NABL 142NABL NATIONAL ACCREDITATION BOARD FOR TESTING AND CALIBRATION LABORATORIES POLICY on TRACEABILITY OF MEASUREMENT RESULTS ISSUE NO : 04 ISSUE DATE: 27.06.2012 AMENDMENT NO :00 AMENDMENT DATE: -- AMENDMENT SHEET Sl Page Clause Date of No. No. Amendment Amendment made Reasons Signature Signature QO Director 1 2 3 4 5 6 7 8 9 10 National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 142 Issue No: 04 NABL Policy on Traceability of Measurement results Issue Date: 27.06.2012 Last Amend No: 00 Amend Date: -- Page No: 1/ 4 CONTENTS Sl. Chapter Page No. Amendment Sheet 1 Contents 2 1. Introduction 3 2. Scope 4 3. NABL Policy 4 National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 142 Issue No: 04 NABL Policy on Traceability of Measurement results Issue Date: 27.06.2012 Last Amend No: 00 Amend Date: -- Page No: 2/ 4 1. INTRODUCTION Metrological traceability is the property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty (VIM: 2010). Traceability of test and or measurement data is very important to adjudge the validity of results. ILAC characterized traceability by six essential elements: i. an unbroken chain of comparisons: going back to stated references acceptable to the parties, usually a national or international standard; ii. uncertainty of measurement: the uncertainty of measurement for each step in the traceability chain must be calculated or estimated according to agreed methods and must be stated so that an overall uncertainty for the whole chain may be calculated or estimated; iii. documentation: each step in the chain must be performed according to documented and generally acknowledged procedures; and the results must be recorded; iv. competence: the laboratories or bodies performing one or more steps in the chain must supply evidence for their technical competence (e.g. by demonstrating that they are accredited); v. reference to SI units: the chain of comparisons must, where possible, end at primary standards for realization of the SI units; vi. calibration intervals: calibrations must be repeated at appropriate intervals; the length in of these intervals will depend on a number of variables (e.g. uncertainty required, frequency of use, way of use, stability of equipment). ISO/IEC 17025 requires all equipment used for test and or calibrations including equipments of subsidiary measurements having significant effect on the accuracy or validity of the result shall be calibrated according to established calibration program to maintain traceability to SI units. Standard also specifies the mechanisms that can be practiced in the absence of such traceability. ISO15189 also requires a laboratory shall design a program for calibration of measuring systems and verification of trueness shall and performed so as to ensure that results are traceable to SI units or by reference to a natural constant or other stated reference. National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 142 Issue No: 04 NABL Policy on Traceability of Measurement results Issue Date: 27.06.2012 Last Amend No: 00 Amend Date: -- Page No: 3/ 4 2. SCOPE This document details the traceability requirements of NABL and acceptable traceability terms for Testing, Calibration and Medical laboratories. The traceability requirements are according to ILAC P10:2002 "ILAC policy on traceability of measurement results" 3. NABL POLICY 1. NABL accredited testing and calibration laboratories are required to have an established program of calibration to ensure that its testing and measuring equipment are traceable to SI units where possible through national or international standards. 2. NABL oblige calibration of equipments from: i. From national metrology institute; National Physical laboratory (NPL) India or from a National metrology institute who is signatory to Comité International des Poids et Mesures (CIPM) Mutual recognition arrangement (MRA) ii. From an NABL accredited calibration laboratory or from an accredited calibration laboratories of APLAC/ ILAC MRA partner when the MRA covers calibration activities. Calibration certificate bearing Accreditation body's symbol / a specific reference to the accreditation status by a recognized accreditation body (ILAC/APLAC MRA partner) shall only be considered for valid traceability. 3. Where such traceability is not possible or reasonable: i. The laboratory shall demonstrated suitable traceability by using certified reference material which gives reliable physical or chemical characterization of a material. CRM shall be acquired from a competent Reference Material producer preferably accredited by an ILAC MRA partner according to ISO Guide 34 or from a National Metrological Institute (NMI) that is a signatory to CIPM MRA. ii. NABL also recognize traceability to specified methods and /or consensus standards that are clearly described and agreed by all parties concerned. The laboratory shall provide satisfactory evidence of correlation of results for example by participating in Proficiency Testing and/ or performance characteristics checks against manufacturer’s standards. National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 142 Issue No: 04 NABL Policy on Traceability of Measurement results Issue Date: 27.06.2012 Last Amend No: 00 Amend Date: -- Page No: 4/ 4 National Accreditation Board for Testing and Calibration Laboratories 3rd Floor, NISCAIR, 14 Satsang Vihar Marg New Mehrauli Road New Delhi – 110067 Tel.: +91-11-46499999 Fax: + 91-11- 26529716 Website: www.nabl-india.org