Types of Pass Box Used in the Pharma Industry

There are two main types of pas boxes used in pharma Clean Room.

1. Dynamic Pass Box, (known as the active pass box).
2. Static Pas Box, (known as the passive pass box).

Dynamic pass boxes are used to transfer materials from uncontrolled to controlled environments while Static pass boxes are used to transfer materials between two rooms of equal cleanliness levels and are designed for minimal personnel movement.

Dynamic Pass Box

• The Dynamic Pass box will be installed in the wall between two different grades of clean rooms and is used for materials transfer between areas of low cleanliness to higher cleaned areas or from higher cleaned areas to low cleaned areas. 
• Dynamic pass box, it can be installed and used for transferring media plates from grade C to Grade A.
• Mainly the Dynamic Pass Box is made of Stainless Steel (SS 304, 316, or 316L), and equipped with the following components:

1. Interlocking Doors
2. Blower
3. Pre Filter
4. HEPA Filter
5. UV Light (18 watts), and fluorescent lamp (20 watts) to produce visible light.
6. Magnehelic gauge ranging from 0 to 25 mm of WC.

Fig.1-Dynamic Pass Box

* Note that the pass box can be maintained as a Sink, bubble, or cascade.

How does Dynamic Pass Box work?

• As we open the door, an air showering system is activated to remove contamination and to create the required pressure inside the pass box.
• Using the dynamic pass is very simple, first of all, open one door and place material inside.
• UV light is also turned on when we close the door & the material shall stay as per the validated time period, from 3 to 5 minutes to properly expose to UV light.
• Finally, open the door from the next area to receive the material and after receiving it, close the door.
• If a Dynamic Pass box is fitted with a Vaporized Hydrogen Peroxide Generator (VHP) as a decontamination system it may also be called a Bio De-Contamination Pass Box.

ALSO READ: SOP for Cleaning of Return Air Risers Filter

Fig. 2 -VHP Pass Box (Biological)

Static Pass Box

• The static Pass box is the transfer box and is used for material transfer between two areas of the same classification.
• The static pass box can be installed and used for:

1. Material transfer between granulation and compression areas.
2. Also between tablets and coating areas

In addition, the static pass box will be used as an interlocking system, (allowing only one door to open at a time). Static Pass box shall be equipped with A UV lamp.

Fig.3- Static Pass Box

* Note that there is no air showering or air filtration systems in Static pass boxes.

Some key differences between dynamic and static pass boxes used in the pharmaceutical industry / clean rooms are Shown in the following table:

Components	Dynamic Pass Box	Static Pass Box
Pass Box Usage	Material Transfer Between deferent classification areas	Material Transfer Between same classification areas
Pre-filter	G4 Class Filter	N/A
Blower	Motor Blower of 1/5 hp	N/A
HEPA Filter H14	HEPA filter, H14 Filter Class	N/A
UV Lamp	UV light of 18 watts	UV light of 8 watts
Fluorescent Lamp	The fluorescent lamp of 20 watts	The fluorescent lamp of 40 watts

Economics

• Dynamic Pass Box Model needs HEPA-filtered air in the arrangement and the additional space occupied leads to the added cost, however, in transfers between two different class areas, the investment is totally worth it for the compliance benefits it provides.
• We have to not make the mistake of providing a static pass box where the situation demands.
• Dynamic, the non-compliance is usually grave and unacceptable for auditors.

ALSO READ: Types of Airlock used in Pharmaceutical