Realization of Negative Gauge Pressure Standard in the National Metrology Institute of Indonesia

Accurate negative gauge pressure measurement is the key factor for many scientific and industrial applications such as clean room technology, medical treatment, and pharmaceutical production. However, there are not much publications regarding to the technical guide when it comes to negative pressure measurement, although several comparison of negative gauge pressure has been performed in Europe. In this study, two methods for negative pressure calibration have been successfully implemented by National Standardization Agency of Indonesia with using pressure balance. The first method is by generating the negative pressure in the bell jar of the pressure balance, and the second method is by using pressure balance in absolute pressure mode and additional barometric pressure measuring instrument. Both methods measurement results show linear relation from the negative to positive pressure and show good agreement by each other with the normalized error (En) less than 0.40 from – 1000 to 1000 hPa with uncertainty up to 0.073 hPa. The expanded uncertainty of the second method is relatively larger due to dominant contribution from the uncertainty of the barometer used. Therefore, it can be concluded that both methods can be used in order to provide traceability for negative gauge pressure measurement instrument in Indonesia.