S. Yadav, A. K. Bandyopadhyay
This paper describes the proficiency testing (PT) of the seven laboratories, accredited by National Accreditation Board for Testing and Calibration of Laboratories (NABL), India having best measurement capabilities better than 0.05% of full-scale pressure by means of interlaboratory comparison using dead weight tester (DWT) as an artifact in the pressure range 7 – 70 MPa. The program started in November 2002 and completed during May 2004. National Physical Laboratory (NPLI), New Delhi has the privilege of coordinating this programme and also acted as a reference laboratory. The comparison was carried out at 10 arbitrarily chosen pressure points (7, 10, 15, 20, 25, 30, 40 50, 60 and 70 MPa) throughout the entire pressure range of 7 – 70 MPa. The normalized error (En) value of six laboratories out of the total seven are found < 1in the entire pressure range and are acceptable well within their reported expanded uncertainty at a coverage factor k = 2. These results are quite encouraging for the manufacturers and calibration laboratories that are facing a new environment after the WTO agreement.