Application of a full-scale testing facility for assessing wind-driven-rain intrusion Girma T. Bitsuamlak a, * , Arindam Gan Chowdhury b , Dhawal Sambare c a Laboratory for Wind Engineering Research, International Hurricane Research Center/Department of Civil and Environmental Engineering, Florida International University,10555 Flagler Street West, EC 3606, Miami, FL 33174, USA b Laboratory for Wind Engineering Research, International Hurricane Research Center/Department of Civil and Environmental Engineering, Florida International University,10555 Flagler Street West, EC 3604, Miami, FL 33174, USA c Department of Civil and Environmental Engineering, Florida International University,10555 Flagler Street West, EC 3664, Miami, FL 33174, USA article info Article history: Received 9 January 2009 Received in revised form 8 April 2009 Accepted 9 April 2009 Keywords: Full-scale Water intrusion Wind-driven rain Roof secondary water barrier Wind profile Turbulence abstract A new full-scale testing apparatus generically named the Wall of Wind (WoW) has been built by the researchers at the International Hurricane Research Center. The paper discusses the development of a full-scale testing methodology that can be adopted for assessing wind-driven-rain intrusion through the building envelope. The current phase of FIU’s WoW is capable of testing full-scale single story building models subjected up to 56 m/s (125 mph) wind speeds and 762 mm/h (30 in./h) of rain. Emphasis has been placed on generating a wind field with a proper boundary-layer profile and turbu- lence characteristics. Artificial rain has been generated by continuously pumping water through a plumbing system with regularly placed spray nozzles. A large wind and wind-driven-rain field 6.7 m wide by 4.8 m high (w22 ft wide by w16 ft high) has been produced, which can engulf the test specimen completely. For example, an assessment of roof secondary water barrier effectiveness in preventing water intrusion is presented. Six different roof secondary water barriers have been investigated. The amount of water intruded through the secondary water barrier and the visual observation of failure have been used as performance indexes. In addition, external and internal pressure measurements, required to explain rain intrusion mechanisms were carried out. Roof slope effects on water intrusion have been investigated by testing three different slopes (2:12, 4:12 and 6:12). Results indicated the following (i) as the slope increases the intrusion decreases, (ii) self-adhered secondary water barrier performed better than nailed secondary water barriers, and (iii) heavy secondary water barriers performed better than light secondary water barriers. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction The growth of hurricane-induced losses from $1.3B/yr pre-1990 to $36B/yr post-2000 [1], is a direct result of over 50 years of accu- mulated socioeconomic decisions to invest in physical infrastructure and community development along coastlines, where now 50% of the US population lives within 50 miles of the seaboard [2]. The physical impact of hurricanes on the built environment is due to the combined interaction of wind, rain, and debris with structures. Wind related damages are initiated, most of the time, either by the direct action of strong winds (where wind load/pressure is proportional to the square of the wind speed) or strong winds that cause flying missiles of wind-borne debris smashing into buildings and breaching the building envelope. Furthermore, hurricanes precipitate heavy rain along with the destructive strong winds. This often causes the wind-driven rain to intrude through damaged or ill-designed building envelope components such as roofs, windows and doors (and their interfaces with walls), and walls. This has been observed during the 2004 hurricane season in Florida [3]. Thus, in addition to structural damages and weakening of building envelopes, intrusion of wind-driven rain through roofs and other building envelope components can cause significant water-related internal property damages. Previous experiments [4] have shown that wind-driven rain can increase the amount of moisture present in the building structure by more than 100 times the amount due to vapor diffusion. In some cases, the intrusion of water did not seem to affect the safety of buildings or the internal occupancy. The health-related hazard, however, can cause the abandonment of buildings by their inhabi- tants. The paper discuses in detail the development of a full-scale testing methodology that can be adopted for assessing wind-driven- rain intrusion through the building envelope (roofs, doors, windows and walls). As an example of application, an assessment of roof components capabilities to withstand wind-driven-rain intrusions is presented. The example focuses on the assessment of wind-driven- rain intrusion through roof secondary water barriers commonly * Corresponding author. Tel.: þ1 305 348 6755; fax: þ1 305 348 2802. E-mail address: bitsuamg@fiu.edu (G.T. Bitsuamlak). Contents lists available at ScienceDirect Building and Environment journal homepage: www.elsevier.com/locate/buildenv 0360-1323/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.buildenv.2009.04.009 Building and Environment 44 (2009) 2430–2441