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Urban Green Infrastructure (UGI) plays a critical role in creating Thermal Resilient Communities (TRCs) by mitigating the adverse climate change impacts and enhancing thermal resilience. In this paper, we consider a range of UGI types, from street trees, urban parks, green spaces, and building-integrated UGI components, such as green roofs and green walls. It is intended that the thermal/aerodynamic effects of UGI be analyzed and the influence of UGI at three spatial scales within urban communities be provided; more specifically: microclimate scale, building scale, and individual scale. The study discusses the findings of 218 papers published since 2010 to elaborate on recent progress in this field. This review delves into three fundamental aspects related to UGI: a) the underlying mechanisms allowing UGI to affect the environment and human health, b) the modeling efforts undertaken to simulate these effects, and c) measurement studies providing empirical data and verifying the models. Additionally, the effects of UGI across the three scales and related aspects are discussed, and the importance of integrative mechanisms and coupled modeling approaches is emphasized. Key methodologies for integrating microclimate and building simulations are summarized, highlighting the data exchange protocols and software tools. In contrast to previous reviews, this study has analyzed major measurement studies, categorizing them into full-scale and sub-scale studies. As a conclusion, several potential directions for future research are identified, including advanced physical and data driven UGI models, enhanced coupled simulations for indoor-outdoor interactions, establishment of measurement datasets for benchmarking both UGI modeling and coupled simulations. • Reviewed 218 post-2010 Urban Green Infrastructure (UGI) studies for Thermal Resilient Communities (TRC). • Analyzed UGI effects on three spatial scales of microclimate, building and individual. • Discussed UGI effects in terms of mechanism, modeling and measurement. • Summarized co-simulation methods for microclimate and buildings with UGI. • Outlined and compared full-scale and sub-scale measurements studies with UGI. [ABSTRACT FROM AUTHOR]

Today, there is an increased research effort on improving energy efficiency in heritage buildings through retrofit measures. Hygrothermal simulations tools are often used to assess the long-term performance of building envelopes and determine whether they are suitable for interior insulation. To reduce the high computation time and cost incurred with these simulations, a moisture reference year (MRY) is typically selected based on long-term annual climatic conditions. Simulation results obtained under MRYs are assumed to represent the long-term performance. However, when assessing the risk to freeze-thaw (FT) damage of historic masonry walls, methods selecting climate-based MRYs have failed to represent the actual performance – determined based on results from simulations over the 31 consecutive years. This paper attempts to find an alternative method to select MRYs, based on the hygrothermal simulations of specific constructions. First, a parametric analysis was proposed to identify the parameters that have the greatest influence on FT damage. Then, simulations are performed for a continuous 31-year period and for each single year. A comparison of their results suggests that there is no accumulative effect on the annual freeze-thaw cycles; and therefore, MRYs can be selected as the single year with the 93rd percentile FT damage severity or the worst year commonly found between masonry walls pre and post retrofit. The application of MRYs was then verified for different insulation types and thicknesses. Results showed that simulation-based MRYs are construction and orientation dependent; however, they are reliable to use for retrofitting design decision making. • Simulation-based approach developed for moisture reference year specific to freeze-thaw damage. • Single-year simulation can be used to select MRY for assessing long-term freeze-thaw damage risk. • Simulation-based MRY verified for various internally insulated historic masonry walls. [ABSTRACT FROM AUTHOR]

The changing climate may influence building performance in several different aspects. In respect to the hygrothermal performance, excessive moisture arising from climate loads and present in wall assemblies over a prolonged period of time is the cause of many detrimental effects on wall components; notably, such effects may become more significant under a changing climate. The occurrence of these effects can be assessed by undertaking hygrothermal simulations. However, numerical simulations can be time-consuming, especially when evaluating the detrimental effects over a long period, which is necessary for assessing the impacts of climate change on building envelope components. A means to reduce such a time consuming and costly simulation effort is to select a set of representative years from the series of long-term climate data; a set of Moisture Reference Year (MRY), with the expectation of obtaining similar results as those obtained from the long-term simulations. This study assesses the reliability of using MRY for evaluating the long-term hygrothermal performance of wall assemblies. The MRY were selected based on moisture index (MI) rankings for historical and future climatological periods. The simulations using MRY were repeated at least 2 times and up to 10 times, with the results compared to those obtained from 31 years of consecutive simulations. Two types of wood-frame wall assemblies, each with different types of exterior cladding, were analyzed. Several criteria were selected for comparison. The results showed that the required number of repetitions of MRY is determined by the parameters used for comparisons. • Assessed the reliability of using moisture reference years (MRYs). • Determined the required number of repetitions of MRYs under different criteria. • Moisture index was used as the criteria for the MRYs selection. • The MRYs approach is suitable for assessing changes in wood frame wall performance. [ABSTRACT FROM AUTHOR]

