The 1990 International Temperature Scale (ITS-90) substituted the platinum-platinum-10% rhodium thermocouple by the high temperature standard platinum resistance thermometer (HTSPRT) and the radiation thermometer, as an interpolating instrument in the 630°C to 1064°C range, due to the lower stability of the thermocouple. Although the uncertainty of reproducing the temperature scale became much lower, the cost of the required measuring equipments was raised. Aiming to offer the Brazilian Calibration Network accredited laboratories a lower cost temperature scale traceability alternative, at a smaller uncertainty than the standard type S thermocouple can provide, a 99,999% purity gold-platinum (AuPt) thermoucouple was exposed systematically to a high temperature environment (close to 1000°C) for more than 1500 hours, with its stability and homogeneity being evaluated with the aid of a silver fixed point cell. It was shown that a ± 25 mK (k=2) uncertainty can be achieved. This works details the methodology and the cares that have to be taken in order assure the reliability of the results.

Using integrated miniature fixed-point cells, a measuring uncertainty of < 1 K can be reached under operating condi tions in the superheated steam range of power plants by a periodic recalibration of the thermocouples, with operating times of > 20000 h. The fixed-point materials used for a temperature range from 500°C to 650°C are technically pure metals and binary alloys.

Resistance bridges, when used for temperature measurements with SPRTs, are able to achieve uncertainties better than 1 ppm. However, they have several shortcomings that prohibit their use in many applications. Among these are cost, size, slow speed, and limited range. An endeavor was made by the author to design a readout for resistance thermometers that achieves less than 1 ppm uncertainty in resistance ratio while overcoming some of the problems of resistance bridges. A new approach was taken with a design that uses the latest integrated-circuit analog-todigital converters. This allows the instrument to have lower cost, smaller size, the capability of increased speed, and additional features. Special effort was made to reduce errors caused by component drift, thermoelectric EMF, component offset, electrical noise, and nonlinearity. The new resistance thermometer readout was tested to identify and evaluate sources of measurement uncertainty. The combined uncertainty was calculated for resistance ratio and W(T90) measurements of an SPRT with self-heating corrections. Measurements made with the resistance thermometer readout were compared with measurements made with a resistance bridge. The results show that the standard uncertainty of the new resistance thermometer readout is about 0.34·10^-6 in measuring resistance ratio at 25 Ω/100 Ω and about 0.68·10^-6 in measuring W(T90) near the triple point of water.

A European Virtual Institute for Thermal Metrology (EVITherM) is being developed by a consortium of 34 European institutes, led by NPL and supported by the EC, to ensure that thermal knowledge and services are made available to industry, for the benefit of industrial processes and the environment, offering low-cost easy access, particularly to SMEs. EVITherM will be a co-ordinated Internet-based infrastructure designed to link together the geographically scattered centres of excellence and other groups and organisations concerned with thermal measurements and technology to provide a focal point for information exchange and knowledge transfer between all these organisations and industry. It will form a website for users, having three levels of access. The first level is free and contains directories of information; the second and third levels are for members only and will allow access to qualified information and member interactions. The first public release of the website is due by early 2004.

The operation of the economy on a global scale and the quality of life for the individual citizen depends on reliable measurements and tests, which are trusted and accepted internationally. The European Commission is supporting two projects linking measurement, regulation, trade and commerce under the Competitive and Sustainable Growth thematic Programme in the Fifth Framework Programme. This paper describes the aims and some findings of the RegMet and MetroTrade projects, including the concept of the development of a measurement template for regulators.