In today’s precision-driven industrial landscape, measurement accuracy is fundamental to ensuring product quality, safety, and regulatory compliance. Whether in manufacturing, laboratories, pharmaceuticals, or food processing, the process of calibration plays a pivotal role in maintaining measurement integrity. At Prism Calibration, we specialise in comprehensive calibration, validation, and testing services, backed by ISO/IEC 17025 accreditation and industry best practices.
This guide provides an in-depth explanation of the calibration process, highlighting each stage involved in achieving accurate, traceable, and reliable results.
What is calibration?
Calibration is a meticulously defined process involving the comparison of an instrument’s output to a known reference standard. The objective is to detect and correct deviations to ensure the instrument’s accuracy. The process of calibration not only ensures operational reliability but also supports quality assurance systems and regulatory audits.
Importance of calibration
Routine calibration of measuring instruments is vital for maintaining:
- Measurement accuracy: Eliminates errors that can affect product quality, process control, or scientific data.
- Traceability: Provides a documented, unbroken chain linking measurement results to national or international standards.
- Regulatory compliance: Meets stringent requirements of ISO/IEC 17025, FDA, NABL, and other bodies.
- Operational consistency: Prevents downtime, rework, and product recalls by ensuring stable instrument performance.
Neglecting the calibration process increases the risk of measurement drift, product failure, and compliance violations.
Detailed step-by-step calibration process
Step 1: Define calibration requirements
- Identify the instrument’s function, measurement range, and required accuracy.
- Understand the applicable regulations and quality system requirements (ISO, GMP, GLP, etc.).
- Define the tolerance limits and acceptable error margins.
Step 2: Preparation and inspection
- Visually inspect the instrument for physical damage or wear.
- Clean the equipment and accessories.
- Stabilise the device in a controlled environment for accurate results.
- Ensure all auxiliary components (leads, probes, sensors) are available and functioning.
Step 3: Select certified calibration standards
- Use reference standards traceable to national or international measurement systems (e.g., NIST, NABL).
- Standards should be at least four times more accurate than the instrument under test.
Step 4: Perform calibration measurements
- Record baseline readings across multiple points within the instrument’s operating range.
- Compare these readings against reference standards.
- Calculate deviations from expected values.
- Repeat the process multiple times to validate repeatability.
Step 5: Adjustment and correction
- If the instrument is outside acceptable tolerances, perform internal adjustments as per manufacturer guidelines.
- Re-calibrate to verify corrected performance.
Step 6: Documentation and reporting
- Create a comprehensive calibration certificate, including:
- Instrument identification (type, serial number, model)
- Calibration method and procedure
- Environmental conditions
- Measurement results, errors, and uncertainties
- Reference standards used with traceability
- Calibration date and next due date
- Technician name and signature
Step 7: Labelling and revalidation schedule
- Attach a calibration label indicating the status, date, and next due date.
- Schedule future calibration based on industry norms or manufacturer specifications.
- Log the certificate for audit trail and historical reference.
Key types of calibration
Different calibration types apply based on instrument function and industry. Prism Calibration offers:
- Temperature calibration: For thermocouples, RTDs, temperature baths, and chambers.
- Pressure calibration: For pressure gauges, transmitters, and manometers.
- Electrical calibration: For voltmeters, ammeters, multimeters, and frequency counters.
- Mass and weight calibration: For weighing balances, load cells, and scales.
- Flow calibration: For volumetric and mass flow meters.
Each calibration process is performed under strictly controlled laboratory conditions.
Instruments that require calibration
Routine calibration is essential for the following:
- Digital weighing balances
- Pressure and temperature sensors
- pH meters and conductivity meters
- Oscilloscopes and signal generators
- Flow meters and level indicators
A systematic process of calibration ensures these instruments provide repeatable, precise results throughout their lifecycle.
Calibration certificate checklist
An effective calibration certificate issued by Prism Calibration includes:
- Complete instrument details
- Manufacturer and model information
- Serial number and asset tag
- Measurement results with uncertainty estimates
- Calibration date, expiry, and re-calibration recommendation
- Traceability reference to national standards
- Calibration lab credentials (e.g., NABL accreditation number)
This documentation supports internal audits and third-party inspections.
Best practices for the calibration process
To ensure a robust calibration process, follow these industry-standard best practices:
- Always calibrate equipment after repairs, relocation, or long storage.
- Use protective gloves or tweezers to handle sensitive calibration weights.
- Maintain calibration history logs for all critical instruments.
- Avoid using non-certified or outdated calibration standards.
- Select a trusted calibration provider with ISO/IEC 17025 accreditation.
These practices safeguard your operations from potential compliance issues and measurement inaccuracies.
Conclusion
The process of calibration is an essential element of operational excellence, ensuring that instruments perform within defined limits and produce reliable data. A structured and traceable calibration process enhances productivity, reduces risks, and ensures long-term equipment accuracy.
Partner with Prism Calibration to access expert calibration services that are precise, compliant, and fully documented. Our team ensures every instrument is validated, certified, and ready for performance.
FAQs
Generally, every 6 to 12 months. However, high-use or critical instruments may require more frequent calibration.
It means that the calibration results can be traced back through an unbroken chain of documented comparisons to recognised national or international standards.
It should be adjusted, repaired, or replaced. Re-calibration must be done post-correction to confirm compliance.
Accredited labs follow standardised, audited processes and provide traceable calibration certificates recognised worldwide.
No. Apparent accuracy can be deceptive. Without proper calibration, results are not verifiable or compliant.
Author Bio
Mr. Parthiv Kinariwala is a leading expert in calibration and testing services, with over 20 years of experience in the industry. As the founder of Prism Calibration, established in 2004, Mr. Kinariwala has been at the forefront of delivering precise and reliable calibration, testing, and validation solutions across various industries. His expertise in providing services that meet international calibration standards has earned the trust of major clients, including Reliance Industries, Zydus Cadila, Indian Oil, ONGC, Adani, and Tata.
With a deep understanding of instrumentation, measurement accuracy, and industrial testing, Mr. Kinariwala ensures that each client receives exceptional service tailored to their specific needs. His unwavering commitment to quality and precision has established Prism Calibration as a trusted partner for some of the largest and most respected organizations in the industry.