• Nature-based solutions (NBS) are promising extreme heat mitigation strategies. • This study investigates the effectiveness of NBS in three Canadian regions. • NBS is evaluated by albedo cooling (ACE) and vegetation cooling effectiveness (VCE). • NBS is most effective in Vancouver with average ACE of 9.8°C and VCE of 5.1°C. The need to mitigate and adapt to a changing climate is becoming more urgent, especially in highly urbanized areas where a growing portion of the population lives. This study quantifies the effectiveness of two Nature-Based Solutions - cool roofs and urban vegetation - in the moderation of urban temperature during past Extreme Heat Events in the Ottawa-Montreal, Calgary, and Vancouver regions of Canada. The Weather Research and Forecasting model coupled with the multi-layer building effect parameterization and building energy model at a horizontal resolution of 1km is evaluated under diverse climates, and is used to simulate different levels of both NBS applied across each of the aforementioned regions. Increasing implementation of cool roofs and urban vegetation lead to reductions of near-surface air temperature and wind speed, and enhancements in relative humidity. The largest cooling occurred when both cool roofs and increased vegetation are implemented in each of the cities. The largest cooling effect was found in Vancouver, where a maximum reduction of 3.5°C in 2m air temperature could be felt, while the weakest effect was found in Ottawa at 1.2°C across the city. [ABSTRACT FROM AUTHOR]

Abstract The Multiplicative Random Cascade (MRC) disaggregation model has been extensively used to disaggregate precipitation in many regions across the globe. In this study, it is adapted to disaggregate a range of climate variables (CV) relevant for hygrothermal modelling of building envelopes. This generalized MRC-G model is further improved by explicitly modelling the cross-correlation structure between CVs in the MRC-G-CV model. A thorough evaluation of MRC, MRC-G, and MRC-G-CV models is performed for five Canadian cities: Ottawa, Vancouver, Calgary, St. Johns, and Winnipeg. Results indicate that the MRC model is able to simulate grid-level statistics with >90% accuracy. Grid-level extreme magnitudes and spatial cross-correlation structures are also well simulated. Error magnitudes associated with hourly predictions indicate superior performance of the models in respect to thermal variables, followed by wind variables, and then moisture related variables. Finally, the performance of MRC-G model towards modelling cross-correlation among CVs is found to improve by >50% in terms of energy distance by explicitly modelling these relationships in the MRC-G-CV model. Results indicate that the MRC model variants demonstrated in this study have the potential to facilitate effective hygrothermal performance evaluation of building envelopes at locations where observational sub-daily climate records are unavailable. Highlights • Use of Multiple Random Cascade (MRC) for multivariable disaggregation demonstrated. • Both spatial and inter-variable dependence structure explicitly modelled. • Comparable performance of MRC method across variables is obtained. • Modelling of inter-variable dependence structures found to improve MRC skill. • Results highlight utility of MRC model variants in hygrothermal assessments. [ABSTRACT FROM AUTHOR]

