Standard Operating Procedure for Calibration of Storage Vessels in API Manufacturing

Department	API Manufacturing
SOP No.	SOP/API/052/2025
Supersedes	SOP/API/052/2022
Page No.	Page 1 of 10
Issue Date	13/04/2025
Effective Date	15/04/2025
Review Date	13/04/2026

1. Purpose

To establish a standard method for the calibration of storage vessels used in API manufacturing, ensuring accurate measurement of liquid volumes and maintaining GMP-compliant process control.

2. Scope

This SOP applies to all vertical and horizontal storage vessels used for holding solvents, intermediates, and reagents in the API manufacturing plant.

3. Responsibilities

• Engineering Department: Perform calibration as per defined procedure.
• Production Department: Prepare the vessel and support calibration activities.
• QA Department: Review calibration data and approve vessel for use.

4. Accountability

The Engineering Head is accountable for the execution of calibration. QA Head is accountable for final approval and regulatory compliance.

5. Procedure

5.1 Preparation for Calibration

1. Ensure the vessel is:
   • Empty and cleaned
   • Free from previous product or solvent residue
   • Fitted with a level gauge or dipstick
2. Verify availability of:
   • Calibrated flow meter / graduated containers
   • Calibration tag and checklist
   • PPE for personnel

5.2 Calibration Procedure

1. Fill the vessel with known volumes of water (or appropriate calibration fluid) in 50 L or 100 L increments.
2. At each level, record:
   • Volume added
   • Dipstick or sight glass reading
3. Continue until the vessel reaches its maximum marked capacity.
4. Plot a calibration chart (Volume vs. Level) for accurate volume referencing.

5.3 Documentation and Labeling

1. Enter all data in the “Storage Vessel Calibration Record” (Annexure-1).
2. Affix calibration chart near the vessel or in the SCADA system if automated.
3. Label the vessel with:
   • Calibration Date
   • Next Due Date
   • Calibrated By

5.4 Recalibration and Frequency

1. Calibrate vessels:
   • Initially during installation
   • Annually thereafter
   • After vessel repair or modification
2. Track due dates in the “Calibration Schedule Register” (Annexure-2).

6. Abbreviations

• SOP: Standard Operating Procedure
• PPE: Personal Protective Equipment
• QA: Quality Assurance
• SCADA: Supervisory Control and Data Acquisition

7. Documents

1. Storage Vessel Calibration Record (Annexure-1)
2. Calibration Schedule Register (Annexure-2)

8. References

• ICH Q7 – Good Manufacturing Practice for Active Pharmaceutical Ingredients
• 21 CFR Part 211 – Equipment Calibration Requirements
• Company Engineering Manual

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Storage Vessel Calibration Record

Vessel ID	Volume Added (L)	Level Reading (cm)	Observed By	Date
SV-01	100	12.5		13/04/2025

Annexure-2: Calibration Schedule Register

Vessel ID	Last Calibration Date	Next Due Date	Status	Remarks
SV-01	13/04/2025	13/04/2026	Calibrated	OK

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
01/01/2022	1.0	Initial SOP Release	New Equipment Commissioning	QA Head
13/04/2025	2.0	Included SCADA and Frequency Guidelines	Audit Feedback	QA Head