Experimental analysis of cavity ventilation behind rainscreen cladding systems: A comparison of four measuring techniques

The present article elaborates on the comparison of four measuring techniques quantifying the ventilation rate behind typical cladding systems in wall elements. In total eight full-scale test walls have been investigated in a test building located in a maritime temperate climate (Belgium). Two different commonly used cladding systems are studied: (a) brick veneer and (b) fibre cement sidings. The test walls were installed on the Southwest and Northeast facades of the building corresponding to the orientations with most extreme exposure regarding solar radiation, wind directions and wind-driven rain. In total four different measurement techniques to quantify the ventilation rate in these systems have been applied: a) tracer gas techniques, b) indirect method based on pressure measurements, c) direct method based on anemometers and d) method based temperature and relative humidity registration. The results indicate that the ventilation rate behind vented brick veneer is two orders of magnitude lower than behind ventilated cladding systems with sidings. It was found that the most appropriate measuring technique of a wall system is depending on the ventilation rate, and hence on the type of cladding. For brick veneer claddings, the method deriving the air flow rate from the pressure gauges was found to be most suitable. In the wall systems with sidings, on the other hand, the ventilation rates were sufficiently high to be measured accurately with the anemometers. (C) 2015 Elsevier Ltd. All rights reserved.