Quantifying building resilience to extreme weather conditions helps identify the capability of a building system to tolerate disturbances and recover from extreme events. The robustness of building retrofit strategies can also be evaluated through their contributions to building resilience. In this study, building thermal resilience to summertime heatwaves is defined based on the concept of resilience trapezoid. The Thermal Resilience Index (TRI) with several labeling classes (Class F to Class A+) is proposed to quantify the resilience levels with respect to the relative improvement from original indoor thermal conditions. In addition to evaluating the overall resilience of a building, the resilience of each thermal zone in the building can be quantified with the proposed TRI criteria. A quantification framework is proposed by using the Standard Effective Temperature (SET) index as the performance indicator, and the entire procedure is demonstrated with a long-term care building of five stories. Four retrofit measures and their combinations are implemented to improve the building resilience to heatwaves. The results show layered multiple strategies are necessary to improve both the overall resilience of the building and the resilience of its component thermal zones. The resilience of the building can achieve the level of Class B after the combined strategies are applied, providing an improvement of 50%–70% in the degree of resilience. The proposed TRI index and spatial distribution analysis are useful in evaluating the overall and zonal resilience of a building. • Thermal Resilience Index (TRI) - a new building resilience parameter against heatwave is proposed. • Building thermal resilience curve is shown to be a trapezoid profile based on field measurements. • TRI is proposed to label the zone-level and building-level resiliences from Class F to Class A+. • TRI is evaluated using Standard Effective Temperature (SET) index as the performance indicator. • The new TRI approach is demoed by a long-term care center by measurements and simulations. [ABSTRACT FROM AUTHOR]

The objective of this study was to develop a prediction model for predicting the mould growth risk in wood-frame walls. A machine learning algorithm, the Partial Least Squares (PLS) regression was used for developing the model. Hygrothermal simulations were performed for a wood-frame wall with brick cladding using hourly historical and projected future climate data for cities located in different climate zones across Canada. The mould index calculated at the exterior layer of OSB was used as the response variable in the PLS model and the most relevant climate parameters were used as inputs including: temperature, relative humidity, wind speed, wind-driven rain, and solar radiation normal to the façade. The model was trained using a training set comprising two climate periods and different wall orientations for three cities. It was then used to predict the mould index for other years and wall orientations without performing the simulations. The coefficient of determination (R2), the Root Mean Square Error (RMSE) and Mean Absolute Error (MAE) was used to evaluate the model's accuracy. Also, ranking and mould risk category analysis were carried out to assess the model's ability to rank the years according to their moisture severity. Results showed that with proper selection of training dataset, the model can be effectively used to predict the hygrothermal performance of brick-clad wood-frame wall assemblies in the selected cities and over both historical and future climates. • Partial Least Squares regression method dealing with multicollinear inputs is used. • Prediction models developed and validated for three cities across Canada. • WDR is the most influential climate parameter in the prediction model for cities studied. • Model developed can predict mould index and categorize years based on moisture severity. • Model can be used by practitioners for screening purposes to reduce simulation efforts. [ABSTRACT FROM AUTHOR]

Climate change has led to prolonged, more frequent, intense, and severe extreme weather events, such as summertime heatwaves, creating many challenges on the economy and society and human health and energy resources. For example, the 2010 and 2018 heatwave in Quebec, Canada, resulted in about 280 and 93 heat-related deaths, and there were around 500 fatalities due to overheated indoor environments in 2021 around entire Canada. Therefore, it is imperative to understand and evaluate the overheating conditions in buildings, for which selecting suitable future reference weather data under climate change is one of the first critical steps. This study evaluated a reference year selection method in terms of typical and extreme reference years based on future climate datasets to assess both outdoor and indoor overheating in the future. The future climate data were collected from the Coordinated Regional Downscaling Experiment (CORDEX) program. Three Canadian cities (Montreal, Toronto, Vancouver) were selected for the overheating evaluation during three selected periods (2001–2020, 2041–2060, 2081–2100). The CORDEX climate projections were first bias-corrected by the multivariate quantile mapping correction method with the observational data. Then, the typical and extreme reference year data were generated as well as climate data from the design summer year for comparison. The performance of the reference year selection method was evaluated by comparing the maximum, minimum, and average overheating hours for the 20-years data of each period. This study demonstrates that the multivariate quantile mapping bias correction method can improve the reliability of future climate data making it one of the most important steps for any future weather projection study. Besides, the reference year selection method could efficiently capture maximum and minimum monthly overheating hours providing the upper and lower boundary of possible outdoor and indoor overheating conditions.. In contrast, neither the severest nor the typical monthly outdoor and indoor overheating conditions could be predicted by the design summer year method. Finally, owing to the effects of climate change, average monthly overheating hours normally increase by around one time (from 50% to 150%) until the mid-term future (2041–2060) and by around two to three times (even up to nine times for some scenarios) during the long-term future (2081–2100). [ABSTRACT FROM AUTHOR]

