Standard Operating Procedure for Calibrating Temperature Sensors in Manufacturing Equipment

Department	Creams
SOP No.	SOP/CRM/084/2025
Supersedes	SOP/CRM/084/2022
Page No.	Page 1 of 5
Issue Date	21/01/2026
Effective Date	26/01/2026
Review Date	21/01/2027

1. Purpose

The purpose of this SOP is to outline the process for calibrating temperature sensors in manufacturing equipment. The objective is to ensure that temperature sensors are accurately measuring and controlling the temperature of materials during production, ensuring consistent product quality.

2. Scope

This SOP applies to the calibration of all temperature sensors in manufacturing equipment within the Creams Department, including those used in mixing, heating, cooling, and storage processes.

3. Responsibilities

• Production Team: Responsible for following the calibration procedure and ensuring that temperature sensors are operating within the required specifications during production.
• Maintenance Team: Responsible for calibrating the temperature sensors as per this SOP and ensuring they are in good working condition.
• Quality Control (QC): Ensures that the calibrated temperature sensors are accurate and that product temperatures are within specified limits during production.

4. Accountability

The Head of Production is accountable for ensuring that temperature sensors are calibrated regularly and accurately. The QA Manager is responsible for reviewing and ensuring the compliance of temperature control with quality standards.

5. Procedure

5.1 Pre-Calibration Checks

1. Ensure that all temperature sensors to be calibrated are disconnected from the production line and are not currently in use.
2. Verify that the calibration equipment, including a certified temperature reference standard (e.g., a calibrated thermometer or bath), is available and in good working condition.
3. Ensure that the sensor calibration area is clean and free of any contaminants that could affect the calibration process.

5.2 Calibration Procedure

1. Set the reference thermometer or bath to a known temperature that matches the expected operating temperature of the sensor being calibrated (e.g., 25°C, 50°C, or 100°C depending on the equipment requirements).
2. Place the temperature sensor in the reference bath or attach it to the reference thermometer, ensuring that it is fully immersed and in good thermal contact.
3. Allow the sensor to stabilize for a few minutes at the calibration temperature.
4. Record the temperature displayed by the sensor and compare it with the reference temperature. If the readings match within the acceptable tolerance (typically ±1°C), the sensor is calibrated.
5. If the sensor is out of tolerance, adjust the sensor’s output to match the reference temperature. Follow the manufacturer’s guidelines for adjusting the sensor, if applicable.
6. Repeat the process for additional calibration points if required (e.g., at different temperatures or in different operational ranges).

5.3 Post-Calibration Checks

1. After calibration, test the sensor again to ensure that it is consistently reading the correct temperature within the specified tolerance limits.
2. Document the calibration results, including the reference temperature, sensor reading, tolerance, and any adjustments made in the Calibration Log (Annexure-1).
3. Label the calibrated sensor with the calibration date and any relevant details (e.g., next calibration due date) for future reference.

5.4 Calibration Frequency

1. Temperature sensors must be calibrated at regular intervals, typically once every six months, or more frequently if there are signs of malfunction or deviation in temperature readings.
2. If any discrepancies are found during production, the sensor must be recalibrated or replaced immediately.

5.5 Documentation

1. Ensure that all calibration records are documented in the Calibration Log (Annexure-1), including the date, sensor identification, calibration points, and any deviations or corrective actions taken.
2. Record any issues found during calibration and corrective actions in the Temperature Sensor Maintenance Log (Annexure-2).

5.6 Final Approval

1. The QA team must review all calibration documentation to ensure that temperature sensors are calibrated in accordance with GMP standards before the equipment is used in production.
2. Upon approval, the sensor may be returned to production for use, ensuring that the temperature control system is fully operational.

6. Abbreviations

• GMP: Good Manufacturing Practices
• QC: Quality Control
• QA: Quality Assurance
• PPE: Personal Protective Equipment
• RTD: Resistance Temperature Detector

7. Documents

1. Annexure-1: Calibration Log
2. Annexure-2: Temperature Sensor Maintenance Log

8. References

• Good Manufacturing Practices (GMP) Guidelines – 21 CFR Part 211
• International Conference on Harmonisation (ICH) Q7 – Good Manufacturing Practice for Active Pharmaceutical Ingredients
• ASTM E2877-13 – Standard Guide for Digital Contact Thermometers

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Calibration Log

Sensor ID	Calibration Date	Calibration Temperature	Sensor Reading	Tolerance	Operator	Comments
RTD-123	21/01/2026	25°C	25.1°C	±0.1°C	John Doe	Calibration successful

Annexure-2: Temperature Sensor Maintenance Log

Sensor ID	Maintenance Date	Issue Reported	Corrective Action	Operator	Comments
RTD-123	21/01/2026	Deviation in reading	Recalibrated sensor	Jane Smith	No further issues

Revision History:

Revision Date	Revision No.	Revision Details	Reason for Revision	Approved By
01/03/2024	1.0	Initial Version	New SOP Creation	QA Head
01/03/2025	2.0	Format Revision and Updates	Standardization of Document	QA Head