A uniform methodology to establish test parameters for watertightness testing: Part I: A critical review

Many of the standards and codes related to watertightness of building components in use today have a long history and in most cases their roots were conceived decades ago. Irrespective of the broad spectrum of research on wind loads, rainfall and wind driven rain (WDR) intensity, little information is available concerning the scientific basis for watertightness test methods or performance criteria. This paper provides an overview of existing methodologies to establish test conditions and a critical review of calculation methods for wind and WDR loads on buildings, from the viewpoint of establishing test parameters for watertightness testing. The operative standard in the field of structural engineering is extended with a gust model to calculate wind loads for varying configurations, return periods and gust lengths, and model implications are discussed. A state-of-the-art on intensity–duration–frequency curves of horizontal rainfall intensity is given, and a new approach to accommodate conflicting models is presented. Furthermore, based on recent advances in WDR research, an adapted semi-empirical model is suggested to calculate extreme WDR intensities on building façades. For two locations boundary conditions for watertightness testing were calculated based on datasets extending over 10 years of 10-min averaged values. Finally, constraints and challenges in extreme value analysis in respect to cut-off values, fitting algorithms, goodness-of-fit (GOF) criteria and co-occurrence of rain and wind are discussed.

► Review of existing methods to establish test conditions for watertightness testing.
► New model for rainfall Intensity–Duration–Frequency curves is presented.
► The sensitivity of extreme value analysis on wind and rain data is discussed.
► Comparison of different approaches and test protocols show large discrepancies.