Abstract: A critical review on boundary conditions for watertightness testing was presented in a related paper forming Part I of “A uniform methodology to establish test parameters for watertightness testing”. Existing methodologies to establish test conditions only partially consider co-occurrence of rain and wind, which yields large uncertainties when determining return periods for extreme wind-driven rain events. This paper presents a new approach based on a Pareto fronts method for which wind driven rain intensities and wind pressures are derived. Straight lines can be fitted to consecutive fronts, and a generalized Pareto distribution describes the corresponding probabilities of occurrence of wind-driven rain events. Assumptions in the use of the methods are given and constraints to its use provided by means of case-studies. Advantages over existing methods for estimating watertightness test parameters are highlighted. Test conditions can be calculated for various configurations and different averaging periods depending on the failure behavior of specific building envelop components. Subsequently it is shown that the conversion of case-based test conditions to generic test protocols and performance levels requires careful consideration. Finally, the paper provides practical guidelines on defining realistic watertightness performance levels for building envelop components. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

The development of alternative details to manage water intrusion at the window-wall interface has produced a number of novel approaches to detailing the interface between the window and the adjacent wall assembly. Many of these approaches advocate the need to provide drainage at the rough opening of the window subsill, given that the window components themselves are susceptible to water entry over their expected life. Depending on the types of windows used and the cladding into which the windows are installed, there arise different methods to provide drainage that may also affect air leakage through the assembly. This in turn may give rise to the formation of condensation along the window, at the sill, or along the window sash and glazing panels. Hence, there is a need to determine if, under cold weather conditions, specific interface details that incorporate sill pans provide a potential for condensation on the window components in which air leakage paths may be prominent at the sill or elsewhere on the window assembly. The paper reports on a laboratory evaluation of conditions suitable for the formation of condensation at the window frame perimeter of the interface assembly as a function of both temperature deferential and air leakage rate across the test assembly. A summary of the laboratory test protocol is provided, which includes a description of the test setup and apparatus, fabrication details of the specimen, information on instrumentation and calibration, and experimental results for one type of window (flange window). In parallel, preliminary simulation results were presented and compared to those obtained from the experiment using the commercially available thermal software BISCO. [ABSTRACT FROM AUTHOR]

Hygrothermal simulations can be used to evaluate the hygrothermal response of building envelope to the effect of climate change. However, to account for the uncertainty in projected future climates, a large number of simulations are required. To reduce computational time, hygrothermal performance of walls is typically evaluated using Moisture Reference Year (MRY), which can be selected based on climate-based indices. This study investigated the reliability of climate-based indices by comparing to the response-based indices obtained from simulations using two methods. Firstly, the direct correlation between two indices is calculated using coefficient of determination (R2). Second method focuses on evaluating the reliability of climate-based indices in ranking the years in terms of moisture severity compared to that based on simulations. Four climate-based indices: Climatic Index (CI), Moisture Index (MI), Severity Index (I sev) and annual WDR and three response-based indices: Mould Index, Moisture Content and RHT index are investigated. In general, R2 between two indices is weak (range of 0–0.79) with highest being 0.79 (between maximum mould index and MI) for stucco cladding wall facing default orientation under historical climate in Calgary. With ranking analysis, the accuracy using climate-based indices in ranking all years is low with some improvement in ranking the first three worst-years. CI and MI perform well and I sev works for north facing walls for cities like Ottawa and Calgary but fails for Vancouver. To have a reliable assessment of moisture risks, further research is needed to improve existing or develop a new climate-based index specific to Canadian climate. • Correlation analysis between climate- & response-based indices for 3 cities & 2 climate periods • A weak correlation is observed for most of the tested scenarios • Ability of climate-based indices to rank years based on moisture severity is low • Climate-based index specific to Canadian climates is required [ABSTRACT FROM AUTHOR]

