Pressure-equalised façade systems: Evaluation of current watertightness test standards used to assess the performance of enclosure components

Watertightness test standards are used to evaluate enclosure components in terms of water penetration resistance. Currently, there is a wide variety of watertightness tests in use for façades elements and wall systems; however, none of them specifically addresses and evaluates the drainage capacity in pressure-equalised façade systems. In addition, recent research has revealed many inconsistencies in the possibility of these test standards to represent all possible conditions that can occur under different operating conditions, varying building configurations and at different locations. As such, the three main variables for water penetration testing (water spray rate, pressure differential and duration of the pressure application) have been called into question. Nonetheless, these studies do not bring up the protocols and other technical specifications incorporated in the test standard procedures. Furthermore, neither are concerns raised about the influence that these other parameters might have on the outcomes of the watertightness test, which is the aim of this research. To this end, the article provides a critical review of current watertightness tests standards from around the world in the first section. Thereafter, a thorough comparison of the information incorporated in the protocols of the test standards has been carried out. The evaluation and discussion of the test parameters and technical specifications incorporated in the tests standards is undertaken based on the state of the art and laboratory experiments of three mock-ups with pressure-equalised façade systems, where the water management capacity of the system is assessed. As a result of this research work, a guideline was prepared for the establishment of test procedures when developing new watertightness standards for pressure-equalised façade systems.