SOP - CALIBRATION OF BALANCES

1.0
PURPOSE:
To provide a written procedure for the steps to be followed while calibration of balances.
2.0
SCOPE:
Applicable to all balances except analytical balances.
3.0
RESPONSIBILITY:
All Department Heads
4.0
ACCOUNTABILITY :
Assistant Manager Manufacturing / Quality Assurance Manager
5.0
DEFINITIONS:
Calibration: The demonstration that an instrument or a device produces results within specified limits when compared to those produced by a reference standard (or) the standard, which is traceable to a national or International standard, over an appropriate range Of measurements.
6.0
PROCEDURE:
6.1
Check the cleanliness of the area.
6.2
Check that platform and exposed parts of the balance are clean and dry.
6.3
Check the level of the balance with the help of spirit level. Adjust level, if not leveled.
6.4
Switch on the main power supply of the balance.
6.5
Following parameters to be checked while performing calibration.
· Accuracy
· Linearity
· Precision
· Corner Load Test
FREQUENCY: Every 3 months (± 7 days)
Note: If balance is not calibrated within the time period, stop using the balance till
satisfactory calibration is done.
6.6
ACCURACY
6.6.1
Check the accuracy of the balance by using 5 standard stamped weights.
6.6.2
Place standard weight one by one in the ascending order in the center of the platform and record the observations in the balance calibration record.
6.6.3
Acceptance Criteria: Standard Weight ± 2 x Least Count
6.7
LINEARITY
Draw the linearity curve for the above readings and find out the correlation factor. Record the observations in the balance calibration record.(Limit: NLT 0.9999)
6.8
PRECISION
6.8.1
Check the Precision of the balance by using standard weight equivalent to 5 % of
Maximum capacity.
6.8.2
Repeat the procedure for 5 time and record the readings.
6.8.3
Repeat 6.8.1 to 6.8.2 using standard weight equivalent to 50 % of maximum
capacity.
6.8.4
Calculate % RSD for both the standard weights. Record the observations in the
Balance calibration record.
6.8.5
Acceptance Criteria :
% RSD NMT 0.5 %
6.9
CORNER LOAD TEST
6.9.1
Place standard weight equivalent to 30 % of maximum capacity in four corners and center of the balance and note down the readings in record. Calculate % RSD.
Record the observations in the balance calibration record.
6.9.2
Acceptance Criteria:
Deviation: Standard Weight ± 2 x Least Count
% RSD: NMT 0.5 %
6.10
If all the parameters fall with the acceptance criteria limit, affix the calibration tag (no. LBGN:003) on the balance.
6.11
If any of the observation is out of limit, correct and reset the balance.
6.12
After resetting, calibrate again all the parameters as mentioned in point 6.6 to 6.9
6.13
Switch off the balance at the end of day.
Note: No repairs should be made to any balance by anyone other than a qualified validation person from validation team.
7.0
REFERENCES:
Nil
8.0
ENCLOSURE:
8.1
Balance calibration record : XXXXXXX
9.0
ABBREVIATIONS:
9.1
NMT : Not More Than
9.2
RSD : Relative Standard deviation