The effect of temperature calibration of PyroButton data-loggers relative to the accuracy of measurements

Case Study 102PB

Proj.ID/DIMS: TCV-20050117/ D21304

Objective:

The objective of the case study is to demonstrate the effect and significance of PyroButton data-logger calibration on the accuracy of temperature measurement. Main components of the study include:

• Demonstration of the non-calibrated data-logger temperature measurements relative to accuracy
• Demonstration of the calibrated data-logger temperature measurements relative to accuracy

Benefits of using calibrated PyroButton data-loggers:

• 21 CFR Part 11 compliance
• Integrity testing performed on each data-logger prior to calibration
• Each PyroButton data-logger is calibrated at 5 different temperatures & the calibration is verified prior to shipment
• Improved temperature accuracy
• Calibration corrections can be automatically calculated for each temperature measurement in the PyroButton software
• Certificate of Calibration is included for each data-logger
• Regulatory compliance
• Extended warranty period

Definitions:

Calibration of PyroButton is the process of temperature measurements at the required intervals against a recognized reference standard (e.g., NIST) for the determination of the adjustment factors needed to ensure that the results of temperature measurements by the calibrated PyroButton are within the required accuracy.

PyroLogger-XT is a 24-channel high performance Self-powered temperature data-logger. Specification characteristics of PyroLogger-XT:

• Temperature resolution is ±0.002 °C
• Temperature dynamic range is -50 °C to 150 °C
• Accuracy is better than ±0.05 °C
• Reproducibility (between sensors) is better than ±0.02 °C
• Precision (within sensor) is better than ±0.02 °C
• PyroLogger-XT has been calibrated against NIST reference prior to use.

PyroDisk-Pro is a 21 CFR Part 11 compliant application program, which administers and integrates the various functions for temperature calibration, temperature validation, and temperature monitoring.

PyroLogger-XT and PyroDisk-Pro communicate through the built in RS 232 interface, providing support for Self-powered operation based on user defined time and data acquisition parameters.

PyroButton-SQL software supports the management and information analysis of sensors/data-loggers. The program includes the integration of intelligent modules for validation and verification of temperature and/or humidity controlled processes such as, sterilization, stability, storage, incubation, refrigeration, warehousing, transportation, container/closure moisture permeability, and environmental monitoring.

Materials & equipment:

• Refrigerator 01 (OPULUS Bioanalitical Laboratory)
• PyroButton-G data-logger (having the temperature range of -40°C to 85°C)
  • Non-calibrated (as received from the manufacturer): 0.5°C resolution, ±1°C accuracy
  • Calibrated by Opulus against NIST reference: accuracy is ±0.5°C
  
  
  
• PyroLogger-XT 24-channel high performance Self-powered data-logger ("PL-XT") having the following specification characteristics:
  • Temperature resolution is ±0.002 °C
  • Temperature dynamic range is -50 °C to 150 °C
  • Accuracy is better than ±0.05 °C
  • Reproducibility (between sensors) is better than ±0.02 °C
  • Precision (within sensor) is better than ±0.02 °C
  • PyroLogger-XT has been calibrated against NIST reference prior to use
  
  
  
• PyroDisk-Pro software
• PyroButton-SQL software
• PB-Adapter-S8 - serial communication & power interface for the parallel programming of 8 PyroButtons
• PC Computer
• Polymer glue

Procedure Summary:

1. Program the temperature data-acquisition requirements of PyroButton
2. Program the temperature data-acquisition requirements of PL-XT
3. Affix the external sensors of the PL-XT to the centre of each PyroButton using the polymer glue
4. Create a PyroButton placement map for Refrigerator 01
5. Place the PyroButtons prepared in step 3 and the PL-XT according to step 4 into Refrigerator 01
6. After the required period, take out the data-loggers from the refrigerator and download the temperature measurements
7. Evaluate the data.

Results:

Interpretation:

1. It is self-evident from the above results that the calibration significantly improves the temperature accuracy of the PyroButton data-logger.
2. While the non-calibrated data-logger satisfies the manufacturer's specification, it provides data, which can result in the wrong decision making.
3. The calibrated data-logger improves the temperature measurement accuracy significantly relative to the non-calibrated device. The worst-case accuracy of ±0.3°C is well within the specification requirement of ±0.5°C.