which is installed in the wall between two different grades of clean rooms and is used to transfer materials from areas of low cleanliness to higher cleaned areas or from higher cleaned areas to low cleaned areas.
The dynamic pass box is also known as the active pass box.
Example
To understand the concept of a dynamic pass box, let’s suppose we want to transfer media plates from grade C to Grade A so these will be transferred through a dynamic pass box.
Components Of Dynamic Pass Box
The Dynamic Pass box has the following components,
- Interlocking Doors
- Pre Filter
- HEPA Filter
- Blower
- UV Light
- Hour Meter
Interlocking Doors
The dynamic pass box has an interlocking door system. The interlocking installed does not allow anyone to open both doors simultaneously.
Pre-Filters
Pre-filters are installed in dynamic pass boxes to filter air and to protect HEPA filters.G4 pre-filters are installed.
HEPA Filters
HEPA filters are installed in the dynamic pass box to purify the air and to provide a clean room of a grade A environment in the pass box.
The H14 HEPA filter is installed having a 0.3-micron pore size.
Motor Blower
A motor blower for air movement is also installed in the dynamic pass box.
UV Light
Ultraviolet light is installed in a dynamic pass to kill microbes which may be on the surface of materials placed inside the pass box.
The UV light of the dynamic pass box is 18 watts.
Hour Meter
The UV lamp installed inside the dynamic pass box has a specified life estimated from its running hours, so an hour meter is also installed in the dynamic pass box.
The UV light of the dynamic pass box must be replaced after 1000 burning hours.
Working Of Dynamic Pass Box
Working of a dynamic pass is very simple, first of all, open one door and place material inside.
As we open the door, an air showering system is activated to remove contamination and to create the required pressure inside the pass box.
The UV light is also turned on when we close the door & the material stays there depending on the validated time period, usually 3 to 5 minutes to properly expose with UV light.
Now open the door from the next area to receive the material and after receiving, close the door.
Important Note
 Like airlocks, the internal environment of the pass box can be maintained as a Sink, bubble or cascade.
Static Pass Box
The static Pass box is the transfer box which is used to transfer material between two areas of the same classification.
It also has an interlocking system which allows only one door to open at a time.
A UV lamp is also installed in the static pass box.
Static pass boxes do not have air showering or air filtration systems.
Static Pass box is also known as the passive pass box.
Example
To understand the usage of static pass box take the example of following,
- Transfer of granulated batch from granulation to compression area.
- Transfer of compressed tablets to the coating area.
Difference Between Dynamic & Static Pass Box
Following are some key differences between dynamic and static pass boxes used in pharmaceutical industries.