SOP For calibration of balance is described in this post which you can follow in the section of the General Industry SOP.
OBJECTIVE
To calibrate the equipment for reliable and accurate results.
SCOPE
This procedure is applicable for balance installed in the quality control department.
RESPONSIBILITY
QC Analyst
ACCOUNTABILITY
Manager Quality Control
PROCEDURE
- Operate the instrument as per respective Standard Operating Procedure.
- Switch ‘ON’ the instrument.
- Switch ‘ON’ the balance.
- After few seconds, the display will show 0.00 g.
- If display is not stable, press the TARE key & wait till the display shows 0.00 g.
- Perform internal calibration.
For Accuracy
- Place 5 gm. on the weighing pan.
- Note the weight.
- Calculate the difference between the weight in certificate and observed weight.
- Repeat the above steps using 50gm & 100 gm. weights.
- Record the reading.
For precision
- Place 5 gm. in the weighing pan.
- Note the weight .
- Repeat the above two steps nine times.
- Record the weight.
- Calculate the Standard deviation.
Calculate the measurement uncertainty using following equation.
2 X SD
Measurement uncertainty = ------------------------------------
Actual weight from certificate
Frequency
Internal calibration and accuracy: Daily
Precision: Once in a month