Uncertainty Evaluation of the New Setup for Measurement of Water-Vapor Permeation Rate by a Dew-Point Sensor

• Published in: International journal of thermophysics 2012-09, Vol.33 (8-9), p.1595-1605
• Main Authors: Hudoklin, D., Šetina, J., Drnovšek, J.
• Format: Article
• Language: English
• Subjects: Classical Mechanics; Condensed Matter Physics; Industrial Chemistry/Chemical Engineering; Physical Chemistry; Physics; Physics and Astronomy
• ISSN: 0195-928X; 1572-9567
• DOI: 10.1007/s10765-012-1213-1

The measurement of the water-vapor permeation rate (WVPR) through materials is very important in many industrial applications such as the development of new fabrics and construction materials, in the semiconductor industry, packaging, vacuum techniques, etc. The demand for this kind of measurement grows considerably and thus many different methods for measuring the WVPR are developed and standardized within numerous national and international standards. However, comparison of existing methods shows a low level of mutual agreement. The objective of this paper is to demonstrate the necessary uncertainty evaluation for WVPR measurements, so as to provide a basis for development of a corresponding reference measurement standard. This paper presents a specially developed measurement setup, which employs a precision dew-point sensor for WVPR measurements on specimens of different shapes. The paper also presents a physical model, which tries to account for both dynamic and quasi-static methods, the common types of WVPR measurements referred to in standards and scientific publications. An uncertainty evaluation carried out according to the ISO/IEC guide to the expression of uncertainty in measurement (GUM) shows the relative expanded ( k = 2) uncertainty to be 3.0 % for WVPR of 6.71 mg . h −1 (corresponding to permeance of 30.4 mg . m −2 . day −1 . hPa −1 ).