Calibration of Single Pan Balance

1.0 PURPOSE

The purpose of the standard operating procedure is to provide guidelines for calibration of Single Pan Balance.

2.0 SCOPE

The scope of this standard operating procedure includes calibration of Single Pan Balance.

3.0 RESPONSIBILITY

3.1 Section In charge

3.2 Technical Manager

3.3 Q.A. Manager

4.0 PROCEDURE

4.1 PRECAUTION BEFORE CALIBRATION:

4.1.1 Ensure that the analytical balance used for weighing should be levelled at zero levelling and is supported on a vibration free rigid table base.

4.1.2 Ensure that a consistent ambient or fixed room temperature is maintained.

There should be no movement of air or air from ceiling fan etc.

4.1.3 Ensure cleanliness of the analytical balance.

4.2 APPARATUS REQUIRED FOR CALIBRATION:

4.2.1 Calibrated weight box traceable to either NPL or NABL accredited laboratory.

4.2.2 Ensure that the calibrated set of weights is clean and free from any dust particles and

any type of deformity.

4.3 CALIBRATION PROCEDURE:

4.3.1 Weigh one by one the standard calibrated set of weights on the balance and record the weights as indicated on the balance.

4.3.2 Repeat the weighing of each set of weights at least two to three times to ensure greater accuracy and reproducibility.

4.3.3 Ensure the precision and accuracy of weighing.

4.4 REPORTING

4.4.1 From the assigned weights of the standard set of weights correlate the accuracy of the weights observed on the balance under calibration.

4.4.2 Make a table for the observed weight on balance of the standard weights, and the actual calibrated weight of the set of weights.

4.4.3 The average of the weights shall be reported same as digits displayed on the balance screen.

4.5 ACCEPTANCE CRITERIA

The balance (to be calibrated) should display the weights in the tolerance limits as given in the table below against the standard weights used:

S.No.	Denomination Metric	Tolerance Limits(g)^*
1	100 g	0.0005
2	50 g	0.0003
3	20 g	0.0025
4	10 g	0.0002
5	5 g	0.0015
6	2 g	0.0012
7	1 g	0.0001
8	500 mg	0.00008
9	200 mg	0.00006
10	100 mg	0.00005
11	50 mg	0.00004