As a consequence of global warming and rapid urbanization around the globe, the magnitudes and frequencies of extreme heat events (EHEs) are increasing and this trend is expected to continue into the future. In this study, the added benefit of modelling climate at convection-permitting spatial resolutions (grid spacing <4 km) is considered for a set of exterior climate and interior building simulations during EHEs in the urban areas of Ottawa and Montreal, Canada over the summer of 2018. The climate is modelled at two spatial resolutions: i) 25 km – typically considered for regional-scale climate modelling; and ii) 1 km. The results derived from modelling at each of these resolutions is compared in respect to their adequacy in predicting different measures of overheating outdoors as well as those within a typical single-detached home. The results clearly demonstrate that simulations undertaken at a 1 km resolution permit more accurately calculate the magnitude of overheating, whereas simulations completed at a 25 km resolution lead to an underestimation of overheating in about 95% of the urban grids within either of these two cities. These results suggest the necessity of using convection-permitting climate simulations for overheating assessments over the urban scale. • Urban climate of Ottawa and Montreal is simulated at 1 and 25 km spatial resolutions. • Added value of convection-permitting model in overheating studies is demonstrated. • Simulations at a high-resolution are found more accurate in simulating urban temperatures and wind. • Use of regional climate simulations leads to underestimation of overheating. [ABSTRACT FROM AUTHOR]

Abstract: Water penetration of a building envelope assembly is typically assessed on the basis of the degree of watertightness (i.e. lack of water ingress) of the components of the assembly when subjected to simulated driving rain conditions. Test standards provide the magnitude and extent of these test conditions as suggested by the test parameters, i.e. the water spray rates and pressure differences and the dwell time over which these are to be applied. Such conditions would presume to simulate driving rain and wind conditions of locations spread over a broad geographical area. For example, the water spray rate suggested for use in watertightness performance tests in EN 12155—Curtain walling–watertightness–laboratory test under static pressure—is considered appropriate for simulating driving rain and wind conditions for locations across Europe. However, test parameters should be based on the expected driving rain intensities and wind pressures that are likely to occur for a specific climate and a given return period. It might also be based on the building type (e.g. high or low-rise building), or even on the location on the building facade. Hence, a method is required for calculating water penetration test parameters for specific buildings located in a specific climate. The purpose of this paper is to propose a method for calculating water penetration test parameters. A survey of existing methods is first provided that focuses on the quantification of driving rain on buildings and thereafter, calculation of water penetration test parameters. The merits and drawbacks of these methods are then discussed. Based on this review, a method for calculating test parameters is proposed and is applied to developing water penetration test parameters for Istanbul, Turkey. A comparison of test parameters calculated from the proposed method with those given in existing Turkish standards TS EN 12155–Curtain walling–watertightness–laboratory test under static pressure—and TS ENV 13050—Curtain walling–watertightness–laboratory test under dynamic condition of air pressure and water spray—related to Istanbul, indicated that the water spray rate given in the TS standards is higher than spray rates calculated from the proposed method for return periods of 5, 10 and 30 years. [Copyright &y& Elsevier]

Abstract: This paper presents derivation of a water entry function of a hardboard siding-clad wood stud wall assembly. Water entry function provides input data to heat, air and moisture simulation models to facilitate the prediction of the long-term water entry performance of the specific assembly. Initially, an experimental work was conducted in which the hardboard siding-clad wood stud wall specimen was subjected to simulated driving rain loads, i.e. spray rates and static pressure differential. The specimen included a drainage cavity and specific deficiencies such as a missing length of sealant at the interface between the cladding and penetrating components, i.e. window, ventilation duct and electrical outlet. Water entering the deficiencies was collected at the drainage and stud cavities just below the penetrating components. Water entry results provided information on water entry rates as functions of simulated driving rain loads, which in turn permitted the development of a water entry function of the assembly. Entry function is a basic relationship that relates the quantity of water entry in a certain location within the assembly to the simulated driving rain loads. Measured climatic data of a specific climate, i.e. rainfall intensity and wind speed, was related to the simulated driving rain loads, and the entry function provided a means of estimating the water entry loads of the hardboard siding-clad wood stud wall assembly located in the specific climate. [Copyright &y& Elsevier]

As a consequence of global warming, buildings in Canada and around the globe are expected to face unprecedented climate over their design lives. The Moisture Index (MI) is a climate-based indicator currently used in the National Building Code of Canada (NBCC) to guide the design of wall assemblies for acceptable durability performance. In this study, future changes in MI are calculated across Canada under 2 and 3.5 °C of future global warming. Results indicate that the coastal and great lakes regions of Canada will have increased MI, whereas prairies and northern regions will in the future have decreased values of MI. Furthermore, it is demonstrated that drastically different projected future MI changes can be obtained with different values of drying potential normalization factor, and it is suggested that this value is chosen by carefully analyzing the historical and future projected drying potential values. Finally, our analysis shows that wall assemblies at an increased number of reference locations given in the NBCC, importantly those falling in the densely populated south-western Ontario region, will need to be designed with additional safety measures such as a capillary break in the future for them to achieve satisfactory moisture performance over their design lives. • Potential moisture risks of building envelopes under a changing climate over Canada. • Projected increases in atmospheric moisture loading requires moisture resilient building design. • Drastic differences in Moisture Index can be obtained with different normalization factors. • Many additional locations will need a capillary break in the future to achieve satisfactory moisture performance. [ABSTRACT FROM AUTHOR]

