STANDARDIIIHG CALIBRATIOH LABORATORY PIULCTICES

C. lhrralikrishna Kumar, SHIEEE

STQC Directorate, Department of Electronics Electronics Niketan, 6, CGO Complex

Lodi Road, New Delhi 110 003.

Abstract

The role of Calibration lab is becoming more and more important in view of 'Global Business' environment. Scheduled, regular calibration of test and measuring instruments with measurement traceability to the nationally accepted standards is a prerequisite. Certification to IS0 9000 - Quality System Standards becoming a must for exports, the calibration activity being the backbone for Quality, the calibration laboratory practices have become more important.

In the present day industrial scenario, setting up of a calibration laboratory by a small scale industry is mostly uneconomical and impractical as the work load does not warrant an in house calibration lab and full time calibration experts, technicians. In which case the ideal solution is to choose an outside agency which can provide calibration services as per the requirements of the organization.

IS0 9000

The international standards organization (ISO) is a federation

of national standards bodies. ISO- 9000 is a series of specifications dealing with 'Quality Management Systems and Quality Assurance Practices'. The series are as follows :

IS0 9000: Quality Management and Quality Assurance Standards- Guidelines for selection and use.

IS0 9001: Quality System - Model for Quality Assurance in Design, Development, Production, Installation and Servicing.

IS0 9002: Quality System - Model for Quality Assurance in Production and Installation.

IS0 9003: Quality System - Model for Quality Assurance in Final Inspection and Testing.

IS0 9004: Quality Management and Quality System elements - Guidelines.

Any organization working towards IS0 9000 registration has to demonstrate accuracy of Test & Measuring Equipments (TME) , being used by the organization. The importance of this aspect has been well appreciated and the IS0 technical committee (TC 176) which

178

developed the IS0 9000 series also developed quality system series IS0 10000. The document IS0 10012- 1 (1992) : Quality Assurance requirement for measuring equipments Part 1: Metrological confirmation system for measuring equipments, is specifically developed and addresses quality assurance requirements of TME.

Calibration System Requirements

Quality assurance in electronic products is a direct function of the measurements being made at various levels using TME. Reliability of measurements made with the help of TME can be ensured through the establishment of traceability in measurements to national standards which is also a vital requirement under international quality requirements like IS0 9000.

The integrity of all measurement work is founded on the selection and proper use of suitable TME and its validation by a system of measurement control and calibration.

An integrated network of 23 laboratories have been setup and are serving the industries under the STQC programme of Department of Electronics. Realizing the important role of calibration in the over all quality assurance system, IISTQC Calibration Servicesww was evolved, inorder to have a uniform calibration system and to provide systematic and effective services to the industries. The system covers important issues like Organization of Standards and Calibration laboratory, Environmental controls, Traceability,

179

Calibration recall system, Calibration procedures, Labeling practices and Reports.

Standard operating / calibration procedures have been evolved for instruments which are regularly calibrated. Standard test result formats have also been evolved which will facilitate the operator in calibration work and help in reducing the turn around time in calibration. These formats can also help in quickly computing the errors in the measurements, which in turn helps in assessing the status of the instrument being calibrated.

Colored labels have also been incorporated to indicate the calibration status of the instrument such as 'Valid Calibration', ' Limited Calibration' and 'Do not use until repaired and recalibrated'.

The laboratories also have an effective calibration recall system and the inhouse standards / equipments are calibrated regularly against standards which are traceable to the national standards, which is the most important requirement for quality assurance of measurements. To aid in the implementation of calibration laboratory requirements and standardizing the calibration laboratory practices, an effective computer aided laboratory management system is also developed and is in use.

Most of the STQC laboratories are members of National Conference of Standards Laboratories (NCSL), USA, an organization devoted to the cause of Standards and Calibration laboratories world

over. NCSL has brought out many useful publications in the area of calibration and calibration laboratory management [l-41.

Lord Kelvin said It.. . When you can measure what you are speaking about and express it in numbers, you know something about it, and when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind."

180

References

[ I 1 Calibration Laboratory Manager' s Guidebook NCSL Publication.

[2] Evaluation of Measurement Control Systems and Calibration Laboratories NCSL RP #2, 1979.

[ 3 ] Calibration Procedures NCSL RP #3, 1990.

c 4 1 Calibration System Specification NCSL RP #4, 1979.

(RP - Recommended Practice).