| 1 INTRODUCTION
To design durable building envelopes, knowlegde of the exposure to local outdoor climate isprimordial. One of the parameters is driving rain, defined as rain that is carried by wind anddriven onto the building envelope. A standard method for building designers to estimate driv-ingrain quantities (BSI 1992) is available only in the UK. There are few other tools and dataavailable, useful for the estimation of driving rain and for laboratory tests of building materialsand structures. In the last two decades computational fluid dynamics (c.f.d.) became available.To the author's knowledge, only a single attempt has been made to compare driving rain c.f.d.simulations with wind tunnel experiments (Hangan and Surry 1998).
Since December 1997 full-scale measurements of wind and driving rain on the westfacade of the Main Building of the Eindhoven University of Technology (TUE) are carried out,along with reference measurements of wind and rain. The aim is to determine the function ofdriving rain quantities as function of reference wind and rain parameters. In this paper, resultsof the full-scale measurements and results of c.f.d. simulations of wind and driving rain of thesame situation are presented.
2 DRIVING RAIN
The general model of driving rain used in this study, has been described in van Mook et al.(1997). Such an approach is also used in e.g. Choi (1993), Karagiozis and Hadjisophocleous(1996), Sankaran and Paterson (1995) and Hangan and Surry (1998). A brief summary of quan-titiesand symbols is provided in this section.
The horizontal rain intensity Rh [mm/s] is the rate of rain water falling through a hori-zontalplane during a certain period in the undisturbed oncoming wind flow, and equals to the
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1 Building Physics group (FAGO), Eindhoven University of Technology (TUE), Postbus 513,
5600 MB Eindhoven, the Netherlands, famo@fago.bwk.tue.nl | 
