What Is Calibration?
Calibration is the process of comparing an instrument's readings against national or international reference standards to determine its accuracy. During this process, measurement deviations are identified and correction factors are applied when necessary.
According to the International Vocabulary of Metrology (VIM), calibration is defined as "a set of operations that establish, under specified conditions, the relationship between values indicated by a measuring instrument or measuring system and the corresponding values realized by standards."
Why Is Calibration Necessary?
Every measurement instrument gradually loses its initial accuracy due to environmental factors, mechanical wear, and usage conditions. Measurements taken with uncalibrated instruments are unreliable and can lead to serious consequences:
- Quality control failures: Inability to detect out-of-tolerance products in manufacturing
- Safety hazards: Errors in pressure, temperature, and force measurements can cause workplace accidents
- Legal penalties: Failure to meet accreditation and regulatory requirements
- Financial losses: Waste, returns, and customer dissatisfaction from inaccurate measurements
ISO 17025 and Accreditation
ISO/IEC 17025 is the international standard that defines the competence of testing and calibration laboratories. In Turkey, accreditation granted by TURKAK (Turkish Accreditation Agency) independently verifies a laboratory's technical capability and management system.
Benefits of an Accredited Certificate
A calibration certificate from an accredited laboratory provides:
- International validity: Recognized in over 100 countries through the ILAC-MRA mutual recognition arrangement
- Measurement uncertainty: Contains uncertainty values demonstrating the reliability of each measurement
- Traceability: Documents the measurement chain to SI units
- Legal protection: Accepted as independent evidence in audits and customer requirements
| Criteria | Accredited Lab | Non-Accredited Lab |
|---|---|---|
| International validity | Yes (ILAC-MRA) | No |
| Uncertainty report | Mandatory | Optional |
| Independent audit | Annual TURKAK audit | None |
| SI traceability | Documented | No guarantee |
How Is Calibration Frequency Determined?
Calibration intervals vary based on the instrument, usage conditions, and industry requirements. Multiple approaches should be combined to determine the right interval:
- Manufacturer recommendation: The initial interval suggested by the instrument manufacturer (typically 12 months)
- Risk-based assessment: Shorter intervals for critical measurements (3-6 months)
- Statistical analysis: Trend analysis based on historical calibration data
- Regulatory requirements: Mandatory intervals in specific sectors (e.g., food, pharmaceutical, aerospace)
Which Industries Require Mandatory Calibration?
Calibration is a legal requirement in many industries. Key mandatory sectors include:
- Food and beverage: ISO 22000, FSSC 22000 requirements
- Pharmaceutical and medical devices: GMP (Good Manufacturing Practice) and FDA requirements
- Automotive: IATF 16949 standard
- Aerospace and defense: AS9100, NADCAP accreditation
- Energy: Nuclear, oil and gas sector standards
SF Metrology Calibration Services
At SF Metrology, our TURKAK-accredited laboratory provides comprehensive calibration services covering dimensional, force, pressure, temperature, and electrical quantities. All our calibration certificates comply with international traceability standards.
For your calibration needs, reach out through our contact page or email us at info@sfmet.com.
Frequently Asked Questions
What is the difference between calibration and verification?
Calibration determines a device's measurement deviations and produces a certificate. Verification checks whether a device meets specified requirements and gives a pass/fail result. Calibration always precedes verification.
How long is a calibration certificate valid?
A calibration certificate itself has no "expiration date" — it documents the condition at the time of calibration. However, organizations plan their next calibration based on risk analysis and historical data. The general practice is 6-12 month intervals.
Why is TURKAK accredited certification important?
TURKAK accredited certificates are recognized in over 100 countries through the ILAC-MRA agreement. They are internationally accepted for exporting companies, serve as independent evidence in audits, and provide reliable reference in legal disputes.
Sources: ISO/IEC 17025:2017, ILAC-G24:2007, VIM (JCGM 200:2012), TURKAK Accreditation Guide