STANDARD OPERATING PROCEDURE FOR OPERATION OF ANALYTICAL WEIGHING BALANCE

 1.      Title:

         Standard operating procedure for operation and calibration of Analytical Balance.

2.      Purpose:

          To lay down the procedure for the operation and calibration of Analytical Balance.            

3.       Scope:

          Analytical Balances are used routinely in the laboratory for weight measurement. The accuracy of any result primarily depends upon the precision of the Analytical Balances. In order to obtain the precise measurement, calibration of Analytical Balances should be carried out at regular intervals.

 

4.       Responsibility: Research Associate / Research Scientist.

5.       Procedure

    5.1.  Clean the weighing pan of the balance. 

    5.2.  Adjust the level of the balance (if necessary) with the help of bubble level (indicator)

            provided in   the center.

     5.3. Switch on the mains electric supply.

     5.4. Press ‘On/Tare’ button. Display will read 0.0000.

     5.5. Perform the Internal Calibration for the balance as described under calibration procedure.

            If the calibration check is found satisfactory then proceed further or else take necessary

            action to rectify the failure.       

   6.0    Calibration of Analytical Balance

     Calibration of Analytical Balances is carried out using Internal as well as using External Method.

6.1 Routine Calibration Method

  6.1.1. Clean the balance and the weighing pan.

  6.1.2 .Adjust the level of the balance (if necessary) with the help of bubble level

            (Indicator) provided in the in the center.

  6.1.3. Switch on the mains electric supply.

  6.1.4. Press ‘On/Tare’ button. Display will read 0.0000.

  6.1.5. Press ‘Cal/Menu’ key. Hold it for few seconds till the display shows ‘CAL’

  6.1.6. Release the key, Internal Calibration process will begin.

  6.1.7. After the completion of calibration the display will go in the weighing mode, if not it will

             show some error message.

 

  6.1.8. Record the error message if any, take necessary action to recalibrate the balance.

          If it does not  pass the calibration test, call the Service Engineer.

   6.2 External Method

The Analytical Balances can be calibrated externally by using Standard Certified Weights or through external agencies having certified weights. The procedure for calibration of Analytical Balances using certified weights is given below:

 

6.2.1.Clean the balance and the weighing pan.

6.2.2.Adjust the level of the balance (if necessary) with the help of bubble level   

         (Indicator)    provided in the in the center.

6.2.3.Switch on the mains electric supply.

6.2.4.Press ‘On/Tare’ button. Display will read 0.0000.

6.2.5.Place each of the given weights using a forceps on the balance and record the value.

6.2.6.The weights and weight box should be stored in a clean place. Care should be taken

         while  handling the weights.

                (Note:  Always use forceps while handling weights).

Note

1. The weights are to be calibrated periodically through Certified External Agency in order to authenticate the calibration results.
2. If any discrepancy is found during the calibration, repeat the calibration. If the discrepancy continues, call the service engineer for immediate action.
3. Record and document the observations in the Form below.

               

7.0 ABBREVIATIONS :

      1) CAL : Calibration

 

8.0 .RECORDS :Calibration format

 

 9.0 REFERENCES :

      Analytical Balance Manual.