What is Calibration?
Calibration is the comparison of two measurement devices or systems; one is the reference standard and the other is the unit under calibration. Instrument calibration is intended to eliminate or reduce bias in an instrument's readings over the range for all continuous values. For this purpose, reference standards (calibration targets) with known values for selected points covering the range of interest are measured with the instrument in question. Then a functional relationship is established between the values of the standards and the corresponding measurements. This process which involves the verification of the operational integrity of instruments is to be carried out periodically in sophisticated laboratories under controlled conditions.

The standards used in calibration has to be calibrated with another reference standard of better accuracies. This process goes up as a chain - called the Traceability Chain, up to the highest level of standards, maintained by a National Laboratory. Thus Traceability means that there is a documented link between the accuracy of an instrument and the National Standards. In India all primary standard are maintained by National Physical Laboratory (NPL), New Delhi.

NABL Accreditation
National Accreditation Board for Testing and Calibration Laboratories (NABL) is the authority, coming under Department of Science and Technology of Govt. of India for accreditation of Laboratories in India. NABL accreditation is a formal recognition of the technical competence of a testing or calibration laboratory for a specific task following ISO/IEC 17025 Standard. This is based on third party assessment.

WTO recognizes non-acceptance of test results and measurement data as Technical Barrier to Trade (TBT). Accreditation is considered to be the first essential step towards removing such technical barriers. NABL has achieved the status of APLAC (Asia Pacific Laboratory Accreditation Cooperation) MRA (Mutual Recognition Arrangement) partner and signatory to ILAC (International Laboratory Accreditation Cooperation) Arrangement based on peer evaluation by a multi-disciplinary team from APLAC. This is a major step towards mutual acceptance of test results and measurement data amongst 40 accreditation bodies representing 31 countries.

Thus being an NABL accredited Laboratory, calibration for the accredited parameters from STIC is valid internationally.