SOP For Recording Pressure Difference in Manufacturing Area


The purpose of this SOP is to provide a procedure for recording pressure difference in cubicle with respect to adjacent area.

  • SCOPE:

This SOP is applicable to checking of pressure difference in cubicles with respect to adjacent area at manufacturing facility.   


Authorized designee of user department shall be responsible for recording of differential pressure.

Authorized designee of engineering department shall be responsible for proper maintain of differential pressure in area.       

    • Ensure that the AHU’s in all areas (Cubicle and adjacent areas) are operational for the last 5 to 10 minutes.
    • Ensure the ‘0’ setting of manometers by moving the knob provided on the manometer boxes wherever applicable or by opening the door of the area.
    • Ensure that the door of the cubicle and adjacent areas are in closed condition.
    • Read the value on manometer, which is directly corresponding to the indicator needle. If the indicator needle rests in between two divisions on the scale, the average of both readings to be considered.

e. g. : Magnehelic manometer

Range :  0 – 6 mm of water gauge

Least count: 0.2 (Value of each division)

If the indicator needle is in between `0.4′ and `0.6′, read `0.5′.

  • Record the observation in Annexure (F/QA00/01).
    • Limit of pressure difference in cubicle with respect to adjacent area is given in Annexure and same should be recorded in the Annexure (F/QA000/01) for respective areas.
    • If pressure difference is not within limit, the concerned department should stop the activity and inform Quality Assurance (QA) and Engineering department.
    • Engineering department along with QA to investigate the reason for deviation in pressure difference and rectify the same. In case of any major breakdown, QA should do review and decide line of action in the necessary change control documents.
    • All concerned departments should maintain the record of pressure difference of each cubicle in the area, wherever applicable.
    • When there is no activity in the area and AHU is off, record the pressure difference as ‘’ —‘’.

NOTE:  Pressure difference should be recorded, twice in a day (Working hours) / according to frequency specified in batch record.  


                        Trainer             : Head – Quality Assurance

                        Trainees           : Staff of Production, Packaging, Stores, Engineering & Microbiology


         Controlled Copy No.1            :  Head of Department – Quality Assurance

         Controlled Copy No.2            :  Head of Department – Production  

Controlled Copy No.3         :  Head of Department – Engineering

Controlled Copy No.4         :  Head of Department – Warehouse / Store

Controlled Copy No.5         :  Head of Department – Packaging

Controlled Copy No. 6        :  Head of Department – Microbiology 

         Original Copy             :  Head – Quality Assurance


Annexure-I                           : Differential pressure monitoring record.

Annexure-II                        : Standard limit of pressure difference in cubicle with      

                                               Respect to adjacent area



Sr. No.Revision No.Change Control NumberDetails of RevisionReasons(s) for Revision  
100———–New SOPNew SOP

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