all pressure gauges installed in production and support areas including:

• Autoclaves
• Vessels and tanks
• Lyophilizers
• Filling machines
• Cleanroom HVAC monitoring panels

3. Responsibilities

• Maintenance Technician: Performs calibration activities as per schedule.
• Production Supervisor: Ensures instruments are available and supports access.
• QA Executive: Reviews and approves calibration certificates and logs.

4. Accountability

The Engineering Head is accountable for the execution and GMP compliance of all pressure gauge calibrations.

5. Procedure

5.1 Preparation

1. Prepare a list of all pressure gauges in use with unique identification numbers.
2. Schedule calibration every 6 months or as per the manufacturer’s recommendation.
3. Use only calibrated and traceable master gauges or calibrators.
4. Verify calibration status on the pressure gauge before use. Instruments with expired calibration should not be used.

5.2 Calibration Procedure

1. Isolate the pressure gauge from the line/equipment.
2. Connect it to a standard pressure calibrator using proper fittings.
3. Apply pressure in incremental steps (e.g., 0, 25%, 50%, 75%, 100% of full scale).
4. Record the readings of the gauge under test and the standard calibrator at each point.
5. Repeat readings during pressure increase and decrease to check hysteresis.
6. Compare results with the allowable deviation limits (±1% of full-scale value unless specified otherwise).
7. If readings are within tolerance, tag the gauge with a “CALIBRATED” label. If not, remove from service and report to QA.

5.3 Documentation

1. Document all readings in the Pressure Gauge Calibration Log (Annexure-1).
2. Prepare a Calibration Certificate and attach a copy to the instrument history file.
3. Update calibration status label on each gauge with the following:
   • Calibration Date
   • Next Due Date
   • Technician Initials

5.4 Handling Out-of-Tolerance Results

1. Immediately quarantine any gauge failing to meet accuracy criteria.
2. Inform QA to investigate any impact on previous batches if the gauge was used during production.
3. Replace with a calibrated spare gauge and record in the Gauge Replacement Log (Annexure-2).

5.5 Recalibration or Repair

1. Defective gauges should be sent for repair to qualified vendors.
2. Post-repair, recalibrate the gauge before reinstallation.
3. Maintain vendor calibration records and service history.

5.6 Safety and Precautions

1. Wear gloves, goggles, and antistatic garments during calibration.
2. Do not exceed gauge pressure range during testing.
3. Perform calibration in a clean and dry environment.

6. Abbreviations

• SOP: Standard Operating Procedure
• QA: Quality Assurance
• GMP: Good Manufacturing Practices
• HVAC: Heating, Ventilation, and Air Conditioning

7. Documents

1. Pressure Gauge Calibration Log – Annexure-1
2. Gauge Replacement Log – Annexure-2
3. Calibration Certificate – Annexure-3

8. References

• WHO GMP Guidelines for Equipment Qualification and Calibration
• ICH Q10 – Pharmaceutical Quality System
• ISO/IEC 17025 – General requirements for the competence of testing and calibration laboratories

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation	Maintenance Executive	QA Executive	Head QA
Department	Engineering	Quality Assurance	Quality Assurance

11. Annexures

Annexure-1: Pressure Gauge Calibration Log

Date	Gauge ID	Range	Observed Reading	Standard Reading	Status	Technician
22/06/2025	PG-102	0–6 bar	6.05	6.00	Pass	Rajesh Kumar

Annexure-2: Gauge Replacement Log

Date	Old Gauge ID	New Gauge ID	Reason	Replaced By
21/06/2025	PG-095	PG-121	OOS Result	Sunita Reddy

Annexure-3: Calibration Certificate

Certificate No.	CAL/PG/2025/088
Gauge ID	PG-102
Calibrated On	22/06/2025
Calibrated By	Rajesh Kumar
Standard Used	TRACE/MASTER-500
Next Due	22/12/2025

Revision History

Revision Date	Revision No.	Details	Reason	Approved By
01/06/2022	1.0	Initial release	New SOP	QA Head
24/06/2025	2.0	Added Annexures and ISO references	Annual Review	QA Head