Sop for Monitoring of Temperature, Relative Humidity and Differential Pressure

  • Objective

To lay down a procedure for monitoring Temperature, Relative Humidity and Differential Pressure of microbiology lab.

  • Scope

This SOP is applicable for monitoring and recording the temperature (0C), Relative humidity (%) and differential pressure (mm of water) using digital hygrometers and Magnehelic gauge for Differential Pressure in microbiology lab.

  • Responsibility
    • Microbiologist responsible for monitoring and verification of Temperature, Relative Humidity and Differential Pressure.
    • Head-Concerned department is responsible to ensure the prevailing Temperature, Relative Humidity and Differential Pressure is within limits as per SOP.

  • Accountability
    • Department Head & QA Head shall be accountable for implementation of this SOP.

  • Abbreviations and Definitions

             QA                              :          Quality Assurance

            °C                               :           Degree Centigrade

            RH                              :           Relative Humidity

            mm WC                       :           Millimeter of water column

            Min                             :           Minimum

            Max                             :           Maximum

           HVAC                           :        Heating Ventilation Air Conditioning

  • Procedure
    • Check the calibration status of the instrument.
    • Check the temperature and relative humidity displayed in the digital hygrometer monitor.
    • Record the Temperature and Relative Humidity at starting of the shift + 30 min and after every 4 hours ± 30 minutes for production, warehouse till completion of the activity or end of shift whichever is later as per Annexure – I.
    • Location:

Media Preparation Room
MLT and LAL Testing Room
Sterility Lab

  • Acceptance Criteria:

Temperature: NMT (Not More Than) 250C

Relative Humidity: NMT 60%


  • Procedure for monitoring of Temperature and Relative Humidity by Digital hygrometer (Model: HTC-1)
    • Record the previous day minimum and maximum Temperature and Relative Humidity.
    • Recording of previous day minimum and maximum Temperature & Relative Humidity shall be performed at the time of observing daily initial reading.
    • Record the minimum and maximum Temperature and Relative Humidity by pressing “Memory” key. Press one time memory key to record max. Temperature & max. Relative Humidity of previous day and again press memory key to record min. Temperature & min. Relative Humidity.
    • Delete the minimum and maximum reading from the memory of hygrometer that is required to leave memory space to record the next day min. and max. reading.
    • For resetting the minimum & maximum value, press “RESET” button provided back side of the digital hygrometer with the help of pin.

  • Procedure for monitoring of Differential Pressure in Different Areas
    • Enter in the respective area and ensure that all doors of microbiology are tightly closed.
    • Ensure that the HVAC is in running condition.
    • Open the door of respective area and ensure zero (0) set, while door is opened.
    • Take the magnehelic gauge reading in the reference of positive and negative pressure of rooms.
    • Record the value.
    • Location:

Media Preparation
Media Preparation Air lock
Change Room
MLT and LAL Testing Room
Buffer Room
Sterility Room

Frequency: Twice a day (Morning and afternoon)

Acceptance criteria :


  • Forms and Records (Annexures)
    • Temperature and Relative Humidity Record –         Annexure-II
    • Record for Differential pressure             –         Annexure-III
  • Distribution
    • Master copy –          Quality Assurance
    • Controlled copies –         Microbiology Lab
  • Reference:   

              If any

  • History
Date Revision Number
Reason for Revision


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