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

12	20 mg	0.00003
13	10 mg	0.00025
14	5 mg	0.00002
15	2 mg	0.00002
16	1 mg	0.00002

^*
With reference to OIML – International Recommendation R111.