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SOP for Operation and Calibration of Contech Precision Balance

OBJECTIVE
To lay down a procedure for Operation and Calibration of the Contech Precision Balance.

SCOPE
This procedure applies to the pharmaceutical manufacturing facilities of XYZ Limited.

RESPONSIBILITY
The Quality Control Chemist is responsible for implementation of the process.
The Quality Control Manager is responsible for the execution of the procedure.

PROCEDURE
Balance location:
  • The balance is to be located in an area with minimum temperature fluctuations and on a firm solid support in to avoid jerks and vibrations.
  • The surface should be checked with a spirit level to confirm that it is horizontal before placing the balance on it.
Operation of the Balance:
  • It is advisable to leave the balance switched on for the entire day so that it attains constant operating temperature that results in improved accuracy.

Switching on the Balance:
  • Switch on the balance by switching on the power supply. Balance goes through self test and subsequently displays ON.
  • Press ON/OFF key to make the display read 0.00 and press TARE key to make the display read 0.000.
  • Before beginning weighing operations, allow a warm up time of 30 minutes. Do not make any adjustment to the balance during this period. After warm up, the balance is ready for weighing.
  • Check calibration of the balance using a standard weight. If the displayed weight is not equal to the weight of the pan, then calibrate the balance.

Calibration Procedure:
  • Before calibration, the balance must be switched on for at least 30 min.
  • Standard weights to be used for calibration are 100gm, 50gm, 20gm, 10gm, 5gm, 2gmand 1gm.
  • Zero the Balance pressing the TARE key.
  • Place the 100g standard weight on the pan
  • Press AUTO CAL key; The balance will show CAL for some time before displaying AC 100.
  • Wait for some time until the balance displays CAL – 100
  • The balance will now display the value of the standard weight and is calibrated for that weight.
  • Repeat procedure ‘a’ to ‘e’ for the rest of the standard weights recording and adjusting any deviations manually with the cursors.
  • Balance is now ready for use.
  • If the weight kept on the pan is not within ± 5% of the standard value, then the balance will display NO - CAL and then it will start displaying weight.
Records:
  • Every day before commencement of work, balance should be check with 10 gm standard weight & records should be maintained (permissible error ± 10mg).
Cleaning:
  • Clean the balance with tissue moistened with water. Wipe off excess moisture with clean dry tissue. Stubborn stains can be removed with tissue moistened with alcohol or Isopropyl Alcohol
  • Clean the balance housing with tissue moistened with water. Stubborn stains may be removed with liquid soap.
Verification of accuracy of calibration weight.
  • Submit the calibration weights to National Bureau of Standards for verification of accuracy.
  • Frequency of verification is once a year.
  • All the calibration details shall be entered in the calibration log for Contech Precision Balance.

REFERENCE(s)
Nil.

ABBREVIATION(s)
SOP : Standard Operating Procedure
Q.A Quality Assurance
No. Number
Q.C Quality control
mg Milli gram
gm Gram

ANNEXURE(s)
Annexure No. – 1 – Calibration log for Contech Precision Balance.

REVISION CARD
Nil

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