In the face of rapid urbanization and global warming, it is important to acquire a better understanding of urban climate and land-atmosphere interactions operating therein. The Weather Research and Forecasting (WRF) model is a limited area model that has been used to study urban microclimate in many cities across the globe. However, such a study is lacking for the Canada's capital city: Ottawa. In this article, the WRF model is set-up at 1 km spatial resolution over the Ottawa region and its sensitivity towards the use of different urban parametrization schemes and land-cover datasets is investigated from 01 June to 31 August 2018 which includes an extreme heat weather event spanning from June 30 to July 6. WRF-simulations are performed using the Noah land surface model with two urban parametrization schemes of different complexity, i.e., a simple bulk urban parametrization and a more advanced multilayer urban canopy model (UCM). Both WRF-simulations used the default land use-land cover data from the Moderate Resolution Imaging Spectroradiometer (MODIS) available in WRF. Between these two WRF-simulations, the simulation with the multilayer UCM is found to be more accurate than the bulk scheme simulation in terms of modeled near-surface wind-speed, relative humidity, and total precipitation compared to observations recorded at one urban weather gauging station located within the city limits. Finally, a third WRF-simulation is performed with the multilayer UCM but using a higher resolution 30 m land use-land cover data product for the urban domain. This third WRF-experiment improved further the near-surface wind speed, relative humidity, and total precipitation correspondence to observations within the city. It is worthy to mention that modeled total precipitation is found to be sensitive to both urban parametrization schemes and urban land use-land cover data sets. • This is the first WRF-urban climate modeling study over the City of Ottawa. • The WRF model is evaluated by considering the impact of spatial resolution and climate parameters such as precipitation and relative humidity. • We have found that the use of an advanced urban canopy model results in more accurate description of near surface wind speed, relative humidity, and precipitation. • Modeled precipitation is found to be sensitive to the use of advanced urban parametrization schemes and more accurate depiction of urban areas in the WRF model. [ABSTRACT FROM AUTHOR]

Many building components rely on pressure equalization to achieve a good performance in respect to watertightness. Guidelines on geometrical constraints derived from numerical models and experiments are widely spread, but it appears these are only valid for dry conditions. To evaluate the impact of rain on the pressure equalization in facades, a generic experimental setup was built and results were compared with simulations. Two types of deficiencies, 4 mm and 8 mm diameter circular holes, were subjected to sinusoidal pressure loading with varying mean pressures, amplitudes, frequencies, airtightness levels, and water spray rates. A semi-implicit numerical model based on mass balance and ideal gas law was developed and validated against the results for dry conditions. Monte-Carlo sensitivity analysis on simulated pressure equalization highlights the importance of accurate leakage characterization for validation, and normally distributed input parameters entail negative skewness in the results. The difference between the measured pressure equalization in wet conditions and simulations for dry conditions shows a clear correlation with the simulated pressure equalization. As a result, the effect of a water runoff film on the pressure equalization can be accounted for in the numerical model by means of a power function. Simulations for dry conditions may overestimate pressure equalization during rain events significantly. Furthermore, the impact and importance of pressure equalization for facade design was evaluated for 6 building components. An analysis of facade components such as precast concrete panels, two types of masonry brick walls, spandrels, windows and curtain wall systems, indicates that current construction practice and guidelines render inadequate to obtain good pressure equalization. • Detailed experimental work on pressure equalization under dynamic conditions. • Validation of a numerical simulation model based on mass balance and ideal gas law. • Analysis of pressures during rain events shows reduced pressure equalization. • A simple approach is suggested to account for rain in PE modelling. • The impact of rain on the PE is simulated for 6 building components. [ABSTRACT FROM AUTHOR]