Clearing the Mystery of Dynamic Pass Box

Few facts about Dynamic Pass Box

Through this blog we will be providing you the qualification and routine maintenance of dynamic pass boxes in your critical and non critical area.  As per the industrial practices some time we do more than the requirement and that create an additional burden for us. Rather than doing extra we should adopt some scientific rationale to define the risk level in our facility. Doing correct things in right time gives us the assurance of better compliance. I will suggest don’t think about the compliance all time, we should confirmed our procedure are made based upon robust scientific background.

Now we will be coming to fact. Dynamic pass box nothing but consider as air lock. It is provide a physical barrier in between different between or in between same grade. Normally dynamic pass box installed in the clean rooms as per follow pattern,

	Uncontrolled	Controlled but unclassified	Grade D	Grade C	Grade B
Uncontrolled	Accepted	Accepted	Not recommended	X	X
Controlled but unclassified	Accepted	Accepted	Accepted	Not recommended	X
Grade D	Not recommended	Accepted	Accepted	Not recommended	X
Grade C	X	X	Not recommended	Accepted	Not recommended
Grade B	X	X	X	Not recommended	Accepted

Requirements Vs risk level

Availability (in between )	Requirements	Risk Level
Uncontrolled to uncontrolled	Transfer input material or dirty material movement  (e. g Scrap)	Low Recommended to installed static pass box
Uncontrolled to control but unclassified	Transfer input material or dirty material movement  (e. g Scrap)	Low Recommended to installed static pass box
Control but unclassified  to Grade D	Transfer input material or dirty material movement  (e. g Scrap)	Low
Uncontrolled to Grade D	Transfer input material or dirty material movement (e.g. used garments, face mask & gloves )	Medium Chance for cross contaminations or breached area cleanliness in case of sudden break down of equipment All material in Grade B should to be transfer after steam sterilization and should unload from steam sterilizer under LAF. Power fail can cause significant impact on the area where the pass box has been installed, so it is recommended to keep dynamic pass box under uninterrupted power supply.
Control but unclassified  to Grade C
Grade D to Grade C
Grade C to Grade B
Control but unclassified  to control but unclassified	Transfer input material or dirty material movement  (e. g Scrap)	Low Recommended to installed static pass box
Grade D to grade D	Movement of dispensed  API or Excipients material	Low

Recommendations for Qualification and routine controls

Test Sr. No	Qualification Test	Qualification frequency in a year		SOP control
		Grade A & B	Grade C & D
1	Air velocity	Twice	Once	Not available
2	Non viable particle count	Twice	Once	As per area test frequency
3	Microbial monitoring	Once	Once	As per area test frequency
4	ΔP	Once	Once	At least once daily
5	Filter integrity	Twice	Once	Not available
6	*Airflow visualization	Initially	Initially	Not available

  

Note: *Airflow visualization should be repeated once any major changed done in the system. (e.g. filter change /repair), In case of Grade B it can be repeated once in a 2 year as a precautionary measure and it is recommended to installed  Grade b to grade B , not preferred to installed between Grade B to Grade C/D.

 Requirements of performing airflow visualization in Pass box

1.       To check the laminarity

2.       Air should be flowing smoothly in one direction with no turbulence or eddies

3.       When doors are opened within areas, air flow is disturbed and becomes turbulent as it sweeps through the air stream when opening. Smoke studies should capture the effects of the disturbance and document the air recovery to smooth unidirectional air flow.

  Additional inputs,

Do you know	Why	Reasons
Front of pass box consider at which side the Makeup  filter grills is places	Not Applicable	Trick to identify pass box direction , as both side looks similar
Pass box takes supply air from the adjoined clean area	It will enhance the filter life	Higher grade/clean zone having more clean air
It is a barrier in between same grade or intra grade clean room area	It don’t allow to passed air in between adjoined area	It act as Airlock (Bubble /shrink)
If you open both door together then also ΔP will maintained , it will not be zero	As it is act as airlock	Its having variable frequency drive (VFD) in the motor , that maintains desired pressure difference
Pass box area cleanliness should to be meet the requirement of adjoin higher grade area	Otherwise chance of cross contamination increases	Particularly when pass box installed between different Grades (e.g. Grade B to grade C)
Viable and non viable should to be performed as per area classification requirements, don’t consider pass box is separate entity from your area.	As it is a part of your area it should consider as same (or higher) classification with respective to area	Not applicable
What grade you should considered for installed pass box for viable and non viable monitoring.	As per the higher classification of the area (if installed between Grade C to Grade D , pass box shall be consider as Grade C)	It minimizes the area contamination risk
You should pass box under UPS connectivity /& don’t switch off (Caution: Directly connect with power supply don’t put ON/OFF switch )	Power Failure /switch off will caused risk to your clean rooms due to cross contaminations	Established power failure recovery periods if UPS not available. Don’t operate during power fails
Leakage from the pass box door gasket should immediately arrest	Efficiency of motor will reduce In long run	Not applicable

Viable test limits as per Regulatory Guidance recommendations:

Grade	Air sample (CFU/m3)	Settle plates (90mm diameter) (CFU/4hours)	Contact plates (55mm diameter) (CFU/plate)	Glove print          (5 fingers) (CFU/glove)
A	< 3	< 3	< 3	< 3
B	10	5	5	5
C	100	50	25	-
D	200	100	50	-