Standard Operating Procedure for Handling of Standard Weights for Calibration of Balances

1.0 Purpose: 

To provide a standard procedure for Handling of Standard Weights for Calibration of Balances. 

2.0 Scope: 

This procedure is applicable to all standard weights used for calibration of weighing balances in Quality Control at [Company name]. 

3.0 Responsibility:

3.1 Quality Control Person:  Responsible for the handling of standard weights for calibration of balances as per the written procedure.

3.2 HOD/ Designee- Quality Control: Responsible for monitoring and ensuring that the activity is performed as per laid down procedure

Quality Assurance: To ensure compliance to this SOP. 

4.0 Definitions:

Standard weights are the calibrated weights having traceability to National or International Standards.

Note: Weights ranging from 1 mg to 200 g, 500 g, 1 kg and 2 kg are available.

5.0 Procedure:

5.1. Procurement (Source): 

5.1.1. Standard weights shall be procured from an authorized agency or supplier and get calibrated from the external calibration agency or directly from National Physical Laboratory, New Delhi. 

5.1.2. Two sets of standard weights shall be procured, when one set of standard weights are in use, additional sets can be sent for calibration purpose and kept as standby.  

5.2. Handling

5.2.1. The certified weights shall be used for calibration of balances.

5.2.2. Weights of 1 g to 200 g, 500 g, 1 kg and 2 kg are integral knob cylindrical stainless steel weights.

5.2.3. Weights of 1 mg to 500 mg are stainless steel wire in a box available.

5.2.4. All standard weights shall be kept separately in the box in a dedicated position.

5.2.5. After Calibration keep all the weights in respective positions and close the box   immediately.

5.2.6. Extra weights (integral knob cylindrical stainless steel weights) 200 g, 20 g and 2 g are provided in the Weight box are marked with (.) or (*).

5.2.7. Extra weights 200 mg, 20 mg and 2 mg are slightly bent in a box available.

5.2.8. The ‘Stand by’ weight box is calibrated in such a way that when the “in-use” weight box is sent for calibration to an external agency; the calibrated ‘stand by’ weight box is available in calibrated state for use in the lab. 

5.3. Precautions during handling of weights:

5.3.1. Weights shall be handled with care.

5.3.2. Tweezers shall be used for picking up the integral knob cylindrical stainless steel            weights during calibration of the balances.

5.3.3. Clean stainless-steel forceps shall be used for picking up the star stainless-steel or flat plate weights during calibration of the balances.

5.3.4. Make sure that the weights don’t fall off on the floor or there are no scratches on the weights. This may disturb their calibration.

5.3.5. Weight box shall be kept in a safe place in weighing room only. 

5.4. Calibration

5.4.1. Calibration frequency of the E1 class and S.S. weights will be provided by the external calibration certificate by service provider.

5.4.2. The weight box shall be sent through courier or hand delivery to the external calibration agency or shall be directly send to National Physical Laboratory.

5.4.3. Calibration schedule shall be maintained as per Sop for Calibration (SOP-QA-SYS-010.)

6.0 Acceptance Criteria:

Not Applicable

7.0 Frequency:

As and when require during the quality control operations

8.0 Format for recording: 

Not applicable